const https = require('https')
const dayjs = require('dayjs')
const utc = require('dayjs/plugin/utc')
const timezone = require('dayjs/plugin/timezone')
dayjs.extend(utc)
dayjs.extend(timezone)
const axios = require('axios')
const { Prometheus } = require('../prometheus')
const { debug, UP, DOWN, PENDING, flipStatus, TimeLogger } = require('../../src/util')
const { tcping, ping, dnsResolve, checkCertificate, checkStatusCode, getTotalClientInRoom, setting, errorLog } = require('../util-server')
const { R } = require('redbean-node')
const { BeanModel } = require('redbean-node/dist/bean-model')
const { Notification } = require('../notification')
const { demoMode } = require('../config')
const version = require('../../package.json').version
const apicache = require('../modules/apicache')

/**
 * status:
 *      0 = DOWN
 *      1 = UP
 *      2 = PENDING
 */
class Monitor extends BeanModel {
  /**
     * Return an object that ready to parse to JSON for public
     * Only show necessary data to public
     */
  async toPublicJSON (showTags = false) {
    const obj = {
      id: this.id,
      name: this.name
    }
    if (showTags) {
      obj.tags = await this.getTags()
    }
    return obj
  }

  /**
     * Return an object that ready to parse to JSON
     */
  async toJSON () {
    const notificationIDList = {}

    const list = await R.find('monitor_notification', ' monitor_id = ? ', [
      this.id
    ])

    for (const bean of list) {
      notificationIDList[bean.notification_id] = true
    }

    const tags = await this.getTags()

    return {
      id: this.id,
      name: this.name,
      url: this.url,
      method: this.method,
      body: this.body,
      headers: this.headers,
      basic_auth_user: this.basic_auth_user,
      basic_auth_pass: this.basic_auth_pass,
      hostname: this.hostname,
      port: this.port,
      maxretries: this.maxretries,
      weight: this.weight,
      active: this.active,
      type: this.type,
      interval: this.interval,
      retryInterval: this.retryInterval,
      keyword: this.keyword,
      ignoreTls: this.getIgnoreTls(),
      upsideDown: this.isUpsideDown(),
      maxredirects: this.maxredirects,
      accepted_statuscodes: this.getAcceptedStatuscodes(),
      dns_resolve_type: this.dns_resolve_type,
      dns_resolve_server: this.dns_resolve_server,
      dns_last_result: this.dns_last_result,
      pushToken: this.pushToken,
      notificationIDList,
      tags: tags
    }
  }

  async getTags () {
    return await R.getAll('SELECT mt.*, tag.name, tag.color FROM monitor_tag mt JOIN tag ON mt.tag_id = tag.id WHERE mt.monitor_id = ?', [this.id])
  }

  /**
     * Encode user and password to Base64 encoding
     * for HTTP "basic" auth, as per RFC-7617
     * @returns {string}
     */
  encodeBase64 (user, pass) {
    return Buffer.from(user + ':' + pass).toString('base64')
  }

  /**
     * Parse to boolean
     * @returns {boolean}
     */
  getIgnoreTls () {
    return Boolean(this.ignoreTls)
  }

  /**
     * Parse to boolean
     * @returns {boolean}
     */
  isUpsideDown () {
    return Boolean(this.upsideDown)
  }

  getAcceptedStatuscodes () {
    return JSON.parse(this.accepted_statuscodes_json)
  }

  start (io) {
    let previousBeat = null
    let retries = 0

    const prometheus = new Prometheus(this)

    const beat = async () => {
      let beatInterval = this.interval

      if (!beatInterval) {
        beatInterval = 1
      }

      if (demoMode) {
        if (beatInterval < 20) {
          console.log('beat interval too low, reset to 20s')
          beatInterval = 20
        }
      }

      // Expose here for prometheus update
      // undefined if not https
      let tlsInfo

      if (!previousBeat) {
        previousBeat = await R.findOne('heartbeat', ' monitor_id = ? ORDER BY time DESC', [
          this.id
        ])
      }

      const isFirstBeat = !previousBeat

      const bean = R.dispense('heartbeat')
      bean.monitor_id = this.id
      bean.time = R.isoDateTime(dayjs.utc())
      bean.status = DOWN

      if (this.isUpsideDown()) {
        bean.status = flipStatus(bean.status)
      }

      // Duration
      if (!isFirstBeat) {
        bean.duration = dayjs(bean.time).diff(dayjs(previousBeat.time), 'second')
      } else {
        bean.duration = 0
      }

      try {
        if (this.type === 'http' || this.type === 'keyword') {
          // Do not do any queries/high loading things before the "bean.ping"
          const startTime = dayjs().valueOf()

          // HTTP basic auth
          let basicAuthHeader = {}
          if (this.basic_auth_user) {
            basicAuthHeader = {
              Authorization: 'Basic ' + this.encodeBase64(this.basic_auth_user, this.basic_auth_pass)
            }
          }

          debug(`[${this.name}] Prepare Options for axios`)

          const options = {
            url: this.url,
            method: (this.method || 'get').toLowerCase(),
            ...(this.body ? { data: JSON.parse(this.body) } : {}),
            timeout: this.interval * 1000 * 0.8,
            headers: {
              Accept: 'text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.9',
              'User-Agent': 'Uptime-Kuma/' + version,
              ...(this.headers ? JSON.parse(this.headers) : {}),
              ...(basicAuthHeader)
            },
            httpsAgent: new https.Agent({
              maxCachedSessions: 0, // Use Custom agent to disable session reuse (https://github.com/nodejs/node/issues/3940)
              rejectUnauthorized: !this.getIgnoreTls()
            }),
            maxRedirects: this.maxredirects,
            validateStatus: (status) => {
              return checkStatusCode(status, this.getAcceptedStatuscodes())
            }
          }

          debug(`[${this.name}] Axios Request`)
          const res = await axios.request(options)
          bean.msg = `${res.status} - ${res.statusText}`
          bean.ping = dayjs().valueOf() - startTime

          // Check certificate if https is used
          const certInfoStartTime = dayjs().valueOf()
          if (this.getUrl()?.protocol === 'https:') {
            debug(`[${this.name}] Check cert`)
            try {
              const tlsInfoObject = checkCertificate(res)
              tlsInfo = await this.updateTlsInfo(tlsInfoObject)

              if (!this.getIgnoreTls()) {
                debug(`[${this.name}] call sendCertNotification`)
                await this.sendCertNotification(tlsInfoObject)
              }
            } catch (e) {
              if (e.message !== 'No TLS certificate in response') {
                console.error(e.message)
              }
            }
          }

          if (process.env.TIMELOGGER === '1') {
            debug('Cert Info Query Time: ' + (dayjs().valueOf() - certInfoStartTime) + 'ms')
          }

          if (process.env.UPTIME_KUMA_LOG_RESPONSE_BODY_MONITOR_ID == this.id) {
            console.log(res.data)
          }

          if (this.type === 'http') {
            bean.status = UP
          } else {
            let data = res.data

            // Convert to string for object/array
            if (typeof data !== 'string') {
              data = JSON.stringify(data)
            }

            if (data.includes(this.keyword)) {
              bean.msg += ', keyword is found'
              bean.status = UP
            } else {
              throw new Error(bean.msg + ', but keyword is not found')
            }
          }
        } else if (this.type === 'port') {
          bean.ping = await tcping(this.hostname, this.port)
          bean.msg = ''
          bean.status = UP
        } else if (this.type === 'ping') {
          bean.ping = await ping(this.hostname)
          bean.msg = ''
          bean.status = UP
        } else if (this.type === 'dns') {
          const startTime = dayjs().valueOf()
          let dnsMessage = ''

          const dnsRes = await dnsResolve(this.hostname, this.dns_resolve_server, this.dns_resolve_type)
          bean.ping = dayjs().valueOf() - startTime

          if (this.dns_resolve_type == 'A' || this.dns_resolve_type == 'AAAA' || this.dns_resolve_type == 'TXT') {
            dnsMessage += 'Records: '
            dnsMessage += dnsRes.join(' | ')
          } else if (this.dns_resolve_type == 'CNAME' || this.dns_resolve_type == 'PTR') {
            dnsMessage = dnsRes[0]
          } else if (this.dns_resolve_type == 'CAA') {
            dnsMessage = dnsRes[0].issue
          } else if (this.dns_resolve_type == 'MX') {
            dnsRes.forEach(record => {
              dnsMessage += `Hostname: ${record.exchange} - Priority: ${record.priority} | `
            })
            dnsMessage = dnsMessage.slice(0, -2)
          } else if (this.dns_resolve_type == 'NS') {
            dnsMessage += 'Servers: '
            dnsMessage += dnsRes.join(' | ')
          } else if (this.dns_resolve_type == 'SOA') {
            dnsMessage += `NS-Name: ${dnsRes.nsname} | Hostmaster: ${dnsRes.hostmaster} | Serial: ${dnsRes.serial} | Refresh: ${dnsRes.refresh} | Retry: ${dnsRes.retry} | Expire: ${dnsRes.expire} | MinTTL: ${dnsRes.minttl}`
          } else if (this.dns_resolve_type == 'SRV') {
            dnsRes.forEach(record => {
              dnsMessage += `Name: ${record.name} | Port: ${record.port} | Priority: ${record.priority} | Weight: ${record.weight} | `
            })
            dnsMessage = dnsMessage.slice(0, -2)
          }

          if (this.dnsLastResult !== dnsMessage) {
            R.exec('UPDATE `monitor` SET dns_last_result = ? WHERE id = ? ', [
              dnsMessage,
              this.id
            ])
          }

          bean.msg = dnsMessage
          bean.status = UP
        } else if (this.type === 'push') { // Type: Push
          const time = R.isoDateTime(dayjs.utc().subtract(this.interval, 'second'))

          const heartbeatCount = await R.count('heartbeat', ' monitor_id = ? AND time > ? ', [
            this.id,
            time
          ])

          debug('heartbeatCount' + heartbeatCount + ' ' + time)

          if (heartbeatCount <= 0) {
            // Fix #922, since previous heartbeat could be inserted by api, it should get from database
            previousBeat = await Monitor.getPreviousHeartbeat(this.id)

            throw new Error('No heartbeat in the time window')
          } else {
            // No need to insert successful heartbeat for push type, so end here
            retries = 0
            this.heartbeatInterval = setTimeout(beat, beatInterval * 1000)
            return
          }
        } else if (this.type === 'steam') {
          const steamApiUrl = 'https://api.steampowered.com/IGameServersService/GetServerList/v1/'
          const steamAPIKey = await setting('steamAPIKey')
          const filter = `addr\\${this.hostname}:${this.port}`

          if (!steamAPIKey) {
            throw new Error('Steam API Key not found')
          }

          const res = await axios.get(steamApiUrl, {
            timeout: this.interval * 1000 * 0.8,
            headers: {
              Accept: '*/*',
              'User-Agent': 'Uptime-Kuma/' + version
            },
            httpsAgent: new https.Agent({
              maxCachedSessions: 0, // Use Custom agent to disable session reuse (https://github.com/nodejs/node/issues/3940)
              rejectUnauthorized: !this.getIgnoreTls()
            }),
            maxRedirects: this.maxredirects,
            validateStatus: (status) => {
              return checkStatusCode(status, this.getAcceptedStatuscodes())
            },
            params: {
              filter: filter,
              key: steamAPIKey
            }
          })

          if (res.data.response && res.data.response.servers && res.data.response.servers.length > 0) {
            bean.status = UP
            bean.msg = res.data.response.servers[0].name

            try {
              bean.ping = await ping(this.hostname)
            } catch (_) { }
          } else {
            throw new Error('Server not found on Steam')
          }
        } else {
          bean.msg = 'Unknown Monitor Type'
          bean.status = PENDING
        }

        if (this.isUpsideDown()) {
          bean.status = flipStatus(bean.status)

          if (bean.status === DOWN) {
            throw new Error('Flip UP to DOWN')
          }
        }

        retries = 0
      } catch (error) {
        bean.msg = error.message

        // If UP come in here, it must be upside down mode
        // Just reset the retries
        if (this.isUpsideDown() && bean.status === UP) {
          retries = 0
        } else if ((this.maxretries > 0) && (retries < this.maxretries)) {
          retries++
          bean.status = PENDING
        }
      }

      debug(`[${this.name}] Check isImportant`)
      const isImportant = Monitor.isImportantBeat(isFirstBeat, previousBeat?.status, bean.status)

      // Mark as important if status changed, ignore pending pings,
      // Don't notify if disrupted changes to up
      if (isImportant) {
        bean.important = true

        debug(`[${this.name}] sendNotification`)
        await Monitor.sendNotification(isFirstBeat, this, bean)

        // Clear Status Page Cache
        debug(`[${this.name}] apicache clear`)
        apicache.clear()
      } else {
        bean.important = false
      }

      if (bean.status === UP) {
        console.info(`Monitor #${this.id} '${this.name}': Successful Response: ${bean.ping} ms | Interval: ${beatInterval} seconds | Type: ${this.type}`)
      } else if (bean.status === PENDING) {
        if (this.retryInterval > 0) {
          beatInterval = this.retryInterval
        }
        console.warn(`Monitor #${this.id} '${this.name}': Pending: ${bean.msg} | Max retries: ${this.maxretries} | Retry: ${retries} | Retry Interval: ${beatInterval} seconds | Type: ${this.type}`)
      } else {
        console.warn(`Monitor #${this.id} '${this.name}': Failing: ${bean.msg} | Interval: ${beatInterval} seconds | Type: ${this.type}`)
      }

      debug(`[${this.name}] Send to socket`)
      io.to(this.user_id).emit('heartbeat', bean.toJSON())
      Monitor.sendStats(io, this.id, this.user_id)

      debug(`[${this.name}] Store`)
      await R.store(bean)

      debug(`[${this.name}] prometheus.update`)
      prometheus.update(bean, tlsInfo)

      previousBeat = bean

      if (!this.isStop) {
        debug(`[${this.name}] SetTimeout for next check.`)
        this.heartbeatInterval = setTimeout(safeBeat, beatInterval * 1000)
      } else {
        console.log(`[${this.name}] isStop = true, no next check.`)
      }
    }

    const safeBeat = async () => {
      try {
        await beat()
      } catch (e) {
        console.trace(e)
        errorLog(e, false)
        console.error('Please report to https://github.com/louislam/uptime-kuma/issues')

        if (!this.isStop) {
          console.log('Try to restart the monitor')
          this.heartbeatInterval = setTimeout(safeBeat, this.interval * 1000)
        }
      }
    }

    // Delay Push Type
    if (this.type === 'push') {
      setTimeout(() => {
        safeBeat()
      }, this.interval * 1000)
    } else {
      safeBeat()
    }
  }

  stop () {
    clearTimeout(this.heartbeatInterval)
    this.isStop = true
  }

  /**
     * Helper Method:
     * returns URL object for further usage
     * returns null if url is invalid
     * @returns {null|URL}
     */
  getUrl () {
    try {
      return new URL(this.url)
    } catch (_) {
      return null
    }
  }

  /**
     * Store TLS info to database
     * @param checkCertificateResult
     * @returns {Promise<object>}
     */
  async updateTlsInfo (checkCertificateResult) {
    let tls_info_bean = await R.findOne('monitor_tls_info', 'monitor_id = ?', [
      this.id
    ])

    if (tls_info_bean == null) {
      tls_info_bean = R.dispense('monitor_tls_info')
      tls_info_bean.monitor_id = this.id
    } else {
      // Clear sent history if the cert changed.
      try {
        const oldCertInfo = JSON.parse(tls_info_bean.info_json)

        const isValidObjects = oldCertInfo && oldCertInfo.certInfo && checkCertificateResult && checkCertificateResult.certInfo

        if (isValidObjects) {
          if (oldCertInfo.certInfo.fingerprint256 !== checkCertificateResult.certInfo.fingerprint256) {
            debug('Resetting sent_history')
            await R.exec("DELETE FROM notification_sent_history WHERE type = 'certificate' AND monitor_id = ?", [
              this.id
            ])
          } else {
            debug('No need to reset sent_history')
            debug(oldCertInfo.certInfo.fingerprint256)
            debug(checkCertificateResult.certInfo.fingerprint256)
          }
        } else {
          debug('Not valid object')
        }
      } catch (e) { }
    }

    tls_info_bean.info_json = JSON.stringify(checkCertificateResult)
    await R.store(tls_info_bean)

    return checkCertificateResult
  }

  static async sendStats (io, monitorID, userID) {
    const hasClients = getTotalClientInRoom(io, userID) > 0

    if (hasClients) {
      await Monitor.sendAvgPing(24, io, monitorID, userID)
      await Monitor.sendUptime(24, io, monitorID, userID)
      await Monitor.sendUptime(24 * 30, io, monitorID, userID)
      await Monitor.sendCertInfo(io, monitorID, userID)
    } else {
      debug('No clients in the room, no need to send stats')
    }
  }

  /**
     *
     * @param duration : int Hours
     */
  static async sendAvgPing (duration, io, monitorID, userID) {
    const timeLogger = new TimeLogger()

    const avgPing = parseInt(await R.getCell(`
            SELECT AVG(ping)
            FROM heartbeat
            WHERE time > DATETIME('now', ? || ' hours')
            AND ping IS NOT NULL
            AND monitor_id = ? `, [
      -duration,
      monitorID
    ]))

    timeLogger.print(`[Monitor: ${monitorID}] avgPing`)

    io.to(userID).emit('avgPing', monitorID, avgPing)
  }

  static async sendCertInfo (io, monitorID, userID) {
    const tls_info = await R.findOne('monitor_tls_info', 'monitor_id = ?', [
      monitorID
    ])
    if (tls_info != null) {
      io.to(userID).emit('certInfo', monitorID, tls_info.info_json)
    }
  }

  /**
     * Uptime with calculation
     * Calculation based on:
     * https://www.uptrends.com/support/kb/reporting/calculation-of-uptime-and-downtime
     * @param duration : int Hours
     */
  static async calcUptime (duration, monitorID) {
    const timeLogger = new TimeLogger()

    const startTime = R.isoDateTime(dayjs.utc().subtract(duration, 'hour'))

    // Handle if heartbeat duration longer than the target duration
    // e.g. If the last beat's duration is bigger that the 24hrs window, it will use the duration between the (beat time - window margin) (THEN case in SQL)
    const result = await R.getRow(`
            SELECT
               -- SUM all duration, also trim off the beat out of time window
                SUM(
                    CASE
                        WHEN (JULIANDAY(\`time\`) - JULIANDAY(?)) * 86400 < duration
                        THEN (JULIANDAY(\`time\`) - JULIANDAY(?)) * 86400
                        ELSE duration
                    END
                ) AS total_duration,

               -- SUM all uptime duration, also trim off the beat out of time window
                SUM(
                    CASE
                        WHEN (status = 1)
                        THEN
                            CASE
                                WHEN (JULIANDAY(\`time\`) - JULIANDAY(?)) * 86400 < duration
                                    THEN (JULIANDAY(\`time\`) - JULIANDAY(?)) * 86400
                                ELSE duration
                            END
                        END
                ) AS uptime_duration
            FROM heartbeat
            WHERE time > ?
            AND monitor_id = ?
        `, [
      startTime, startTime, startTime, startTime, startTime,
      monitorID
    ])

    timeLogger.print(`[Monitor: ${monitorID}][${duration}] sendUptime`)

    const totalDuration = result.total_duration
    const uptimeDuration = result.uptime_duration
    let uptime = 0

    if (totalDuration > 0) {
      uptime = uptimeDuration / totalDuration
      if (uptime < 0) {
        uptime = 0
      }
    } else {
      // Handle new monitor with only one beat, because the beat's duration = 0
      const status = parseInt(await R.getCell('SELECT `status` FROM heartbeat WHERE monitor_id = ?', [monitorID]))

      if (status === UP) {
        uptime = 1
      }
    }

    return uptime
  }

  /**
     * Send Uptime
     * @param duration : int Hours
     */
  static async sendUptime (duration, io, monitorID, userID) {
    const uptime = await this.calcUptime(duration, monitorID)
    io.to(userID).emit('uptime', monitorID, duration, uptime)
  }

  static isImportantBeat (isFirstBeat, previousBeatStatus, currentBeatStatus) {
    // * ? -> ANY STATUS = important [isFirstBeat]
    // UP -> PENDING = not important
    // * UP -> DOWN = important
    // UP -> UP = not important
    // PENDING -> PENDING = not important
    // * PENDING -> DOWN = important
    // PENDING -> UP = not important
    // DOWN -> PENDING = this case not exists
    // DOWN -> DOWN = not important
    // * DOWN -> UP = important
    const isImportant = isFirstBeat ||
            (previousBeatStatus === UP && currentBeatStatus === DOWN) ||
            (previousBeatStatus === DOWN && currentBeatStatus === UP) ||
            (previousBeatStatus === PENDING && currentBeatStatus === DOWN)
    return isImportant
  }

  static async sendNotification (isFirstBeat, monitor, bean) {
    if (!isFirstBeat || bean.status === DOWN) {
      const notificationList = await Monitor.getNotificationList(monitor)

      let text
      if (bean.status === UP) {
        text = '✅ Up'
      } else {
        text = '🔴 Down'
      }

      const msg = `[${monitor.name}] [${text}] ${bean.msg}`

      for (const notification of notificationList) {
        try {
          await Notification.send(JSON.parse(notification.config), msg, await monitor.toJSON(), bean.toJSON())
        } catch (e) {
          console.error('Cannot send notification to ' + notification.name)
          console.log(e)
        }
      }
    }
  }

  static async getNotificationList (monitor) {
    const notificationList = await R.getAll('SELECT notification.* FROM notification, monitor_notification WHERE monitor_id = ? AND monitor_notification.notification_id = notification.id ', [
      monitor.id
    ])
    return notificationList
  }

  async sendCertNotification (tlsInfoObject) {
    if (tlsInfoObject && tlsInfoObject.certInfo && tlsInfoObject.certInfo.daysRemaining) {
      const notificationList = await Monitor.getNotificationList(this)

      debug('call sendCertNotificationByTargetDays')
      await this.sendCertNotificationByTargetDays(tlsInfoObject.certInfo.daysRemaining, 21, notificationList)
      await this.sendCertNotificationByTargetDays(tlsInfoObject.certInfo.daysRemaining, 14, notificationList)
      await this.sendCertNotificationByTargetDays(tlsInfoObject.certInfo.daysRemaining, 7, notificationList)
    }
  }

  async sendCertNotificationByTargetDays (daysRemaining, targetDays, notificationList) {
    if (daysRemaining > targetDays) {
      debug(`No need to send cert notification. ${daysRemaining} > ${targetDays}`)
      return
    }

    if (notificationList.length > 0) {
      const row = await R.getRow('SELECT * FROM notification_sent_history WHERE type = ? AND monitor_id = ? AND days = ?', [
        'certificate',
        this.id,
        targetDays
      ])

      // Sent already, no need to send again
      if (row) {
        debug('Sent already, no need to send again')
        return
      }

      let sent = false
      debug('Send certificate notification')

      for (const notification of notificationList) {
        try {
          debug('Sending to ' + notification.name)
          await Notification.send(JSON.parse(notification.config), `[${this.name}][${this.url}] Certificate will be expired in ${daysRemaining} days`)
          sent = true
        } catch (e) {
          console.error('Cannot send cert notification to ' + notification.name)
          console.error(e)
        }
      }

      if (sent) {
        await R.exec('INSERT INTO notification_sent_history (type, monitor_id, days) VALUES(?, ?, ?)', [
          'certificate',
          this.id,
          targetDays
        ])
      }
    } else {
      debug('No notification, no need to send cert notification')
    }
  }

  static async getPreviousHeartbeat (monitorID) {
    return await R.getRow(`
            SELECT status, time FROM heartbeat
            WHERE id = (select MAX(id) from heartbeat where monitor_id = ?)
        `, [
      monitorID
    ])
  }
}

module.exports = Monitor