import * as fs from 'fs'
import * as path from 'path'

import Logger, { LoggerType } from '#application/logger'

export class LogReader {
  private logger = Logger.type(LoggerType.CONSOLE)
  private watchers: fs.FSWatcher[] = []
  private readonly logsDirectory: string

  constructor(rootPath: string) {
    this.logsDirectory = path.join(rootPath, 'logs')
  }

  public start(): void {
    this.logger.info('Starting log reader...')
    this.watchLogs()
  }

  public stop(): void {
    this.watchers.forEach((watcher) => watcher.close())
    this.watchers = []
  }

  private watchLogs(): void {
    // Watch directory for new files
    const directoryWatcher = fs.watch(this.logsDirectory, (_, filename) => {
      if (filename?.endsWith('.log')) {
        this.watchLogFile(filename)
      }
    })
    this.watchers.push(directoryWatcher)

    // Watch existing files
    try {
      fs.readdirSync(this.logsDirectory)
        .filter((file) => file.endsWith('.log'))
        .forEach((file) => this.watchLogFile(file))
    } catch (error) {
      this.logger.error(`Error reading logs directory: ${error}`)
    }
  }

  private watchLogFile(filename: string): void {
    const filePath = path.join(this.logsDirectory, filename)
    let currentPosition = fs.existsSync(filePath) ? fs.statSync(filePath).size : 0

    const watcher = fs.watch(filePath, () => {
      try {
        const stat = fs.statSync(filePath)
        const newPosition = stat.size

        if (newPosition < currentPosition) {
          currentPosition = 0
        }

        if (newPosition > currentPosition) {
          const stream = fs.createReadStream(filePath, {
            start: currentPosition,
            end: newPosition
          })

          stream.on('data', (data) => {
            console.log(`[${filename}]`);
            console.log(data.toString()); //
          })

          currentPosition = newPosition
        }
      } catch {
        watcher.close()
      }
    })

    this.watchers.push(watcher)
  }
}