// app.post("/photos/upload", uploadPhoto.single("photo"), (req, res) => {
//     if (!req.file) {
//         return res.status(400).json({
//             success: false,
//             error: 'Expect form‑data field "photo" (file)'
//         });
//     }
//     return res.json({
//         success: true,
//         saved_as: `photos/${req.file.filename}`
//     });
// });


// app.post("/photos/upload", uploadPhoto.single("photo"), (req, res) => {
//     if (!req.file) {
//         return res.status(400).json({
//             success: false,
//             error: 'Expect form‑data field "photo" (file)'
//         });
//     }

//     // 🔁 Run register.py automatically
//     const python = spawn("python", ["./python/register.py"]);

//     python.stdout.on("data", (data) => {
//         console.log(`✅ register.py: ${data}`);
//     });

//     python.stderr.on("data", (data) => {
//         console.error(`❌ register.py error: ${data}`);
//     });

//     python.on("close", (code) => {
//         console.log(`🔁 register.py exited with code ${code}`);
//     });

//     return res.json({
//         success: true,
//         saved_as: `photos/${req.file.filename}`,
//         message: "Photo uploaded and registration triggered"
//     });
// });




//verify

app.post("/verify", upload.single("photo"), async (req, res) => {
    if (!req.file)
        return res.status(400).json({ error: 'Expect form‑data field "photo"' });

    try {
        const result = await runPython(
            "./python/verify.py",
            [resolve(req.file.path)]
        );
        res.json(result);
    } catch (e) {
        console.error(e);
        res.status(500).json({ error: "Verification failed", details: String(e) });
    }
});


//verify2

app.post("/verify", upload.single("photo"), async (req, res) => {
    if (!req.file)
        return res.status(400).json({ error: 'Expect form‑data field "photo"' });

    // 1️⃣ Run Python verifier
    let verification;
    try {
        verification = await runPython(
            "./python/verify.py",
            [resolve(req.file.path)]
        );
    } catch (e) {
        console.error(e);
        return res.status(500).json({ error: "Verification failed", details: String(e) });
    }

    // 2️⃣ Prepare async DB helpers
    const query = promisify(db.query).bind(db);
    const today = new Date().toISOString().slice(0, 10);         // YYYY‑MM‑DD
    const grpImg = path.basename(req.file.filename);               // saved name

    // 3️⃣ Process each student asynchronously
    const ops = (verification.results || []).map(async (rec) => {
        if (!rec.name) return;

        try {
            // fetch student_id
            const rows = await query("SELECT id FROM students WHERE name = ? LIMIT 1", [rec.name]);
            if (rows.length === 0) {
                console.warn(`⚠️ No DB student for "${rec.name}"`);
                return;
            }
            const studentId = rows[0].id;

            // insert/update attendance
            const sql = `
          INSERT INTO attendance
            (student_id, date, status, image)
          VALUES (?, ?, ?, ?)
          ON DUPLICATE KEY UPDATE
            status     = VALUES(status),
            image      = VALUES(image),
            updatedAt  = CURRENT_TIMESTAMP
        `;
            await query(sql, [
                studentId,
                today,
                rec.attendance,
                grpImg
            ]);
            console.log(`📌 Attendance logged: ${rec.name} -> ${rec.attendance}`);
        } catch (err) {
            console.error(`❌ DB op failed for ${rec.name}:`, err);
        }
    });

    await Promise.all(ops);   // wait for every insert before responding

    // 4️⃣ Send the SAME JSON back to client
    res.json(verification);
});


//verify3

// import { promisify } from "util"; // At top

app.post("/verify", upload.single("photo"), async (req, res) => {
    if (!req.file)
        return res.status(400).json({ error: 'Expect form‑data field "photo"' });

    // 1️⃣ Run Python verifier
    let verification;
    try {
        verification = await runPython(
            "./python/verify.py",
            [resolve(req.file.path)]
        );
    } catch (e) {
        console.error(e);
        return res.status(500).json({ error: "Verification failed", details: String(e) });
    }

    // 2️⃣ Check if there are any registered students
    const query = promisify(db.query).bind(db);
    const today = new Date().toISOString().slice(0, 10);         // YYYY‑MM‑DD
    const grpImg = path.basename(req.file.filename);             // saved name

    let studentRows = [];
    try {
        studentRows = await query("SELECT id, name FROM students");
        if (studentRows.length === 0) {
            return res.status(200).json({
                image: grpImg,
                message: "No registered student found in database",
                class_strength: 0,
                present: 0,
                absent: 0,
                results: []
            });
        }
    } catch (err) {
        console.error("❌ MySQL query failed:", err);
        return res.status(500).json({ error: "Database error", details: String(err) });
    }

    // 3️⃣ Process attendance logging
    const ops = (verification.results || []).map(async (rec) => {
        if (!rec.name) return;

        try {
            // fetch student_id
            const rows = await query("SELECT id FROM students WHERE name = ? LIMIT 1", [rec.name]);
            if (rows.length === 0) {
                console.warn(`⚠️ No DB student for "${rec.name}"`);
                return;
            }
            const studentId = rows[0].id;

            // insert/update attendance
            const sql = `
                INSERT INTO attendance
                    (student_id, date, status, image)
                VALUES (?, ?, ?, ?)
                ON DUPLICATE KEY UPDATE
                    status = VALUES(status),
                    image = VALUES(image),
                    updatedAt = CURRENT_TIMESTAMP
            `;
            await query(sql, [studentId, today, rec.attendance, grpImg]);
            console.log(`📌 Attendance logged: ${rec.name} -> ${rec.attendance}`);
        } catch (err) {
            console.error(`❌ DB op failed for ${rec.name}:`, err);
        }
    });

    await Promise.all(ops);

    // 4️⃣ Send the same enriched response
    res.json(verification);
});