import {FileImporter, Importer} from './importer';
import {Logger} from './logger';
import {Value} from './value';
import {PromiseOr} from './util/promise_or';

/**
 * Syntaxes supported by Sass:
 *
 * - `'scss'` is the [SCSS
 *   syntax](https://sass-lang.com/documentation/syntax#scss).
 * - `'indented'` is the [indented
 *   syntax](https://sass-lang.com/documentation/syntax#the-indented-syntax)
 * - `'css'` is plain CSS, which is parsed like SCSS but forbids the use of any
 *   special Sass features.
 *
 * @category Options
 */
export type Syntax = 'scss' | 'indented' | 'css';

/**
 * Possible output styles for the compiled CSS:
 *
 * - `"expanded"` (the default for Dart Sass) writes each selector and
 *   declaration on its own line.
 *
 * - `"compressed"` removes as many extra characters as possible, and writes
 *   the entire stylesheet on a single line.
 *
 * @category Options
 */
export type OutputStyle = 'expanded' | 'compressed';

/**
 * A callback that implements a custom Sass function. This can be passed to
 * [[Options.functions]].
 *
 * ```js
 * const result = sass.compile('style.scss', {
 *   functions: {
 *     "sum($arg1, $arg2)": (args) => {
 *       const value1 = args[0].assertNumber('arg1').value;
 *       const value2 = args[1].assertNumber('arg2')
 *           .convertValueToMatch(arg1, 'arg2', 'arg1');
 *       return new sass.SassNumber(value1 + value2).coerceToMatch(arg1);
 *     }
 *   }
 * });
 * ```
 *
 * @typeParam sync - A `CustomFunction<'sync'>` must return synchronously, but
 * in return it can be passed to [[compile]] and [[compileString]] in addition
 * to [[compileAsync]] and [[compileStringAsync]].
 *
 * A `CustomFunction<'async'>` may either return synchronously or
 * asynchronously, but it can only be used with [[compileAsync]] and
 * [[compileStringAsync]].
 *
 * @param args - An array of arguments passed by the function's caller. If the
 * function takes [arbitrary
 * arguments](https://sass-lang.com/documentation/at-rules/function#taking-arbitrary-arguments),
 * the last element will be a [[SassArgumentList]].
 *
 * @returns The function's result. This may be in the form of a `Promise`, but
 * if it is the function may only be passed to [[compileAsync]] and
 * [[compileStringAsync]], not [[compile]] or [[compileString]].
 *
 * @throws any - This function may throw an error, which the Sass compiler will
 * treat as the function call failing. If the exception object has a `message`
 * property, it will be used as the wrapped exception's message; otherwise, the
 * exception object's `toString()` will be used. This means it's safe for custom
 * functions to throw plain strings.
 *
 * @category Custom Function
 */
export type CustomFunction<sync extends 'sync' | 'async'> = (
  args: Value[]
) => PromiseOr<Value, sync>;

/**
 * Options that can be passed to [[compile]], [[compileAsync]],
 * [[compileString]], or [[compileStringAsync]].
 *
 * @typeParam sync - This lets the TypeScript checker verify that asynchronous
 * [[Importer]]s, [[FileImporter]]s, and [[CustomFunction]]s aren't passed to
 * [[compile]] or [[compileString]].
 *
 * @category Options
 */
export interface Options<sync extends 'sync' | 'async'> {
  /**
   * If this is `true`, the compiler will exclusively use ASCII characters in
   * its error and warning messages. Otherwise, it may use non-ASCII Unicode
   * characters as well.
   *
   * @defaultValue `false`
   * @category Messages
   */
  alertAscii?: boolean;

  /**
   * If this is `true`, the compiler will use ANSI color escape codes in its
   * error and warning messages. If it's `false`, it won't use these. If it's
   * undefined, the compiler will determine whether or not to use colors
   * depending on whether the user is using an interactive terminal.
   *
   * @category Messages
   */
  alertColor?: boolean;

  /**
   * Additional built-in Sass functions that are available in all stylesheets.
   * This option takes an object whose keys are Sass function signatures like
   * you'd write for the [`@function
   * rule`](https://sass-lang.com/documentation/at-rules/function) and whose
   * values are [[CustomFunction]]s.
   *
   * Functions are passed JavaScript representations of [Sass value
   * types](https://sass-lang.com/documentation/js-api#value-types), and must
   * return the same.
   *
   * When writing custom functions, it's important to make them as user-friendly
   * and as close to the standards set by Sass's core functions as possible. Some
   * good guidelines to follow include:
   *
   * * Use `Value.assert*` methods, like [[Value.assertString]], to cast untyped
   *   `Value` objects to more specific types. For values that were passed
   *   directly as arguments, pass in the argument name as well. This ensures
   *   that the user gets good error messages when they pass in the wrong type
   *   to your function.
   *
   * * Individual classes may have more specific `assert*` methods, like
   *   [[SassNumber.assertInt]], which should be used when possible.
   *
   * * In Sass, every value counts as a list. Rather than trying to detect the
   *   [[SassList]] type, you should use [[Value.asList]] to treat all values as
   *   lists.
   *
   * * When manipulating values like lists, strings, and numbers that have
   *   metadata (comma versus space separated, bracketed versus unbracketed,
   *   quoted versus unquoted, units), the output metadata should match the
   *   input metadata.
   *
   * * When in doubt, lists should default to comma-separated, strings should
   *   default to quoted, and numbers should default to unitless.
   *
   * * In Sass, lists and strings use one-based indexing and use negative
   *   indices to index from the end of value. Functions should follow these
   *   conventions. [[Value.sassIndexToListIndex]] and
   *   [[SassString.sassIndexToStringIndex]] can be used to do this
   *   automatically.
   *
   * * String indexes in Sass refer to Unicode code points while JavaScript
   *   string indices refer to UTF-16 code units. For example, the character
   *   U+1F60A SMILING FACE WITH SMILING EYES is a single Unicode code point but
   *   is represented in UTF-16 as two code units (`0xD83D` and `0xDE0A`). So in
   *   JavaScript, `"a😊b".charCodeAt(1)` returns `0xD83D`, whereas in Sass
   *   `str-slice("a😊b", 1, 1)` returns `"😊"`. Functions should follow Sass's
   *   convention. [[SassString.sassIndexToStringIndex]] can be used to do this
   *   automatically, and the [[SassString.sassLength]] getter can be used to
   *   access a string's length in code points.
   *
   * @example
   *
   * ```js
   * sass.compileString(`
   * h1 {
   *   font-size: pow(2, 5) * 1px;
   * }`, {
   *   functions: {
   *     // Note: in real code, you should use `math.pow()` from the built-in
   *     // `sass:math` module.
   *     'pow($base, $exponent)': function(args) {
   *       const base = args[0].assertNumber('base').assertNoUnits('base');
   *       const exponent =
   *           args[1].assertNumber('exponent').assertNoUnits('exponent');
   *
   *       return new sass.SassNumber(Math.pow(base.value, exponent.value));
   *     }
   *   }
   * });
   * ```
   *
   * @category Plugins
   */
  functions?: Record<string, CustomFunction<sync>>;

  /**
   * Custom importers that control how Sass resolves loads from rules like
   * [`@use`](https://sass-lang.com/documentation/at-rules/use) and
   * [`@import`](https://sass-lang.com/documentation/at-rules/import).
   *
   * Loads are resolved by trying, in order:
   *
   * - The importer that was used to load the current stylesheet, with the
   *   loaded URL resolved relative to the current stylesheet's canonical URL.
   *
   * - Each [[Importer]] or [[FileImporter]] in [[importers]], in order.
   *
   * - Each load path in [[loadPaths]], in order.
   *
   * If none of these return a Sass file, the load fails and Sass throws an
   * error.
   *
   * @category Plugins
   */
  importers?: (Importer<sync> | FileImporter<sync>)[];

  /**
   * Paths in which to look for stylesheets loaded by rules like
   * [`@use`](https://sass-lang.com/documentation/at-rules/use) and
   * [`@import`](https://sass-lang.com/documentation/at-rules/import).
   *
   * A load path `loadPath` is equivalent to the following [[FileImporter]]:
   *
   * ```js
   * {
   *   findFileUrl(url) {
   *     // Load paths only support relative URLs.
   *     if (/^[a-z]+:/i.test(url)) return null;
   *     return new URL(url, pathToFileURL(loadPath));
   *   }
   * }
   * ```
   *
   * @category Input
   */
  loadPaths?: string[];

  /**
   * An object to use to handle warnings and/or debug messages from Sass.
   *
   * By default, Sass emits warnings and debug messages to standard error, but
   * if [[Logger.warn]] or [[Logger.debug]] is set, this will invoke them
   * instead.
   *
   * The special value [[Logger.silent]] can be used to easily silence all
   * messages.
   *
   * @category Messages
   */
  logger?: Logger;

  /**
   * If this option is set to `true`, Sass won’t print warnings that are caused
   * by dependencies. A “dependency” is defined as any file that’s loaded
   * through [[loadPaths]] or [[importer]]. Stylesheets that are imported
   * relative to the entrypoint are not considered dependencies.
   *
   * This is useful for silencing deprecation warnings that you can’t fix on
   * your own. However, please <em>also</em> notify your dependencies of the deprecations
   * so that they can get fixed as soon as possible!
   *
   * **Heads up!** If [[compileString]] or [[compileStringAsync]] is called
   * without [[StringWithoutImporter.url]], <em>all</em> stylesheets it loads
   * will be considered dependencies. Since it doesn’t have a path of its own,
   * everything it loads is coming from a load path rather than a relative
   * import.
   *
   * @defaultValue `false`
   * @category Messages
   */
  quietDeps?: boolean;

  /**
   * Whether or not Sass should generate a source map. If it does, the source
   * map will be available as [[CompileResult.sourceMap]].
   *
   * **Heads up!** Sass doesn't automatically add a `sourceMappingURL` comment
   * to the generated CSS. It's up to callers to do that, since callers have
   * full knowledge of where the CSS and the source map will exist in relation
   * to one another and how they'll be served to the browser.
   *
   * @defaultValue `false`
   * @category Output
   */
  sourceMap?: boolean;

  /**
   * Whether Sass should include the sources in the generated source map.
   *
   * This option has no effect if [[sourceMap]] is `false`.
   *
   * @defaultValue `false`
   * @category Output
   */
  sourceMapIncludeSources?: boolean;

  /**
   * The [[OutputStyle]] of the compiled CSS.
   *
   * @example
   *
   * ```js
   * const source = `
   * h1 {
   *   font-size: 40px;
   *   code {
   *     font-face: Roboto Mono;
   *   }
   * }`;
   *
   * let result = sass.compileString(source, {style: "expanded"});
   * console.log(result.css.toString());
   * // h1 {
   * //   font-size: 40px;
   * // }
   * // h1 code {
   * //   font-face: Roboto Mono;
   * // }
   *
   * result = sass.compileString(source, {style: "compressed"})
   * console.log(result.css.toString());
   * // h1{font-size:40px}h1 code{font-face:Roboto Mono}
   * ```
   *
   * @category Output
   */
  style?: OutputStyle;

  /**
   * By default, Dart Sass will print only five instances of the same
   * deprecation warning per compilation to avoid deluging users in console
   * noise. If you set `verbose` to `true`, it will instead print every
   * deprecation warning it encounters.
   *
   * @defaultValue `false`
   * @category Messages
   */
  verbose?: boolean;
}

/**
 * Options that can be passed to [[compileString]] or [[compileStringAsync]].
 *
 * If the [[StringOptionsWithImporter.importer]] field isn't passed, the
 * entrypoint file can't load files relative to itself and the [[url]] field is
 * optional.
 *
 * @typeParam sync - This lets the TypeScript checker verify that asynchronous
 * [[Importer]]s, [[FileImporter]]s, and [[CustomFunction]]s aren't passed to
 * [[compile]] or [[compileString]].
 *
 * @category Options
 */
export interface StringOptionsWithoutImporter<sync extends 'sync' | 'async'>
  extends Options<sync> {
  /**
   * The [[Syntax]] to use to parse the entrypoint stylesheet.
   *
   * @default `'scss'`
   *
   * @category Input
   */
  syntax?: Syntax;

  /**
   * The canonical URL of the entrypoint stylesheet. If this isn't passed along
   * with [[StringOptionsWithoutImporter.importer]], it's optional and only used
   * for error reporting.
   *
   * @category Input
   */
  url?: URL;
}

/**
 * Options that can be passed to [[compileString]] or [[compileStringAsync]].
 *
 * If the [[StringOptionsWithImporter.importer]] field is passed, the entrypoint
 * file uses it to load files relative to itself and the [[url]] field is
 * mandatory.
 *
 * @typeParam sync - This lets the TypeScript checker verify that asynchronous
 * [[Importer]]s, [[FileImporter]]s, and [[CustomFunction]]s aren't passed to
 * [[compile]] or [[compileString]].
 *
 * @category Options
 */
export interface StringOptionsWithImporter<sync extends 'sync' | 'async'>
  extends StringOptionsWithoutImporter<sync> {
  /**
   * The importer to use to handle loads that are relative to the entrypoint
   * stylesheet.
   *
   * A relative load's URL is first resolved relative to [[url]], then passed to
   * [[importer]]. If the importer doesn't recognize it, it's then passed to
   * [[importers]] and [[loadPaths]].
   *
   * @category Input
   */
  importer: Importer<sync> | FileImporter<sync>;

  /**
   * The canonical URL of the entrypoint stylesheet. If this is passed along
   * with [[importer]], it's used to resolve relative loads in the entrypoint
   * stylesheet.
   *
   * @category Input
   */
  url: URL;
}

/**
 * Options that can be passed to [[compileString]] or [[compileStringAsync]].
 *
 * This is a [[StringOptionsWithImporter]] if it has a
 * [[StringOptionsWithImporter.importer]] field, and a
 * [[StringOptionsWithoutImporter]] otherwise.
 *
 * @typeParam sync - This lets the TypeScript checker verify that asynchronous
 * [[Importer]]s, [[FileImporter]]s, and [[CustomFunction]]s aren't passed to
 * [[compile]] or [[compileString]].
 *
 * @category Options
 */
export type StringOptions<sync extends 'sync' | 'async'> =
  | StringOptionsWithImporter<sync>
  | StringOptionsWithoutImporter<sync>;