package service

import (
	"context"
	"database/sql"
	"fmt"

	"boc/repository"
)

// FinanceService handles business logic for finance operations
type FinanceService struct {
	repo *repository.FinanceRepository
	db   *sql.DB
}

func NewFinanceService(db *sql.DB) *FinanceService {
	return &FinanceService{
		repo: repository.NewFinanceRepository(db),
		db:   db,
	}
}

// ListInvoices returns all invoices
func (s *FinanceService) ListInvoices(ctx context.Context) ([]repository.Invoice, error) {
	return s.repo.ListInvoices(ctx)
}

// ListExpenses returns all expenses
func (s *FinanceService) ListExpenses(ctx context.Context) ([]repository.Expense, error) {
	return s.repo.ListExpenses(ctx)
}

// CreateExpense creates a new expense with validation
func (s *FinanceService) CreateExpense(ctx context.Context, e *repository.Expense) error {
	if e.Category == "" {
		return fmt.Errorf("expense category is required")
	}
	if e.Amount <= 0 {
		return fmt.Errorf("expense amount must be positive")
	}
	if e.Status == "" {
		e.Status = "pending"
	}
	return s.repo.CreateExpense(ctx, e)
}

// GetCashFlow returns income, outstanding, and expenses
func (s *FinanceService) GetCashFlow(ctx context.Context) (income, outstanding, expenses float64, err error) {
	return s.repo.GetCashFlow(ctx)
}

// GetAccounts returns all ledger accounts
func (s *FinanceService) GetAccounts(ctx context.Context) ([]repository.Account, error) {
	return s.repo.GetAccounts(ctx)
}

// GetBalanceSheet returns a simplified balance sheet
func (s *FinanceService) GetBalanceSheet(ctx context.Context) (map[string]interface{}, error) {
	accounts, err := s.repo.GetAccounts(ctx)
	if err != nil {
		return nil, err
	}

	var assets, liabilities, equity float64
	for _, a := range accounts {
		switch a.Type {
		case "asset":
			assets += a.Balance
		case "liability":
			liabilities += a.Balance
		case "equity":
			equity += a.Balance
		}
	}

	return map[string]interface{}{
		"assets":      assets,
		"liabilities": liabilities,
		"equity":      equity,
		"accounts":    accounts,
	}, nil
}