zellyy-finance/src/contexts/budget/budgetUtils.ts

import { BudgetData, BudgetPeriod, CategoryBudget, Transaction } from './types';
import { EXPENSE_CATEGORIES } from '@/constants/categoryIcons';

// 기본 데이터 상수 (기본값을 0으로 설정)
export const DEFAULT_CATEGORY_BUDGETS: Record<string, number> = {
  식비: 0,
  생활비: 0,
  교통비: 0
};

export const DEFAULT_MONTHLY_BUDGET = 0;

// 카테고리별 지출 계산
export const calculateCategorySpending = (
  transactions: Transaction[],
  categoryBudgets: Record<string, number>
): CategoryBudget[] => {
  const expenseTransactions = transactions.filter(t => t.type === 'expense');
  const categorySpending: Record<string, number> = {};
  
  // 모든 카테고리에 대해 초기값 0 설정
  Object.keys(categoryBudgets).forEach(category => {
    // 3개 카테고리만 유지
    if (EXPENSE_CATEGORIES.includes(category)) {
      categorySpending[category] = 0;
    }
  });
  
  // 지원되는 카테고리가 없을 경우 기본값 설정
  if (Object.keys(categorySpending).length === 0) {
    EXPENSE_CATEGORIES.forEach(category => {
      categorySpending[category] = 0;
    });
  }
  
  expenseTransactions.forEach(t => {
    if (t.category in categorySpending) {
      categorySpending[t.category] += t.amount;
    } else if (EXPENSE_CATEGORIES.includes(t.category)) {
      // 지원되는 카테고리이지만 초기화되지 않은 경우
      categorySpending[t.category] = t.amount;
    } else {
      // 지원되지 않는 카테고리는 '생활비'로 집계
      categorySpending['생활비'] = (categorySpending['생활비'] || 0) + t.amount;
    }
  });
  
  return EXPENSE_CATEGORIES.map(category => ({
    title: category,
    current: categorySpending[category] || 0,
    total: categoryBudgets[category] || 0
  }));
};

// 예산 데이터 업데이트 계산
export const calculateUpdatedBudgetData = (
  prevBudgetData: BudgetData,
  type: BudgetPeriod,
  amount: number
): BudgetData => {
  if (type === 'monthly') {
    const dailyAmount = Math.round(amount / 30);
    const weeklyAmount = Math.round(amount / 4.3);
    
    return {
      daily: {
        targetAmount: dailyAmount,
        spentAmount: prevBudgetData.daily.spentAmount,
        remainingAmount: Math.max(0, dailyAmount - prevBudgetData.daily.spentAmount)
      },
      weekly: {
        targetAmount: weeklyAmount,
        spentAmount: prevBudgetData.weekly.spentAmount,
        remainingAmount: Math.max(0, weeklyAmount - prevBudgetData.weekly.spentAmount)
      },
      monthly: {
        targetAmount: amount,
        spentAmount: prevBudgetData.monthly.spentAmount,
        remainingAmount: Math.max(0, amount - prevBudgetData.monthly.spentAmount)
      }
    };
  } else if (type === 'weekly') {
    // 주간 예산이 설정되면 월간 예산도 자동 계산
    const monthlyAmount = Math.round(amount * 4.3);
    const dailyAmount = Math.round(amount / 7);
    
    return {
      daily: {
        targetAmount: dailyAmount,
        spentAmount: prevBudgetData.daily.spentAmount,
        remainingAmount: Math.max(0, dailyAmount - prevBudgetData.daily.spentAmount)
      },
      weekly: {
        targetAmount: amount,
        spentAmount: prevBudgetData.weekly.spentAmount,
        remainingAmount: Math.max(0, amount - prevBudgetData.weekly.spentAmount)
      },
      monthly: {
        targetAmount: monthlyAmount,
        spentAmount: prevBudgetData.monthly.spentAmount,
        remainingAmount: Math.max(0, monthlyAmount - prevBudgetData.monthly.spentAmount)
      }
    };
  } else {
    // 일일 예산이 설정되면 주간/월간 예산도 자동 계산
    const weeklyAmount = Math.round(amount * 7);
    const monthlyAmount = Math.round(amount * 30);
    
    return {
      daily: {
        targetAmount: amount,
        spentAmount: prevBudgetData.daily.spentAmount,
        remainingAmount: Math.max(0, amount - prevBudgetData.daily.spentAmount)
      },
      weekly: {
        targetAmount: weeklyAmount,
        spentAmount: prevBudgetData.weekly.spentAmount,
        remainingAmount: Math.max(0, weeklyAmount - prevBudgetData.weekly.spentAmount)
      },
      monthly: {
        targetAmount: monthlyAmount,
        spentAmount: prevBudgetData.monthly.spentAmount,
        remainingAmount: Math.max(0, monthlyAmount - prevBudgetData.monthly.spentAmount)
      }
    };
  }
};

// 지출액 계산 (일일, 주간, 월간)
export const calculateSpentAmounts = (
  transactions: Transaction[],
  prevBudgetData: BudgetData
): BudgetData => {
  // 지출 거래 필터링
  const expenseTransactions = transactions.filter(t => t.type === 'expense');
  
  // 오늘 지출 계산
  const todayExpenses = expenseTransactions.filter(t => {
    if (t.date.includes('오늘')) return true;
    return false;
  });
  const dailySpent = todayExpenses.reduce((sum, t) => sum + t.amount, 0);
  
  // 이번 주 지출 계산 (단순화된 버전)
  const weeklyExpenses = expenseTransactions.filter(t => {
    if (t.date.includes('오늘') || t.date.includes('어제') || t.date.includes('이번주')) return true;
    return true;
  });
  const weeklySpent = weeklyExpenses.reduce((sum, t) => sum + t.amount, 0);
  
  // 이번 달 총 지출 계산
  const monthlySpent = expenseTransactions.reduce((sum, t) => sum + t.amount, 0);

  // 예산 데이터 업데이트
  return {
    daily: {
      ...prevBudgetData.daily,
      spentAmount: dailySpent,
      remainingAmount: Math.max(0, prevBudgetData.daily.targetAmount - dailySpent)
    },
    weekly: {
      ...prevBudgetData.weekly,
      spentAmount: weeklySpent,
      remainingAmount: Math.max(0, prevBudgetData.weekly.targetAmount - weeklySpent)
    },
    monthly: {
      ...prevBudgetData.monthly,
      spentAmount: monthlySpent,
      remainingAmount: Math.max(0, prevBudgetData.monthly.targetAmount - monthlySpent)
    }
  };
};

// 초기 예산 데이터 생성
export const getInitialBudgetData = (): BudgetData => {
  return {
    daily: {
      targetAmount: 0,
      spentAmount: 0,
      remainingAmount: 0
    },
    weekly: {
      targetAmount: 0,
      spentAmount: 0,
      remainingAmount: 0
    },
    monthly: {
      targetAmount: 0,
      spentAmount: 0,
      remainingAmount: 0
    }
  };
};