'use strict'
module.exports = npa
module.exports.resolve = resolve
module.exports.Result = Result

const url = require('url')
const HostedGit = require('hosted-git-info')
const semver = require('semver')
const path = global.FAKE_WINDOWS ? require('path').win32 : require('path')
const validatePackageName = require('validate-npm-package-name')
const { homedir } = require('os')

const isWindows = process.platform === 'win32' || global.FAKE_WINDOWS
const hasSlashes = isWindows ? /\\|[/]/ : /[/]/
const isURL = /^(?:git[+])?[a-z]+:/i
const isGit = /^[^@]+@[^:.]+\.[^:]+:.+$/i
const isFilename = /[.](?:tgz|tar.gz|tar)$/i

function npa (arg, where) {
  let name
  let spec
  if (typeof arg === 'object') {
    if (arg instanceof Result && (!where || where === arg.where))
      return arg
    else if (arg.name && arg.rawSpec)
      return npa.resolve(arg.name, arg.rawSpec, where || arg.where)
    else
      return npa(arg.raw, where || arg.where)
  }
  const nameEndsAt = arg[0] === '@' ? arg.slice(1).indexOf('@') + 1 : arg.indexOf('@')
  const namePart = nameEndsAt > 0 ? arg.slice(0, nameEndsAt) : arg
  if (isURL.test(arg))
    spec = arg
  else if (isGit.test(arg))
    spec = `git+ssh://${arg}`
  else if (namePart[0] !== '@' && (hasSlashes.test(namePart) || isFilename.test(namePart)))
    spec = arg
  else if (nameEndsAt > 0) {
    name = namePart
    spec = arg.slice(nameEndsAt + 1)
  } else {
    const valid = validatePackageName(arg)
    if (valid.validForOldPackages)
      name = arg
    else
      spec = arg
  }
  return resolve(name, spec, where, arg)
}

const isFilespec = isWindows ? /^(?:[.]|~[/]|[/\\]|[a-zA-Z]:)/ : /^(?:[.]|~[/]|[/]|[a-zA-Z]:)/

function resolve (name, spec, where, arg) {
  const res = new Result({
    raw: arg,
    name: name,
    rawSpec: spec,
    fromArgument: arg != null,
  })

  if (name)
    res.setName(name)

  if (spec && (isFilespec.test(spec) || /^file:/i.test(spec)))
    return fromFile(res, where)
  else if (spec && /^npm:/i.test(spec))
    return fromAlias(res, where)

  const hosted = HostedGit.fromUrl(spec, {
    noGitPlus: true,
    noCommittish: true,
  })
  if (hosted)
    return fromHostedGit(res, hosted)
  else if (spec && isURL.test(spec))
    return fromURL(res)
  else if (spec && (hasSlashes.test(spec) || isFilename.test(spec)))
    return fromFile(res, where)
  else
    return fromRegistry(res)
}

function invalidPackageName (name, valid) {
  const err = new Error(`Invalid package name "${name}": ${valid.errors.join('; ')}`)
  err.code = 'EINVALIDPACKAGENAME'
  return err
}
function invalidTagName (name) {
  const err = new Error(`Invalid tag name "${name}": Tags may not have any characters that encodeURIComponent encodes.`)
  err.code = 'EINVALIDTAGNAME'
  return err
}

function Result (opts) {
  this.type = opts.type
  this.registry = opts.registry
  this.where = opts.where
  if (opts.raw == null)
    this.raw = opts.name ? opts.name + '@' + opts.rawSpec : opts.rawSpec
  else
    this.raw = opts.raw

  this.name = undefined
  this.escapedName = undefined
  this.scope = undefined
  this.rawSpec = opts.rawSpec == null ? '' : opts.rawSpec
  this.saveSpec = opts.saveSpec
  this.fetchSpec = opts.fetchSpec
  if (opts.name)
    this.setName(opts.name)
  this.gitRange = opts.gitRange
  this.gitCommittish = opts.gitCommittish
  this.hosted = opts.hosted
}

Result.prototype.setName = function (name) {
  const valid = validatePackageName(name)
  if (!valid.validForOldPackages)
    throw invalidPackageName(name, valid)

  this.name = name
  this.scope = name[0] === '@' ? name.slice(0, name.indexOf('/')) : undefined
  // scoped packages in couch must have slash url-encoded, e.g. @foo%2Fbar
  this.escapedName = name.replace('/', '%2f')
  return this
}

Result.prototype.toString = function () {
  const full = []
  if (this.name != null && this.name !== '')
    full.push(this.name)
  const spec = this.saveSpec || this.fetchSpec || this.rawSpec
  if (spec != null && spec !== '')
    full.push(spec)
  return full.length ? full.join('@') : this.raw
}

Result.prototype.toJSON = function () {
  const result = Object.assign({}, this)
  delete result.hosted
  return result
}

function setGitCommittish (res, committish) {
  if (committish != null && committish.length >= 7 && committish.slice(0, 7) === 'semver:') {
    res.gitRange = decodeURIComponent(committish.slice(7))
    res.gitCommittish = null
  } else
    res.gitCommittish = committish === '' ? null : committish

  return res
}

function fromFile (res, where) {
  if (!where)
    where = process.cwd()
  res.type = isFilename.test(res.rawSpec) ? 'file' : 'directory'
  res.where = where

  // always put the '/' on where when resolving urls, or else
  // file:foo from /path/to/bar goes to /path/to/foo, when we want
  // it to be /path/to/foo/bar

  let specUrl
  let resolvedUrl
  const prefix = (!/^file:/.test(res.rawSpec) ? 'file:' : '')
  const rawWithPrefix = prefix + res.rawSpec
  let rawNoPrefix = rawWithPrefix.replace(/^file:/, '')
  try {
    resolvedUrl = new url.URL(rawWithPrefix, `file://${path.resolve(where)}/`)
    specUrl = new url.URL(rawWithPrefix)
  } catch (originalError) {
    const er = new Error('Invalid file: URL, must comply with RFC 8909')
    throw Object.assign(er, {
      raw: res.rawSpec,
      spec: res,
      where,
      originalError,
    })
  }

  // environment switch for testing
  if (process.env.NPM_PACKAGE_ARG_8909_STRICT !== '1') {
    // XXX backwards compatibility lack of compliance with 8909
    // Remove when we want a breaking change to come into RFC compliance.
    if (resolvedUrl.host && resolvedUrl.host !== 'localhost') {
      const rawSpec = res.rawSpec.replace(/^file:\/\//, 'file:///')
      resolvedUrl = new url.URL(rawSpec, `file://${path.resolve(where)}/`)
      specUrl = new url.URL(rawSpec)
      rawNoPrefix = rawSpec.replace(/^file:/, '')
    }
    // turn file:/../foo into file:../foo
    if (/^\/\.\.?(\/|$)/.test(rawNoPrefix)) {
      const rawSpec = res.rawSpec.replace(/^file:\//, 'file:')
      resolvedUrl = new url.URL(rawSpec, `file://${path.resolve(where)}/`)
      specUrl = new url.URL(rawSpec)
      rawNoPrefix = rawSpec.replace(/^file:/, '')
    }
    // XXX end 8909 violation backwards compatibility section
  }

  // file:foo - relative url to ./foo
  // file:/foo - absolute path /foo
  // file:///foo - absolute path to /foo, no authority host
  // file://localhost/foo - absolute path to /foo, on localhost
  // file://foo - absolute path to / on foo host (error!)
  if (resolvedUrl.host && resolvedUrl.host !== 'localhost') {
    const msg = `Invalid file: URL, must be absolute if // present`
    throw Object.assign(new Error(msg), {
      raw: res.rawSpec,
      parsed: resolvedUrl,
    })
  }

  // turn /C:/blah into just C:/blah on windows
  let specPath = decodeURIComponent(specUrl.pathname)
  let resolvedPath = decodeURIComponent(resolvedUrl.pathname)
  if (isWindows) {
    specPath = specPath.replace(/^\/+([a-z]:\/)/i, '$1')
    resolvedPath = resolvedPath.replace(/^\/+([a-z]:\/)/i, '$1')
  }

  // replace ~ with homedir, but keep the ~ in the saveSpec
  // otherwise, make it relative to where param
  if (/^\/~(\/|$)/.test(specPath)) {
    res.saveSpec = `file:${specPath.substr(1)}`
    resolvedPath = path.resolve(homedir(), specPath.substr(3))
  } else if (!path.isAbsolute(rawNoPrefix))
    res.saveSpec = `file:${path.relative(where, resolvedPath)}`
  else
    res.saveSpec = `file:${path.resolve(resolvedPath)}`

  res.fetchSpec = path.resolve(where, resolvedPath)
  return res
}

function fromHostedGit (res, hosted) {
  res.type = 'git'
  res.hosted = hosted
  res.saveSpec = hosted.toString({ noGitPlus: false, noCommittish: false })
  res.fetchSpec = hosted.getDefaultRepresentation() === 'shortcut' ? null : hosted.toString()
  return setGitCommittish(res, hosted.committish)
}

function unsupportedURLType (protocol, spec) {
  const err = new Error(`Unsupported URL Type "${protocol}": ${spec}`)
  err.code = 'EUNSUPPORTEDPROTOCOL'
  return err
}

function matchGitScp (spec) {
  // git ssh specifiers are overloaded to also use scp-style git
  // specifiers, so we have to parse those out and treat them special.
  // They are NOT true URIs, so we can't hand them to `url.parse`.
  //
  // This regex looks for things that look like:
  // git+ssh://git@my.custom.git.com:username/project.git#deadbeef
  //
  // ...and various combinations. The username in the beginning is *required*.
  const matched = spec.match(/^git\+ssh:\/\/([^:#]+:[^#]+(?:\.git)?)(?:#(.*))?$/i)
  return matched && !matched[1].match(/:[0-9]+\/?.*$/i) && {
    fetchSpec: matched[1],
    gitCommittish: matched[2] == null ? null : matched[2],
  }
}

function fromURL (res) {
  // eslint-disable-next-line node/no-deprecated-api
  const urlparse = url.parse(res.rawSpec)
  res.saveSpec = res.rawSpec
  // check the protocol, and then see if it's git or not
  switch (urlparse.protocol) {
    case 'git:':
    case 'git+http:':
    case 'git+https:':
    case 'git+rsync:':
    case 'git+ftp:':
    case 'git+file:':
    case 'git+ssh:': {
      res.type = 'git'
      const match = urlparse.protocol === 'git+ssh:' ? matchGitScp(res.rawSpec)
        : null
      if (match) {
        setGitCommittish(res, match.gitCommittish)
        res.fetchSpec = match.fetchSpec
      } else {
        setGitCommittish(res, urlparse.hash != null ? urlparse.hash.slice(1) : '')
        urlparse.protocol = urlparse.protocol.replace(/^git[+]/, '')
        if (urlparse.protocol === 'file:' && /^git\+file:\/\/[a-z]:/i.test(res.rawSpec)) {
          // keep the drive letter : on windows file paths
          urlparse.host += ':'
          urlparse.hostname += ':'
        }
        delete urlparse.hash
        res.fetchSpec = url.format(urlparse)
      }
      break
    }
    case 'http:':
    case 'https:':
      res.type = 'remote'
      res.fetchSpec = res.saveSpec
      break

    default:
      throw unsupportedURLType(urlparse.protocol, res.rawSpec)
  }

  return res
}

function fromAlias (res, where) {
  const subSpec = npa(res.rawSpec.substr(4), where)
  if (subSpec.type === 'alias')
    throw new Error('nested aliases not supported')

  if (!subSpec.registry)
    throw new Error('aliases only work for registry deps')

  res.subSpec = subSpec
  res.registry = true
  res.type = 'alias'
  res.saveSpec = null
  res.fetchSpec = null
  return res
}

function fromRegistry (res) {
  res.registry = true
  const spec = res.rawSpec === '' ? 'latest' : res.rawSpec.trim()
  // no save spec for registry components as we save based on the fetched
  // version, not on the argument so this can't compute that.
  res.saveSpec = null
  res.fetchSpec = spec
  const version = semver.valid(spec, true)
  const range = semver.validRange(spec, true)
  if (version)
    res.type = 'version'
  else if (range)
    res.type = 'range'
  else {
    if (encodeURIComponent(spec) !== spec)
      throw invalidTagName(spec)

    res.type = 'tag'
  }
  return res
}