// Original at https://github.com/fitzgen/glob-to-regexp

/*
Copyright (c) 2013, Nick Fitzgerald

All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

    Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.

    Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/

export function globToRegExp(glob: string, opts?: any) {
  if (typeof glob !== 'string')
    throw new TypeError('Expected a string')

  const str = String(glob)

  // The regexp we are building, as a string.
  let reStr = ''

  // Whether we are matching so called "extended" globs (like bash) and should
  // support single character matching, matching ranges of characters, group
  // matching, etc.
  const extended = opts ? !!opts.extended : false

  // When globstar is _false_ (default), '/foo/*' is translated a regexp like
  // '^\/foo\/.*$' which will match any string beginning with '/foo/'
  // When globstar is _true_, '/foo/*' is translated to regexp like
  // '^\/foo\/[^/]*$' which will match any string beginning with '/foo/' BUT
  // which does not have a '/' to the right of it.
  // E.g. with '/foo/*' these will match: '/foo/bar', '/foo/bar.txt' but
  // these will not '/foo/bar/baz', '/foo/bar/baz.txt'
  // Lastely, when globstar is _true_, '/foo/**' is equivelant to '/foo/*' when
  // globstar is _false_
  const globstar = opts ? !!opts.globstar : false

  // If we are doing extended matching, this boolean is true when we are inside
  // a group (eg {*.html,*.js}), and false otherwise.
  let inGroup = false

  // RegExp flags (eg "i" ) to pass in to RegExp constructor.
  const flags = (opts && typeof (opts.flags) === 'string') ? opts.flags : ''

  let c
  for (let i = 0, len = str.length; i < len; i++) {
    c = str[i]

    switch (c) {
      case '/':
      case '$':
      case '^':
      case '+':
      case '.':
      case '(':
      case ')':
      case '=':
      case '!':
      case '|':
        reStr += `\\${c}`
        break

      case '?':
        if (extended)
          reStr += '.'
        break

      case '[':
      case ']':
        if (extended)
          reStr += c

        break

      case '{':
        if (extended) {
          inGroup = true
          reStr += '('
        }
        break

      case '}':
        if (extended) {
          inGroup = false
          reStr += ')'
        }
        break

      case ',':
        if (inGroup)
          reStr += '|'
        else
          reStr += `\\${c}`
        break

      case '*':
        {
          // Move over all consecutive "*"'s.
          // Also store the previous and next characters
          const prevChar = str[i - 1]
          let starCount = 1
          while (str[i + 1] === '*') {
            starCount++
            i++
          }
          const nextChar = str[i + 1]

          if (!globstar) {
            // globstar is disabled, so treat any number of "*" as one
            reStr += '.*'
          }
          else {
            // globstar is enabled, so determine if this is a globstar segment
            const isGlobstar = starCount > 1 // multiple "*"'s
              && (prevChar === '/' || prevChar === undefined) // from the start of the segment
              && (nextChar === '/' || nextChar === undefined) // to the end of the segment

            if (isGlobstar) {
              // it's a globstar, so match zero or more path segments
              reStr += '((?:[^/]*(?:\/|$))*)'
              i++ // move over the "/"
            }
            else {
              // it's not a globstar, so only match one path segment
              reStr += '([^/]*)'
            }
          }
        }
        break

      default:
        reStr += c
    }
  }

  // When regexp 'g' flag is specified don't
  // constrain the regular expression with ^ & $
  if (!flags || !flags.includes('g'))
    reStr = `^${reStr}$`

  return new RegExp(reStr, flags)
}