import { createLogger, format, transports } from 'winston'
import Transport from 'winston-transport'
import type { SqliteCache } from './adapters/cache/sqlite.js'

/**
 * Custom winston transport that writes log entries to a SqliteCache instance.
 */
export class SqliteTransport extends Transport {
  private cache: SqliteCache

  constructor(cache: SqliteCache, opts?: Transport.TransportStreamOptions) {
    super(opts)
    this.cache = cache
  }

  log(info: { level: string; message: string }, callback: () => void): void {
    setImmediate(() => this.emit('logged', info))
    this.cache.writeLog(info.level, info.message)
    callback()
  }
}

/**
 * Global logger instance. Starts with console transport only.
 * The SQLite transport is added later once a SqliteCache is available.
 */
export const logger = createLogger({
  level: 'info',
  format: format.combine(
    format.timestamp(),
    format.printf(({ timestamp, level, message }) => {
      return `${timestamp as string} [${level}] ${message as string}`
    }),
  ),
  transports: [
    new transports.Console(),
  ],
})

/**
 * Attaches the SQLite transport to the global logger.
 * Called once during startup after the SqliteCache is created.
 */
export function attachSqliteTransport(cache: SqliteCache): void {
  logger.add(new SqliteTransport(cache))
}

/**
 * Removes the console transport from the logger.
 * Called when the process is running as a background service.
 */
export function removeConsoleTransport(): void {
  logger.transports
    .filter(t => t instanceof transports.Console)
    .forEach(t => logger.remove(t))
}