import * as express from 'express'
import { AccessDeniedError } from 'oauth2-server'
import { logger } from '../helpers/logger'
import { UserModel } from '../models/account/user'
import { OAuthClientModel } from '../models/oauth/oauth-client'
import { OAuthTokenModel } from '../models/oauth/oauth-token'
import { LRU_CACHE } from '../initializers/constants'
import { Transaction } from 'sequelize'
import { CONFIG } from '../initializers/config'
import * as LRUCache from 'lru-cache'
import { MOAuthTokenUser } from '@server/typings/models/oauth/oauth-token'
import { MUser } from '@server/typings/models/user/user'
import { UserAdminFlag } from '@shared/models/users/user-flag.model'
import { createUserAccountAndChannelAndPlaylist } from './user'
import { UserRole } from '@shared/models/users/user-role'
import { PluginManager } from '@server/lib/plugins/plugin-manager'
import { ActorModel } from '@server/models/activitypub/actor'

type TokenInfo = { accessToken: string, refreshToken: string, accessTokenExpiresAt: Date, refreshTokenExpiresAt: Date }

const accessTokenCache = new LRUCache<string, MOAuthTokenUser>({ max: LRU_CACHE.USER_TOKENS.MAX_SIZE })
const userHavingToken = new LRUCache<number, string>({ max: LRU_CACHE.USER_TOKENS.MAX_SIZE })

// ---------------------------------------------------------------------------

function deleteUserToken (userId: number, t?: Transaction) {
  clearCacheByUserId(userId)

  return OAuthTokenModel.deleteUserToken(userId, t)
}

function clearCacheByUserId (userId: number) {
  const token = userHavingToken.get(userId)

  if (token !== undefined) {
    accessTokenCache.del(token)
    userHavingToken.del(userId)
  }
}

function clearCacheByToken (token: string) {
  const tokenModel = accessTokenCache.get(token)

  if (tokenModel !== undefined) {
    userHavingToken.del(tokenModel.userId)
    accessTokenCache.del(token)
  }
}

async function getAccessToken (bearerToken: string) {
  logger.debug('Getting access token (bearerToken: ' + bearerToken + ').')

  if (!bearerToken) return undefined

  let tokenModel: MOAuthTokenUser

  if (accessTokenCache.has(bearerToken)) {
    tokenModel = accessTokenCache.get(bearerToken)
  } else {
    tokenModel = await OAuthTokenModel.getByTokenAndPopulateUser(bearerToken)

    if (tokenModel) {
      accessTokenCache.set(bearerToken, tokenModel)
      userHavingToken.set(tokenModel.userId, tokenModel.accessToken)
    }
  }

  if (!tokenModel) return undefined

  if (tokenModel.User.pluginAuth) {
    const valid = await PluginManager.Instance.isTokenValid(tokenModel, 'access')

    if (valid !== true) return undefined
  }

  return tokenModel
}

function getClient (clientId: string, clientSecret: string) {
  logger.debug('Getting Client (clientId: ' + clientId + ', clientSecret: ' + clientSecret + ').')

  return OAuthClientModel.getByIdAndSecret(clientId, clientSecret)
}

async function getRefreshToken (refreshToken: string) {
  logger.debug('Getting RefreshToken (refreshToken: ' + refreshToken + ').')

  const tokenInfo = await OAuthTokenModel.getByRefreshTokenAndPopulateClient(refreshToken)
  if (!tokenInfo) return undefined

  const tokenModel = tokenInfo.token

  if (tokenModel.User.pluginAuth) {
    const valid = await PluginManager.Instance.isTokenValid(tokenModel, 'refresh')

    if (valid !== true) return undefined
  }

  return tokenInfo
}

async function getUser (usernameOrEmail?: string, password?: string) {
  const res: express.Response = this.request.res

  // Special treatment coming from a plugin
  if (res.locals.bypassLogin && res.locals.bypassLogin.bypass === true) {
    const obj = res.locals.bypassLogin
    logger.info('Bypassing oauth login by plugin %s.', obj.pluginName)

    let user = await UserModel.loadByEmail(obj.user.email)
    if (!user) user = await createUserFromExternal(obj.pluginName, obj.user)

    // Cannot create a user
    if (!user) throw new AccessDeniedError('Cannot create such user: an actor with that name already exists.')

    // If the user does not belongs to a plugin, it was created before its installation
    // Then we just go through a regular login process
    if (user.pluginAuth !== null) {
      // This user does not belong to this plugin, skip it
      if (user.pluginAuth !== obj.pluginName) return null

      return user
    }
  }

  logger.debug('Getting User (username/email: ' + usernameOrEmail + ', password: ******).')

  const user = await UserModel.loadByUsernameOrEmail(usernameOrEmail)
  // If we don't find the user, or if the user belongs to a plugin
  if (!user || user.pluginAuth !== null || !password) return null

  const passwordMatch = await user.isPasswordMatch(password)
  if (passwordMatch !== true) return null

  if (user.blocked) throw new AccessDeniedError('User is blocked.')

  if (CONFIG.SIGNUP.REQUIRES_EMAIL_VERIFICATION && user.emailVerified === false) {
    throw new AccessDeniedError('User email is not verified.')
  }

  return user
}

async function revokeToken (tokenInfo: { refreshToken: string }) {
  const res: express.Response = this.request.res
  const token = await OAuthTokenModel.getByRefreshTokenAndPopulateUser(tokenInfo.refreshToken)

  if (token) {
    if (res.locals.explicitLogout === true && token.User.pluginAuth && token.authName) {
      PluginManager.Instance.onLogout(token.User.pluginAuth, token.authName, token.User)
    }

    clearCacheByToken(token.accessToken)

    token.destroy()
         .catch(err => logger.error('Cannot destroy token when revoking token.', { err }))

    return true
  }

  return false
}

async function saveToken (token: TokenInfo, client: OAuthClientModel, user: UserModel) {
  const res: express.Response = this.request.res

  let authName: string = null
  if (res.locals.bypassLogin?.bypass === true) {
    authName = res.locals.bypassLogin.authName
  } else if (res.locals.refreshTokenAuthName) {
    authName = res.locals.refreshTokenAuthName
  }

  logger.debug('Saving token ' + token.accessToken + ' for client ' + client.id + ' and user ' + user.id + '.')

  const tokenToCreate = {
    accessToken: token.accessToken,
    accessTokenExpiresAt: token.accessTokenExpiresAt,
    refreshToken: token.refreshToken,
    refreshTokenExpiresAt: token.refreshTokenExpiresAt,
    authName,
    oAuthClientId: client.id,
    userId: user.id
  }

  const tokenCreated = await OAuthTokenModel.create(tokenToCreate)

  user.lastLoginDate = new Date()
  await user.save()

  return Object.assign(tokenCreated, { client, user })
}

// ---------------------------------------------------------------------------

// See https://github.com/oauthjs/node-oauth2-server/wiki/Model-specification for the model specifications
export {
  deleteUserToken,
  clearCacheByUserId,
  clearCacheByToken,
  getAccessToken,
  getClient,
  getRefreshToken,
  getUser,
  revokeToken,
  saveToken
}

async function createUserFromExternal (pluginAuth: string, options: {
  username: string
  email: string
  role: UserRole
  displayName: string
}) {
  // Check an actor does not already exists with that name (removed user)
  const actor = await ActorModel.loadLocalByName(options.username)
  if (actor) return null

  const userToCreate = new UserModel({
    username: options.username,
    password: null,
    email: options.email,
    nsfwPolicy: CONFIG.INSTANCE.DEFAULT_NSFW_POLICY,
    autoPlayVideo: true,
    role: options.role,
    videoQuota: CONFIG.USER.VIDEO_QUOTA,
    videoQuotaDaily: CONFIG.USER.VIDEO_QUOTA_DAILY,
    adminFlags: UserAdminFlag.NONE,
    pluginAuth
  }) as MUser

  const { user } = await createUserAccountAndChannelAndPlaylist({
    userToCreate,
    userDisplayName: options.displayName
  })

  return user
}