const mongoose = require('mongoose');
const bcrypt = require('bcryptjs');

const userSchema = new mongoose.Schema({
    username: {
        type: String,
        required: true,
        unique: true,
        trim: true
    },
    password: {
        type: String,
        required: true
    },
    role: {
        type: String,
        enum: ['student', 'teacher', 'admin'],
        default: 'student'
    },
    createdAt: {
        type: Date,
        default: Date.now
    }
});

// 密码加密中间件
userSchema.pre('save', async function (next) {
    if (!this.isModified('password')) return next();

    try {
        const salt = await bcrypt.genSalt(10);
        this.password = await bcrypt.hash(this.password, salt);
        next();
    } catch (err) {
        next(err);
    }
});

// 密码验证方法
userSchema.methods.comparePassword = async function (candidatePassword) {
    return await bcrypt.compare(candidatePassword, this.password);
};

module.exports = mongoose.model('User', userSchema);