/**
 * Copyright (c) 2013-present, Facebook, Inc.
 * All rights reserved.
 *
 * This source code is licensed under the BSD-style license found in the
 * LICENSE file in the root directory of this source tree. An additional grant
 * of patent rights can be found in the PATENTS file in the same directory.
 *
 * @flow
 * @format
 */

type _BabelSourceMap = {
  file?: string,
  mappings: string,
  names: Array<string>,
  sourceRoot?: string,
  sources: Array<string>,
  sourcesContent?: Array<?string>,
  version: number,
};

// based on babylon v6.13.1
type BabylonOptions = {
  allowImportExportEverywhere?: boolean,
  allowReturnOutsideFunction?: boolean,
  allowSuperOutsideMethod?: boolean,
  sourceType?: 'script' | 'module',
  sourceFilename?: 'string',
  plugins?: Array<
    | 'jsx'
    | 'flow'
    | 'doExpressions'
    | 'objectRestSpread'
    | 'decorators'
    | 'classProperties'
    | 'exportExtensions'
    | 'asyncGenerators'
    | 'functionBind'
    | 'functionSent'
    | 'dynamicImport',
  >,
};

// based on babel-generator v6.18.0
type GeneratorOptions = {
  auxiliaryCommentBefore?: string,
  auxiliaryCommentAfter?: string,
  shouldPrintComment?: (comment: string) => boolean,
  retainLines?: boolean,
  retainFunctionParens?: boolean,
  comments?: boolean,
  compact?: boolean | 'auto',
  minified?: boolean,
  concise?: boolean,
  quotes?: 'single' | 'double',
  filename?: string,
  sourceMaps?: boolean,
  sourceMapTarget?: string,
  sourceRoot?: string,
  sourceFileName?: string,
};

type InlinePlugin = string | {} | (() => {});
type _Plugins = Array<string | Object | [InlinePlugin] | [InlinePlugin, mixed]>;

// based on https://babeljs.io/docs/usage/options/ -- 2016-11-11
type __TransformOptions = {
  filename?: string,
  filenameRelative?: string,
  presets?: _Plugins,
  plugins?: _Plugins,
  parserOpts?: BabylonOptions,
  generatorOpts?: GeneratorOptions,
  highlightCode?: boolean,
  only?: string | RegExp | Array<string | RegExp>,
  ignore?: string | RegExp | Array<string | RegExp>,
  auxiliaryCommentBefore?: boolean,
  auxiliaryCommentAfter?: boolean,
  sourceMaps?: boolean,
  inputSourceMap?: ?Object,
  sourceMapTarget?: string,
  sourceFileName?: string,
  sourceRoot?: string,
  moduleRoot?: string,
  moduleIds?: boolean,
  moduleId?: string,
  getModuleId?: (moduleName: string) => string,
  resolveModuleSource?: (source: string, filename: string) => string,
  code?: boolean,
  babelrc?: boolean,
  ast?: boolean,
  compact?: boolean | 'auto',
  minified?: boolean,
  comments?: boolean,
  shouldPrintComment?: (comment: string) => boolean,
  retainLines?: boolean,
  extends?: string,
};

type _TransformOptions = __TransformOptions & {
  env?: {[key: string]: __TransformOptions},
};

type BabelNode = $FlowFixMe;

type TransformResult = {
  ast: BabelNode,
  code: ?string,
  ignored: boolean,
  map: ?_BabelSourceMap,
};
// https://github.com/babel/babel/blob/master/packages/babel-generator/src/buffer.js#L42
type GeneratorResult = {
  code: string,
  map: ?_BabelSourceMap,
  rawMappings: ?Array<_BabelSourceMapSegment>,
};
type VisitFn = <State>(path: Object, state: State) => any;

type BabelTypes = {[key: string]: Function};

declare module 'babel-core' {
  declare type Plugins = _Plugins;
  declare type BabelSourceMap = _BabelSourceMap;
  declare type Ast = BabelNode;
  declare type TransformOptions = _TransformOptions;
  declare var transform: TransformSync /*(
    code: string,
    options?: _TransformOptions,
  ): TransformResult*/;
  declare function traverse<State>(
    ast: BabelNode,
    visitor: BabelVisitor,
    scope?: ?Object,
    state?: State,
    parentPath?: ?Object,
  ): void;
  declare var types: BabelTypes;
  declare var transformFile: TransformFile;
  declare var transformFromAst: TransformFromAst /*(
    ast: BabelNode,
    code?: ?string,
    babelOptions?: _TransformOptions,
  ): TransformResult*/;
}

type _BabelSourceMapSegment = {
  generated: {column: number, line: number},
  name?: string,
  original?: {column: number, line: number},
  source?: string,
};

// https://github.com/babel/babel/tree/master/packages/babel-generator
declare module 'babel-generator' {
  declare export type BabelSourceMapSegment = _BabelSourceMapSegment;
  declare export default (
    ast: BabelNode,
    options?: GeneratorOptions,
    code?: string | {[string]: string},
  ) => GeneratorResult
}

// #############################################
// ############     Babel 7    #################
// #############################################
// (Mostly compatible with Babel 6...)

// https://github.com/babel/babel/tree/master/packages/babylon#options
type Babylon7Options = {|
  allowImportExportEverywhere?: boolean,
  allowReturnOutsideFunction?: boolean,
  allowSuperOutsideMethod?: mixed, // "TODO" okay. Maybe don't use this yet.
  sourceType?: 'script' | 'module' | 'unambiguous',
  sourceFilename?: string,
  startLine?: number,
  plugins?: Array<string>, // "plugins" here are built-in features to enable
  strictMode?: boolean, // "TODO" ehh to consider this strict mode?
  ranges?: boolean,
  tokens?: boolean,
|};

// https://github.com/babel/babel/tree/master/packages/babel-core#options
type BabelCoreOptions = {|
  ast?: boolean,
  auxiliaryCommentAfter?: ?string,
  auxiliaryCommentBefore?: ?string,
  babelrc?: boolean,
  envName?: string,
  code?: boolean,
  comments?: boolean,
  compact?: 'auto' | boolean,
  env?: {production: {[string]: mixed}, staging: {[string]: mixed}},
  extends?: ?string,
  filename?: string,
  filenameRelative?: 'string',
  generatorOpts?: ?GeneratorOptions,
  getModuleId?: ?(string) => string | boolean,
  highlightCode?: boolean,
  ignore?: ?(string | Array<string> | RegExp | Array<string | RegExp>),
  inputSourceMap?: ?_BabelSourceMap,
  minified?: boolean,
  moduleId?: ?string,
  moduleIds?: ?{[string]: string},
  moduleRoot?: string,
  only?: ?(string | Array<string> | RegExp | Array<string | RegExp>),
  parserOpts?: ?Babylon7Options,
  plugins?: Array<BabelPlugin>,
  presets?: Array<string>,
  retainLines?: boolean,
  shouldPrintComment?: ?(string) => boolean,
  sourceFileName?: string,
  sourceMaps?: boolean | 'inline' | 'both',
  sourceMapTarget?: string,
  sourceRoot?: string,
  sourceType?: 'module' | 'script' | 'unambiguous',
  wrapPluginVisitorMethod?: ?(
    pluginAlias: string,
    visitorType: string,
    callback: () => void,
  ) => void,
|};

type TemplateOptions = Babylon7Options & {|
  placeholderWhitelist?: Set<string>,
  placeholderPattern?: RegExp | false,
  preserveComments?: boolean,
|};

type Templatable = ({|[tokenName: string]: string|}) => BabelNode;

type TemplateFunc = (tpl: string, options: TemplateOptions) => Templatable;

// note: ast is not optional, babel will throw if it would be empty:
// https://github.com/babel/babel/blob/98969b8a7335e831c069164f5c56132111847224/packages/babel-core/src/transform-ast.js#L52
// https://github.com/babel/babel/blob/98969b8a7335e831c069164f5c56132111847224/packages/babel-core/src/transform-ast-sync.js#L15
export type Transform7Result = {|
  code: string,
  map?: _BabelSourceMap,
  ast: BabelNode, // note: babel never allows falsy ast value here
|};

// Do NOT make this an optional type!
type TransformCallback = (Error => void) | ((void, Transform7Result) => void);

type TraverseFunc = (
  ast: BabelNode | Array<BabelNode>,
  visitor: BabelVisitor,
  scope?: ?Object,
  state?: ?Object,
  parentPath?: ?Object,
) => void;

export type TransformSync = (
  code: string,
  options: BabelCoreOptions,
) => Transform7Result;

export type TransformFileSync = (
  filename: string,
  options: BabelCoreOptions,
) => Transform7Result;

export type TransformFromAstSync = (
  ast: BabelNode,
  code?: string,
  options?: BabelCoreOptions,
) => Transform7Result;

// Use the sync versions if you expect a result
type void_DO_NOT_USE_SYNC = void;

// https://github.com/babel/babel/tree/master/packages/babel-core
declare module '@babel/core' {
  declare type Ast = BabelNode;
  declare type BabelSourceMap = _BabelSourceMap;
  declare type TransformResult = Transform7Result;

  // use @babel/types instead!
  declare var types: BabelTypes;
  // use @babel/traverse instead!
  declare var traverse: TraverseFunc;

  // Note: DO NOT USE WITHOUT CALLBACK. Use transformSync instead.
  declare function transform(
    code: string,
    options: BabelCoreOptions,
    callback: TransformCallback,
  ): void_DO_NOT_USE_SYNC;
  declare var transformSync: TransformSync;
  // Note: DO NOT USE WITHOUT CALLBACK. Use transformFileSync instead.
  declare function transformFile(
    filename: string,
    options: BabelCoreOptions,
    callback: TransformCallback,
  ): void_DO_NOT_USE_SYNC;
  declare var transformFileSync: TransformFileSync;
  // Note: DO NOT USE WITHOUT CALLBACK. Use transformFromAstSync instead.
  declare function transformFromAst(
    ast: BabelNode,
    code?: string,
    options?: BabelCoreOptions,
    callback: TransformCallback,
  ): void_DO_NOT_USE_SYNC;
  declare var transformFromAstSync: TransformFromAstSync;
}

// https://github.com/babel/babel/tree/master/packages/babylon
declare module 'babylon7' {
  declare function parse(
    code: string,
    options?: Babylon7Options,
  ): BabelNode & {program: {body: BabelNode}};
  declare function parseExpression(
    code: string,
    options?: Babylon7Options,
  ): BabelNode;
}

// https://github.com/babel/babel/tree/master/packages/babel-generator
declare module '@babel/generator' {
  declare export default (
    ast: BabelNode,
    options?: GeneratorOptions,
    code?: string | {|[filename: string]: string|},
  ) => GeneratorResult
}

// https://github.com/babel/babel/tree/master/packages/babel-template
declare module '@babel/template' {
  declare module.exports: TemplateFunc;
  // & {
  //   ast: (code: string) => Ast,
  //   smart: TemplateFunc,
  //   statement: TemplateFunc,
  //   statements: TemplateFunc,
  //   expression: TemplateFunc,
  //   program: TemplateFunc,
  // };
}

declare module '@babel/types' {
  // TODO we should make this types thing explicit (see pckg babel-flow-types)
  declare module.exports: BabelTypes;
}

declare module '@babel/traverse' {
  declare module.exports: TraverseFunc;
}