/**
 * Clawlink Plugin — Logger
 *
 * 统一日志模块，写入 OpenClaw 标准日志目录。
 * 禁止在 Gateway 运行时使用任何 console 输出。
 *
 * 级别控制优先级：环境变量 > 默认 DEBUG（产品发布后改为 INFO）
 */

import fs from "node:fs";
import os from "node:os";
import path from "node:path";

import { resolvePreferredOpenClawTmpDir } from "openclaw/plugin-sdk/infra-runtime";

// ── 常量 ──

const LOG_DIR: string = resolvePreferredOpenClawTmpDir();

const SUBSYSTEM = "gateway/channels/clawlink";
const HOSTNAME: string = os.hostname() || "unknown";

const LEVEL_IDS: Record<string, number> = {
  TRACE: 1,
  DEBUG: 2,
  INFO: 3,
  WARN: 4,
  ERROR: 5,
  FATAL: 6,
};

const DEFAULT_LEVEL = "DEBUG";

// ── 级别控制 ──

/**
 * 解析最终日志级别。
 * 优先级：环境变量 > 默认 DEBUG
 */
function resolveMinLevel(): number {
  const env = process.env.OPENCLAW_LOG_LEVEL?.toUpperCase();
  if (env && env in LEVEL_IDS) return LEVEL_IDS[env];

  return LEVEL_IDS[DEFAULT_LEVEL];
}

let minLevelId: number = resolveMinLevel();

/** 运行时动态修改日志级别 */
export function setLogLevel(level: string): void {
  const upper = level.toUpperCase();
  if (!(upper in LEVEL_IDS)) {
    throw new Error(`Invalid log level: ${level}. Valid: ${Object.keys(LEVEL_IDS).join(", ")}`);
  }
  minLevelId = LEVEL_IDS[upper];
}

// ── 时间格式化 ──

function toLocalISO(now: Date): string {
  const offsetMs = -now.getTimezoneOffset() * 60_000;
  const sign = offsetMs >= 0 ? "+" : "-";
  const abs = Math.abs(now.getTimezoneOffset());
  const hh = String(Math.floor(abs / 60)).padStart(2, "0");
  const mm = String(abs % 60).padStart(2, "0");
  return new Date(now.getTime() + offsetMs).toISOString().replace("Z", `${sign}${hh}:${mm}`);
}

function resolveLogPath(): string {
  const dateKey = toLocalISO(new Date()).slice(0, 10);
  return path.join(LOG_DIR, `openclaw-${dateKey}.log`);
}

// ── 写入 ──

let logDirEnsured = false;

function writeLog(level: string, message: string): void {
  const levelId = LEVEL_IDS[level] ?? LEVEL_IDS.INFO;
  if (levelId < minLevelId) return;

  const now = new Date();
  const entry = JSON.stringify({
    "0": SUBSYSTEM,
    "1": message,
    _meta: {
      runtime: "node",
      runtimeVersion: process.versions.node,
      hostname: HOSTNAME,
      name: SUBSYSTEM,
      parentNames: ["openclaw"],
      date: now.toISOString(),
      logLevelId: levelId,
      logLevelName: level,
    },
    time: toLocalISO(now),
  });

  try {
    if (!logDirEnsured) {
      fs.mkdirSync(LOG_DIR, { recursive: true });
      logDirEnsured = true;
    }
    fs.appendFileSync(resolveLogPath(), `${entry}\n`, "utf-8");
  } catch {
    // 写日志失败不应阻塞业务
  }
}

// ── 导出 ──

export type Logger = {
  trace(message: string): void;
  debug(message: string): void;
  info(message: string): void;
  warn(message: string): void;
  error(message: string): void;
  fatal(message: string): void;
  getLogFilePath(): string;
};

export const logger: Logger = {
  trace(message: string): void { writeLog("TRACE", message); },
  debug(message: string): void { writeLog("DEBUG", message); },
  info(message: string): void  { writeLog("INFO", message); },
  warn(message: string): void  { writeLog("WARN", message); },
  error(message: string): void { writeLog("ERROR", message); },
  fatal(message: string): void { writeLog("FATAL", message); },

  getLogFilePath(): string { return resolveLogPath(); },
};