/***********************************************************************************************************************************************************************
 * File Name: payment.service.js
 * Type of Program: Service
 * Description: Provider-agnostic payment orchestration.
 *              - Loads payment policy per plan (promo rules, refund policy, allowed providers)
 *              - Evaluates promo codes server-side (type: flat | percent)
 *              - Calculates refund eligibility window (unit: minutes | hours | days)
 *              - Delegates create/capture/refund to the provider registry
 * Author: Kenneth Obsequio (@lash0000)
 * Date Created: Jun. 29, 2026
 ***********************************************************************************************************************************************************************/
'use strict';

const registry            = require('../providers/registry');
const mdl_PaymentPolicies = require('../models/tiers/payment_policies.mdl');
const mdl_Payments        = require('../models/tiers/payments.mdl');

// ─── Defaults ─────────────────────────────────────────────────────────────────

const DEFAULT_REFUND_POLICY = {
  allowed:         true,
  window_value:    5,
  window_unit:     'minutes',
  reason_required: false,
};

const UNIT_MS = { minutes: 60_000, hours: 3_600_000, days: 86_400_000 };

// ─── Policy ───────────────────────────────────────────────────────────────────

async function getPolicyForPlan(plan_id) {
  return mdl_PaymentPolicies.findOne({ where: { plan_id } });
}

// ─── Refund window ────────────────────────────────────────────────────────────

function getRefundWindowMs(policy) {
  const rp = policy?.refund_policy ?? DEFAULT_REFUND_POLICY;
  const { window_value = 5, window_unit = 'minutes' } = rp;
  return Number(window_value) * (UNIT_MS[window_unit] ?? 60_000);
}

function isRefundAllowed(policy) {
  return policy?.refund_policy?.allowed ?? DEFAULT_REFUND_POLICY.allowed;
}

// ─── Promo evaluation ─────────────────────────────────────────────────────────

// effectivePrice — pass the localized price when charging in a non-base currency
// so discounts are computed against the actual amount being charged.
async function evaluatePromo(policy, plan, rawCode, effectivePrice = null) {
  const code = rawCode?.trim?.().toUpperCase?.() ?? null;
  if (!code) return { valid: false, reason: 'No promo code provided.' };

  const rules = policy?.promo_rules ?? [];
  const rule = rules.find((r) => r.code?.toUpperCase() === code);
  if (!rule) return { valid: false, reason: 'Invalid promo code.' };

  if (rule.expires_at && new Date(rule.expires_at) < new Date())
    return { valid: false, reason: 'Promo code has expired.' };

  // Count how many completed payments used this code for this plan. Scoped to
  // 'completed' only — pending/failed/cancelled attempts must NOT consume a
  // limited-use code, or anyone can exhaust max_uses by creating orders they
  // never pay for.
  if (rule.max_uses != null) {
    const uses = await mdl_Payments.count({
      where: { promo_code: code, plan_id: plan.plan_id, status: 'completed' },
    });
    if (uses >= Number(rule.max_uses))
      return { valid: false, reason: 'Promo code has reached its usage limit.' };
  }

  const subtotal = effectivePrice !== null ? Number(effectivePrice) : Number(plan.price);

  if (rule.min_amount != null && subtotal < Number(rule.min_amount))
    return { valid: false, reason: `This promo code requires a minimum purchase of ${rule.min_amount}.` };

  let discount;
  if (rule.type === 'flat') {
    discount = Math.min(Number(rule.value), subtotal);
  } else if (rule.type === 'percent') {
    const pct = Math.min(Number(rule.value), 100);
    const raw = (subtotal * pct) / 100;
    discount = rule.max_discount != null ? Math.min(raw, Number(rule.max_discount)) : raw;
    discount = Math.min(discount, subtotal);
  } else {
    return { valid: false, reason: 'Unsupported promo type.' };
  }

  return {
    valid:    true,
    code,
    type:     rule.type,
    value:    rule.value,
    discount: Number(discount.toFixed(2)),
    reason:   null,
  };
}

// ─── Provider delegation ──────────────────────────────────────────────────────

function createOrder(provider, opts) {
  return registry.get(provider).createOrder(opts);
}

function captureOrder(provider, orderId) {
  return registry.get(provider).captureOrder(orderId);
}

function refundCapture(provider, captureId, amount, currency) {
  return registry.get(provider).refundCapture(captureId, amount, currency);
}

module.exports = {
  getPolicyForPlan,
  getRefundWindowMs,
  isRefundAllowed,
  evaluatePromo,
  createOrder,
  captureOrder,
  refundCapture,
};