// Copyright Joyent, Inc. and other Node contributors.
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to permit
// persons to whom the Software is furnished to do so, subject to the
// following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
// USE OR OTHER DEALINGS IN THE SOFTWARE.

// https://github.com/browserify/path-browserify/blob/master/index.js

function assertPath(path: string) {
  if (typeof path !== 'string') {
    throw new TypeError('Path must be a string. Received ' + JSON.stringify(path))
  }
}

// Resolves . and .. elements in a path with directory names
function normalizeStringPosix(path: string, allowAboveRoot?: boolean) {
  let res = ''
  let lastSegmentLength = 0
  let lastSlash = -1
  let dots = 0
  let code
  for (let i = 0; i <= path.length; ++i) {
    if (i < path.length) {
      code = path.charCodeAt(i)
    } else if (code === 47 /*/*/) {
      break
    } else {
      code = 47 /*/*/
    }
    if (code === 47 /*/*/) {
      if (lastSlash === i - 1 || dots === 1) {
        // NOOP
      } else if (lastSlash !== i - 1 && dots === 2) {
        if (
          res.length < 2 ||
          lastSegmentLength !== 2 ||
          res.charCodeAt(res.length - 1) !== 46 /*.*/ ||
          res.charCodeAt(res.length - 2) !== 46 /*.*/
        ) {
          if (res.length > 2) {
            const lastSlashIndex = res.lastIndexOf('/')
            if (lastSlashIndex !== res.length - 1) {
              if (lastSlashIndex === -1) {
                res = ''
                lastSegmentLength = 0
              } else {
                res = res.slice(0, lastSlashIndex)
                lastSegmentLength = res.length - 1 - res.lastIndexOf('/')
              }
              lastSlash = i
              dots = 0
              continue
            }
          } else if (res.length === 2 || res.length === 1) {
            res = ''
            lastSegmentLength = 0
            lastSlash = i
            dots = 0
            continue
          }
        }
        if (allowAboveRoot) {
          if (res.length > 0) res += '/..'
          else res = '..'
          lastSegmentLength = 2
        }
      } else {
        if (res.length > 0) res += '/' + path.slice(lastSlash + 1, i)
        else res = path.slice(lastSlash + 1, i)
        lastSegmentLength = i - lastSlash - 1
      }
      lastSlash = i
      dots = 0
    } else if (code === 46 /*.*/ && dots !== -1) {
      ++dots
    } else {
      dots = -1
    }
  }
  return res
}

// path.resolve([from ...], to)
export function resolve(...segments: string[]) {
  let resolvedPath = ''
  let resolvedAbsolute = false

  for (let i = segments.length - 1; i >= -1 && !resolvedAbsolute; i--) {
    let path
    if (i >= 0) {
      path = segments[i]
    } else {
      path = '/'
    }

    assertPath(path)

    // Skip empty entries
    if (path.length === 0) {
      continue
    }

    resolvedPath = path + '/' + resolvedPath
    resolvedAbsolute = path.charCodeAt(0) === 47 /*/*/
  }

  // At this point the path should be resolved to a full absolute path, but
  // handle relative paths to be safe (might happen when process.cwd() fails)

  // Normalize the path
  resolvedPath = normalizeStringPosix(resolvedPath, !resolvedAbsolute)

  if (resolvedAbsolute) {
    if (resolvedPath.length > 0) {
      return '/' + resolvedPath
    }
    return '/'
  }
  if (resolvedPath.length > 0) {
    return resolvedPath
  }
  return '.'
}