import { DynamicModule } from '@nestjs/common';
import { LoggerModule } from 'nestjs-pino';

/** 解析调用栈，返回打印日志的「文件:行号」（相对 src 的源码路径）。 */
function getCaller(): string | undefined {
  const stack = new Error().stack?.split('\n') ?? [];
  for (const line of stack) {
    const m = line.match(/(?:file:\/\/)?(\/[^\s:]+):(\d+):\d+\)?$/);
    if (!m) continue;
    const path = m[1];
    // 跳过依赖与日志模块自身；只认本项目编译产物（dist）里的调用帧
    if (path.includes('node_modules') || path.includes('/logging/')) continue;
    if (!path.includes('/dist/')) continue;
    const parts = path.split('/');
    const distIdx = parts.indexOf('dist');
    const rel = distIdx >= 0 ? parts.slice(distIdx + 1) : parts.slice(-2);
    const file = rel[rel.length - 1].replace(/\.js$/, '.ts');
    const dir = rel.slice(0, -1).join('/');
    return dir ? `${dir}/${file}:${m[2]}` : `${file}:${m[2]}`;
  }
  return undefined;
}

/**
 * 日志配置：pino 结构化日志。
 * - stdout 默认开启：开发环境用 pino-pretty 可读格式（LOG_PRETTY 默认 true），生产设 false 输出 JSON
 * - 文件输出默认关闭，LOG_FILE_ENABLED=true 开启（文件始终为 JSON，便于采集）
 * - 每条日志附加 src（文件:行号），便于定位打印位置
 * - 级别 LOG_LEVEL（默认 info）、路径 LOG_FILE_PATH（默认 logs/app.log）
 */
export function createLoggerModule(): DynamicModule {
  const level = process.env.LOG_LEVEL ?? 'info';
  const pretty = process.env.LOG_PRETTY !== 'false';
  const fileEnabled = process.env.LOG_FILE_ENABLED === 'true';
  const filePath = process.env.LOG_FILE_PATH ?? 'logs/app.log';

  const stdoutTarget = pretty
    ? { target: 'pino-pretty', options: { colorize: true, translateTime: 'SYS:yyyy-mm-dd HH:MM:ss.l', singleLine: true } }
    : { target: 'pino/file', options: { destination: 1 } };

  const targets: any[] = [stdoutTarget];
  if (fileEnabled) {
    targets.push({ target: 'pino-roll', options: { file: filePath, size: '10m', limit: { count: 10 } } });
  }

  return LoggerModule.forRoot({
    pinoHttp: {
      level,
      transport: { targets },
      serializers: {
        req: (req: any) => ({
          id: req.id,
          method: req.method,
          url: req.url,
          query: req.query,
          params: req.params,
          remoteAddress: req.remoteAddress,
          remotePort: req.remotePort,
        }),
        res: (res: any) => ({ statusCode: res.statusCode }),
      },
      mixin() {
        const src = getCaller();
        return src ? { src } : {};
      },
    },
  });
}