import * as types from "./types";
import * as protocol from "./stdio_protocol";

declare const ESBUILD_VERSION: string;

const quote: (x: string) => string = JSON.stringify

const buildLogLevelDefault = 'warning';
const transformLogLevelDefault = 'silent';

function validateTarget(target: string): string {
  validateStringValue(target, 'target')
  if (target.indexOf(',') >= 0) throw new Error(`Invalid target: ${target}`)
  return target
}

let canBeAnything = () => null;

let mustBeBoolean = (value: boolean | undefined): string | null =>
  typeof value === 'boolean' ? null : 'a boolean';

let mustBeString = (value: string | undefined): string | null =>
  typeof value === 'string' ? null : 'a string';

let mustBeRegExp = (value: RegExp | undefined): string | null =>
  value instanceof RegExp ? null : 'a RegExp object';

let mustBeInteger = (value: number | undefined): string | null =>
  typeof value === 'number' && value === (value | 0) ? null : 'an integer';

let mustBeFunction = (value: Function | undefined): string | null =>
  typeof value === 'function' ? null : 'a function';

let mustBeArray = <T>(value: T[] | undefined): string | null =>
  Array.isArray(value) ? null : 'an array';

let mustBeObject = (value: Object | undefined): string | null =>
  typeof value === 'object' && value !== null && !Array.isArray(value) ? null : 'an object';

let mustBeWebAssemblyModule = (value: WebAssembly.Module | undefined): string | null =>
  value instanceof WebAssembly.Module ? null : 'a WebAssembly.Module';

let mustBeArrayOrRecord = <T extends string>(value: T[] | Record<T, T> | undefined): string | null =>
  typeof value === 'object' && value !== null ? null : 'an array or an object';

let mustBeObjectOrNull = (value: Object | null | undefined): string | null =>
  typeof value === 'object' && !Array.isArray(value) ? null : 'an object or null';

let mustBeStringOrBoolean = (value: string | boolean | undefined): string | null =>
  typeof value === 'string' || typeof value === 'boolean' ? null : 'a string or a boolean';

let mustBeStringOrObject = (value: string | Object | undefined): string | null =>
  typeof value === 'string' || typeof value === 'object' && value !== null && !Array.isArray(value) ? null : 'a string or an object';

let mustBeStringOrArray = (value: string | string[] | undefined): string | null =>
  typeof value === 'string' || Array.isArray(value) ? null : 'a string or an array';

let mustBeStringOrUint8Array = (value: string | Uint8Array | undefined): string | null =>
  typeof value === 'string' || value instanceof Uint8Array ? null : 'a string or a Uint8Array';

let mustBeStringOrURL = (value: string | URL | undefined): string | null =>
  typeof value === 'string' || value instanceof URL ? null : 'a string or a URL';

type OptionKeys = { [key: string]: boolean };

function getFlag<T, K extends (keyof T & string)>(object: T, keys: OptionKeys, key: K, mustBeFn: (value: T[K]) => string | null): T[K] | undefined {
  let value = object[key];
  keys[key + ''] = true;
  if (value === undefined) return undefined;
  let mustBe = mustBeFn(value);
  if (mustBe !== null) throw new Error(`${quote(key)} must be ${mustBe}`);
  return value;
}

function checkForInvalidFlags(object: Object, keys: OptionKeys, where: string): void {
  for (let key in object) {
    if (!(key in keys)) {
      throw new Error(`Invalid option ${where}: ${quote(key)}`);
    }
  }
}

export function validateInitializeOptions(options: types.InitializeOptions): types.InitializeOptions {
  let keys: OptionKeys = Object.create(null);
  let wasmURL = getFlag(options, keys, 'wasmURL', mustBeStringOrURL);
  let wasmModule = getFlag(options, keys, 'wasmModule', mustBeWebAssemblyModule);
  let worker = getFlag(options, keys, 'worker', mustBeBoolean);
  checkForInvalidFlags(options, keys, 'in initialize() call');
  return {
    wasmURL,
    wasmModule,
    worker,
  };
}

type MangleCache = Record<string, string | false>

function validateMangleCache(mangleCache: MangleCache | undefined): MangleCache | undefined {
  let validated: MangleCache | undefined
  if (mangleCache !== undefined) {
    validated = Object.create(null) as MangleCache
    for (let key in mangleCache) {
      let value = mangleCache[key]
      if (typeof value === 'string' || value === false) {
        validated[key] = value
      } else {
        throw new Error(`Expected ${quote(key)} in mangle cache to map to either a string or false`)
      }
    }
  }
  return validated
}

type CommonOptions = types.BuildOptions | types.TransformOptions;

function pushLogFlags(flags: string[], options: CommonOptions, keys: OptionKeys, isTTY: boolean, logLevelDefault: types.LogLevel): void {
  let color = getFlag(options, keys, 'color', mustBeBoolean);
  let logLevel = getFlag(options, keys, 'logLevel', mustBeString);
  let logLimit = getFlag(options, keys, 'logLimit', mustBeInteger);

  if (color !== void 0) flags.push(`--color=${color}`);
  else if (isTTY) flags.push(`--color=true`); // This is needed to fix "execFileSync" which buffers stderr
  flags.push(`--log-level=${logLevel || logLevelDefault}`);
  flags.push(`--log-limit=${logLimit || 0}`);
}

function validateStringValue(value: unknown, what: string, key?: string): string {
  if (typeof value !== 'string') {
    throw new Error(`Expected value for ${what}${key !== void 0 ? ' ' + quote(key) : ''} to be a string, got ${typeof value} instead`);
  }
  return value
}

function pushCommonFlags(flags: string[], options: CommonOptions, keys: OptionKeys): void {
  let legalComments = getFlag(options, keys, 'legalComments', mustBeString);
  let sourceRoot = getFlag(options, keys, 'sourceRoot', mustBeString);
  let sourcesContent = getFlag(options, keys, 'sourcesContent', mustBeBoolean);
  let target = getFlag(options, keys, 'target', mustBeStringOrArray);
  let format = getFlag(options, keys, 'format', mustBeString);
  let globalName = getFlag(options, keys, 'globalName', mustBeString);
  let mangleProps = getFlag(options, keys, 'mangleProps', mustBeRegExp);
  let reserveProps = getFlag(options, keys, 'reserveProps', mustBeRegExp);
  let mangleQuoted = getFlag(options, keys, 'mangleQuoted', mustBeBoolean);
  let minify = getFlag(options, keys, 'minify', mustBeBoolean);
  let minifySyntax = getFlag(options, keys, 'minifySyntax', mustBeBoolean);
  let minifyWhitespace = getFlag(options, keys, 'minifyWhitespace', mustBeBoolean);
  let minifyIdentifiers = getFlag(options, keys, 'minifyIdentifiers', mustBeBoolean);
  let drop = getFlag(options, keys, 'drop', mustBeArray);
  let charset = getFlag(options, keys, 'charset', mustBeString);
  let treeShaking = getFlag(options, keys, 'treeShaking', mustBeBoolean);
  let ignoreAnnotations = getFlag(options, keys, 'ignoreAnnotations', mustBeBoolean);
  let jsx = getFlag(options, keys, 'jsx', mustBeString);
  let jsxFactory = getFlag(options, keys, 'jsxFactory', mustBeString);
  let jsxFragment = getFlag(options, keys, 'jsxFragment', mustBeString);
  let jsxImportSource = getFlag(options, keys, 'jsxImportSource', mustBeString);
  let jsxDev = getFlag(options, keys, 'jsxDev', mustBeBoolean);
  let jsxSideEffects = getFlag(options, keys, 'jsxSideEffects', mustBeBoolean);
  let define = getFlag(options, keys, 'define', mustBeObject);
  let logOverride = getFlag(options, keys, 'logOverride', mustBeObject);
  let supported = getFlag(options, keys, 'supported', mustBeObject);
  let pure = getFlag(options, keys, 'pure', mustBeArray);
  let keepNames = getFlag(options, keys, 'keepNames', mustBeBoolean);
  let platform = getFlag(options, keys, 'platform', mustBeString);

  if (legalComments) flags.push(`--legal-comments=${legalComments}`);
  if (sourceRoot !== void 0) flags.push(`--source-root=${sourceRoot}`);
  if (sourcesContent !== void 0) flags.push(`--sources-content=${sourcesContent}`);
  if (target) {
    if (Array.isArray(target)) flags.push(`--target=${Array.from(target).map(validateTarget).join(',')}`)
    else flags.push(`--target=${validateTarget(target)}`)
  }
  if (format) flags.push(`--format=${format}`);
  if (globalName) flags.push(`--global-name=${globalName}`);
  if (platform) flags.push(`--platform=${platform}`);

  if (minify) flags.push('--minify');
  if (minifySyntax) flags.push('--minify-syntax');
  if (minifyWhitespace) flags.push('--minify-whitespace');
  if (minifyIdentifiers) flags.push('--minify-identifiers');
  if (charset) flags.push(`--charset=${charset}`);
  if (treeShaking !== void 0) flags.push(`--tree-shaking=${treeShaking}`);
  if (ignoreAnnotations) flags.push(`--ignore-annotations`);
  if (drop) for (let what of drop) flags.push(`--drop:${validateStringValue(what, 'drop')}`);
  if (mangleProps) flags.push(`--mangle-props=${mangleProps.source}`);
  if (reserveProps) flags.push(`--reserve-props=${reserveProps.source}`);
  if (mangleQuoted !== void 0) flags.push(`--mangle-quoted=${mangleQuoted}`)

  if (jsx) flags.push(`--jsx=${jsx}`);
  if (jsxFactory) flags.push(`--jsx-factory=${jsxFactory}`);
  if (jsxFragment) flags.push(`--jsx-fragment=${jsxFragment}`);
  if (jsxImportSource) flags.push(`--jsx-import-source=${jsxImportSource}`);
  if (jsxDev) flags.push(`--jsx-dev`);
  if (jsxSideEffects) flags.push(`--jsx-side-effects`);

  if (define) {
    for (let key in define) {
      if (key.indexOf('=') >= 0) throw new Error(`Invalid define: ${key}`);
      flags.push(`--define:${key}=${validateStringValue(define[key], 'define', key)}`);
    }
  }
  if (logOverride) {
    for (let key in logOverride) {
      if (key.indexOf('=') >= 0) throw new Error(`Invalid log override: ${key}`);
      flags.push(`--log-override:${key}=${validateStringValue(logOverride[key], 'log override', key)}`);
    }
  }
  if (supported) {
    for (let key in supported) {
      if (key.indexOf('=') >= 0) throw new Error(`Invalid supported: ${key}`);
      const value = supported[key]
      if (typeof value !== 'boolean') throw new Error(`Expected value for supported ${quote(key)} to be a boolean, got ${typeof value} instead`);
      flags.push(`--supported:${key}=${value}`);
    }
  }
  if (pure) for (let fn of pure) flags.push(`--pure:${validateStringValue(fn, 'pure')}`);
  if (keepNames) flags.push(`--keep-names`);
}

function flagsForBuildOptions(
  callName: string,
  options: types.BuildOptions,
  isTTY: boolean,
  logLevelDefault: types.LogLevel,
  writeDefault: boolean,
): {
  entries: [string, string][],
  flags: string[],
  write: boolean,
  stdinContents: Uint8Array | null,
  stdinResolveDir: string | null,
  absWorkingDir: string | undefined,
  nodePaths: string[],
  mangleCache: MangleCache | undefined,
} {
  let flags: string[] = [];
  let entries: [string, string][] = [];
  let keys: OptionKeys = Object.create(null);
  let stdinContents: Uint8Array | null = null;
  let stdinResolveDir: string | null = null;
  pushLogFlags(flags, options, keys, isTTY, logLevelDefault);
  pushCommonFlags(flags, options, keys);

  let sourcemap = getFlag(options, keys, 'sourcemap', mustBeStringOrBoolean);
  let bundle = getFlag(options, keys, 'bundle', mustBeBoolean);
  let splitting = getFlag(options, keys, 'splitting', mustBeBoolean);
  let preserveSymlinks = getFlag(options, keys, 'preserveSymlinks', mustBeBoolean);
  let metafile = getFlag(options, keys, 'metafile', mustBeBoolean);
  let outfile = getFlag(options, keys, 'outfile', mustBeString);
  let outdir = getFlag(options, keys, 'outdir', mustBeString);
  let outbase = getFlag(options, keys, 'outbase', mustBeString);
  let tsconfig = getFlag(options, keys, 'tsconfig', mustBeString);
  let resolveExtensions = getFlag(options, keys, 'resolveExtensions', mustBeArray);
  let nodePathsInput = getFlag(options, keys, 'nodePaths', mustBeArray);
  let mainFields = getFlag(options, keys, 'mainFields', mustBeArray);
  let conditions = getFlag(options, keys, 'conditions', mustBeArray);
  let external = getFlag(options, keys, 'external', mustBeArray);
  let packages = getFlag(options, keys, 'packages', mustBeString);
  let alias = getFlag(options, keys, 'alias', mustBeObject);
  let loader = getFlag(options, keys, 'loader', mustBeObject);
  let outExtension = getFlag(options, keys, 'outExtension', mustBeObject);
  let publicPath = getFlag(options, keys, 'publicPath', mustBeString);
  let entryNames = getFlag(options, keys, 'entryNames', mustBeString);
  let chunkNames = getFlag(options, keys, 'chunkNames', mustBeString);
  let assetNames = getFlag(options, keys, 'assetNames', mustBeString);
  let inject = getFlag(options, keys, 'inject', mustBeArray);
  let banner = getFlag(options, keys, 'banner', mustBeObject);
  let footer = getFlag(options, keys, 'footer', mustBeObject);
  let entryPoints = getFlag(options, keys, 'entryPoints', mustBeArrayOrRecord);
  let absWorkingDir = getFlag(options, keys, 'absWorkingDir', mustBeString);
  let stdin = getFlag(options, keys, 'stdin', mustBeObject);
  let write = getFlag(options, keys, 'write', mustBeBoolean) ?? writeDefault; // Default to true if not specified
  let allowOverwrite = getFlag(options, keys, 'allowOverwrite', mustBeBoolean);
  let mangleCache = getFlag(options, keys, 'mangleCache', mustBeObject);
  keys.plugins = true; // "plugins" has already been read earlier
  checkForInvalidFlags(options, keys, `in ${callName}() call`);

  if (sourcemap) flags.push(`--sourcemap${sourcemap === true ? '' : `=${sourcemap}`}`);
  if (bundle) flags.push('--bundle');
  if (allowOverwrite) flags.push('--allow-overwrite');
  if (splitting) flags.push('--splitting');
  if (preserveSymlinks) flags.push('--preserve-symlinks');
  if (metafile) flags.push(`--metafile`);
  if (outfile) flags.push(`--outfile=${outfile}`);
  if (outdir) flags.push(`--outdir=${outdir}`);
  if (outbase) flags.push(`--outbase=${outbase}`);
  if (tsconfig) flags.push(`--tsconfig=${tsconfig}`);
  if (packages) flags.push(`--packages=${packages}`);
  if (resolveExtensions) {
    let values: string[] = [];
    for (let value of resolveExtensions) {
      validateStringValue(value, 'resolve extension')
      if (value.indexOf(',') >= 0) throw new Error(`Invalid resolve extension: ${value}`);
      values.push(value);
    }
    flags.push(`--resolve-extensions=${values.join(',')}`);
  }
  if (publicPath) flags.push(`--public-path=${publicPath}`);
  if (entryNames) flags.push(`--entry-names=${entryNames}`);
  if (chunkNames) flags.push(`--chunk-names=${chunkNames}`);
  if (assetNames) flags.push(`--asset-names=${assetNames}`);
  if (mainFields) {
    let values: string[] = [];
    for (let value of mainFields) {
      validateStringValue(value, 'main field')
      if (value.indexOf(',') >= 0) throw new Error(`Invalid main field: ${value}`);
      values.push(value);
    }
    flags.push(`--main-fields=${values.join(',')}`);
  }
  if (conditions) {
    let values: string[] = [];
    for (let value of conditions) {
      validateStringValue(value, 'condition')
      if (value.indexOf(',') >= 0) throw new Error(`Invalid condition: ${value}`);
      values.push(value);
    }
    flags.push(`--conditions=${values.join(',')}`);
  }
  if (external) for (let name of external) flags.push(`--external:${validateStringValue(name, 'external')}`);
  if (alias) {
    for (let old in alias) {
      if (old.indexOf('=') >= 0) throw new Error(`Invalid package name in alias: ${old}`);
      flags.push(`--alias:${old}=${validateStringValue(alias[old], 'alias', old)}`);
    }
  }
  if (banner) {
    for (let type in banner) {
      if (type.indexOf('=') >= 0) throw new Error(`Invalid banner file type: ${type}`);
      flags.push(`--banner:${type}=${validateStringValue(banner[type], 'banner', type)}`);
    }
  }
  if (footer) {
    for (let type in footer) {
      if (type.indexOf('=') >= 0) throw new Error(`Invalid footer file type: ${type}`);
      flags.push(`--footer:${type}=${validateStringValue(footer[type], 'footer', type)}`);
    }
  }
  if (inject) for (let path of inject) flags.push(`--inject:${validateStringValue(path, 'inject')}`);
  if (loader) {
    for (let ext in loader) {
      if (ext.indexOf('=') >= 0) throw new Error(`Invalid loader extension: ${ext}`);
      flags.push(`--loader:${ext}=${validateStringValue(loader[ext], 'loader', ext)}`);
    }
  }
  if (outExtension) {
    for (let ext in outExtension) {
      if (ext.indexOf('=') >= 0) throw new Error(`Invalid out extension: ${ext}`);
      flags.push(`--out-extension:${ext}=${validateStringValue(outExtension[ext], 'out extension', ext)}`);
    }
  }

  if (entryPoints) {
    if (Array.isArray(entryPoints)) {
      for (let entryPoint of entryPoints) {
        entries.push(['', validateStringValue(entryPoint, 'entry point')]);
      }
    } else {
      for (let key in entryPoints) {
        entries.push([key, validateStringValue(entryPoints[key], 'entry point', key)]);
      }
    }
  }

  if (stdin) {
    let stdinKeys: OptionKeys = Object.create(null);
    let contents = getFlag(stdin, stdinKeys, 'contents', mustBeStringOrUint8Array);
    let resolveDir = getFlag(stdin, stdinKeys, 'resolveDir', mustBeString);
    let sourcefile = getFlag(stdin, stdinKeys, 'sourcefile', mustBeString);
    let loader = getFlag(stdin, stdinKeys, 'loader', mustBeString);
    checkForInvalidFlags(stdin, stdinKeys, 'in "stdin" object');

    if (sourcefile) flags.push(`--sourcefile=${sourcefile}`);
    if (loader) flags.push(`--loader=${loader}`);
    if (resolveDir) stdinResolveDir = resolveDir;
    if (typeof contents === 'string') stdinContents = protocol.encodeUTF8(contents)
    else if (contents instanceof Uint8Array) stdinContents = contents
  }

  let nodePaths: string[] = [];
  if (nodePathsInput) {
    for (let value of nodePathsInput) {
      value += '';
      nodePaths.push(value);
    }
  }

  return {
    entries,
    flags,
    write,
    stdinContents,
    stdinResolveDir,
    absWorkingDir,
    nodePaths,
    mangleCache: validateMangleCache(mangleCache),
  };
}

function flagsForTransformOptions(
  callName: string,
  options: types.TransformOptions,
  isTTY: boolean,
  logLevelDefault: types.LogLevel,
): {
  flags: string[],
  mangleCache: MangleCache | undefined,
} {
  let flags: string[] = [];
  let keys: OptionKeys = Object.create(null);
  pushLogFlags(flags, options, keys, isTTY, logLevelDefault);
  pushCommonFlags(flags, options, keys);

  let sourcemap = getFlag(options, keys, 'sourcemap', mustBeStringOrBoolean);
  let tsconfigRaw = getFlag(options, keys, 'tsconfigRaw', mustBeStringOrObject);
  let sourcefile = getFlag(options, keys, 'sourcefile', mustBeString);
  let loader = getFlag(options, keys, 'loader', mustBeString);
  let banner = getFlag(options, keys, 'banner', mustBeString);
  let footer = getFlag(options, keys, 'footer', mustBeString);
  let mangleCache = getFlag(options, keys, 'mangleCache', mustBeObject);
  checkForInvalidFlags(options, keys, `in ${callName}() call`);

  if (sourcemap) flags.push(`--sourcemap=${sourcemap === true ? 'external' : sourcemap}`);
  if (tsconfigRaw) flags.push(`--tsconfig-raw=${typeof tsconfigRaw === 'string' ? tsconfigRaw : JSON.stringify(tsconfigRaw)}`);
  if (sourcefile) flags.push(`--sourcefile=${sourcefile}`);
  if (loader) flags.push(`--loader=${loader}`);
  if (banner) flags.push(`--banner=${banner}`);
  if (footer) flags.push(`--footer=${footer}`);

  return {
    flags,
    mangleCache: validateMangleCache(mangleCache),
  };
}

export interface StreamIn {
  writeToStdin: (data: Uint8Array) => void;
  readFileSync?: (path: string, encoding: 'utf8') => string;
  isSync: boolean;
  hasFS: boolean;
  esbuild: types.PluginBuild['esbuild'];
}

export interface StreamOut {
  readFromStdout: (data: Uint8Array) => void;
  afterClose: (error: Error | null) => void;
  service: StreamService;
}

export interface StreamFS {
  writeFile(contents: string | Uint8Array, callback: (path: string | null) => void): void;
  readFile(path: string, callback: (err: Error | null, contents: string | null) => void): void;
}

export interface Refs {
  ref(): void;
  unref(): void;
}

export interface StreamService {
  buildOrContext(args: {
    callName: string,
    refs: Refs | null,
    options: types.BuildOptions,
    isTTY: boolean,
    defaultWD: string,
    callback: (err: Error | null, res: types.BuildResult | types.BuildContext | null) => void,
  }): void;

  transform(args: {
    callName: string,
    refs: Refs | null,
    input: string | Uint8Array,
    options: types.TransformOptions,
    isTTY: boolean,
    fs: StreamFS,
    callback: (err: Error | null, res: types.TransformResult | null) => void,
  }): void;

  formatMessages(args: {
    callName: string,
    refs: Refs | null,
    messages: types.PartialMessage[],
    options: types.FormatMessagesOptions,
    callback: (err: Error | null, res: string[] | null) => void,
  }): void;

  analyzeMetafile(args: {
    callName: string,
    refs: Refs | null,
    metafile: string,
    options: types.AnalyzeMetafileOptions | undefined,
    callback: (err: Error | null, res: string | null) => void,
  }): void;
}

type CloseData = { didClose: boolean, reason: string }
type RequestCallback = (id: number, request: any) => Promise<void> | void

// This can't use any promises in the main execution flow because it must work
// for both sync and async code. There is an exception for plugin code because
// that can't work in sync code anyway.
export function createChannel(streamIn: StreamIn): StreamOut {
  const requestCallbacksByKey: { [key: number]: { [command: string]: RequestCallback } } = {};
  const closeData: CloseData = { didClose: false, reason: '' }
  let responseCallbacks: { [id: number]: (error: string | null, response: protocol.Value) => void } = {};
  let nextRequestID = 0;
  let nextBuildKey = 0;

  // Use a long-lived buffer to store stdout data
  let stdout = new Uint8Array(16 * 1024);
  let stdoutUsed = 0;
  let readFromStdout = (chunk: Uint8Array) => {
    // Append the chunk to the stdout buffer, growing it as necessary
    let limit = stdoutUsed + chunk.length;
    if (limit > stdout.length) {
      let swap = new Uint8Array(limit * 2);
      swap.set(stdout);
      stdout = swap;
    }
    stdout.set(chunk, stdoutUsed);
    stdoutUsed += chunk.length;

    // Process all complete (i.e. not partial) packets
    let offset = 0;
    while (offset + 4 <= stdoutUsed) {
      let length = protocol.readUInt32LE(stdout, offset);
      if (offset + 4 + length > stdoutUsed) {
        break;
      }
      offset += 4;
      handleIncomingPacket(stdout.subarray(offset, offset + length));
      offset += length;
    }
    if (offset > 0) {
      stdout.copyWithin(0, offset, stdoutUsed);
      stdoutUsed -= offset;
    }
  };

  let afterClose = (error: Error | null) => {
    // When the process is closed, fail all pending requests
    closeData.didClose = true
    if (error) closeData.reason = ': ' + (error.message || error)
    const text = 'The service was stopped' + closeData.reason;
    for (let id in responseCallbacks) {
      responseCallbacks[id](text, null);
    }
    responseCallbacks = {};
  };

  let sendRequest = <Req, Res>(refs: Refs | null, value: Req, callback: (error: string | null, response: Res | null) => void): void => {
    if (closeData.didClose) return callback('The service is no longer running' + closeData.reason, null);
    let id = nextRequestID++;
    responseCallbacks[id] = (error, response) => {
      try {
        callback(error, response as any);
      } finally {
        if (refs) refs.unref() // Do this after the callback so the callback can extend the lifetime if needed
      }
    };
    if (refs) refs.ref()
    streamIn.writeToStdin(protocol.encodePacket({ id, isRequest: true, value: value as any }));
  };

  let sendResponse = (id: number, value: protocol.Value): void => {
    if (closeData.didClose) throw new Error('The service is no longer running' + closeData.reason);
    streamIn.writeToStdin(protocol.encodePacket({ id, isRequest: false, value }));
  };

  let handleRequest = async (id: number, request: any) => {
    // Catch exceptions in the code below so they get passed to the caller
    try {
      if (request.command === 'ping') {
        sendResponse(id, {});
        return
      }

      if (typeof request.key === 'number') {
        const requestCallbacks = requestCallbacksByKey[request.key]
        if (requestCallbacks) {
          const callback = requestCallbacks[request.command]
          if (callback) {
            await callback(id, request)
            return
          }
        }
      }

      throw new Error(`Invalid command: ` + request.command);
    } catch (e) {
      sendResponse(id, { errors: [extractErrorMessageV8(e, streamIn, null, void 0, '')] } as any);
    }
  };

  let isFirstPacket = true;

  let handleIncomingPacket = (bytes: Uint8Array): void => {
    // The first packet is a version check
    if (isFirstPacket) {
      isFirstPacket = false;

      // Validate the binary's version number to make sure esbuild was installed
      // correctly. This check was added because some people have reported
      // errors that appear to indicate an incorrect installation.
      let binaryVersion = String.fromCharCode(...bytes);
      if (binaryVersion !== ESBUILD_VERSION) {
        throw new Error(`Cannot start service: Host version "${ESBUILD_VERSION}" does not match binary version ${quote(binaryVersion)}`);
      }
      return;
    }

    let packet = protocol.decodePacket(bytes) as any;

    if (packet.isRequest) {
      handleRequest(packet.id, packet.value);
    }

    else {
      let callback = responseCallbacks[packet.id]!;
      delete responseCallbacks[packet.id];
      if (packet.value.error) callback(packet.value.error, {});
      else callback(null, packet.value);
    }
  };

  let buildOrContext: StreamService['buildOrContext'] = ({ callName, refs, options, isTTY, defaultWD, callback }) => {
    let refCount = 0;
    const buildKey = nextBuildKey++;
    const requestCallbacks: { [command: string]: RequestCallback } = {};
    const buildRefs: Refs = {
      ref() {
        if (++refCount === 1) {
          if (refs) refs.ref()
        }
      },
      unref() {
        if (--refCount === 0) {
          delete requestCallbacksByKey[buildKey]
          if (refs) refs.unref()
        }
      },
    }
    requestCallbacksByKey[buildKey] = requestCallbacks;

    // Guard the whole "build" request with a temporary ref count bump. We
    // don't want the ref count to be bumped above zero and then back down
    // to zero before the callback is called.
    buildRefs.ref()
    buildOrContextImpl(
      callName,
      buildKey,
      sendRequest,
      sendResponse,
      buildRefs,
      streamIn,
      requestCallbacks,
      options,
      isTTY,
      defaultWD,
      (err, res) => {
        // Now that the initial "build" request is done, we can release our
        // temporary ref count bump. Any code that wants to extend the life
        // of the build will have to do so by explicitly retaining a count.
        try {
          callback(err, res)
        } finally {
          buildRefs.unref()
        }
      },
    )
  };

  let transform: StreamService['transform'] = ({ callName, refs, input, options, isTTY, fs, callback }) => {
    const details = createObjectStash();

    // Ideally the "transform()" API would be faster than calling "build()"
    // since it doesn't need to touch the file system. However, performance
    // measurements with large files on macOS indicate that sending the data
    // over the stdio pipe can be 2x slower than just using a temporary file.
    //
    // This appears to be an OS limitation. Both the JavaScript and Go code
    // are using large buffers but the pipe only writes data in 8kb chunks.
    // An investigation seems to indicate that this number is hard-coded into
    // the OS source code. Presumably files are faster because the OS uses
    // a larger chunk size, or maybe even reads everything in one syscall.
    //
    // The cross-over size where this starts to be faster is around 1mb on
    // my machine. In that case, this code tries to use a temporary file if
    // possible but falls back to sending the data over the stdio pipe if
    // that doesn't work.
    let start = (inputPath: string | null) => {
      try {
        if (typeof input !== 'string' && !(input instanceof Uint8Array))
          throw new Error('The input to "transform" must be a string or a Uint8Array');
        let {
          flags,
          mangleCache,
        } = flagsForTransformOptions(callName, options, isTTY, transformLogLevelDefault);
        let request: protocol.TransformRequest = {
          command: 'transform',
          flags,
          inputFS: inputPath !== null,
          input: inputPath !== null ? protocol.encodeUTF8(inputPath)
            : typeof input === 'string' ? protocol.encodeUTF8(input)
              : input,
        };
        if (mangleCache) request.mangleCache = mangleCache;
        sendRequest<protocol.TransformRequest, protocol.TransformResponse>(refs, request, (error, response) => {
          if (error) return callback(new Error(error), null);
          let errors = replaceDetailsInMessages(response!.errors, details);
          let warnings = replaceDetailsInMessages(response!.warnings, details);
          let outstanding = 1;
          let next = () => {
            if (--outstanding === 0) {
              let result: types.TransformResult = {
                warnings,
                code: response!.code,
                map: response!.map,
                mangleCache: undefined,
                legalComments: undefined,
              }
              if ('legalComments' in response!) result.legalComments = response?.legalComments
              if (response!.mangleCache) result.mangleCache = response?.mangleCache
              callback(null, result)
            }
          };
          if (errors.length > 0) return callback(failureErrorWithLog('Transform failed', errors, warnings), null);

          // Read the JavaScript file from the file system
          if (response!.codeFS) {
            outstanding++;
            fs.readFile(response!.code, (err, contents) => {
              if (err !== null) {
                callback(err, null);
              } else {
                response!.code = contents!;
                next();
              }
            });
          }

          // Read the source map file from the file system
          if (response!.mapFS) {
            outstanding++;
            fs.readFile(response!.map, (err, contents) => {
              if (err !== null) {
                callback(err, null);
              } else {
                response!.map = contents!;
                next();
              }
            });
          }

          next();
        });
      } catch (e) {
        let flags: string[] = [];
        try { pushLogFlags(flags, options, {}, isTTY, transformLogLevelDefault) } catch { }
        const error = extractErrorMessageV8(e, streamIn, details, void 0, '');
        sendRequest(refs, { command: 'error', flags, error }, () => {
          error.detail = details.load(error.detail);
          callback(failureErrorWithLog('Transform failed', [error], []), null);
        });
      }
    };
    if ((typeof input === 'string' || input instanceof Uint8Array) && input.length > 1024 * 1024) {
      let next = start;
      start = () => fs.writeFile(input, next);
    }
    start(null);
  };

  let formatMessages: StreamService['formatMessages'] = ({ callName, refs, messages, options, callback }) => {
    let result = sanitizeMessages(messages, 'messages', null, '');
    if (!options) throw new Error(`Missing second argument in ${callName}() call`);
    let keys: OptionKeys = {};
    let kind = getFlag(options, keys, 'kind', mustBeString);
    let color = getFlag(options, keys, 'color', mustBeBoolean);
    let terminalWidth = getFlag(options, keys, 'terminalWidth', mustBeInteger);
    checkForInvalidFlags(options, keys, `in ${callName}() call`);
    if (kind === void 0) throw new Error(`Missing "kind" in ${callName}() call`);
    if (kind !== 'error' && kind !== 'warning') throw new Error(`Expected "kind" to be "error" or "warning" in ${callName}() call`);
    let request: protocol.FormatMsgsRequest = {
      command: 'format-msgs',
      messages: result,
      isWarning: kind === 'warning',
    }
    if (color !== void 0) request.color = color;
    if (terminalWidth !== void 0) request.terminalWidth = terminalWidth;
    sendRequest<protocol.FormatMsgsRequest, protocol.FormatMsgsResponse>(refs, request, (error, response) => {
      if (error) return callback(new Error(error), null);
      callback(null, response!.messages);
    });
  };

  let analyzeMetafile: StreamService['analyzeMetafile'] = ({ callName, refs, metafile, options, callback }) => {
    if (options === void 0) options = {}
    let keys: OptionKeys = {};
    let color = getFlag(options, keys, 'color', mustBeBoolean);
    let verbose = getFlag(options, keys, 'verbose', mustBeBoolean);
    checkForInvalidFlags(options, keys, `in ${callName}() call`);
    let request: protocol.AnalyzeMetafileRequest = {
      command: 'analyze-metafile',
      metafile,
    }
    if (color !== void 0) request.color = color;
    if (verbose !== void 0) request.verbose = verbose;
    sendRequest<protocol.AnalyzeMetafileRequest, protocol.AnalyzeMetafileResponse>(refs, request, (error, response) => {
      if (error) return callback(new Error(error), null);
      callback(null, response!.result);
    });
  };

  return {
    readFromStdout,
    afterClose,
    service: {
      buildOrContext,
      transform,
      formatMessages,
      analyzeMetafile,
    },
  };
}

function buildOrContextImpl(
  callName: string,
  buildKey: number,
  sendRequest: <Req, Res>(refs: Refs | null, value: Req, callback: (error: string | null, response: Res | null) => void) => void,
  sendResponse: (id: number, value: protocol.Value) => void,
  refs: Refs,
  streamIn: StreamIn,
  requestCallbacks: { [command: string]: RequestCallback },
  options: types.BuildOptions,
  isTTY: boolean,
  defaultWD: string,
  callback: (err: Error | null, res: types.BuildResult | types.BuildContext | null) => void,
): void {
  const details = createObjectStash();
  const isContext = callName === 'context';

  const handleError = (e: any, pluginName: string): void => {
    const flags: string[] = [];
    try { pushLogFlags(flags, options, {}, isTTY, buildLogLevelDefault) } catch { }
    const message = extractErrorMessageV8(e, streamIn, details, void 0, pluginName)
    sendRequest(refs, { command: 'error', flags, error: message }, () => {
      message.detail = details.load(message.detail);
      callback(failureErrorWithLog(isContext ? 'Context failed' : 'Build failed', [message], []), null);
    });
  };

  let plugins: types.Plugin[] | undefined;
  if (typeof options === 'object') {
    const value = options.plugins;
    if (value !== void 0) {
      if (!Array.isArray(value)) return handleError(new Error(`"plugins" must be an array`), '');
      plugins = value;
    }
  }

  if (plugins && plugins.length > 0) {
    if (streamIn.isSync) return handleError(new Error('Cannot use plugins in synchronous API calls'), '');

    // Plugins can use async/await because they can't be run with "buildSync"
    handlePlugins(
      buildKey,
      sendRequest,
      sendResponse,
      refs,
      streamIn,
      requestCallbacks,
      options,
      plugins,
      details,
    ).then(
      result => {
        if (!result.ok) return handleError(result.error, result.pluginName);
        try {
          buildOrContextContinue(result.requestPlugins, result.runOnEndCallbacks)
        } catch (e) {
          handleError(e, '');
        }
      },
      e => handleError(e, ''),
    )
    return
  }

  try {
    buildOrContextContinue(null, (result, done) => done([], []));
  } catch (e) {
    handleError(e, '');
  }

  // "buildOrContext" cannot be written using async/await due to "buildSync"
  // and must be written in continuation-passing style instead
  function buildOrContextContinue(requestPlugins: protocol.BuildPlugin[] | null, runOnEndCallbacks: RunOnEndCallbacks) {
    const writeDefault = streamIn.hasFS;
    const {
      entries,
      flags,
      write,
      stdinContents,
      stdinResolveDir,
      absWorkingDir,
      nodePaths,
      mangleCache,
    } = flagsForBuildOptions(callName, options, isTTY, buildLogLevelDefault, writeDefault);
    if (write && !streamIn.hasFS) throw new Error(`The "write" option is unavailable in this environment`);

    // Construct the request
    const request: protocol.BuildRequest = {
      command: 'build',
      key: buildKey,
      entries,
      flags,
      write,
      stdinContents,
      stdinResolveDir,
      absWorkingDir: absWorkingDir || defaultWD,
      nodePaths,
      context: isContext,
    };
    if (requestPlugins) request.plugins = requestPlugins;
    if (mangleCache) request.mangleCache = mangleCache;

    // Factor out response handling so it can be reused for rebuilds
    const buildResponseToResult = (
      response: protocol.BuildResponse | null,
      callback: (error: types.BuildFailure | null, result: types.BuildResult | null, onEndErrors: types.Message[], onEndWarnings: types.Message[]) => void,
    ): void => {
      const result: types.BuildResult = {
        errors: replaceDetailsInMessages(response!.errors, details),
        warnings: replaceDetailsInMessages(response!.warnings, details),
        outputFiles: undefined,
        metafile: undefined,
        mangleCache: undefined,
      };
      const originalErrors = result.errors.slice()
      const originalWarnings = result.warnings.slice()
      if (response!.outputFiles) result.outputFiles = response!.outputFiles.map(convertOutputFiles);
      if (response!.metafile) result.metafile = JSON.parse(response!.metafile);
      if (response!.mangleCache) result.mangleCache = response!.mangleCache;
      if (response!.writeToStdout !== void 0) console.log(protocol.decodeUTF8(response!.writeToStdout).replace(/\n$/, ''));
      runOnEndCallbacks(result, (onEndErrors, onEndWarnings) => {
        if (originalErrors.length > 0 || onEndErrors.length > 0) {
          const error = failureErrorWithLog('Build failed', originalErrors.concat(onEndErrors), originalWarnings.concat(onEndWarnings))
          return callback(error, null, onEndErrors, onEndWarnings);
        }
        callback(null, result, onEndErrors, onEndWarnings);
      });
    };

    // In context mode, Go runs the "onEnd" callbacks instead of JavaScript
    let latestResultPromise: Promise<types.BuildResult> | undefined
    let provideLatestResult: ((error: types.BuildFailure | null, result: types.BuildResult | null) => void) | undefined
    if (isContext)
      requestCallbacks['on-end'] = (id, request: protocol.OnEndRequest) =>
        new Promise(resolve => {
          buildResponseToResult(request, (err, result, onEndErrors, onEndWarnings) => {
            const response: protocol.OnEndResponse = {
              errors: onEndErrors,
              warnings: onEndWarnings,
            }
            if (provideLatestResult) provideLatestResult(err, result)
            latestResultPromise = undefined
            provideLatestResult = undefined
            sendResponse(id, response as any)
            resolve()
          })
        })

    sendRequest<protocol.BuildRequest, protocol.BuildResponse>(refs, request, (error, response) => {
      if (error) return callback(new Error(error), null);
      if (!isContext) {
        return buildResponseToResult(response!, callback);
      }

      // Construct a context object
      if (response!.errors.length > 0) {
        return callback(failureErrorWithLog('Context failed', response!.errors, response!.warnings), null);
      }
      let didDispose = false;
      const result: types.BuildContext = {
        rebuild: () => {
          if (!latestResultPromise) latestResultPromise = new Promise((resolve, reject) => {
            let settlePromise: (() => void) | undefined
            provideLatestResult = (err, result) => {
              if (!settlePromise) settlePromise = () => err ? reject(err) : resolve(result!)
            }
            const triggerAnotherBuild = (): void => {
              const request: protocol.RebuildRequest = {
                command: 'rebuild',
                key: buildKey,
              }
              sendRequest<protocol.RebuildRequest, protocol.RebuildResponse>(refs, request, (error, response) => {
                if (error) {
                  reject(new Error(error));
                } else if (settlePromise) {
                  // It's possible to settle the promise that we returned from
                  // this "rebuild()" function earlier than this point. However,
                  // at that point the user could call "rebuild()" again which
                  // would unexpectedly merge with the same build that's still
                  // ongoing. To prevent that, we defer settling the promise
                  // until now when we know that the build has finished.
                  settlePromise()
                } else {
                  // When we call "rebuild()", we call out to the Go "Rebuild()"
                  // API over IPC. That may trigger a build, but may also "join"
                  // an existing build. At some point the Go code sends us an
                  // "on-end" message with the build result to tell us to run
                  // our "onEnd" plugins. We capture that build result and return
                  // it here.
                  //
                  // However, there's a potential problem: For performance, the
                  // Go code will only send us the result if it's needed, which
                  // only happens if there are "onEnd" callbacks or if "rebuild"
                  // was called. So there's a race where the following things
                  // happen:
                  //
                  // 1. Go starts a rebuild (e.g. due to watch mode)
                  // 2. JS calls "rebuild()"
                  // 3. Go ends the build and starts Go's "OnEnd" callback
                  // 4. Go's "OnEnd" callback sees no need to send the result
                  // 5. JS asks Go to rebuild, which merges with the existing build
                  // 6. Go's existing build ends
                  // 7. The merged build ends, which wakes up JS and ends up here
                  //
                  // In that situation we didn't get an "on-end" message since
                  // Go thought it wasn't necessary. In that situation, we
                  // trigger another rebuild below so that Go will (almost
                  // surely) send us an "on-end" message next time. I suspect
                  // that this is a very rare case, so the performance impact
                  // of building twice shouldn't really matter. It also only
                  // happens when "rebuild()" is used with "watch()" and/or
                  // "serve()".
                  triggerAnotherBuild()
                }
              })
            }
            triggerAnotherBuild()
          })
          return latestResultPromise
        },

        watch: (options = {}) => new Promise((resolve, reject) => {
          if (!streamIn.hasFS) throw new Error(`Cannot use the "watch" API in this environment`);
          const keys: OptionKeys = {};
          checkForInvalidFlags(options, keys, `in watch() call`);
          const request: protocol.WatchRequest = {
            command: 'watch',
            key: buildKey,
          };
          sendRequest<protocol.WatchRequest, null>(refs, request, error => {
            if (error) reject(new Error(error));
            else resolve(undefined);
          })
        }),

        serve: (options = {}) => new Promise((resolve, reject) => {
          if (!streamIn.hasFS) throw new Error(`Cannot use the "serve" API in this environment`);
          const keys: OptionKeys = {};
          const port = getFlag(options, keys, 'port', mustBeInteger);
          const host = getFlag(options, keys, 'host', mustBeString);
          const servedir = getFlag(options, keys, 'servedir', mustBeString);
          const keyfile = getFlag(options, keys, 'keyfile', mustBeString);
          const certfile = getFlag(options, keys, 'certfile', mustBeString);
          const onRequest = getFlag(options, keys, 'onRequest', mustBeFunction);
          checkForInvalidFlags(options, keys, `in serve() call`);

          const request: protocol.ServeRequest = {
            command: 'serve',
            key: buildKey,
            onRequest: !!onRequest,
          }
          if (port !== void 0) request.port = port;
          if (host !== void 0) request.host = host;
          if (servedir !== void 0) request.servedir = servedir;
          if (keyfile !== void 0) request.keyfile = keyfile;
          if (certfile !== void 0) request.certfile = certfile;

          sendRequest<protocol.ServeRequest, protocol.ServeResponse>(refs, request, (error, response) => {
            if (error) return reject(new Error(error))
            if (onRequest) {
              requestCallbacks['serve-request'] = (id, request: protocol.OnServeRequest) => {
                onRequest(request.args)
                sendResponse(id, {})
              }
            }
            resolve(response!)
          });
        }),

        dispose: () => new Promise(resolve => {
          if (didDispose) return resolve();
          const request: protocol.DisposeRequest = {
            command: 'dispose',
            key: buildKey,
          }
          sendRequest<protocol.DisposeRequest, null>(refs, request, () => {
            resolve(); // We don't care about errors here

            // Only remove the reference here when we know the Go code has seen
            // this "dispose" call. We don't want to remove any registered
            // callbacks before that point because the Go code might still be
            // sending us events. If we remove the reference earlier then we
            // will return errors for those events, which may end up being
            // printed to the terminal where the user can see them, which would
            // be very confusing.
            refs.unref()
          });
        }),
      };
      refs.ref(); // Keep a reference until "dispose" is called
      callback(null, result);
    });
  }
}

type RunOnEndCallbacks = (result: types.BuildResult, done: (errors: types.Message[], warnings: types.Message[]) => void) => void;

let handlePlugins = async (
  buildKey: number,
  sendRequest: <Req, Res>(refs: Refs | null, value: Req, callback: (error: string | null, response: Res | null) => void) => void,
  sendResponse: (id: number, value: protocol.Value) => void,
  refs: Refs,
  streamIn: StreamIn,
  requestCallbacks: { [command: string]: RequestCallback },
  initialOptions: types.BuildOptions,
  plugins: types.Plugin[],
  details: ObjectStash,
): Promise<
  | { ok: true, requestPlugins: protocol.BuildPlugin[], runOnEndCallbacks: RunOnEndCallbacks }
  | { ok: false, error: any, pluginName: string }
> => {
  let onStartCallbacks: {
    name: string,
    note: () => types.Note | undefined,
    callback: () =>
      (types.OnStartResult | null | void | Promise<types.OnStartResult | null | void>),
  }[] = [];

  let onEndCallbacks: {
    name: string,
    note: () => types.Note | undefined,
    callback: (result: types.BuildResult) =>
      (types.OnEndResult | null | void | Promise<types.OnEndResult | null | void>),
  }[] = [];

  let onResolveCallbacks: {
    [id: number]: {
      name: string,
      note: () => types.Note | undefined,
      callback: (args: types.OnResolveArgs) =>
        (types.OnResolveResult | null | undefined | Promise<types.OnResolveResult | null | undefined>),
    },
  } = {};

  let onLoadCallbacks: {
    [id: number]: {
      name: string,
      note: () => types.Note | undefined,
      callback: (args: types.OnLoadArgs) =>
        (types.OnLoadResult | null | undefined | Promise<types.OnLoadResult | null | undefined>),
    },
  } = {};

  let nextCallbackID = 0;
  let i = 0;
  let requestPlugins: protocol.BuildPlugin[] = [];
  let isSetupDone = false;

  // Clone the plugin array to guard against mutation during iteration
  plugins = [...plugins];

  for (let item of plugins) {
    let keys: OptionKeys = {};
    if (typeof item !== 'object') throw new Error(`Plugin at index ${i} must be an object`);
    const name = getFlag(item, keys, 'name', mustBeString);
    if (typeof name !== 'string' || name === '') throw new Error(`Plugin at index ${i} is missing a name`);
    try {
      let setup = getFlag(item, keys, 'setup', mustBeFunction);
      if (typeof setup !== 'function') throw new Error(`Plugin is missing a setup function`);
      checkForInvalidFlags(item, keys, `on plugin ${quote(name)}`);

      let plugin: protocol.BuildPlugin = {
        name,
        onStart: false,
        onEnd: false,
        onResolve: [],
        onLoad: [],
      };
      i++;

      let resolve = (path: string, options: types.ResolveOptions = {}): Promise<types.ResolveResult> => {
        if (!isSetupDone) throw new Error('Cannot call "resolve" before plugin setup has completed');
        if (typeof path !== 'string') throw new Error(`The path to resolve must be a string`);
        let keys: OptionKeys = Object.create(null);
        let pluginName = getFlag(options, keys, 'pluginName', mustBeString);
        let importer = getFlag(options, keys, 'importer', mustBeString);
        let namespace = getFlag(options, keys, 'namespace', mustBeString);
        let resolveDir = getFlag(options, keys, 'resolveDir', mustBeString);
        let kind = getFlag(options, keys, 'kind', mustBeString);
        let pluginData = getFlag(options, keys, 'pluginData', canBeAnything);
        checkForInvalidFlags(options, keys, 'in resolve() call');

        return new Promise((resolve, reject) => {
          const request: protocol.ResolveRequest = {
            command: 'resolve',
            path,
            key: buildKey,
            pluginName: name,
          }
          if (pluginName != null) request.pluginName = pluginName
          if (importer != null) request.importer = importer
          if (namespace != null) request.namespace = namespace
          if (resolveDir != null) request.resolveDir = resolveDir
          if (kind != null) request.kind = kind
          else throw new Error(`Must specify "kind" when calling "resolve"`)
          if (pluginData != null) request.pluginData = details.store(pluginData)

          sendRequest<protocol.ResolveRequest, protocol.ResolveResponse>(refs, request, (error, response) => {
            if (error !== null) reject(new Error(error))
            else resolve({
              errors: replaceDetailsInMessages(response!.errors, details),
              warnings: replaceDetailsInMessages(response!.warnings, details),
              path: response!.path,
              external: response!.external,
              sideEffects: response!.sideEffects,
              namespace: response!.namespace,
              suffix: response!.suffix,
              pluginData: details.load(response!.pluginData),
            })
          })
        })
      }

      let promise = setup({
        initialOptions,

        resolve,

        onStart(callback) {
          let registeredText = `This error came from the "onStart" callback registered here:`
          let registeredNote = extractCallerV8(new Error(registeredText), streamIn, 'onStart');
          onStartCallbacks.push({ name: name!, callback, note: registeredNote });
          plugin.onStart = true;
        },

        onEnd(callback) {
          let registeredText = `This error came from the "onEnd" callback registered here:`
          let registeredNote = extractCallerV8(new Error(registeredText), streamIn, 'onEnd');
          onEndCallbacks.push({ name: name!, callback, note: registeredNote });
          plugin.onEnd = true;
        },

        onResolve(options, callback) {
          let registeredText = `This error came from the "onResolve" callback registered here:`
          let registeredNote = extractCallerV8(new Error(registeredText), streamIn, 'onResolve');
          let keys: OptionKeys = {};
          let filter = getFlag(options, keys, 'filter', mustBeRegExp);
          let namespace = getFlag(options, keys, 'namespace', mustBeString);
          checkForInvalidFlags(options, keys, `in onResolve() call for plugin ${quote(name)}`);
          if (filter == null) throw new Error(`onResolve() call is missing a filter`);
          let id = nextCallbackID++;
          onResolveCallbacks[id] = { name: name!, callback, note: registeredNote };
          plugin.onResolve.push({ id, filter: filter.source, namespace: namespace || '' });
        },

        onLoad(options, callback) {
          let registeredText = `This error came from the "onLoad" callback registered here:`
          let registeredNote = extractCallerV8(new Error(registeredText), streamIn, 'onLoad');
          let keys: OptionKeys = {};
          let filter = getFlag(options, keys, 'filter', mustBeRegExp);
          let namespace = getFlag(options, keys, 'namespace', mustBeString);
          checkForInvalidFlags(options, keys, `in onLoad() call for plugin ${quote(name)}`);
          if (filter == null) throw new Error(`onLoad() call is missing a filter`);
          let id = nextCallbackID++;
          onLoadCallbacks[id] = { name: name!, callback, note: registeredNote };
          plugin.onLoad.push({ id, filter: filter.source, namespace: namespace || '' });
        },

        esbuild: streamIn.esbuild,
      });

      // Await a returned promise if there was one. This allows plugins to do
      // some asynchronous setup while still retaining the ability to modify
      // the build options. This deliberately serializes asynchronous plugin
      // setup instead of running them concurrently so that build option
      // modifications are easier to reason about.
      if (promise) await promise;

      requestPlugins.push(plugin);
    } catch (e) {
      return { ok: false, error: e, pluginName: name }
    }
  }

  requestCallbacks['on-start'] = async (id, request: protocol.OnStartRequest) => {
    let response: protocol.OnStartResponse = { errors: [], warnings: [] };
    await Promise.all(onStartCallbacks.map(async ({ name, callback, note }) => {
      try {
        let result = await callback();

        if (result != null) {
          if (typeof result !== 'object') throw new Error(`Expected onStart() callback in plugin ${quote(name)} to return an object`);
          let keys: OptionKeys = {};
          let errors = getFlag(result, keys, 'errors', mustBeArray);
          let warnings = getFlag(result, keys, 'warnings', mustBeArray);
          checkForInvalidFlags(result, keys, `from onStart() callback in plugin ${quote(name)}`);

          if (errors != null) response.errors!.push(...sanitizeMessages(errors, 'errors', details, name));
          if (warnings != null) response.warnings!.push(...sanitizeMessages(warnings, 'warnings', details, name));
        }
      } catch (e) {
        response.errors!.push(extractErrorMessageV8(e, streamIn, details, note && note(), name));
      }
    }))
    sendResponse(id, response as any)
  }

  requestCallbacks['on-resolve'] = async (id, request: protocol.OnResolveRequest) => {
    let response: protocol.OnResolveResponse = {}, name = '', callback, note;
    for (let id of request.ids) {
      try {
        ({ name, callback, note } = onResolveCallbacks[id]);
        let result = await callback({
          path: request.path,
          importer: request.importer,
          namespace: request.namespace,
          resolveDir: request.resolveDir,
          kind: request.kind,
          pluginData: details.load(request.pluginData),
        });

        if (result != null) {
          if (typeof result !== 'object') throw new Error(`Expected onResolve() callback in plugin ${quote(name)} to return an object`);
          let keys: OptionKeys = {};
          let pluginName = getFlag(result, keys, 'pluginName', mustBeString);
          let path = getFlag(result, keys, 'path', mustBeString);
          let namespace = getFlag(result, keys, 'namespace', mustBeString);
          let suffix = getFlag(result, keys, 'suffix', mustBeString);
          let external = getFlag(result, keys, 'external', mustBeBoolean);
          let sideEffects = getFlag(result, keys, 'sideEffects', mustBeBoolean);
          let pluginData = getFlag(result, keys, 'pluginData', canBeAnything);
          let errors = getFlag(result, keys, 'errors', mustBeArray);
          let warnings = getFlag(result, keys, 'warnings', mustBeArray);
          let watchFiles = getFlag(result, keys, 'watchFiles', mustBeArray);
          let watchDirs = getFlag(result, keys, 'watchDirs', mustBeArray);
          checkForInvalidFlags(result, keys, `from onResolve() callback in plugin ${quote(name)}`);

          response.id = id;
          if (pluginName != null) response.pluginName = pluginName;
          if (path != null) response.path = path;
          if (namespace != null) response.namespace = namespace;
          if (suffix != null) response.suffix = suffix;
          if (external != null) response.external = external;
          if (sideEffects != null) response.sideEffects = sideEffects;
          if (pluginData != null) response.pluginData = details.store(pluginData);
          if (errors != null) response.errors = sanitizeMessages(errors, 'errors', details, name);
          if (warnings != null) response.warnings = sanitizeMessages(warnings, 'warnings', details, name);
          if (watchFiles != null) response.watchFiles = sanitizeStringArray(watchFiles, 'watchFiles');
          if (watchDirs != null) response.watchDirs = sanitizeStringArray(watchDirs, 'watchDirs');
          break;
        }
      } catch (e) {
        response = { id, errors: [extractErrorMessageV8(e, streamIn, details, note && note(), name)] };
        break
      }
    }
    sendResponse(id, response as any)
  }

  requestCallbacks['on-load'] = async (id, request: protocol.OnLoadRequest) => {
    let response: protocol.OnLoadResponse = {}, name = '', callback, note;
    for (let id of request.ids) {
      try {
        ({ name, callback, note } = onLoadCallbacks[id]);
        let result = await callback({
          path: request.path,
          namespace: request.namespace,
          suffix: request.suffix,
          pluginData: details.load(request.pluginData),
        });

        if (result != null) {
          if (typeof result !== 'object') throw new Error(`Expected onLoad() callback in plugin ${quote(name)} to return an object`);
          let keys: OptionKeys = {};
          let pluginName = getFlag(result, keys, 'pluginName', mustBeString);
          let contents = getFlag(result, keys, 'contents', mustBeStringOrUint8Array);
          let resolveDir = getFlag(result, keys, 'resolveDir', mustBeString);
          let pluginData = getFlag(result, keys, 'pluginData', canBeAnything);
          let loader = getFlag(result, keys, 'loader', mustBeString);
          let errors = getFlag(result, keys, 'errors', mustBeArray);
          let warnings = getFlag(result, keys, 'warnings', mustBeArray);
          let watchFiles = getFlag(result, keys, 'watchFiles', mustBeArray);
          let watchDirs = getFlag(result, keys, 'watchDirs', mustBeArray);
          checkForInvalidFlags(result, keys, `from onLoad() callback in plugin ${quote(name)}`);

          response.id = id;
          if (pluginName != null) response.pluginName = pluginName;
          if (contents instanceof Uint8Array) response.contents = contents;
          else if (contents != null) response.contents = protocol.encodeUTF8(contents);
          if (resolveDir != null) response.resolveDir = resolveDir;
          if (pluginData != null) response.pluginData = details.store(pluginData);
          if (loader != null) response.loader = loader;
          if (errors != null) response.errors = sanitizeMessages(errors, 'errors', details, name);
          if (warnings != null) response.warnings = sanitizeMessages(warnings, 'warnings', details, name);
          if (watchFiles != null) response.watchFiles = sanitizeStringArray(watchFiles, 'watchFiles');
          if (watchDirs != null) response.watchDirs = sanitizeStringArray(watchDirs, 'watchDirs');
          break;
        }
      } catch (e) {
        response = { id, errors: [extractErrorMessageV8(e, streamIn, details, note && note(), name)] };
        break
      }
    }
    sendResponse(id, response as any)
  }

  let runOnEndCallbacks: RunOnEndCallbacks = (result, done) => done([], []);

  if (onEndCallbacks.length > 0) {
    runOnEndCallbacks = (result, done) => {
      (async () => {
        const onEndErrors: types.Message[] = [];
        const onEndWarnings: types.Message[] = [];

        for (const { name, callback, note } of onEndCallbacks) {
          let newErrors: types.Message[] | undefined
          let newWarnings: types.Message[] | undefined

          try {
            const value = await callback(result)

            if (value != null) {
              if (typeof value !== 'object') throw new Error(`Expected onEnd() callback in plugin ${quote(name)} to return an object`);
              let keys: OptionKeys = {};
              let errors = getFlag(value, keys, 'errors', mustBeArray);
              let warnings = getFlag(value, keys, 'warnings', mustBeArray);
              checkForInvalidFlags(value, keys, `from onEnd() callback in plugin ${quote(name)}`);

              if (errors != null) newErrors = sanitizeMessages(errors, 'errors', details, name);
              if (warnings != null) newWarnings = sanitizeMessages(warnings, 'warnings', details, name);
            }
          } catch (e) {
            newErrors = [extractErrorMessageV8(e, streamIn, details, note && note(), name)]
          }

          // Try adding the errors and warnings to the result object, but
          // continue if something goes wrong. If error-reporting has errors
          // then nothing can help us...
          if (newErrors) {
            onEndErrors.push(...newErrors)
            try {
              result.errors.push(...newErrors)
            } catch {
            }
          }
          if (newWarnings) {
            onEndWarnings.push(...newWarnings)
            try {
              result.warnings.push(...newWarnings)
            } catch {
            }
          }
        }

        done(onEndErrors, onEndWarnings)
      })()
    }
  }

  isSetupDone = true;
  return {
    ok: true,
    requestPlugins,
    runOnEndCallbacks,
  }
};

// This stores JavaScript objects on the JavaScript side and temporarily
// substitutes them with an integer that can be passed through the Go side
// and back. That way we can associate JavaScript objects with Go objects
// even if the JavaScript objects aren't serializable. And we also avoid
// the overhead of serializing large JavaScript objects.
interface ObjectStash {
  load(id: number): any;
  store(value: any): number;
}

function createObjectStash(): ObjectStash {
  const map = new Map<number, any>();
  let nextID = 0;
  return {
    load(id) {
      return map.get(id);
    },
    store(value) {
      if (value === void 0) return -1;
      const id = nextID++;
      map.set(id, value);
      return id;
    },
  };
}

function extractCallerV8(e: Error, streamIn: StreamIn, ident: string): () => types.Note | undefined {
  let note: types.Note | undefined
  let tried = false
  return () => {
    if (tried) return note
    tried = true
    try {
      let lines = (e.stack + '').split('\n')
      lines.splice(1, 1)
      let location = parseStackLinesV8(streamIn, lines, ident)
      if (location) {
        note = { text: e.message, location }
        return note
      }
    } catch {
    }
  }
}

function extractErrorMessageV8(e: any, streamIn: StreamIn, stash: ObjectStash | null, note: types.Note | undefined, pluginName: string): types.Message {
  let text = 'Internal error'
  let location: types.Location | null = null

  try {
    text = ((e && e.message) || e) + '';
  } catch {
  }

  // Optionally attempt to extract the file from the stack trace, works in V8/node
  try {
    location = parseStackLinesV8(streamIn, (e.stack + '').split('\n'), '')
  } catch {
  }

  return { id: '', pluginName, text, location, notes: note ? [note] : [], detail: stash ? stash.store(e) : -1 }
}

function parseStackLinesV8(streamIn: StreamIn, lines: string[], ident: string): types.Location | null {
  let at = '    at '

  // Check to see if this looks like a V8 stack trace
  if (streamIn.readFileSync && !lines[0].startsWith(at) && lines[1].startsWith(at)) {
    for (let i = 1; i < lines.length; i++) {
      let line = lines[i]
      if (!line.startsWith(at)) continue
      line = line.slice(at.length)
      while (true) {
        // Unwrap a function name
        let match = /^(?:new |async )?\S+ \((.*)\)$/.exec(line)
        if (match) {
          line = match[1]
          continue
        }

        // Unwrap an eval wrapper
        match = /^eval at \S+ \((.*)\)(?:, \S+:\d+:\d+)?$/.exec(line)
        if (match) {
          line = match[1]
          continue
        }

        // Match on the file location
        match = /^(\S+):(\d+):(\d+)$/.exec(line)
        if (match) {
          let contents
          try {
            contents = streamIn.readFileSync(match[1], 'utf8')
          } catch {
            break
          }
          let lineText = contents.split(/\r\n|\r|\n|\u2028|\u2029/)[+match[2] - 1] || ''
          let column = +match[3] - 1
          let length = lineText.slice(column, column + ident.length) === ident ? ident.length : 0
          return {
            file: match[1],
            namespace: 'file',
            line: +match[2],
            column: protocol.encodeUTF8(lineText.slice(0, column)).length,
            length: protocol.encodeUTF8(lineText.slice(column, column + length)).length,
            lineText: lineText + '\n' + lines.slice(1).join('\n'),
            suggestion: '',
          }
        }
        break
      }
    }
  }

  return null;
}

function failureErrorWithLog(text: string, errors: types.Message[], warnings: types.Message[]): types.BuildFailure {
  let limit = 5
  let summary = errors.length < 1 ? '' : ` with ${errors.length} error${errors.length < 2 ? '' : 's'}:` +
    errors.slice(0, limit + 1).map((e, i) => {
      if (i === limit) return '\n...';
      if (!e.location) return `\nerror: ${e.text}`;
      let { file, line, column } = e.location;
      let pluginText = e.pluginName ? `[plugin: ${e.pluginName}] ` : '';
      return `\n${file}:${line}:${column}: ERROR: ${pluginText}${e.text}`;
    }).join('');
  let error: any = new Error(`${text}${summary}`);
  error.errors = errors;
  error.warnings = warnings;
  return error;
}

function replaceDetailsInMessages(messages: types.Message[], stash: ObjectStash): types.Message[] {
  for (const message of messages) {
    message.detail = stash.load(message.detail);
  }
  return messages;
}

function sanitizeLocation(location: types.PartialMessage['location'], where: string): types.Message['location'] {
  if (location == null) return null;

  let keys: OptionKeys = {};
  let file = getFlag(location, keys, 'file', mustBeString);
  let namespace = getFlag(location, keys, 'namespace', mustBeString);
  let line = getFlag(location, keys, 'line', mustBeInteger);
  let column = getFlag(location, keys, 'column', mustBeInteger);
  let length = getFlag(location, keys, 'length', mustBeInteger);
  let lineText = getFlag(location, keys, 'lineText', mustBeString);
  let suggestion = getFlag(location, keys, 'suggestion', mustBeString);
  checkForInvalidFlags(location, keys, where);

  return {
    file: file || '',
    namespace: namespace || '',
    line: line || 0,
    column: column || 0,
    length: length || 0,
    lineText: lineText || '',
    suggestion: suggestion || '',
  };
}

function sanitizeMessages(messages: types.PartialMessage[], property: string, stash: ObjectStash | null, fallbackPluginName: string): types.Message[] {
  let messagesClone: types.Message[] = [];
  let index = 0;

  for (const message of messages) {
    let keys: OptionKeys = {};
    let id = getFlag(message, keys, 'id', mustBeString);
    let pluginName = getFlag(message, keys, 'pluginName', mustBeString);
    let text = getFlag(message, keys, 'text', mustBeString);
    let location = getFlag(message, keys, 'location', mustBeObjectOrNull);
    let notes = getFlag(message, keys, 'notes', mustBeArray);
    let detail = getFlag(message, keys, 'detail', canBeAnything);
    let where = `in element ${index} of "${property}"`;
    checkForInvalidFlags(message, keys, where);

    let notesClone: types.Note[] = [];
    if (notes) {
      for (const note of notes) {
        let noteKeys: OptionKeys = {};
        let noteText = getFlag(note, noteKeys, 'text', mustBeString);
        let noteLocation = getFlag(note, noteKeys, 'location', mustBeObjectOrNull);
        checkForInvalidFlags(note, noteKeys, where);
        notesClone.push({
          text: noteText || '',
          location: sanitizeLocation(noteLocation, where),
        });
      }
    }

    messagesClone.push({
      id: id || '',
      pluginName: pluginName || fallbackPluginName,
      text: text || '',
      location: sanitizeLocation(location, where),
      notes: notesClone,
      detail: stash ? stash.store(detail) : -1,
    });
    index++;
  }

  return messagesClone;
}

function sanitizeStringArray(values: any[], property: string): string[] {
  const result: string[] = [];
  for (const value of values) {
    if (typeof value !== 'string') throw new Error(`${quote(property)} must be an array of strings`);
    result.push(value);
  }
  return result;
}

function convertOutputFiles({ path, contents }: protocol.BuildOutputFile): types.OutputFile {
  // The text is lazily-generated for performance reasons. If no one asks for
  // it, then it never needs to be generated.
  let text: string | null = null;
  return {
    path,
    contents,
    get text() {
      // People want to be able to set "contents" and have esbuild automatically
      // derive "text" for them, so grab the contents off of this object instead
      // of using our original value.
      const binary = this.contents;

      // This deliberately doesn't do bidirectional derivation because that could
      // result in the inefficiency. For example, if we did do this and then you
      // set "contents" and "text" and then asked for "contents", the second
      // setter for "text" will have erased our cached "contents" value so we'd
      // need to regenerate it again. Instead, "contents" is unambiguously the
      // primary value and "text" is unambiguously the derived value.
      if (text === null || binary !== contents) {
        contents = binary;
        text = protocol.decodeUTF8(binary);
      }
      return text;
    },
  }
}
