import qs from 'querystring'
import oauth from 'oauth-libre'
import { v1 as uuidV1 } from 'uuid'
import crypto from 'crypto'

import config from '../../scripts/load-config'
import http from '../../scripts/http'
import models from './models'
import Image from './image'
import UAPI from './index'

const userFields = ['username', 'email', 'avatar_file', 'display_name', 'ip_address']

let twitterApp
let discordApp

const API = {
  Common: {
    // Generate a hash based on the current session
    stateGenerator: (req) => {
      const sessionCrypto = req.session.id + ':' + config.server.session_secret
      return crypto.createHash('sha256').update(sessionCrypto).digest('hex')
    },
    // Find an user with an external ID
    getExternal: async (service, identifier) => {
      let extr = await models.External.query().where('service', service).andWhere('identifier', identifier)
      if (!extr || !extr.length) return null
      extr = extr[0]
      extr.user = null

      if (extr.user_id !== null) {
        const user = await UAPI.User.get(extr.user_id)
        if (user) {
          extr.user = user
        }
      }

      return extr
    },
    // Get user ban status
    getBan: async (user, ipAddress) => {
      const banList = await UAPI.User.getBanStatus(ipAddress || user.id, ipAddress != null)
      return banList
    },
    // Create a new `external` instance for a user
    new: async (service, identifier, user) => {
      const data = {
        user_id: user.id,
        service: service,
        identifier: identifier,
        created_at: new Date()
      }

      await await models.External.query().insert(data)
      return true
    },
    // Create a new user
    newUser: async (service, identifier, data) => {
      if (config.external.registrations !== true) throw new Error('Registrations from third-party websites are not allowed.')
      const udataLimited = Object.assign({
        activated: 1,
        created_at: new Date(),
        updated_at: new Date(),
        uuid: uuidV1()
      }, data)

      // Some data cleanups

      // Limit display name length
      udataLimited.display_name = udataLimited.display_name.substring(0, 32)

      // Remove illegal characters from the username
      udataLimited.username = udataLimited.username.replace(/\W+/gi, '')

      // Limit user name length
      udataLimited.username = udataLimited.username.substring(0, 26)

      // Check if the username is already taken
      if (await UAPI.User.get(udataLimited.username) != null || udataLimited.username.length < 4) {
        udataLimited.username = udataLimited.username + UAPI.Hash(4)
      }

      // Check if the email given to us is already registered, if so,
      // tell them to log in first.
      if (udataLimited.email && udataLimited.email !== '') {
        const getByEmail = await UAPI.User.get(udataLimited.email)
        if (getByEmail) {
          throw new Error('An user with this email address is already registered, but this external account is are not linked. If you wish to link the account, please log in first.')
        }
      }

      // Create a new user based on the information we got from an external service
      const newUser = await models.User.query().insert(udataLimited)
      await API.Common.new(service, identifier, newUser)

      return newUser
    },
    // Remove an `external` object (thus unlinking from a service)
    remove: async (user, service) => {
      user = await UAPI.User.ensureObject(user, ['password'])
      const userExterns = await models.External.query().orderBy('created_at', 'asc').where('user_id', user.id)

      if (!userExterns.length) {
        return false
      }

      // Do not remove the service the user signed up with
      if (userExterns[0] && (user.password === '' || user.password === null) && userExterns[0].service === service) {
        return false
      }

      return models.External.query().delete().where('user_id', user.id).andWhere('service', service)
    },
    // Common code for all auth callbacks
    callback: async (identifier, uid, user, ipAddress, remoteData, avatarFunc) => {
      const exists = await API.Common.getExternal(identifier, uid)

      if (user) {
        // Get bans for user
        const bans = await API.Common.getBan(user)
        if (bans.length) return { banned: bans, ip: false }

        if (exists) return { error: null, user: user }

        await API.Common.new(identifier, uid, user)
        return { error: null, user: user }
      }

      // Callback succeeded with user id and the external table exists, we log in the user
      if (exists) {
        // Get bans for user
        const bans = await API.Common.getBan(exists.user)

        if (bans.length) return { banned: bans, ip: false }
        return { error: null, user: exists.user }
      }

      // Get bans for IP address
      const bans = await API.Common.getBan(null, ipAddress)
      if (bans.length) return { banned: bans, ip: true }

      // Run the function for avatar fetching
      let avatar = null
      if (avatarFunc) {
        avatar = await avatarFunc(remoteData)
      }

      // Assign the data
      const newUData = Object.assign({
        email: remoteData.email || '',
        avatar_file: avatar,
        ip_address: ipAddress
      }, remoteData)

      // Remove unnecessary fields
      for (const i in newUData) {
        if (userFields.indexOf(i) === -1) {
          delete newUData[i]
        }
      }

      let newUser
      try {
        newUser = await API.Common.newUser(identifier, uid, newUData)
      } catch (e) {
        return { error: e.message }
      }

      return { error: null, user: newUser }
    }
  },
  Facebook: {
    getAvatar: async (rawData) => {
      let profilepic = null

      if (rawData.picture) {
        if (rawData.picture.is_silhouette === false && rawData.picture.url) {
          const imgdata = await Image.downloadImage(rawData.picture.url)
          if (imgdata && imgdata.fileName) {
            profilepic = imgdata.fileName
          }
        }
      }

      return profilepic
    },
    callback: async (user, authResponse, ipAddress) => {
      if (!authResponse) {
        return { error: 'No Authorization' }
      }

      const uid = authResponse.userID
      if (!uid) {
        return { error: 'No Authorization' }
      }

      // Get facebook user information in order to create a new user or verify
      let fbdata
      const intel = {
        access_token: authResponse.accessToken,
        fields: 'name,email,picture,short_name'
      }

      try {
        fbdata = await http.GET('https://graph.facebook.com/v2.10/' + uid + '?' + qs.stringify(intel))
        fbdata = JSON.parse(fbdata)
      } catch (e) {
        return { error: 'Could not get user information', errorObject: e }
      }

      if (fbdata.error) {
        return { error: fbdata.error.message }
      }

      const cleanedData = Object.assign(fbdata, {
        username: fbdata.short_name || 'FB' + UAPI.Hash(4),
        display_name: fbdata.name,
        email: fbdata.email || ''
      })

      return API.Common.callback('facebook', uid, user, ipAddress, cleanedData, API.Facebook.getAvatar)
    }
  },
  Twitter: {
    getAvatar: async function (rawData) {
      let profilepic = null

      if (rawData.profile_image_url_https) {
        const imgdata = await Image.downloadImage(rawData.profile_image_url_https)
        if (imgdata && imgdata.fileName) {
          profilepic = imgdata.fileName
        }
      }

      return profilepic
    },
    oauthApp: function () {
      if (!twitterApp) {
        const redirectUri = config.server.domain + '/api/external/twitter/callback'
        twitterApp = new oauth.PromiseOAuth(
          'https://api.twitter.com/oauth/request_token',
          'https://api.twitter.com/oauth/access_token',
          config.external.twitter.api,
          config.external.twitter.api_secret,
          '1.0A',
          redirectUri,
          'HMAC-SHA1'
        )
      }
    },
    getRequestToken: async function () {
      if (!twitterApp) API.Twitter.oauthApp()
      let tokens

      try {
        tokens = await twitterApp.getOAuthRequestToken()
      } catch (e) {
        console.error(e)
        return { error: 'No tokens returned' }
      }

      if (tokens[2].oauth_callback_confirmed !== 'true') return { error: 'No tokens returned.' }

      return { error: null, token: tokens[0], token_secret: tokens[1] }
    },
    getAccessTokens: async function (token, secret, verifier) {
      if (!twitterApp) API.Twitter.oauthApp()
      let tokens

      try {
        tokens = await twitterApp.getOAuthAccessToken(token, secret, verifier)
      } catch (e) {
        console.error(e)
        return { error: 'No tokens returned' }
      }

      if (!tokens || !tokens.length) return { error: 'No tokens returned' }

      return { error: null, access_token: tokens[0], access_token_secret: tokens[1] }
    },
    callback: async function (user, accessTokens, ipAddress) {
      if (!twitterApp) API.Twitter.oauthApp()
      let twdata
      try {
        const resp = await twitterApp.get('https://api.twitter.com/1.1/account/verify_credentials.json?include_email=true',
          accessTokens.access_token, accessTokens.access_token_secret)
        twdata = JSON.parse(resp[0])
      } catch (e) {
        console.error(e)
        return { error: 'Failed to verify user credentials.' }
      }

      const uid = twdata.id_str

      const cleanedData = Object.assign(twdata, {
        username: twdata.screen_name,
        display_name: twdata.name,
        email: twdata.email || ''
      })

      return API.Common.callback('twitter', uid, user, ipAddress, cleanedData, API.Twitter.getAvatar)
    }
  },
  Google: {
    getAvatar: async (rawData) => {
      let profilepic = null
      if (rawData.image) {
        const imgdata = await Image.downloadImage(rawData.image)
        if (imgdata && imgdata.fileName) {
          profilepic = imgdata.fileName
        }
      }

      return profilepic
    },
    callback: async (user, data, ipAddress) => {
      let uid

      try {
        const test = await http.GET('https://www.googleapis.com/oauth2/v3/tokeninfo?id_token=' + data.id_token)
        if (!test) throw new Error('No response!')

        const jsondata = JSON.parse(test)
        if (!jsondata || !jsondata.email || !jsondata.name) throw new Error('Please allow Basic Profile and Email.')

        if (jsondata.email !== data.email || jsondata.name !== data.name) throw new Error('Conflicting data. Please try again!')

        if (new Date(parseInt(jsondata.exp) * 1000) < Date.now()) throw new Error('Expired token! Please try again!')

        uid = jsondata.sub
      } catch (e) {
        return { error: e.message }
      }

      const cleanedData = Object.assign(data, {
        username: data.name,
        display_name: data.name,
        email: data.email || ''
      })

      return API.Common.callback('google', uid, user, ipAddress, cleanedData, API.Google.getAvatar)
    }
  },
  Discord: {
    getAvatar: async (rawData) => {
      let profilepic = null
      const aviSnowflake = rawData.avatar
      if (aviSnowflake) {
        try {
          const avpt = await Image.downloadImage('https://cdn.discordapp.com/avatars/' + rawData.id + '/' + aviSnowflake + '.png')
          if (avpt && avpt.fileName) {
            profilepic = avpt.fileName
          }
        } catch (e) {
          profilepic = null
        }
      }

      return profilepic
    },
    oauth2App: function () {
      if (discordApp) return
      discordApp = new oauth.PromiseOAuth2(
        config.external.discord.api,
        config.external.discord.api_secret,
        'https://discordapp.com/api/',
        'oauth2/authorize',
        'oauth2/token'
      )

      discordApp.useAuthorizationHeaderforGET(true)
    },
    getAuthorizeURL: function (req) {
      if (!discordApp) API.Discord.oauth2App()
      const state = API.Common.stateGenerator(req)
      const redirectUri = config.server.domain + '/api/external/discord/callback'

      const params = {
        client_id: config.external.discord.api,
        redirect_uri: redirectUri,
        scope: 'identify email',
        response_type: 'code',
        state: state
      }

      const url = discordApp.getAuthorizeUrl(params)

      return { error: null, state: state, url: url }
    },
    getAccessToken: async function (code) {
      if (!discordApp) API.Discord.oauth2App()

      const redirectUri = config.server.domain + '/api/external/discord/callback'
      let tokens
      try {
        tokens = await discordApp.getOAuthAccessToken(code, { grant_type: 'authorization_code', redirect_uri: redirectUri })
      } catch (e) {
        console.error(e)
        return { error: 'No Authorization' }
      }

      if (!tokens.length) return { error: 'No Tokens' }
      tokens = tokens[2]

      return { error: null, accessToken: tokens.access_token }
    },
    callback: async function (user, accessToken, ipAddress) {
      if (!discordApp) API.Discord.oauth2App()

      let ddata
      try {
        const resp = await discordApp.get('https://discordapp.com/api/users/@me', accessToken)
        ddata = JSON.parse(resp)
      } catch (e) {
        console.error(e)
        return { error: 'Could not get user information' }
      }

      const uid = ddata.id

      // Create a new user
      const cleanedData = Object.assign(ddata, {
        display_name: ddata.username,
        email: ddata.email || ''
      })

      return API.Common.callback('discord', uid, user, ipAddress, cleanedData, API.Discord.getAvatar)
    }
  }
}

module.exports = API