var Cookies       = require('cookies')
var express       = require('express')
var fs            = require('fs')
var Error         = require('http-errors')
var Auth          = require('./auth')
var Logger        = require('./logger')
var Config        = require('./config')
var Middleware    = require('./middleware')
var Cats          = require('./status-cats')
var Storage       = require('./storage')
var Utils         = require('./utils')
var expect_json   = Middleware.expect_json
var media         = Middleware.media
var validate_name = Middleware.validate_name

function match(regexp) {
  return function(req, res, next, value, name) {
    if (regexp.exec(value)) {
      next()
    } else {
      next('route')
    }
  }
}

module.exports = function(config_hash) {
  var config  = Config(config_hash)
  var storage = Storage(config)
  var auth    = Auth(config)

  var can = function(action) {
    return function(req, res, next) {
      if (config['allow_'+action](req.params.package, req.remote_user)) {
        next()
      } else {
        if (!req.remote_user.name) {
          if (req.remote_user.error) {
            var message = "can't "+action+' restricted package, ' + req.remote_user.error
          } else {
            var message = "can't "+action+" restricted package without auth, did you forget 'npm set always-auth true'?"
          }
          next( Error[403](message) )
        } else {
          next( Error[403]('user ' + req.remote_user.name
                        + ' not allowed to ' + action + ' it') )
        }
      }
    }
  }

  var app = express()

  // run in production mode by default, just in case
  // it shouldn't make any difference anyway
  app.set('env', process.env.NODE_ENV || 'production')

  function error_reporting_middleware(req, res, next) {
    res.report_error = res.report_error || function(err) {
      if (err.status && err.status >= 400 && err.status < 600) {
        if (!res.headersSent) {
          res.status(err.status)
          res.send({ error: err.message || 'unknown error' })
        }
      } else {
        Logger.logger.error( { err: err }
                           , 'unexpected error: @{!err.message}\n@{err.stack}')
        if (!res.status || !res.send) {
          Logger.logger.error('this is an error in express.js, please report this')
          res.destroy()
        } else if (!res.headersSent) {
          res.status(500)
          res.send({ error: 'internal server error' })
        } else {
          // socket should be already closed
        }
      }
    }
    next()
  }

  app.use(error_reporting_middleware)
  app.use(Middleware.log_and_etagify)
  app.use(function(req, res, next) {
    res.setHeader('X-Powered-By', config.user_agent)
    next()
  })
  app.use(Cats.middleware)
  app.use(auth.auth_middleware())
  app.use(express.json({ strict: false, limit: config.max_body_size || '10mb' }))
  app.use(express.compress())
  app.use(Middleware.anti_loop(config))

  // validate all of these params as a package name
  // this might be too harsh, so ask if it causes trouble
  app.param('package',  validate_name)
  app.param('filename', validate_name)
  app.param('tag',      validate_name)
  app.param('version',  validate_name)
  app.param('revision', validate_name)

  // these can't be safely put into express url for some reason
  app.param('_rev',             match(/^-rev$/))
  app.param('org_couchdb_user', match(/^org\.couchdb\.user:/))
  app.param('anything',         match(/.*/))

/*  app.get('/-/all', function(req, res) {
    var https = require('https')
    var JSONStream = require('JSONStream')
    var request = require('request')({
      url: 'https://registry.npmjs.org/-/all',
    })
    .pipe(JSONStream.parse('*'))
    .on('data', function(d) {
      console.log(d)
    })
  })*/

  // TODO: anonymous user?
  app.get('/:package/:version?', can('access'), function(req, res, next) {
    storage.get_package(req.params.package, { req: req }, function(err, info) {
      if (err) return next(err)
      info = Utils.filter_tarball_urls(info, req, config)

      var version = req.params.version
      if (!version) return res.send(info)

      var t = Utils.get_version(info, version)
      if (t != null) return res.send(t)

      if (info['dist-tags'] != null) {
        if (info['dist-tags'][version] != null) {
          version = info['dist-tags'][version]
          if ((t = Utils.get_version(info, version)) != null) {
            return res.send(t)
          }
        }
      }

      return next( Error[404]('version not found: ' + req.params.version) )
    })
  })

  app.get('/:package/-/:filename', can('access'), function(req, res, next) {
    var stream = storage.get_tarball(req.params.package, req.params.filename)
    stream.on('content-length', function(v) {
      res.header('Content-Length', v)
    })
    stream.on('error', function(err) {
      return res.report_error(err)
    })
    res.header('Content-Type', 'application/octet-stream')
    stream.pipe(res)
  })

  // searching packages
  app.get('/-/all/:anything?', function(req, res, next) {
    storage.search(req.param.startkey || 0, {req: req}, function(err, result) {
      if (err) return next(err)
      for (var pkg in result) {
        if (!config.allow_access(pkg, req.remote_user)) {
          delete result[pkg]
        }
      }
      return res.send(result)
    })
  })

  //app.get('/*', function(req, res) {
  //  proxy.request(req, res)
  //})

  // placeholder 'cause npm require to be authenticated to publish
  // we do not do any real authentication yet
  app.post('/_session', Cookies.express(), function(req, res) {
    res.cookies.set('AuthSession', String(Math.random()), {
      // npmjs.org sets 10h expire
      expires: new Date(Date.now() + 10*60*60*1000)
    })
    res.send({ ok: true, name: 'somebody', roles: [] })
  })

  app.get('/-/user/:org_couchdb_user', function(req, res, next) {
    res.status(200)
    return res.send({
      ok: 'you are authenticated as "' + req.remote_user.name + '"',
    })
  })

  app.put('/-/user/:org_couchdb_user/:_rev?/:revision?', function(req, res, next) {
    if (req.remote_user.name != null) {
      res.status(201)
      return res.send({
        ok: 'you are authenticated as "' + req.remote_user.name + '"',
      })
    } else {
      if (typeof(req.body.name) !== 'string' || typeof(req.body.password) !== 'string') {
        if (typeof(req.body.password_sha)) {
          return next( Error[422]("your npm version is outdated\nPlease update to npm@1.4.5 or greater.\nSee https://github.com/rlidwka/sinopia/issues/93 for details.") )
        } else {
          return next( Error[422]('user/password is not found in request (npm issue?)') )
        }
      }
      auth.add_user(req.body.name, req.body.password, function(err) {
        if (err) {
          if (err.status < 500 && err.message === 'this user already exists') {
            // with npm registering is the same as logging in
            // so we replace message in case of conflict
            return next( Error[409]('bad username/password, access denied') )
          }
          return next(err)
        }

        res.status(201)
        return res.send({ ok: 'user "' + req.body.name + '" created' })
      })
    }
  })

  // tagging a package
  app.put('/:package/:tag', can('publish'), media('application/json'), function(req, res, next) {
    if (typeof(req.body) !== 'string') return next('route')

    var tags = {}
    tags[req.params.tag] = req.body
    storage.add_tags(req.params.package, tags, function(err) {
      if (err) return next(err)
      res.status(201)
      return res.send({ ok: 'package tagged' })
    })
  })

  // publishing a package
  app.put('/:package/:_rev?/:revision?', can('publish'), media('application/json'), expect_json, function(req, res, next) {
    var name = req.params.package

    if (Object.keys(req.body).length == 1 && Utils.is_object(req.body.users)) {
      // 501 status is more meaningful, but npm doesn't show error message for 5xx
      return next( Error[404]('npm star|unstar calls are not implemented') )
    }

    try {
      var metadata = Utils.validate_metadata(req.body, name)
    } catch(err) {
      return next( Error[422]('bad incoming package data') )
    }

    if (req.params._rev) {
      storage.change_package(name, metadata, req.params.revision, function(err) {
        after_change(err, 'package changed')
      })
    } else {
      storage.add_package(name, metadata, function(err) {
        after_change(err, 'created new package')
      })
    }

    function after_change(err, ok_message) {
      // old npm behaviour
      if (metadata._attachments == null) {
        if (err) return next(err)
        res.status(201)
        return res.send({ ok: ok_message })
      }

      // npm-registry-client 0.3+ embeds tarball into the json upload
      // https://github.com/isaacs/npm-registry-client/commit/e9fbeb8b67f249394f735c74ef11fe4720d46ca0
      // issue #31, dealing with it here:

      if (typeof(metadata._attachments) !== 'object'
      ||  Object.keys(metadata._attachments).length !== 1
      ||  typeof(metadata.versions) !== 'object'
      ||  Object.keys(metadata.versions).length !== 1) {

        // npm is doing something strange again
        // if this happens in normal circumstances, report it as a bug
        return next( Error[400]('unsupported registry call') )
      }

      if (err && err.status != 409) return next(err)

      // at this point document is either created or existed before
      var t1 = Object.keys(metadata._attachments)[0]
      create_tarball(t1, metadata._attachments[t1], function(err) {
        if (err) return next(err)

        var t2 = Object.keys(metadata.versions)[0]
        metadata.versions[t2].readme = metadata.readme != null ? String(metadata.readme) : ''
        create_version(t2, metadata.versions[t2], function(err) {
          if (err) return next(err)

          add_tags(metadata['dist-tags'], function(err) {
            if (err) return next(err)

            res.status(201)
            return res.send({ ok: ok_message })
          })
        })
      })
    }

    function create_tarball(filename, data, cb) {
      var stream = storage.add_tarball(name, filename)
      stream.on('error', function(err) {
        cb(err)
      })
      stream.on('success', function() {
        cb()
      })

      // this is dumb and memory-consuming, but what choices do we have?
      stream.end(Buffer(data.data, 'base64'))
      stream.done()
    }

    function create_version(version, data, cb) {
      storage.add_version(name, version, data, null, cb)
    }

    function add_tags(tags, cb) {
      storage.add_tags(name, tags, cb)
    }
  })

  // unpublishing an entire package
  app.delete('/:package/-rev/*', can('publish'), function(req, res, next) {
    storage.remove_package(req.params.package, function(err) {
      if (err) return next(err)
      res.status(201)
      return res.send({ ok: 'package removed' })
    })
  })

  // removing a tarball
  app.delete('/:package/-/:filename/-rev/:revision', can('publish'), function(req, res, next) {
    storage.remove_tarball(req.params.package, req.params.filename, req.params.revision, function(err) {
      if (err) return next(err)
      res.status(201)
      return res.send({ ok: 'tarball removed' })
    })
  })

  // uploading package tarball
  app.put('/:package/-/:filename/*', can('publish'), media('application/octet-stream'), function(req, res, next) {
    var name = req.params.package

    var stream = storage.add_tarball(name, req.params.filename)
    req.pipe(stream)

    // checking if end event came before closing
    var complete = false
    req.on('end', function() {
      complete = true
      stream.done()
    })
    req.on('close', function() {
      if (!complete) {
        stream.abort()
      }
    })

    stream.on('error', function(err) {
      return res.report_error(err)
    })
    stream.on('success', function() {
      res.status(201)
      return res.send({
        ok: 'tarball uploaded successfully'
      })
    })
  })

  // adding a version
  app.put('/:package/:version/-tag/:tag', can('publish'), media('application/json'), expect_json, function(req, res, next) {
    var name = req.params.package
    var version = req.params.version
    var tag = req.params.tag

    storage.add_version(name, version, req.body, tag, function(err) {
      if (err) return next(err)
      res.status(201)
      return res.send({ ok: 'package published' })
    })
  })

  // hook for tests only
  if (config._debug) {
    app.get('/-/_debug', function(req, res) {
      var do_gc = typeof(global.gc) !== 'undefined'
      if (do_gc) global.gc()
      res.send({
        pid  : process.pid,
        main : process.mainModule.filename,
        conf : config.self_path,
        mem  : process.memoryUsage(),
        gc   : do_gc,
      })
    })
  }

  app.use(app.router)
  app.use(function(err, req, res, next) {
    if (typeof(res.report_error) !== 'function') {
      // in case of very early error this middleware may not be loaded before error is generated
      // fixing that
      error_reporting_middleware(req, res, function(){})
    }
    res.report_error(err)
  })

  if (config.web && config.web.enable) {
    app.use(require('./index-web')(config, auth, storage))
  } else {
    app.get('/', function(req, res) {
      res.send('Web interface is disabled in the config file')
    })
  }

  return app
}