// System health & monitoring routes — 2026-03-29
module.exports = async function systemRoutes(app, opts) {
    const os = require('os');

    // GET /api/v1/system/health — comprehensive system status
    app.get('/system/health', async (request, reply) => {
        // System info
        const system = {
            hostname: os.hostname(),
            uptime: Math.floor(os.uptime()),
            loadavg: os.loadavg(),
            cpus: os.cpus().length,
            memory: {
                total: Math.round(os.totalmem() / 1024 / 1024),
                free: Math.round(os.freemem() / 1024 / 1024),
                used_pct: Math.round((1 - os.freemem() / os.totalmem()) * 100)
            }
        };

        // DB check
        let db_status = { status: 'error' };
        try {
            const { rows } = await app.db.query('SELECT NOW() as time, pg_database_size(current_database()) as size');
            db_status = {
                status: 'ok',
                time: rows[0].time,
                size_mb: Math.round(rows[0].size / 1024 / 1024)
            };
        } catch (e) {
            db_status = { status: 'error', message: e.message };
        }

        // Redis check
        let redis_status = { status: 'error' };
        try {
            const pong = await app.redis.ping();
            const info = await app.redis.info('memory');
            const usedMem = info.match(/used_memory_human:(.+)/)?.[1]?.trim();
            redis_status = {
                status: pong === 'PONG' ? 'ok' : 'error',
                memory: usedMem
            };
        } catch (e) {
            redis_status = { status: 'error', message: e.message };
        }

        // Task stats
        let task_stats = {};
        try {
            const { rows } = await app.db.query(`
                SELECT status, count(*)::int as count FROM tasks GROUP BY status
                UNION ALL SELECT 'total', count(*)::int FROM tasks
                UNION ALL SELECT 'users', count(*)::int FROM users
                UNION ALL SELECT 'goals', count(*)::int FROM goals
            `);
            task_stats = Object.fromEntries(rows.map(r => [r.status, r.count]));
        } catch (e) {
            task_stats = { error: e.message };
        }

        // Determine overall status
        const overall = (db_status.status === 'ok' && redis_status.status === 'ok') ? 'ok' : 'degraded';

        return {
            status: overall,
            timestamp: new Date().toISOString(),
            system,
            database: db_status,
            redis: redis_status,
            tasks: task_stats,
            version: require('../../package.json').version || '1.0.0'
        };
    });

    // GET /api/v1/system/ping — lightweight liveness check
    app.get('/system/ping', async () => ({ pong: true, ts: Date.now() }));
};