import pino from 'pino'
import { join } from 'node:path'
import { mkdirSync, existsSync } from 'node:fs'

let rootLogger: pino.Logger

export interface LoggerConfig {
  debug: boolean
  logDir?: string
}

/** Pretty-print config for console output */
const PRETTY_CONFIG = {
  colorize: true,
  translateTime: 'SYS:HH:MM:ss.l',
  ignore: 'pid,hostname',
} as const

export function initLogger(config: LoggerConfig): pino.Logger {
  const { debug, logDir } = config

  if (debug) {
    const dir = logDir || join(process.cwd(), '.acp-proxy')
    if (!existsSync(dir)) {
      mkdirSync(dir, { recursive: true })
    }

    const now = new Date()
    const timestamp = now
      .toISOString()
      .replace(/T/, '_')
      .replace(/:/g, '-')
      .replace(/\..+/, '')
    const logFile = join(dir, `acp-proxy-${timestamp}.log`)

    // Debug mode: JSON to file + pretty to console (multistream)
    rootLogger = pino(
      {
        level: 'trace',
        timestamp: pino.stdTimeFunctions.isoTime,
      },
      pino.transport({
        targets: [
          { target: 'pino/file', options: { destination: logFile } },
          {
            target: 'pino-pretty',
            options: { ...PRETTY_CONFIG, destination: 1 },
          },
        ],
      }),
    )

    console.log(`📝 Debug logging enabled: ${logFile}`)
  } else {
    rootLogger = pino(
      { level: 'info', timestamp: pino.stdTimeFunctions.isoTime },
      pino.transport({
        target: 'pino-pretty',
        options: { ...PRETTY_CONFIG, destination: 1 },
      }),
    )
  }

  return rootLogger
}

/** Get the root logger (auto-creates a default one if not initialized). */
export function getLogger(): pino.Logger {
  if (!rootLogger) {
    rootLogger = pino(
      { level: 'info' },
      pino.transport({
        target: 'pino-pretty',
        options: { ...PRETTY_CONFIG, destination: 1 },
      }),
    )
  }
  return rootLogger
}

/**
 * Create a child logger scoped to a module.
 * Usage: `const log = createLogger("agent"); log.info({ pid }, "spawned")`
 */
export function createLogger(module: string): pino.Logger {
  return getLogger().child({ module })
}