'use strict'
module.exports = npa
module.exports.resolve = resolve
module.exports.toPurl = toPurl
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 log = require('proc-log')

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
      spec = '*'
    } 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)
  }
}

const defaultRegistry = 'https://registry.npmjs.org'

function toPurl (arg, reg = defaultRegistry) {
  const res = npa(arg)

  if (res.type !== 'version') {
    throw invalidPurlType(res.type, res.raw)
  }

  // URI-encode leading @ of scoped packages
  let purl = 'pkg:npm/' + res.name.replace(/^@/, '%40') + '@' + res.rawSpec
  if (reg !== defaultRegistry) {
    purl += '?repository_url=' + reg
  }

  return purl
}

function invalidPackageName (name, valid, raw) {
  // eslint-disable-next-line max-len
  const err = new Error(`Invalid package name "${name}" of package "${raw}": ${valid.errors.join('; ')}.`)
  err.code = 'EINVALIDPACKAGENAME'
  return err
}

function invalidTagName (name, raw) {
  // eslint-disable-next-line max-len
  const err = new Error(`Invalid tag name "${name}" of package "${raw}": Tags may not have any characters that encodeURIComponent encodes.`)
  err.code = 'EINVALIDTAGNAME'
  return err
}

function invalidPurlType (type, raw) {
  // eslint-disable-next-line max-len
  const err = new Error(`Invalid type "${type}" of package "${raw}": Purl can only be generated for "version" types.`)
  err.code = 'EINVALIDPURLTYPE'
  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 || ''
  this.saveSpec = opts.saveSpec
  this.fetchSpec = opts.fetchSpec
  if (opts.name) {
    this.setName(opts.name)
  }
  this.gitRange = opts.gitRange
  this.gitCommittish = opts.gitCommittish
  this.gitSubdir = opts.gitSubdir
  this.hosted = opts.hosted
}

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

  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
}

// sets res.gitCommittish, res.gitRange, and res.gitSubdir
function setGitAttrs (res, committish) {
  if (!committish) {
    res.gitCommittish = null
    return
  }

  // for each :: separated item:
  for (const part of committish.split('::')) {
    // if the item has no : the n it is a commit-ish
    if (!part.includes(':')) {
      if (res.gitRange) {
        throw new Error('cannot override existing semver range with a committish')
      }
      if (res.gitCommittish) {
        throw new Error('cannot override existing committish with a second committish')
      }
      res.gitCommittish = part
      continue
    }
    // split on name:value
    const [name, value] = part.split(':')
    // if name is semver do semver lookup of ref or tag
    if (name === 'semver') {
      if (res.gitCommittish) {
        throw new Error('cannot override existing committish with a semver range')
      }
      if (res.gitRange) {
        throw new Error('cannot override existing semver range with a second semver range')
      }
      res.gitRange = decodeURIComponent(value)
      continue
    }
    if (name === 'path') {
      if (res.gitSubdir) {
        throw new Error('cannot override existing path with a second path')
      }
      res.gitSubdir = `/${value}`
      continue
    }
    log.warn('npm-package-arg', `ignoring unknown key "${name}"`)
  }
}

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/bar/foo

  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(rawWithPrefix, `file://${path.resolve(where)}/`)
    specUrl = new URL(rawWithPrefix)
  } catch (originalError) {
    const er = new Error('Invalid file: URL, must comply with RFC 8089')
    throw Object.assign(er, {
      raw: res.rawSpec,
      spec: res,
      where,
      originalError,
    })
  }

  // XXX backwards compatibility lack of compliance with RFC 8089
  if (resolvedUrl.host && resolvedUrl.host !== 'localhost') {
    const rawSpec = res.rawSpec.replace(/^file:\/\//, 'file:///')
    resolvedUrl = new URL(rawSpec, `file://${path.resolve(where)}/`)
    specUrl = new URL(rawSpec)
    rawNoPrefix = rawSpec.replace(/^file:/, '')
  }
  // turn file:/../foo into file:../foo
  // for 1, 2 or 3 leading slashes since we attempted
  // in the previous step to make it a file protocol url with a leading slash
  if (/^\/{1,3}\.\.?(\/|$)/.test(rawNoPrefix)) {
    const rawSpec = res.rawSpec.replace(/^file:\/{1,3}/, 'file:')
    resolvedUrl = new URL(rawSpec, `file://${path.resolve(where)}/`)
    specUrl = new URL(rawSpec)
    rawNoPrefix = rawSpec.replace(/^file:/, '')
  }
  // XXX end RFC 8089 violation backwards compatibility section

  // 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()
  setGitAttrs(res, hosted.committish)
  return res
}

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

function fromURL (res) {
  let rawSpec = res.rawSpec
  res.saveSpec = rawSpec
  if (rawSpec.startsWith('git+ssh:')) {
    // 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.

    // 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 = rawSpec.match(/^git\+ssh:\/\/([^:#]+:[^#]+(?:\.git)?)(?:#(.*))?$/i)
    if (matched && !matched[1].match(/:[0-9]+\/?.*$/i)) {
      res.type = 'git'
      setGitAttrs(res, matched[2])
      res.fetchSpec = matched[1]
      return res
    }
  } else if (rawSpec.startsWith('git+file://')) {
    // URL can't handle windows paths
    rawSpec = rawSpec.replace(/\\/g, '/')
  }
  const parsedUrl = new URL(rawSpec)
  // check the protocol, and then see if it's git or not
  switch (parsedUrl.protocol) {
    case 'git:':
    case 'git+http:':
    case 'git+https:':
    case 'git+rsync:':
    case 'git+ftp:':
    case 'git+file:':
    case 'git+ssh:':
      res.type = 'git'
      setGitAttrs(res, parsedUrl.hash.slice(1))
      if (parsedUrl.protocol === 'git+file:' && /^git\+file:\/\/[a-z]:/i.test(rawSpec)) {
        // URL can't handle drive letters on windows file paths, the host can't contain a :
        res.fetchSpec = `git+file://${parsedUrl.host.toLowerCase()}:${parsedUrl.pathname}`
      } else {
        parsedUrl.hash = ''
        res.fetchSpec = parsedUrl.toString()
      }
      if (res.fetchSpec.startsWith('git+')) {
        res.fetchSpec = res.fetchSpec.slice(4)
      }
      break
    case 'http:':
    case 'https:':
      res.type = 'remote'
      res.fetchSpec = res.saveSpec
      break

    default:
      throw unsupportedURLType(parsedUrl.protocol, 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.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.raw)
    }
    res.type = 'tag'
  }
  return res
}