// A simple implementation of make-array
function makeArray(subject) {
  return Array.isArray(subject) ? subject : [subject];
}

const EMPTY = '';
const SPACE = ' ';
const ESCAPE = '\\';
const REGEX_TEST_BLANK_LINE = /^\s+$/;
const REGEX_INVALID_TRAILING_BACKSLASH = /(?:[^\\]|^)\\$/;
const REGEX_REPLACE_LEADING_EXCAPED_EXCLAMATION = /^\\!/;
const REGEX_REPLACE_LEADING_EXCAPED_HASH = /^\\#/;
const REGEX_SPLITALL_CRLF = /\r?\n/g;
// /foo,
// ./foo,
// ../foo,
// .
// ..
const REGEX_TEST_INVALID_PATH = /^\.*\/|^\.+$/;

const SLASH = '/';

// Do not use ternary expression here, since "istanbul ignore next" is buggy
let TMP_KEY_IGNORE = 'node-ignore';
/* istanbul ignore else */
if (typeof Symbol !== 'undefined') {
  TMP_KEY_IGNORE = Symbol.for('node-ignore');
}
const KEY_IGNORE = TMP_KEY_IGNORE;

const define = (object, key, value) =>
  Object.defineProperty(object, key, { value });

const REGEX_REGEXP_RANGE = /([0-z])-([0-z])/g;

const RETURN_FALSE = () => false;

// Sanitize the range of a regular expression
// The cases are complicated, see test cases for details
const sanitizeRange = (range) =>
  range.replace(REGEX_REGEXP_RANGE, (match, from, to) =>
    from.charCodeAt(0) <= to.charCodeAt(0) ?
      match
      // Invalid range (out of order) which is ok for gitignore rules but
      //   fatal for JavaScript regular expression, so eliminate it.
    : EMPTY
  );

// See fixtures #59
const cleanRangeBackSlash = (slashes) => {
  const { length } = slashes;
  return slashes.slice(0, length - (length % 2));
};

// > If the pattern ends with a slash,
// > it is removed for the purpose of the following description,
// > but it would only find a match with a directory.
// > In other words, foo/ will match a directory foo and paths underneath it,
// > but will not match a regular file or a symbolic link foo
// >  (this is consistent with the way how pathspec works in general in Git).
// '`foo/`' will not match regular file '`foo`' or symbolic link '`foo`'
// -> ignore-rules will not deal with it, because it costs extra `fs.stat` call
//      you could use option `mark: true` with `glob`

// '`foo/`' should not continue with the '`..`'
const REPLACERS = [
  [
    // remove BOM
    // TODO:
    // Other similar zero-width characters?
    /^\uFEFF/,
    () => EMPTY,
  ],

  // > Trailing spaces are ignored unless they are quoted with backslash ("\")
  [
    // (a\ ) -> (a )
    // (a  ) -> (a)
    // (a ) -> (a)
    // (a \ ) -> (a  )
    /((?:\\\\)*?)(\\?\s+)$/,
    (_, m1, m2) => m1 + (m2.indexOf('\\') === 0 ? SPACE : EMPTY),
  ],

  // replace (\ ) with ' '
  // (\ ) -> ' '
  // (\\ ) -> '\\ '
  // (\\\ ) -> '\\ '
  [
    /(\\+?)\s/g,
    (_, m1) => {
      const { length } = m1;
      return m1.slice(0, length - (length % 2)) + SPACE;
    },
  ],

  // Escape metacharacters
  // which is written down by users but means special for regular expressions.

  // > There are 12 characters with special meanings:
  // > - the backslash \,
  // > - the caret ^,
  // > - the dollar sign $,
  // > - the period or dot .,
  // > - the vertical bar or pipe symbol |,
  // > - the question mark ?,
  // > - the asterisk or star *,
  // > - the plus sign +,
  // > - the opening parenthesis (,
  // > - the closing parenthesis ),
  // > - and the opening square bracket [,
  // > - the opening curly brace {,
  // > These special characters are often called "metacharacters".
  [/[\\$.|*+(){^]/g, (match) => `\\${match}`],

  [
    // > a question mark (?) matches a single character
    /(?!\\)\?/g,
    () => '[^/]',
  ],

  // leading slash
  [
    // > A leading slash matches the beginning of the pathname.
    // > For example, "/*.c" matches "cat-file.c" but not "mozilla-sha1/sha1.c".
    // A leading slash matches the beginning of the pathname
    /^\//,
    () => '^',
  ],

  // replace special metacharacter slash after the leading slash
  [/\//g, () => '\\/'],

  [
    // > A leading "**" followed by a slash means match in all directories.
    // > For example, "**/foo" matches file or directory "foo" anywhere,
    // > the same as pattern "foo".
    // > "**/foo/bar" matches file or directory "bar" anywhere that is directly
    // >   under directory "foo".
    // Notice that the '*'s have been replaced as '\\*'
    /^\^*\\\*\\\*\\\//,

    // '**/foo' <-> 'foo'
    () => '^(?:.*\\/)?',
  ],

  // starting
  [
    // there will be no leading '/'
    //   (which has been replaced by section "leading slash")
    // If starts with '**', adding a '^' to the regular expression also works
    /^(?=[^^])/,
    function startingReplacer() {
      // If has a slash `/` at the beginning or middle
      return !/\/(?!$)/.test(this) ?
          // > Prior to 2.22.1
          // > If the pattern does not contain a slash /,
          // >   Git treats it as a shell glob pattern
          // Actually, if there is only a trailing slash,
          //   git also treats it as a shell glob pattern

          // After 2.22.1 (compatible but clearer)
          // > If there is a separator at the beginning or middle (or both)
          // > of the pattern, then the pattern is relative to the directory
          // > level of the particular .gitignore file itself.
          // > Otherwise the pattern may also match at any level below
          // > the .gitignore level.
          '(?:^|\\/)'
          // > Otherwise, Git treats the pattern as a shell glob suitable for
          // >   consumption by fnmatch(3)
        : '^';
    },
  ],

  // two globstars
  [
    // Use lookahead assertions so that we could match more than one `'/**'`
    /\\\/\\\*\\\*(?=\\\/|$)/g,

    // Zero, one or several directories
    // should not use '*', or it will be replaced by the next replacer

    // Check if it is not the last `'/**'`
    (_, index, str) =>
      index + 6 < str.length ?
        // case: /**/
        // > A slash followed by two consecutive asterisks then a slash matches
        // >   zero or more directories.
        // > For example, "a/**/b" matches "a/b", "a/x/b", "a/x/y/b" and so on.
        // '/**/'
        '(?:\\/[^\\/]+)*'
        // case: /**
        // > A trailing `"/**"` matches everything inside.
        // #21: everything inside but it should not include the current folder
      : '\\/.+',
  ],

  // normal intermediate wildcards
  [
    // Never replace escaped '*'
    // ignore rule '\*' will match the path '*'

    // 'abc.*/' -> go
    // 'abc.*'  -> skip this rule,
    //    coz trailing single wildcard will be handed by [trailing wildcard]
    /(^|[^\\]+)(\\\*)+(?=.+)/g,

    // '*.js' matches '.js'
    // '*.js' doesn't match 'abc'
    (_, p1, p2) => {
      // 1.
      // > An asterisk "*" matches anything except a slash.
      // 2.
      // > Other consecutive asterisks are considered regular asterisks
      // > and will match according to the previous rules.
      const unescaped = p2.replace(/\\\*/g, '[^\\/]*');
      return p1 + unescaped;
    },
  ],

  [
    // unescape, revert step 3 except for back slash
    // For example, if a user escape a '\\*',
    // after step 3, the result will be '\\\\\\*'
    /\\\\\\(?=[$.|*+(){^])/g,
    () => ESCAPE,
  ],

  [
    // '\\\\' -> '\\'
    /\\\\/g,
    () => ESCAPE,
  ],

  [
    // > The range notation, e.g. [a-zA-Z],
    // > can be used to match one of the characters in a range.

    // `\` is escaped by step 3
    /(\\)?\[([^\]/]*?)(\\*)($|\])/g,
    (match, leadEscape, range, endEscape, close) =>
      leadEscape === ESCAPE ?
        // '\\[bar]' -> '\\\\[bar\\]'
        `\\[${range}${cleanRangeBackSlash(endEscape)}${close}`
      : close === ']' ?
        endEscape.length % 2 === 0 ?
          // A normal case, and it is a range notation
          // '[bar]'
          // '[bar\\\\]'
          `[${sanitizeRange(range)}${endEscape}]`
          // Invalid range notaton
          // '[bar\\]' -> '[bar\\\\]'
        : '[]'
      : '[]',
  ],

  // ending
  [
    // 'js' will not match 'js.'
    // 'ab' will not match 'abc'
    /(?:[^*])$/,

    // WTF!
    // https://git-scm.com/docs/gitignore
    // changes in [2.22.1](https://git-scm.com/docs/gitignore/2.22.1)
    // which re-fixes #24, #38

    // > If there is a separator at the end of the pattern then the pattern
    // > will only match directories, otherwise the pattern can match both
    // > files and directories.

    // 'js*' will not match 'a.js'
    // 'js/' will not match 'a.js'
    // 'js' will match 'a.js' and 'a.js/'
    (match) =>
      /\/$/.test(match) ?
        // foo/ will not match 'foo'
        `${match}$`
        // foo matches 'foo' and 'foo/'
      : `${match}(?=$|\\/$)`,
  ],

  // trailing wildcard
  [
    /(\^|\\\/)?\\\*$/,
    (_, p1) => {
      const prefix =
        p1 ?
          // '\^':
          // '/*' does not match EMPTY
          // '/*' does not match everything

          // '\\\/':
          // 'abc/*' does not match 'abc/'
          `${p1}[^/]+`
          // 'a*' matches 'a'
          // 'a*' matches 'aa'
        : '[^/]*';

      return `${prefix}(?=$|\\/$)`;
    },
  ],
];

// A simple cache, because an ignore rule only has only one certain meaning
const regexCache = Object.create(null);

// @param {pattern}
const makeRegex = (pattern, ignoreCase) => {
  let source = regexCache[pattern];

  if (!source) {
    source = REPLACERS.reduce(
      (prev, [matcher, replacer]) =>
        prev.replace(matcher, replacer.bind(pattern)),
      pattern
    );
    regexCache[pattern] = source;
  }

  return ignoreCase ? new RegExp(source, 'i') : new RegExp(source);
};

const isString = (subject) => typeof subject === 'string';

// > A blank line matches no files, so it can serve as a separator for readability.
const checkPattern = (pattern) =>
  pattern &&
  isString(pattern) &&
  !REGEX_TEST_BLANK_LINE.test(pattern) &&
  !REGEX_INVALID_TRAILING_BACKSLASH.test(pattern) &&
  // > A line starting with # serves as a comment.
  pattern.indexOf('#') !== 0;

const splitPattern = (pattern) => pattern.split(REGEX_SPLITALL_CRLF);

class IgnoreRule {
  constructor(origin, pattern, negative, regex) {
    this.origin = origin;
    this.pattern = pattern;
    this.negative = negative;
    this.regex = regex;
  }
}

const createRule = (pattern, ignoreCase) => {
  const origin = pattern;
  let negative = false;

  // > An optional prefix "!" which negates the pattern;
  if (pattern.indexOf('!') === 0) {
    negative = true;
    pattern = pattern.substr(1);
  }

  pattern = pattern
    // > Put a backslash ("\") in front of the first "!" for patterns that
    // >   begin with a literal "!", for example, `"\!important!.txt"`.
    .replace(REGEX_REPLACE_LEADING_EXCAPED_EXCLAMATION, '!')
    // > Put a backslash ("\") in front of the first hash for patterns that
    // >   begin with a hash.
    .replace(REGEX_REPLACE_LEADING_EXCAPED_HASH, '#');

  const regex = makeRegex(pattern, ignoreCase);

  return new IgnoreRule(origin, pattern, negative, regex);
};

const throwError = (message, Ctor) => {
  throw new Ctor(message);
};

const checkPath = (path, originalPath, doThrow) => {
  if (!isString(path)) {
    return doThrow(
      `path must be a string, but got \`${originalPath}\``,
      TypeError
    );
  }

  // We don't know if we should ignore EMPTY, so throw
  if (!path) {
    return doThrow(`path must not be empty`, TypeError);
  }

  // Check if it is a relative path
  if (checkPath.isNotRelative(path)) {
    const r = '`path.relative()`d';
    return doThrow(
      `path should be a ${r} string, but got "${originalPath}"`,
      RangeError
    );
  }

  return true;
};

const isNotRelative = (path) => REGEX_TEST_INVALID_PATH.test(path);

checkPath.isNotRelative = isNotRelative;
checkPath.convert = (p) => p;

class Ignore {
  constructor({
    ignorecase = true,
    ignoreCase = ignorecase,
    allowRelativePaths = false,
  } = {}) {
    define(this, KEY_IGNORE, true);

    this._rules = [];
    this._ignoreCase = ignoreCase;
    this._allowRelativePaths = allowRelativePaths;
    this._initCache();
  }

  _initCache() {
    this._ignoreCache = Object.create(null);
    this._testCache = Object.create(null);
  }

  _addPattern(pattern) {
    // #32
    if (pattern && pattern[KEY_IGNORE]) {
      this._rules = this._rules.concat(pattern._rules);
      this._added = true;
      return;
    }

    if (checkPattern(pattern)) {
      const rule = createRule(pattern, this._ignoreCase);
      this._added = true;
      this._rules.push(rule);
    }
  }

  // @param {Array<string> | string | Ignore} pattern
  add(pattern) {
    this._added = false;

    makeArray(isString(pattern) ? splitPattern(pattern) : pattern).forEach(
      this._addPattern,
      this
    );

    // Some rules have just added to the ignore,
    // making the behavior changed.
    if (this._added) {
      this._initCache();
    }

    return this;
  }

  // legacy
  addPattern(pattern) {
    return this.add(pattern);
  }

  //          |           ignored : unignored
  // negative |   0:0   |   0:1   |   1:0   |   1:1
  // -------- | ------- | ------- | ------- | --------
  //     0    |  TEST   |  TEST   |  SKIP   |    X
  //     1    |  TESTIF |  SKIP   |  TEST   |    X

  // - SKIP: always skip
  // - TEST: always test
  // - TESTIF: only test if checkUnignored
  // - X: that never happen

  // @param {boolean} whether should check if the path is unignored,
  //   setting `checkUnignored` to `false` could reduce additional
  //   path matching.

  // @returns {TestResult} true if a file is ignored
  _testOne(path, checkUnignored) {
    let ignored = false;
    let unignored = false;

    this._rules.forEach((rule) => {
      const { negative } = rule;
      if (
        (unignored === negative && ignored !== unignored) ||
        (negative && !ignored && !unignored && !checkUnignored)
      ) {
        return;
      }

      const matched = rule.regex.test(path);

      if (matched) {
        ignored = !negative;
        unignored = negative;
      }
    });

    return {
      ignored,
      unignored,
    };
  }

  // @returns {TestResult}
  _test(originalPath, cache, checkUnignored, slices) {
    const path =
      originalPath &&
      // Supports nullable path
      checkPath.convert(originalPath);

    checkPath(
      path,
      originalPath,
      this._allowRelativePaths ? RETURN_FALSE : throwError
    );

    return this._t(path, cache, checkUnignored, slices);
  }

  _t(path, cache, checkUnignored, slices) {
    if (path in cache) {
      return cache[path];
    }

    if (!slices) {
      // path/to/a.js
      // ['path', 'to', 'a.js']
      slices = path.split(SLASH);
    }

    slices.pop();

    // If the path has no parent directory, just test it
    if (!slices.length) {
      return (cache[path] = this._testOne(path, checkUnignored));
    }

    const parent = this._t(
      slices.join(SLASH) + SLASH,
      cache,
      checkUnignored,
      slices
    );

    // If the path contains a parent directory, check the parent first
    return (cache[path] =
      parent.ignored ?
        // > It is not possible to re-include a file if a parent directory of
        // >   that file is excluded.
        parent
      : this._testOne(path, checkUnignored));
  }

  ignores(path) {
    return this._test(path, this._ignoreCache, false).ignored;
  }

  createFilter() {
    return (path) => !this.ignores(path);
  }

  filter(paths) {
    return makeArray(paths).filter(this.createFilter());
  }

  // @returns {TestResult}
  test(path) {
    return this._test(path, this._testCache, true);
  }
}

const factory = (options) => new Ignore(options);

const isPathValid = (path) =>
  checkPath(path && checkPath.convert(path), path, RETURN_FALSE);

factory.isPathValid = isPathValid;

// Fixes typescript
factory.default = factory;

module.exports = factory;

// Windows
// --------------------------------------------------------------
/* istanbul ignore if */
if (
  // Detect `process` so that it can run in browsers.
  typeof process !== 'undefined' &&
  ((process.env && process.env.IGNORE_TEST_WIN32) ||
    process.platform === 'win32')
) {
  /* eslint no-control-regex: "off" */
  const makePosix = (str) =>
    /^\\\\\?\\/.test(str) || /["<>|\u0000-\u001F]+/u.test(str) ?
      str
    : str.replace(/\\/g, '/');

  checkPath.convert = makePosix;

  // 'C:\\foo'     <- 'C:\\foo' has been converted to 'C:/'
  // 'd:\\foo'
  const REGIX_IS_WINDOWS_PATH_ABSOLUTE = /^[a-z]:\//i;
  checkPath.isNotRelative = (path) =>
    REGIX_IS_WINDOWS_PATH_ABSOLUTE.test(path) || isNotRelative(path);
}