// /components/payments/paymentModel.js
'use strict';

const mongoose = require('mongoose');

const { getPayableAmount, normalizeDiscount } = require('../../utils/paymentAmount');

const transactionSchema = new mongoose.Schema({
  amount: { type: Number, required: true },
  method: {
    type: String,
    enum: ['online', 'card', 'cash'],
    default: 'card'
  },
  receiptNumber: { type: String, trim: true },
  notes: { type: String, trim: true, maxlength: 5000 },
  recordedBy: { type: mongoose.Schema.Types.ObjectId, ref: 'User' },
  date: { type: Date, default: Date.now }
}, { _id: true });

const paymentSchema = new mongoose.Schema({
  user: {
    type: mongoose.Schema.Types.ObjectId,
    ref: 'User',
    required: true,
    index: true
  },
  classes: [{
    type: mongoose.Schema.Types.ObjectId,
    ref: 'Class'
  }],
  course: {
    type: mongoose.Schema.Types.ObjectId,
    ref: 'Course'
  },
  amount: {
    type: Number,
    required: true,
    min: 0
  },
  discount: {
    type: Number,
    default: 0,
    min: 0
  },
  paidAmount: {
    type: Number,
    default: 0,
    min: 0
  },
  dueDate: {
    type: Date
  },
  status: {
    type: String,
    enum: ['pending', 'partial', 'paid', 'overdue'],
    default: 'pending'
  },
  transactions: [transactionSchema],
  notes: { type: String, trim: true, maxlength: 5000 }
}, {
  timestamps: true
});

// Auto-update status based on paid amount vs payable (amount - discount)
paymentSchema.pre('save', function (next) {
  this.discount = normalizeDiscount(this.discount, this.amount);
  const payable = getPayableAmount(this);
  if (this.paidAmount >= payable) {
    this.status = 'paid';
  } else if (this.paidAmount > 0) {
    this.status = 'partial';
  } else if (this.dueDate && new Date() > this.dueDate) {
    this.status = 'overdue';
  } else {
    this.status = 'pending';
  }
  next();
});

module.exports = mongoose.model('Payment', paymentSchema);