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

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

    static async create(teacherData) {
        const { id, name, department, title, contact_info } = teacherData;
        await db.query(
            'INSERT INTO teachers (id, name, department, title, contact_info) VALUES (?, ?, ?, ?, ?)',
            [id, name, department, title, contact_info]
        );
    }

    static async update(id, data) {
        const fields = [];
        const values = [];
        if (data.name) { fields.push('name = ?'); values.push(data.name); }
        if (data.department) { fields.push('department = ?'); values.push(data.department); }
        if (data.title !== undefined) { fields.push('title = ?'); values.push(data.title); }
        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 teachers SET ${fields.join(', ')} WHERE id = ?`;
        await db.query(sql, values);
        return true;
    }

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

module.exports = Teacher;