// CQ Calculation Engine
// calculateQuoteTotals — unified totals for display, PDF, signing
// Depends on: cq-pricing-data.js, cq-line-items.js

// ========================================================================
// UNIFIED CALCULATION ENGINE — Single source of truth for all totals
// Used by: on-screen display, PDF generation, signing flow
// ========================================================================
window.calculateQuoteTotals = (lineItems, options = {}) => {
  const {
    additionalRecurringDiscounts = [],
    additionalOneTimeDiscounts = [],
    multiYearDiscount = {},
    contractLength = 1,
    paymentFrequency = 'annual',
    financingFeeWaived = false,
    monthlyFinancingFee = 10,
    quarterlyFinancingFee = 5,
  } = options;

  // Start from line item totals (per-item discounts already applied)
  let annual = lineItems.recurringTotal || 0;
  let oneTime = lineItems.oneTimeTotal || 0;
  // Pick the right deposit based on payment frequency
  // Use != null check (not > 0) so explicit $0 deposits are respected instead of falling back
  const rawFinancingOneTimeAmt = lineItems.financingOneTimeAmount || 0;
  const financingOneTimeAmt = paymentFrequency === 'monthly' && lineItems.monthlyDepositAmount != null
    ? lineItems.monthlyDepositAmount
    : paymentFrequency === 'quarterly' && lineItems.quarterlyDepositAmount != null
      ? lineItems.quarterlyDepositAmount
      : rawFinancingOneTimeAmt;

  // --- Additional Recurring Discounts ---
  let recurringDiscountAmount = 0;
  const recurringDiscountItems = [];
  (additionalRecurringDiscounts || []).forEach(discount => {
    if (discount && discount.amount > 0) {
      const discountValue = discount.type === 'percent'
        ? annual * (discount.amount / 100)
        : discount.amount;
      recurringDiscountAmount += discountValue;
      recurringDiscountItems.push({
        name: discount.name || 'Discount',
        amount: discountValue,
        type: discount.type,
        value: discount.amount
      });
    }
  });
  annual = annual - recurringDiscountAmount;

  // --- Additional One-Time Discounts ---
  let oneTimeDiscountAmount = 0;
  const oneTimeDiscountItems = [];
  (additionalOneTimeDiscounts || []).forEach(discount => {
    if (discount && discount.amount > 0) {
      const discountValue = discount.type === 'percent'
        ? oneTime * (discount.amount / 100)
        : discount.amount;
      oneTimeDiscountAmount += discountValue;
      oneTimeDiscountItems.push({
        name: discount.name || 'Discount',
        amount: discountValue,
        type: discount.type,
        value: discount.amount
      });
    }
  });
  oneTime = oneTime - oneTimeDiscountAmount;

  const hasAdditionalDiscounts = recurringDiscountAmount > 0 || oneTimeDiscountAmount > 0;

  // --- Multi-Year Discount ---
  let multiYearDiscountPercent = 0;
  if (contractLength === 2 && multiYearDiscount.twoYearEnabled) {
    multiYearDiscountPercent = multiYearDiscount.twoYear || 0;
  } else if (contractLength === 3 && multiYearDiscount.threeYearEnabled) {
    multiYearDiscountPercent = multiYearDiscount.threeYear || 0;
  }
  let multiYearDiscountAmount = 0;
  if (multiYearDiscountPercent > 0) {
    multiYearDiscountAmount = annual * (multiYearDiscountPercent / 100);
    annual = annual - multiYearDiscountAmount;
  }

  // --- Financing ---
  const isFinanced = paymentFrequency !== 'annual';
  const currentFinancingFee = paymentFrequency === 'monthly' ? monthlyFinancingFee : quarterlyFinancingFee;
  const financingFeeAmount = isFinanced && !financingFeeWaived
    ? annual * (currentFinancingFee / 100)
    : 0;
  const totalFinanced = annual + financingFeeAmount - (isFinanced ? financingOneTimeAmt : 0);

  const baseAmount = paymentFrequency === 'monthly'
    ? (isFinanced ? totalFinanced / 12 : annual / 12)
    : paymentFrequency === 'quarterly'
      ? (isFinanced ? totalFinanced / 4 : annual / 4)
      : annual;

  const displayAmount = baseAmount;
  const periodLabel = paymentFrequency === 'monthly' ? '/mo' : paymentFrequency === 'quarterly' ? '/qtr' : '/yr';
  const firstPeriodLabel = paymentFrequency === 'monthly' ? 'First Month' : paymentFrequency === 'quarterly' ? 'First Quarter' : 'First Year';
  const dueAtSigning = displayAmount + oneTime + (isFinanced ? financingOneTimeAmt : 0);

  const totalSavings = (lineItems.recurringDiscountTotal || 0)
    + (lineItems.oneTimeDiscountTotal || 0)
    + recurringDiscountAmount
    + oneTimeDiscountAmount
    + multiYearDiscountAmount;

  return {
    annual,
    oneTime,
    financingOneTimeAmt,
    recurringDiscountAmount,
    recurringDiscountItems,
    oneTimeDiscountAmount,
    oneTimeDiscountItems,
    hasAdditionalDiscounts,
    multiYearDiscountPercent,
    multiYearDiscountAmount,
    isFinanced,
    currentFinancingFee,
    financingFeeAmount,
    financingFeeWaived,
    totalFinanced,
    baseAmount,
    displayAmount,
    periodLabel,
    firstPeriodLabel,
    dueAtSigning,
    totalSavings
  };
};