'use strict';
const mdl_CoursePurchase = require('../../models/courses/course_purchases.mdl');
const mdl_Product        = require('../../models/courses/products.mdl');
const paymentSvc         = require('../../services/payment.service');
const R                  = require('../../utils/response.util');

// ─── CREATE ORDER ─────────────────────────────────────────────────────────────

exports.createCourseOrder = async (req, res) => {
  try {
    const { product_id } = req.body;
    if (!product_id) return R.error(res, 'product_id is required.', 400);

    const product = await mdl_Product.findOne({ where: { id: product_id, is_active: true } });
    if (!product) return R.error(res, 'Product not found or inactive.', 404);

    const existing = await mdl_CoursePurchase.findOne({
      where: { user_id: req.user.user_id, product_id, status: 'completed' },
    });
    if (existing) {
      const stillActive = !existing.expires_at || new Date(existing.expires_at) > new Date();
      if (stillActive) return R.error(res, 'You already have active access to this course.', 409);
    }

    const ppOrder = await paymentSvc.createOrder('paypal', {
      amount:      Number(product.price).toFixed(2),
      currency:    product.currency,
      referenceId: `user_${req.user.user_id}_product_${product_id}`,
      returnUrl:   `${process.env.FRONTEND_URL}/course/${product.course_id}/checkout`,
      cancelUrl:   `${process.env.FRONTEND_URL}/course/${product.course_id}/checkout?cancelled=true`,
    });

    const approvalUrl = ppOrder.links?.find((l) => l.rel === 'approve')?.href ?? null;

    const expiresAt = product.access_days
      ? new Date(Date.now() + product.access_days * 86400000)
      : null;

    const purchase = await mdl_CoursePurchase.create({
      user_id:          req.user.user_id,
      product_id,
      amount:           product.price,
      currency:         product.currency,
      status:           'pending',
      provider:         'paypal',
      expires_at:       expiresAt,
      provider_payload: { order_id: ppOrder.id, approval_url: approvalUrl },
    });

    return R.success(res, 'Order created.', {
      purchase_id:  purchase.id,
      order_id:     ppOrder.id,
      approval_url: approvalUrl,
      amount:       product.price,
      currency:     product.currency,
    }, 201);
  } catch (err) {
    console.error('[CLIENT][COURSE PURCHASE][CREATE ORDER]', err);
    return R.error(res, 'Could not create order.', 500);
  }
};

// ─── CAPTURE ORDER ────────────────────────────────────────────────────────────

exports.captureCourseOrder = async (req, res) => {
  try {
    const { order_id } = req.body;
    if (!order_id) return R.error(res, 'order_id is required.', 400);

    const purchase = await mdl_CoursePurchase.findOne({
      where:   { user_id: req.user.user_id, status: 'pending' },
      include: [{ model: mdl_Product, as: 'product' }],
      order:   [['createdAt', 'DESC']],
    });

    if (!purchase || purchase.provider_payload?.order_id !== order_id)
      return R.error(res, 'Pending purchase not found.', 404);

    let captureData;
    try {
      captureData = await paymentSvc.captureOrder(purchase.provider, order_id);
    } catch (ppErr) {
      await purchase.update({
        status:           'failed',
        provider_payload: { ...purchase.provider_payload, error: ppErr?.response?.data ?? {} },
      });
      return R.error(res, 'Payment capture failed.', 402);
    }

    const capture = captureData.purchase_units?.[0]?.payments?.captures?.[0];

    await purchase.update({
      status:           'completed',
      paid_at:          new Date(),
      provider_payload: {
        ...purchase.provider_payload,
        capture_id: capture?.id,
        payer_id:   captureData.payer?.payer_id,
        capture:    captureData,
      },
    });

    return R.success(res, 'Payment successful. Course access granted.', {
      purchase_id: purchase.id,
      expires_at:  purchase.expires_at,
      course_id:   purchase.product.course_id,
    });
  } catch (err) {
    console.error('[CLIENT][COURSE PURCHASE][CAPTURE]', err);
    return R.error(res, 'Could not capture order.', 500);
  }
};

// ─── CANCEL ORDER ─────────────────────────────────────────────────────────────

exports.cancelCourseOrder = async (req, res) => {
  try {
    const { order_id } = req.body;
    if (!order_id) return R.error(res, 'order_id is required.', 400);

    const purchase = await mdl_CoursePurchase.findOne({
      where: { user_id: req.user.user_id, status: 'pending' },
      order: [['createdAt', 'DESC']],
    });

    if (!purchase || purchase.provider_payload?.order_id !== order_id)
      return R.error(res, 'Pending purchase not found.', 404);

    await purchase.update({
      status:           'cancelled',
      provider_payload: { ...purchase.provider_payload, cancelled_at: new Date().toISOString() },
    });

    return R.success(res, 'Purchase cancelled.');
  } catch (err) {
    console.error('[CLIENT][COURSE PURCHASE][CANCEL]', err);
    return R.error(res, 'Could not cancel purchase.', 500);
  }
};

// ─── MY PURCHASES ─────────────────────────────────────────────────────────────

exports.getMyPurchases = async (req, res) => {
  try {
    const purchases = await mdl_CoursePurchase.findAll({
      where:      { user_id: req.user.user_id },
      include:    [{ model: mdl_Product, as: 'product', attributes: ['id', 'name', 'course_id', 'access_days'] }],
      attributes: { exclude: ['provider_payload'] },
      order:      [['createdAt', 'DESC']],
    });
    return R.success(res, 'Purchases retrieved.', purchases);
  } catch (err) {
    console.error('[CLIENT][COURSE PURCHASE][GET MINE]', err);
    return R.error(res, 'Could not retrieve purchases.', 500);
  }
};