/**
 * 统一日志基座（主进程）：
 * - 结构化行：`<ISO时间> <LEVEL> [<scope>] <message> k=v ...`，文件按天滚动
 *   （userData/logs/main-YYYY-MM-DD.log，保留 14 天）
 * - 级别：dev 默认 debug、打包默认 info；ASO_LOG_LEVEL=debug|info|warn|error 可覆盖
 * - 子 logger：getLogger(scope) —— 各模块用固定 scope（plugin-host / agent-service / ipc / renderer /
 *   browser），插件日志经 plugin-host 注入 scope=plugin 且带 pluginId 字段
 * - 全局兜底：uncaughtException / unhandledRejection / will-quit 落盘
 *
 * Agent 自诊断约定：日志文件路径固定，pi 侧可直接读文件排查（见 docs/plugins/06-self-diagnosis.md）。
 */
import { app } from 'electron'
import { appendFileSync, existsSync, mkdirSync, readdirSync, statSync, unlinkSync } from 'node:fs'
import { join } from 'node:path'

export type LogLevel = 'debug' | 'info' | 'warn' | 'error'

const LEVEL_ORDER: Record<LogLevel, number> = { debug: 10, info: 20, warn: 30, error: 40 }
const RETAIN_DAYS = 14
const MAX_LINE = 8 * 1024

let level: LogLevel = 'info'
let logDir: string | null = null
/** 当天文件名（含日期）缓存；跨天自动切换 */
let fileDay = ''
let fileReady = false
/** 文件不可用时保留最近日志（进程内仍可读） */
const memoryTail: string[] = []

function resolveLevel(): LogLevel {
  const env = process.env.ASO_LOG_LEVEL
  if (env === 'debug' || env === 'info' || env === 'warn' || env === 'error') return env
  return app.isPackaged ? 'info' : 'debug'
}

function ensureFile(now: Date): string | null {
  const day = now.toISOString().slice(0, 10)
  if (fileReady && fileDay === day && logDir) return join(logDir, `main-${day}.log`)
  try {
    if (!logDir) logDir = join(app.getPath('userData'), 'logs')
    if (!existsSync(logDir)) mkdirSync(logDir, { recursive: true })
    pruneOldLogs(logDir, day)
    fileDay = day
    fileReady = true
    return join(logDir, `main-${day}.log`)
  } catch {
    return null
  }
}

function pruneOldLogs(dir: string, today: string): void {
  try {
    for (const name of readdirSync(dir)) {
      const m = /^main-(\d{4}-\d{2}-\d{2})\.log$/.exec(name)
      if (!m) continue
      const ageDays = (Date.now() - statSync(join(dir, name)).mtimeMs) / 86_400_000
      if (m[1] !== today && (ageDays > RETAIN_DAYS || m[1] > today)) unlinkSync(join(dir, name))
    }
  } catch {
    // 清理失败不影响写日志
  }
}

function fmtValue(v: unknown): string {
  if (v === undefined) return 'undefined'
  if (v === null) return 'null'
  if (v instanceof Error) return v.stack ? v.stack.replace(/\s+/g, ' ').slice(0, 600) : v.message
  if (typeof v === 'object') {
    try {
      return JSON.stringify(v).slice(0, 400)
    } catch {
      return '[object]'
    }
  }
  return String(v).slice(0, 400)
}

function write(level_: LogLevel, scope: string, message: string, kv?: Record<string, unknown>): void {
  if (LEVEL_ORDER[level_] < LEVEL_ORDER[level]) return
  const now = new Date()
  const parts = [
    now.toISOString(),
    level_.toUpperCase().padEnd(5),
    `[${scope}]`,
    message.slice(0, 500)
  ]
  if (kv) {
    for (const [k, v] of Object.entries(kv)) parts.push(`${k}=${fmtValue(v)}`)
  }
  const line = parts.join(' ').slice(0, MAX_LINE)

  // 控制台镜像（dev 终端可读）
  // eslint-disable-next-line no-console
  ;(level_ === 'error' ? console.error : level_ === 'warn' ? console.warn : console.log)(line)

  memoryTail.push(line)
  if (memoryTail.length > 500) memoryTail.shift()
  const file = ensureFile(now)
  if (file) {
    try {
      appendFileSync(file, line + '\n', 'utf8')
    } catch {
      fileReady = false
    }
  }
}

export interface Logger {
  debug(message: string, kv?: Record<string, unknown>): void
  info(message: string, kv?: Record<string, unknown>): void
  warn(message: string, kv?: Record<string, unknown>): void
  error(message: string, kv?: Record<string, unknown>): void
}

export function getLogger(scope: string): Logger {
  return {
    debug: (message, kv) => write('debug', scope, message, kv),
    info: (message, kv) => write('info', scope, message, kv),
    warn: (message, kv) => write('warn', scope, message, kv),
    error: (message, kv) => write('error', scope, message, kv)
  }
}

/** 最近日志（内存尾部；诊断 IPC 预留） */
export function recentLines(count = 100): string[] {
  return memoryTail.slice(-count)
}

export function initLogger(): void {
  level = resolveLevel()
  const log = getLogger('logger')
  process.on('uncaughtException', (err) => {
    log.error('uncaughtException', { err })
  })
  process.on('unhandledRejection', (reason) => {
    log.error('unhandledRejection', { err: reason })
  })
  app.on('will-quit', () => {
    log.info('app quit')
  })
  log.info('logger init', { level, userData: app.getPath('userData') })
}