import express from 'express';
import cors from 'cors';
import { createClient } from '@supabase/supabase-js';

// ==========================================
// ⚙️ CONFIGURATION & SETTINGS
// ==========================================
const PORT = process.env.PORT || 7860; 
const SUPABASE_URL = process.env.SUPABASE_URL;
const SUPABASE_KEY = process.env.SUPABASE_SERVICE_KEY;
const CRON_SECRET = process.env.CRON_SECRET || "default_secret";

// 🔴 VARIABLE BOOLEAN: Should past/missed jobs fire immediately on server startup?
const RUN_PAST_EVENTS_ON_STARTUP = true; 

if (!SUPABASE_URL || !SUPABASE_KEY) {
    console.error("❌ Missing Supabase Credentials");
    process.exit(1);
}

const app = express();
const supabase = createClient(SUPABASE_URL, SUPABASE_KEY);
const activeJobs = new Map();

app.use(express.json());
app.use(cors());

// ==========================================
// ⏱️ BULLETPROOF TIMEZONE MATH
// ==========================================
function getNextFiveAMDetails(rawOffset = 0) {
    let offsetHours = 0;
    
    // Auto-detect if payload sent Minutes (from JS) or standard Hours
    // JS getTimezoneOffset() is large (e.g. 300 for EST, -60 for CET)
    if (Math.abs(rawOffset) >= 30) {
        offsetHours = -(rawOffset / 60); 
    } else {
        offsetHours = Number(rawOffset); // Already in hours (e.g. -5)
    }

    const now = new Date();
    const target = new Date(now.getTime());
    
    // Set to today's midnight UTC
    target.setUTCHours(0, 0, 0, 0);
    
    // Target 5 AM in the specified timezone
    // Example (EST / UTC-5): 5 - (-5) = 10:00 AM UTC
    // Example (CET / UTC+1): 5 - (+1) = 04:00 AM UTC
    target.setUTCHours(5 - offsetHours);
    
    // If 5 AM has ALREADY PASSED in that timezone today, schedule for tomorrow
    if (target.getTime() <= now.getTime()) {
        target.setUTCDate(target.getUTCDate() + 1);
    }

    return {
        delayMs: target.getTime() - now.getTime(),
        offsetHours: offsetHours
    };
}

// ==========================================
// 🚀 JOB EXECUTION & SCHEDULING
// ==========================================
async function executeJob(jobId) {
    const job = activeJobs.get(jobId);
    if (!job) return;

    console.log(`⏰ [${new Date().toLocaleTimeString()}] Executing: ${jobId}`);
    try {
        const res = await fetch(job.url, {
            method: 'POST',
            headers: { 'Content-Type': 'application/json' },
            body: JSON.stringify(job.payload)
        });
        
        console.log(`   └─ Response: ${res.status}`);

        // ✅ UPDATE DATABASE ON SUCCESS
        if (res.ok) {
            const { error } = await supabase
                .from('system_jobs')
                .update({ updated_at: new Date().toISOString() })
                .eq('id', jobId);

            if (!error) {
                console.log(`   └─ 💾 Database 'updated_at' successfully synced.`);
            } else {
                console.error(`   └─ ❌ Failed to update DB:`, error.message);
            }
        }

    } catch (e) {
        console.error(`❌ Job ${jobId} HTTP Failed:`, e.message);
    }
}

function startJobInternal(jobId, intervalMs, url, payload, delayData, runImmediately = false) {
    let delay = delayData.delayMs;
    let offsetHours = delayData.offsetHours;

    // Failsafe format for log printing (e.g., UTC+1 or UTC-5)
    const tzString = `UTC${offsetHours >= 0 ? '+' : ''}${offsetHours}`;

    const nextRunAt = Date.now() + delay;
    const hours = (delay / 1000 / 60 / 60).toFixed(2);
    const minutes = (delay / 1000 / 60).toFixed(2);

    activeJobs.set(jobId, {
        url,
        payload,
        intervalMs,
        offset: offsetHours,
        nextRunAt
    });

    if (runImmediately) {
        console.log(`⚡ [Startup] Missed event detected! Firing immediately: ${jobId}`);
        executeJob(jobId); 
        console.log(`⏳ Job ${jobId} re-scheduled. Target: 5AM (${tzString}). Next run in ${hours} hours (${minutes} mins).`);
    } else {
        console.log(`⏳ Job ${jobId} scheduled. Target: 5AM (${tzString}). Next run in ${hours} hours (${minutes} mins).`);
    }
}

// ==========================================
// ⚙️ THE TICK ENGINE (WATCHDOG)
// ==========================================
setInterval(() => {
    const now = Date.now();

    for (const [jobId, job] of activeJobs.entries()) {
        if (now >= job.nextRunAt) {
            executeJob(jobId); 
            
            const nextDelayData = getNextFiveAMDetails(job.offset);
            job.nextRunAt = now + nextDelayData.delayMs;
            
            const hours = (nextDelayData.delayMs / 1000 / 60 / 60).toFixed(2);
            console.log(`🔄 Job ${jobId} entered 24h cycle. Target: 5AM (UTC${job.offset >= 0 ? '+' : ''}${job.offset}). Next run in ${hours} hours.`);
        }
    }
}, 60000); 

// ==========================================
// 💾 DB HYDRATION USING `updated_at`
// ==========================================
async function hydrateJobs() {
    console.log("💧 Hydrating Cron Jobs from DB...");
    const { data, error } = await supabase.from('system_jobs').select('*');
    
    if (error) {
        console.error("❌ Hydration Failed:", error.message);
        return;
    }

    let count = 0;
    const now = Date.now();

    for (const job of data) {
        const delayData = getNextFiveAMDetails(job.payload?.timezoneOffset ?? 0);
        let runImmediately = false;

        // ✅ CHECK LAST UPDATED TIME
        if (job.updated_at) {
            const lastUpdatedTime = new Date(job.updated_at).getTime();
            const timeSinceLastRunMs = now - lastUpdatedTime;
            
            // If it's been more than 24 hours (86,400,000 ms), fire it immediately to catch up.
            if (RUN_PAST_EVENTS_ON_STARTUP && timeSinceLastRunMs >= 86400000) {
                runImmediately = true;
            }
        } else if (RUN_PAST_EVENTS_ON_STARTUP) {
            runImmediately = true;
        }

        startJobInternal(job.id, job.interval_ms, job.webhook_url, job.payload, delayData, runImmediately);
        count++;
    }
    console.log(`✅ Successfully hydrated and scheduled ${count} jobs.`);
}

app.get('/', (req, res) => res.json({ status: "Cron Registry Active", active_jobs: activeJobs.size }));

app.post('/register', async (req, res) => {
    const { secret, jobId, intervalMs, webhookUrl, payload, initialDelay, leadId } = req.body;

    if (secret !== CRON_SECRET) return res.status(403).json({ error: "Unauthorized" });

    const { error } = await supabase.from('system_jobs').upsert({
        id: jobId,
        lead_id: leadId,
        interval_ms: intervalMs,
        webhook_url: webhookUrl,
        payload: payload,
        updated_at: new Date().toISOString()
    });
  
    if (error) return res.status(500).json({ error: error.message });

    const delayData = getNextFiveAMDetails(payload?.timezoneOffset || 0);
    if (initialDelay !== undefined) {
        delayData.delayMs = initialDelay;
    }
    
    startJobInternal(jobId, intervalMs, webhookUrl, payload, delayData, false);

    console.log(`➕ Registered & Scheduled Job (5AM Anchor): ${jobId}`);
    res.json({ success: true, jobId });
});

app.post('/deregister', async (req, res) => {
    const { secret, jobId } = req.body;
    if (secret !== CRON_SECRET) return res.status(403).json({ error: "Unauthorized" });
    
    await supabase.from('system_jobs').delete().eq('id', jobId);
    if (activeJobs.has(jobId)) {
        activeJobs.delete(jobId);
    }
    
    console.log(`➖ Deregistered Job: ${jobId}`);
    res.json({ success: true });
});

app.listen(PORT, async () => {
    console.log(`🚀 Cron Registry live on port ${PORT}`);
    setTimeout(hydrateJobs, 2000);
});