import { Router } from "express";
import { createRequire } from "module";
import { getPoolStats } from "../services/browser.js";
import { pool } from "../services/db.js";
const require = createRequire(import.meta.url);
const { version: APP_VERSION } = require("../../package.json");
export const healthRouter = Router();
const HEALTH_CHECK_TIMEOUT_MS = 3000;
/**
 * @openapi
 * /health:
 *   get:
 *     tags: [System]
 *     summary: Health check
 *     description: Returns service health status including database connectivity and browser pool stats.
 *     responses:
 *       200:
 *         description: Service is healthy
 *         content:
 *           application/json:
 *             schema:
 *               type: object
 *               properties:
 *                 status:
 *                   type: string
 *                   enum: [ok, degraded]
 *                 version:
 *                   type: string
 *                   example: '0.4.0'
 *                 database:
 *                   type: object
 *                   properties:
 *                     status:
 *                       type: string
 *                       enum: [ok, error]
 *                     version:
 *                       type: string
 *                       example: 'PostgreSQL 17.4'
 *                 pool:
 *                   type: object
 *                   properties:
 *                     size:
 *                       type: integer
 *                     active:
 *                       type: integer
 *                     available:
 *                       type: integer
 *                     queueDepth:
 *                       type: integer
 *                     pdfCount:
 *                       type: integer
 *                     restarting:
 *                       type: boolean
 *                     uptimeSeconds:
 *                       type: integer
 *       503:
 *         description: Service is degraded (database issue)
 */
healthRouter.get("/", async (_req, res) => {
    const poolStats = getPoolStats();
    let databaseStatus;
    let overallStatus = "ok";
    let httpStatus = 200;
    // Check database connectivity with a real query and timeout
    try {
        const dbCheck = async () => {
            const client = await pool.connect();
            try {
                // Use SELECT 1 as a lightweight liveness probe
                await client.query('SELECT 1');
                const result = await client.query('SELECT version()');
                const version = result.rows[0]?.version || 'Unknown';
                const versionMatch = version.match(/PostgreSQL ([\d.]+)/);
                const shortVersion = versionMatch ? `PostgreSQL ${versionMatch[1]}` : 'PostgreSQL';
                client.release();
                return { status: "ok", version: shortVersion };
            }
            catch (queryErr) {
                // Destroy the bad connection so it doesn't go back to the pool
                try {
                    client.release(true);
                }
                catch (_) { }
                throw queryErr;
            }
        };
        const timeout = new Promise((_resolve, reject) => setTimeout(() => reject(new Error("Database health check timed out")), HEALTH_CHECK_TIMEOUT_MS));
        databaseStatus = await Promise.race([dbCheck(), timeout]);
    }
    catch (error) {
        databaseStatus = {
            status: "error",
            message: error instanceof Error ? error.message : "Database connection failed"
        };
        overallStatus = "degraded";
        httpStatus = 503;
    }
    const response = {
        status: overallStatus,
        version: APP_VERSION,
        database: databaseStatus,
        pool: {
            size: poolStats.poolSize,
            active: poolStats.totalPages - poolStats.availablePages,
            available: poolStats.availablePages,
            queueDepth: poolStats.queueDepth,
            pdfCount: poolStats.pdfCount,
            restarting: poolStats.restarting,
            uptimeSeconds: Math.round(poolStats.uptimeMs / 1000),
        },
    };
    res.status(httpStatus).json(response);
});