require('dotenv').config();

const cron = require('node-cron');
const http = require('http');

const PHP_BASE    = process.env.PHP_BASE_URL || 'http://127.0.0.1';
const PHP_WEBROOT = process.env.PHP_WEBROOT  || '/brnwms/app';
const SECRET      = process.env.EMIT_SECRET  || '';
const NODE_PORT   = process.env.PORT         || 3000;

if (!SECRET) {
    // The PHP cron endpoints refuse an empty secret; fail loudly instead of
    // sending unauthenticated calls every schedule tick.
    console.error('EMIT_SECRET is not set — scheduler not started.');
    process.exit(1);
}

function callPhp(path, body) {
    return new Promise((resolve, reject) => {
        const payload = JSON.stringify(body);
        const url     = new URL(PHP_BASE + PHP_WEBROOT + path);

        const options = {
            hostname: url.hostname,
            port:     url.port || 80,
            path:     url.pathname,
            method:   'POST',
            headers: {
                'Content-Type':    'application/json',
                'Content-Length':  Buffer.byteLength(payload),
                'x-cron-secret':   SECRET,
            },
        };

        const req = http.request(options, (res) => {
            let data = '';
            res.on('data', (chunk) => { data += chunk; });
            res.on('end', () => {
                try { resolve(JSON.parse(data)); }
                catch (e) { reject(new Error('Bad JSON: ' + data.slice(0, 100))); }
            });
        });

        req.on('error', reject);
        req.write(payload);
        req.end();
    });
}

function callEmit(company_id, event, data) {
    const payload = JSON.stringify({ event, data, company_id });
    const options = {
        hostname: '127.0.0.1',
        port:     NODE_PORT,
        path:     '/emit',
        method:   'POST',
        headers: {
            'Content-Type':   'application/json',
            'Content-Length': Buffer.byteLength(payload),
            'x-emit-secret':  SECRET,
        },
    };
    const req = http.request(options);
    req.on('error', (e) => console.error(`[alert] emit failed company=${company_id}:`, e.message));
    req.write(payload);
    req.end();
}

// ── ETL GL Summary maintenance — runs every hour ─────────────────────────────
// Checks and repairs etl_gl_summary (GL aggregation table).
// Each company has a fixed slot = company_id % 24 — load is spread across 24 hours.
// For etl_stock_summary add a separate schedule below when ready.
cron.schedule('0 * * * *', async () => {
    const slot = new Date().getHours();
    console.log(`[scheduler] etl_gl slot=${slot}`);

    try {
        const result = await callPhp('/cron/etl_gl_maintenance.php', { slot });
        const summary = (result.results || []).map(r =>
            r.error
                ? `company=${r.company_id} ERROR: ${r.error}`
                : `company=${r.company_id} gaps=${r.gaps_found} rebuilt=${r.periods_rebuilt}`
        );
        if (summary.length === 0) {
            console.log(`[scheduler] etl_gl slot=${slot} — no companies`);
        } else {
            summary.forEach(s => console.log(`[scheduler] etl_gl ${s}`));
        }
    } catch (e) {
        console.error('[scheduler] etl_gl_maintenance failed:', e.message);
    }
});

// ── ETL Stock Summary maintenance — runs every hour ──────────────────────────
// Checks and repairs etl_stock_summary (stock aggregation table).
// Same slot-based distribution as GL: company_id % 24.
cron.schedule('30 * * * *', async () => {
    const slot = new Date().getHours();
    console.log(`[scheduler] etl_stock slot=${slot}`);

    try {
        const result = await callPhp('/cron/etl_stock_maintenance.php', { slot });
        const summary = (result.results || []).map(r =>
            r.error
                ? `company=${r.company_id} ERROR: ${r.error}`
                : `company=${r.company_id} gaps=${r.gaps_found} rebuilt=${r.periods_rebuilt}`
        );
        if (summary.length === 0) {
            console.log(`[scheduler] etl_stock slot=${slot} — no companies`);
        } else {
            summary.forEach(s => console.log(`[scheduler] etl_stock ${s}`));
        }
    } catch (e) {
        console.error('[scheduler] etl_stock_maintenance failed:', e.message);
    }
});

// ── Low stock alert — runs daily at 08:00 ────────────────────────────────────
cron.schedule('0 8 * * *', async () => {
    console.log('[scheduler] alert_low_stock running');
    try {
        const result = await callPhp('/cron/alert_low_stock.php', {});
        for (const { company_id, count } of (result.alerts || [])) {
            const msg = count === 1
                ? '1 product is below minimum stock level.'
                : `${count} products are below minimum stock level.`;
            callEmit(parseInt(company_id), 'notification', { message: msg, type: 'warning' });
            console.log(`[alert] low_stock company=${company_id} count=${count}`);
        }
    } catch (e) {
        console.error('[scheduler] alert_low_stock failed:', e.message);
    }
});

// ── Overdue invoice alert — runs daily at 09:00 ───────────────────────────────
cron.schedule('0 9 * * *', async () => {
    console.log('[scheduler] alert_overdue_invoices running');
    try {
        const result = await callPhp('/cron/alert_overdue_invoices.php', {});
        for (const { company_id, count } of (result.alerts || [])) {
            const msg = count === 1
                ? '1 invoice is overdue and awaiting payment.'
                : `${count} invoices are overdue and awaiting payment.`;
            callEmit(parseInt(company_id), 'notification', { message: msg, type: 'danger' });
            console.log(`[alert] overdue_invoices company=${company_id} count=${count}`);
        }
    } catch (e) {
        console.error('[scheduler] alert_overdue_invoices failed:', e.message);
    }
});

console.log('[scheduler] running — etl_gl + etl_stock (hourly) | low_stock + overdue_invoices alerts (daily)');