const xtend = require('xtend')
const jwt = require('jsonwebtoken')
const UnauthorizedError = require('./UnauthorizedError')

function noQsMethod (options) {
  const defaults = { required: true }
  options = xtend(defaults, options)

  return (socket) => {
    'use strict' // Node 4.x workaround
    const server = this.server || socket.server

    if (!server.$emit) {
      //then is socket.io 1.0
      const Namespace = Object.getPrototypeOf(server.sockets).constructor
      if (!~Namespace.events.indexOf('authenticated')) {
        Namespace.events.push('authenticated')
      }
    }

    let auth_timeout = null
    if (options.required) {
      auth_timeout = setTimeout(() => {
        socket.disconnect('unauthorized')
      }, options.timeout || 5000)
    }

    socket.on('authenticate', (data) => {
      if (options.required) {
        clearTimeout(auth_timeout)
      }

      // error handler
      const onError = (err, code) => {
        if (err) {
          code = code || 'unknown'
          const error = new UnauthorizedError(code, {
            message:
              Object.prototype.toString.call(err) === '[object Object]' &&
              err.message
                ? err.message
                : err
          })

          let callback_timeout
          // If callback explicitly set to false, start timeout to disconnect socket
          if (
            options.callback === false ||
            typeof options.callback === 'number'
          ) {
            if (typeof options.callback === 'number') {
              if (options.callback < 0) {
                // If callback is negative(invalid value), make it positive
                options.callback = Math.abs(options.callback)
              }
            }

            callback_timeout = setTimeout(
              () => {
                socket.disconnect('unauthorized')
              },
              options.callback === false ? 0 : options.callback
            )
          }

          socket.emit('unauthorized', error, () => {
            if (typeof options.callback === 'number') {
              clearTimeout(callback_timeout)
            }
            socket.disconnect('unauthorized')
          })
          return // stop logic, socket will be close on next tick
        }
      }

      const token = options.cookie
        ? socket.request.cookies[options.cookie]
        : data
        ? data.token
        : undefined

      if (!token || typeof token !== 'string') {
        return onError({ message: 'invalid token datatype' }, 'invalid_token')
      }

      // Store encoded JWT
      socket[options.encodedPropertyName] = token

      const onJwtVerificationReady = (err, decoded) => {
        if (err) {
          return onError(err, 'invalid_token')
        }

        // success handler
        const onSuccess = () => {
          socket[options.decodedPropertyName] = options.customDecoded
            ? options.customDecoded(decoded)
            : decoded
          socket.emit('authenticated')
          if (server.$emit) {
            server.$emit('authenticated', socket)
          } else {
            //try getting the current namespace otherwise fallback to all sockets.
            const namespace =
              (server.nsps && socket.nsp && server.nsps[socket.nsp.name]) ||
              server.sockets

            // explicit namespace
            namespace.emit('authenticated', socket)
          }
        }

        if (
          options.additional_auth &&
          typeof options.additional_auth === 'function'
        ) {
          options.additional_auth(decoded, onSuccess, onError)
        } else {
          onSuccess()
        }
      }

      const onSecretReady = (err, secret) => {
        if (err || !secret) {
          return onError(err, 'invalid_secret')
        }

        jwt.verify(token, secret, options, onJwtVerificationReady)
      }

      getSecret(socket.request, options.secret, token, onSecretReady)
    })
  }
}

function authorize (options) {
  options = xtend(
    {
      decodedPropertyName: 'decoded_token',
      encodedPropertyName: 'encoded_token'
    },
    options
  )

  if (
    typeof options.secret !== 'string' &&
    typeof options.secret !== 'function'
  ) {
    throw new Error(
      `Provided secret ${options.secret} is invalid, must be of type string or function.`
    )
  }

  if (!options.handshake) {
    return noQsMethod(options)
  }

  const defaults = {
    success: (socket, accept) => {
      if (socket.request) {
        accept()
      } else {
        accept(null, true)
      }
    },
    fail: (error, socket, accept) => {
      if (socket.request) {
        accept(error)
      } else {
        accept(null, false)
      }
    }
  }

  const auth = xtend(defaults, options)

  return (socket, accept) => {
    'use strict' // Node 4.x workaround
    let token, error

    const handshake = socket.handshake
    const req = socket.request || socket
    const authorization_header = (req.headers || {}).authorization

    if (authorization_header) {
      const parts = authorization_header.split(' ')
      if (parts.length == 2) {
        const scheme = parts[0],
          credentials = parts[1]

        if (scheme.toLowerCase() === 'bearer') {
          token = credentials
        }
      } else {
        error = new UnauthorizedError('credentials_bad_format', {
          message: 'Format is Authorization: Bearer [token]'
        })
        return auth.fail(error, socket, accept)
      }
    }

    // Check if the header has to include authentication
    if (options.auth_header_required && !token) {
      return auth.fail(
        new UnauthorizedError('missing_authorization_header', {
          message: 'Server requires Authorization Header'
        }),
        socket,
        accept
      )
    }

    // Get the token from handshake or query string
    if (handshake && handshake.query.token) {
      token = handshake.query.token
    } else if (req._query && req._query.token) {
      token = req._query.token
    } else if (req.query && req.query.token) {
      token = req.query.token
    }

    if (!token) {
      error = new UnauthorizedError('credentials_required', {
        message: 'no token provided'
      })
      return auth.fail(error, socket, accept)
    }

    // Store encoded JWT
    socket[options.encodedPropertyName] = token

    const onJwtVerificationReady = (err, decoded) => {
      if (err) {
        error = new UnauthorizedError(err.code || 'invalid_token', err)
        return auth.fail(error, socket, accept)
      }

      socket[options.decodedPropertyName] = options.customDecoded
        ? options.customDecoded(decoded)
        : decoded

      return auth.success(socket, accept)
    }

    const onSecretReady = (err, secret) => {
      if (err) {
        error = new UnauthorizedError(err.code || 'invalid_secret', err)
        return auth.fail(error, socket, accept)
      }

      jwt.verify(token, secret, options, onJwtVerificationReady)
    }

    getSecret(req, options.secret, token, onSecretReady)
  }
}

function getSecret (request, secret, token, callback) {
  'use strict' // Node 4.x workaround

  if (typeof secret === 'function') {
    if (!token) {
      return callback({
        code: 'invalid_token',
        message: 'jwt must be provided'
      })
    }

    const parts = token.split('.')

    if (parts.length < 3) {
      return callback({ code: 'invalid_token', message: 'jwt malformed' })
    }

    if (parts[2].trim() === '') {
      return callback({
        code: 'invalid_token',
        message: 'jwt signature is required'
      })
    }

    let decodedToken = jwt.decode(token, { complete: true })

    if (!decodedToken) {
      return callback({ code: 'invalid_token', message: 'jwt malformed' })
    }

    const arity = secret.length
    if (arity == 4) {
      secret(request, decodedToken.header, decodedToken.payload, callback)
    } else {
      // arity == 3
      secret(request, decodedToken.payload, callback)
    }
  } else {
    callback(null, secret)
  }
}

exports.authorize = authorize
exports.UnauthorizedError = UnauthorizedError