const db = require('../config/database');

class Student {
    static async findById(id) {
        const students = await db.query('SELECT * FROM students WHERE id = ?', [id]);
        return students[0];
    }

    static async create(studentData) {
        const { id, name, class: className, major, grade, contact_info } = studentData;
        await db.query(
            'INSERT INTO students (id, name, class, major, grade, contact_info) VALUES (?, ?, ?, ?, ?, ?)',
            [id, name, className, major, grade, contact_info]
        );
    }

    static async update(id, data) {
        const fields = [];
        const values = [];
        if (data.name) { fields.push('name = ?'); values.push(data.name); }
        if (data.class) { fields.push('class = ?'); values.push(data.class); }
        if (data.major !== undefined) { fields.push('major = ?'); values.push(data.major); }
        if (data.grade !== undefined) { fields.push('grade = ?'); values.push(data.grade); }
        if (data.contact_info !== undefined) { fields.push('contact_info = ?'); values.push(data.contact_info); }

        if (fields.length === 0) return true;

        values.push(id);
        const sql = `UPDATE students SET ${fields.join(', ')} WHERE id = ?`;
        await db.query(sql, values);
        return true;
    }

    static async delete(id) {
        await db.query('DELETE FROM students WHERE id = ?', [id]);
    }
}

module.exports = Student;