/* eslint-disable camelcase */
/* eslint-disable  no-restricted-imports */
/* istanbul ignore file */
import './bootstrap'
import http from 'http'
import express, { Express } from 'express'

// `express-async-errors` patches express to catch errors in async handlers. no variable needed
import 'express-async-errors'
import compression from 'compression'
import cookieParser from 'cookie-parser'

import { createTerminus } from '@godaddy/terminus'
import Logging from '@/logging'
import { startupLogger, shutdownLogger, subscriptionLogger } from '@/logging/logging'
import {
  DetermineRequestIdMiddleware,
  LoggingExpressMiddleware,
  sanitizeHeaders
} from '@/logging/expressLogging'

import { errorLoggingMiddleware } from '@/logging/errorLogging'
import prometheusClient from 'prom-client'

import { ApolloServer } from '@apollo/server'
import { expressMiddleware } from '@apollo/server/express4'
import { ApolloServerPluginLandingPageLocalDefault } from '@apollo/server/plugin/landingPage/default'
import { ApolloServerPluginUsageReporting } from '@apollo/server/plugin/usageReporting'
import { ApolloServerPluginUsageReportingDisabled } from '@apollo/server/plugin/disabled'

import type { ConnectionContext, ExecutionParams } from 'subscriptions-transport-ws'
import { SubscriptionServer } from 'subscriptions-transport-ws'
import { execute, subscribe } from 'graphql'

import knex, { db } from '@/db/knex'
import { monitorActiveConnections } from '@/logging/httpServerMonitoring'
import { buildErrorFormatter } from '@/modules/core/graph/setup'
import {
  getFileSizeLimitMB,
  isDevEnv,
  isTestEnv,
  useNewFrontend,
  isApolloMonitoringEnabled,
  enableMixpanel
} from '@/modules/shared/helpers/envHelper'
import * as ModulesSetup from '@/modules'
import { GraphQLContext, Optional } from '@/modules/shared/helpers/typeHelper'
import { createRateLimiterMiddleware } from '@/modules/core/services/ratelimiter'

import { get, has, isString, toNumber } from 'lodash'
import { corsMiddleware } from '@/modules/core/configs/cors'
import {
  authContextMiddleware,
  buildContext,
  determineClientIpAddressMiddleware,
  mixpanelTrackerHelperMiddlewareFactory
} from '@/modules/shared/middleware'
import { GraphQLError } from 'graphql'
import { redactSensitiveVariables } from '@/logging/loggingHelper'
import { buildMocksConfig } from '@/modules/mocks'
import { defaultErrorHandler } from '@/modules/core/rest/defaultErrorHandler'
import { migrateDbToLatest } from '@/db/migrations'
import { statusCodePlugin } from '@/modules/core/graph/plugins/statusCode'
import { BaseError, ForbiddenError } from '@/modules/shared/errors'
import { loggingPlugin } from '@/modules/core/graph/plugins/logging'
import { shouldLogAsInfoLevel } from '@/logging/graphqlError'
import { getUserFactory } from '@/modules/core/repositories/users'

const GRAPHQL_PATH = '/graphql'

let graphqlServer: ApolloServer<GraphQLContext>

// eslint-disable-next-line @typescript-eslint/no-explicit-any
type SubscriptionResponse = { errors?: GraphQLError[]; data?: any }

function logSubscriptionOperation(params: {
  ctx: GraphQLContext
  execParams: ExecutionParams
  error?: Error
  response?: SubscriptionResponse
}) {
  const { error, response, ctx, execParams } = params
  const userId = ctx.userId
  if (!error && !response) return

  const logger = ctx.log.child({
    graphql_query: execParams.query.toString(),
    graphql_variables: redactSensitiveVariables(execParams.variables),
    graphql_operation_name: execParams.operationName,
    graphql_operation_type: 'subscription',
    userId
  })

  const errMsg = 'GQL subscription event {graphql_operation_name} errored'
  const errors = response?.errors || (error ? [error] : [])
  if (errors.length) {
    for (const error of errors) {
      let errorLogger = logger
      if (error instanceof BaseError) {
        errorLogger = errorLogger.child({ ...error.info() })
      }
      if (shouldLogAsInfoLevel(error)) {
        errorLogger.info({ err: error }, errMsg)
      } else {
        errorLogger.error({ err: error }, errMsg)
      }
    }
  } else if (response?.data) {
    logger.info('GQL subscription event {graphql_operation_name} emitted')
  }
}

/**
 * TODO: subscriptions-transport-ws is no longer maintained, we should migrate to graphql-ws insted. The problem
 * is that graphql-ws uses an entirely different protocol, so the client-side has to change as well, and so old clients
 * will be unable to use any WebSocket/subscriptions functionality with the updated server
 */
function buildApolloSubscriptionServer(server: http.Server): SubscriptionServer {
  const schema = ModulesSetup.graphSchema()

  // Init metrics
  prometheusClient.register.removeSingleMetric('speckle_server_apollo_connect')
  const metricConnectCounter = new prometheusClient.Counter({
    name: 'speckle_server_apollo_connect',
    help: 'Number of connects'
  })
  prometheusClient.register.removeSingleMetric('speckle_server_apollo_clients')
  const metricConnectedClients = new prometheusClient.Gauge({
    name: 'speckle_server_apollo_clients',
    help: 'Number of currently connected clients'
  })

  prometheusClient.register.removeSingleMetric(
    'speckle_server_apollo_graphql_total_subscription_operations'
  )
  const metricSubscriptionTotalOperations = new prometheusClient.Counter({
    name: 'speckle_server_apollo_graphql_total_subscription_operations',
    help: 'Number of total subscription operations served by this instance',
    labelNames: ['subscriptionType'] as const
  })

  prometheusClient.register.removeSingleMetric(
    'speckle_server_apollo_graphql_total_subscription_responses'
  )
  const metricSubscriptionTotalResponses = new prometheusClient.Counter({
    name: 'speckle_server_apollo_graphql_total_subscription_responses',
    help: 'Number of total subscription responses served by this instance',
    labelNames: ['subscriptionType', 'status'] as const
  })

  return SubscriptionServer.create(
    {
      schema,
      execute,
      subscribe,
      onConnect: async (
        connectionParams: Record<string, unknown>,
        webSocket: WebSocket,
        connContext: ConnectionContext
      ) => {
        metricConnectCounter.inc()
        metricConnectedClients.inc()

        const logger = connContext.request.log || subscriptionLogger

        const possiblePaths = [
          'Authorization',
          'authorization',
          'headers.Authorization',
          'headers.authorization'
        ]

        // Resolve token
        let token: string
        try {
          const requestId = get(connectionParams, 'headers.x-request-id') as string
          logger.debug(
            { requestId, headers: sanitizeHeaders(connContext.request.headers) },
            'New websocket connection'
          )
          let header: Optional<string>

          for (const possiblePath of possiblePaths) {
            if (has(connectionParams, possiblePath)) {
              header = get(connectionParams, possiblePath) as string
              if (header) break
            }
          }

          if (!header) {
            throw new Error("Couldn't resolve auth header for subscription")
          }

          token = header.split(' ')[1]
          if (!token) {
            throw new Error("Couldn't resolve token from auth header")
          }
        } catch (e) {
          throw new ForbiddenError('You need a token to subscribe')
        }

        // Build context (Apollo Server v3 no longer triggers context building automatically
        // for subscriptions)
        try {
          const buildCtx = await buildContext({
            req: null,
            token,
            cleanLoadersEarly: false
          })
          buildCtx.log.info(
            {
              userId: buildCtx.userId,
              ws_protocol: webSocket.protocol,
              ws_url: webSocket.url,
              headers: sanitizeHeaders(connContext.request.headers)
            },
            'Websocket connected and subscription context built.'
          )
          return buildCtx
        } catch (e) {
          throw new ForbiddenError('Subscription context build failed')
        }
      },
      onDisconnect: (webSocket: WebSocket, connContext: ConnectionContext) => {
        const logger = connContext.request.log || subscriptionLogger
        logger.debug(
          {
            ws_protocol: webSocket.protocol,
            ws_url: webSocket.url,
            headers: sanitizeHeaders(connContext.request.headers)
          },
          'Websocket disconnected.'
        )
        metricConnectedClients.dec()
      },
      onOperation: (...params: [() => void, ExecutionParams]) => {
        // kinda hacky, but we're using this as an "subscription event emitted"
        // callback to clear subscription connection dataloaders to avoid stale cache
        const baseParams = params[1]
        metricSubscriptionTotalOperations.inc({
          subscriptionType: baseParams.operationName
        })
        const ctx = baseParams.context as GraphQLContext

        const logger = ctx.log || subscriptionLogger
        logger.debug(
          {
            graphql_operation_name: baseParams.operationName,
            userId: baseParams.context.userId,
            graphql_query: baseParams.query.toString(),
            graphql_variables: redactSensitiveVariables(baseParams.variables),
            graphql_operation_type: 'subscription'
          },
          'Subscription started for {graphqlOperationName}'
        )

        baseParams.formatResponse = (val: SubscriptionResponse) => {
          ctx.loaders.clearAll()
          logSubscriptionOperation({ ctx, execParams: baseParams, response: val })
          metricSubscriptionTotalResponses.inc({
            subscriptionType: baseParams.operationName,
            status: 'success'
          })
          return val
        }
        baseParams.formatError = (e: Error) => {
          ctx.loaders.clearAll()
          logSubscriptionOperation({ ctx, execParams: baseParams, error: e })

          metricSubscriptionTotalResponses.inc({
            subscriptionType: baseParams.operationName,
            status: 'error'
          })
          return e
        }

        return baseParams
      },
      keepAlive: 30000 //milliseconds. Loadbalancers may close the connection after inactivity. e.g. nginx default is 60000ms.
    },
    {
      server,
      path: GRAPHQL_PATH
    }
  )
}

/**
 * Create Apollo Server instance
 */
export async function buildApolloServer(options?: {
  subscriptionServer?: SubscriptionServer
}): Promise<ApolloServer<GraphQLContext>> {
  const includeStacktraceInErrorResponses = isDevEnv() || isTestEnv()
  const subscriptionServer = options?.subscriptionServer
  const schema = ModulesSetup.graphSchema(await buildMocksConfig())

  const server = new ApolloServer({
    schema,
    plugins: [
      statusCodePlugin,
      loggingPlugin,
      ApolloServerPluginLandingPageLocalDefault({
        embed: true,
        includeCookies: true
      }),
      ...(subscriptionServer
        ? [
            {
              async serverWillStart() {
                return {
                  async drainServer() {
                    subscriptionServer?.close()
                  }
                }
              }
            }
          ]
        : []),
      ...(isApolloMonitoringEnabled()
        ? [
            ApolloServerPluginUsageReporting({
              // send all headers (except auth ones)
              sendHeaders: { all: true }
            })
          ]
        : [ApolloServerPluginUsageReportingDisabled()])
    ],
    introspection: true,
    cache: 'bounded',
    persistedQueries: false,
    csrfPrevention: true,
    formatError: buildErrorFormatter({ includeStacktraceInErrorResponses }),
    includeStacktraceInErrorResponses
  })
  await server.start()

  return server
}

/**
 * Initialises all server (express/subscription/http) instances
 */
export async function init() {
  if (useNewFrontend()) {
    startupLogger.info('🖼️  Serving for frontend-2...')
  }

  const app = express()
  app.disable('x-powered-by')

  Logging(app)

  // Moves things along automatically on restart.
  // Should perhaps be done manually?
  await migrateDbToLatest(knex)()

  app.use(cookieParser())
  app.use(DetermineRequestIdMiddleware)
  app.use(determineClientIpAddressMiddleware)
  app.use(LoggingExpressMiddleware)

  if (process.env.COMPRESSION) {
    app.use(compression())
  }

  app.use(corsMiddleware())
  app.use(express.json({ limit: '100mb' }))
  app.use(express.urlencoded({ limit: `${getFileSizeLimitMB()}mb`, extended: false }))

  // Trust X-Forwarded-* headers (for https protocol detection)
  app.enable('trust proxy')

  // Log errors
  app.use(errorLoggingMiddleware)
  app.use(authContextMiddleware)
  app.use(createRateLimiterMiddleware())
  app.use(
    async (
      _req: express.Request,
      res: express.Response,
      next: express.NextFunction
    ) => {
      res.setHeader('Content-Security-Policy', "frame-ancestors 'none'")
      next()
    }
  )
  if (enableMixpanel())
    app.use(mixpanelTrackerHelperMiddlewareFactory({ getUser: getUserFactory({ db }) }))

  // Initialize default modules, including rest api handlers
  await ModulesSetup.init(app)

  // Init HTTP server & subscription server
  const server = http.createServer(app)
  const subscriptionServer = buildApolloSubscriptionServer(server)

  // Initialize graphql server
  graphqlServer = await buildApolloServer({
    subscriptionServer
  })
  app.use(
    GRAPHQL_PATH,
    expressMiddleware(graphqlServer, {
      context: buildContext
    })
  )

  // Expose prometheus metrics
  app.get('/metrics', async (req, res) => {
    try {
      res.set('Content-Type', prometheusClient.register.contentType)
      res.end(await prometheusClient.register.metrics())
    } catch (ex: unknown) {
      res.status(500).end(ex instanceof Error ? ex.message : `${ex}`)
    }
  })

  // At the very end adding default error handler middleware
  app.use(defaultErrorHandler)

  return { app, graphqlServer, server, subscriptionServer }
}

export async function shutdown(): Promise<void> {
  await ModulesSetup.shutdown()
}

const shouldUseFrontendProxy = () =>
  process.env.NODE_ENV === 'development' && process.env.USE_FRONTEND_2 !== 'true'

async function createFrontendProxy() {
  const frontendHost = process.env.FRONTEND_HOST || '127.0.0.1'
  const frontendPort = process.env.FRONTEND_PORT || 8080
  const { createProxyMiddleware } = await import('http-proxy-middleware')

  // even tho it has default values, it fixes http-proxy setting `Connection: close` on each request
  // slowing everything down
  const defaultAgent = new http.Agent()

  return createProxyMiddleware({
    target: `http://${frontendHost}:${frontendPort}`,
    changeOrigin: true,
    ws: false,
    agent: defaultAgent
  })
}

/**
 * Starts a http server, hoisting the express app to it.
 */
export async function startHttp(
  server: http.Server,
  app: Express,
  customPortOverride?: number
) {
  let bindAddress = process.env.BIND_ADDRESS || '127.0.0.1'
  let port = process.env.PORT ? toNumber(process.env.PORT) : 3000

  if (customPortOverride || customPortOverride === 0) port = customPortOverride
  if (shouldUseFrontendProxy()) {
    // app.use('/', frontendProxy)
    app.use(await createFrontendProxy())

    startupLogger.info('✨ Proxying frontend-1 (dev mode):')
    startupLogger.info(`👉 main application: http://127.0.0.1:${port}/`)
  }

  // Production mode
  else {
    bindAddress = process.env.BIND_ADDRESS || '0.0.0.0'
  }

  monitorActiveConnections(server)

  app.set('port', port)

  // large timeout to allow large downloads on slow connections to finish
  createTerminus(server, {
    signals: ['SIGTERM', 'SIGINT'],
    timeout: 5 * 60 * 1000,
    beforeShutdown: async () => {
      shutdownLogger.info('Shutting down (signal received)...')
    },
    onSignal: async () => {
      await shutdown()
    },
    onShutdown: () => {
      shutdownLogger.info('Shutdown completed')
      process.exit(0)
    }
  })

  server.on('listening', () => {
    const address = server.address()
    const addressString = isString(address) ? address : address?.address
    const port = isString(address) ? null : address?.port

    startupLogger.info(
      `🚀 My name is Speckle Server, and I'm running at ${addressString}:${port}`
    )
    app.emit('appStarted')
  })

  server.listen(port, bindAddress)

  server.keepAliveTimeout = 61 * 1000
  server.headersTimeout = 65 * 1000

  return { server }
}