import fs from 'fs'
import { Tail } from 'tail'
import express from 'express'

import { Config } from './Config'

export type LogLine = {
  username: string
  message: string
} | null

type Callback = (data: LogLine) => void

class MinecraftHandler {
  config: Config

  app: express.Application
  tail: Tail

  constructor(config: Config) {
    this.config = config
  }

  fixMinecraftUsername (username: string) {
    return username.replace(/(§[A-Z-a-z0-9])/g, '')
  }

  private parseLogLine (data: string): LogLine {
    if (this.config.DEBUG) console.log('[DEBUG] Received ' + data)

    const ignored = new RegExp(this.config.REGEX_IGNORED_CHAT)

    if (ignored.test(data)) {
      if (this.config.DEBUG) console.log('[DEBUG] Line ignored')
      return null
    }

    const logLineDataRegex = new RegExp(
      `${(this.config.REGEX_SERVER_PREFIX || "\\[Server thread/INFO\\]:")} (.*)`
    )

    const logLineData = data.match(logLineDataRegex)

    if (data.includes('Rcon connection')) return null
    if (!logLineDataRegex.test(data) || !logLineData) {
      console.log('[ERROR] Regex could not match the string! Please verify it is correct!')
      console.log('Received: "' + data + '", Regex matches lines that start with: "' + this.config.REGEX_SERVER_PREFIX + '"')
      return null
    }

    const logLine = logLineData[1]

    const serverUsername = `${this.config.SERVER_NAME} - Server`

    if (logLine.startsWith('<')) {
      if (this.config.DEBUG){
        console.log('[DEBUG]: A player sent a chat message')
      }

      const re = new RegExp(this.config.REGEX_MATCH_CHAT_MC)
      const matches = logLine.match(re)

      if (!matches) {
        console.log('[ERROR] Could not parse message: ' + logLine)
        return null
      }

      const username = this.fixMinecraftUsername(matches[1])
      const message = matches[2]
      if (this.config.DEBUG) {
        console.log('[DEBUG] Username: ' + matches[1])
        console.log('[DEBUG] Text: ' + matches[2])
      }
      return { username, message }
    } else if (
      this.config.SHOW_PLAYER_CONN_STAT && (
        logLine.includes('left the game') ||
        logLine.includes('joined the game')
      )
    ) {
      // handle disconnection etc.
      if (this.config.DEBUG){
        console.log(`[DEBUG]: A player's connection status changed`)
      }

      return { username: serverUsername, message: logLine }
    } else if (this.config.SHOW_PLAYER_ADVANCEMENT && logLine.includes('granted the advancement')) {
      // handle achievement earning
      if (this.config.DEBUG){
        console.log('[DEBUG] A player has earned an achievement')
      }
      return { username: `${this.config.SERVER_NAME} - Server`, message: logLine }
    } else if (this.config.SHOW_PLAYER_ME && logLine.startsWith('* ')) {
      const usernameMatch = data.match(/: \* ([a-zA-Z0-9_]{1,16}) (.*)/)
      if (usernameMatch) {
        const username = usernameMatch[1]
        const rest = usernameMatch[2]
        return { username: serverUsername, message: `**${username}** ${rest}` }
      }
    } else if (this.config.SHOW_PLAYER_DEATH) {
      for (let word of this.config.DEATH_KEY_WORDS){
        if (data.includes(word)){
          if (this.config.DEBUG) {
            console.log(
              `[DEBUG] A player died. Matched key word "${word}"`
            )
          }
          return { username: serverUsername, message: logLine }
        }
      }
    }

    return null
  }

  private initWebServer (callback: Callback) {
    // init the webserver
    this.app = express()
    const http = require('http').Server(this.app)

    this.app.use((request: express.Request, response: express.Response, next: express.NextFunction) => {
      request.rawBody = ''
      request.setEncoding('utf8')

      request.on('data', (chunk: string) => {
        request.rawBody += chunk
      })

      request.on('end', function () {
        next()
      })
    })

    this.app.post(this.config.WEBHOOK, (req, res) => {
      if (req.rawBody) {
        const logLine = this.parseLogLine(req.rawBody)
        callback(logLine)
      }
      res.json({ received: true })
    })

    const port = process.env.PORT || this.config.PORT

    http.listen(port, () => {
      console.log('[INFO] Bot listening on *:' + port)

      if (!this.config.IS_LOCAL_FILE && this.config.SHOW_INIT_MESSAGE) {
        console.log('[INFO] Please enter the following command on your server to send the logs to the server.')
        console.log('       Be sure to replace "PATH_TO_MINECRAFT_SERVER_INSTALL" with the path to your Minecraft install')
        console.log('       and replace "YOUR_URL" with the URL/IP of the server running Shulker!')
        console.log(`  \`tail -F /PATH_TO_MINECRAFT_SERVER_INSTALL/logs/latest.log | grep --line-buffered ": <" | while read x ; do echo -ne $x | curl -X POST -d @- http://YOUR_URL:${port}${this.config.WEBHOOK} ; done\``)
      }
    })
  }

  private initTail (callback: Callback) {
    if (fs.existsSync(this.config.LOCAL_FILE_PATH)) {
      console.log(`[INFO] Using configuration for local file at "${this.config.LOCAL_FILE_PATH}"`)
      this.tail = new Tail(this.config.LOCAL_FILE_PATH)
    } else {
      throw new Error(`[ERROR] Local file not found at "${this.config.LOCAL_FILE_PATH}"`)
    }
    this.tail.on('line', (data: string) => {
      // Parse the line to see if we care about it
      let logLine = this.parseLogLine(data)
      if (data) {
        callback(logLine)
      }
    })
    this.tail.on('error', (error: any) => {
      console.log('[ERROR] Error tailing file: ' + error)
    })
  }

  init (callback: Callback) {
    if (this.config.IS_LOCAL_FILE) {
      this.initTail(callback)
    } else {
      this.initWebServer(callback)
    }
  }
}

export default MinecraftHandler