package services

import (
	"context"
	"fmt"

	"github.com/shopspring/decimal"
	"go.uber.org/zap"

	"tyapi-server/internal/domains/finance/entities"
	"tyapi-server/internal/domains/finance/repositories"
)

// FinanceService 财务领域服务
// 负责财务相关的业务逻辑，包括钱包管理、余额操作等
type FinanceService struct {
	walletRepo repositories.WalletRepository
	logger     *zap.Logger
}

// NewFinanceService 创建财务领域服务
func NewFinanceService(
	walletRepo repositories.WalletRepository,
	logger *zap.Logger,
) *FinanceService {
	return &FinanceService{
		walletRepo: walletRepo,
		logger:     logger,
	}
}

// CreateWallet 创建钱包
func (s *FinanceService) CreateWallet(ctx context.Context, userID string) (*entities.Wallet, error) {
	// 检查用户是否已有钱包
	existingWallet, err := s.walletRepo.GetByUserID(ctx, userID)
	if err == nil && existingWallet != nil {
		return nil, fmt.Errorf("用户已有钱包")
	}

	// 创建钱包
	wallet := &entities.Wallet{
		UserID:       userID,
		Balance:      decimal.Zero,
		IsActive:     true,
		WalletType:   "MAIN",
	}

	createdWallet, err := s.walletRepo.Create(ctx, *wallet)
	if err != nil {
		s.logger.Error("创建钱包失败", zap.Error(err))
		return nil, fmt.Errorf("创建钱包失败: %w", err)
	}

	s.logger.Info("钱包创建成功",
		zap.String("wallet_id", createdWallet.ID),
		zap.String("user_id", userID),
	)

	return &createdWallet, nil
}

// GetWallet 获取钱包信息
func (s *FinanceService) GetWallet(ctx context.Context, userID string) (*entities.Wallet, error) {
	wallet, err := s.walletRepo.GetByUserID(ctx, userID)
	if err != nil {
		return nil, fmt.Errorf("钱包不存在: %w", err)
	}
	return wallet, nil
}

// GetWalletByID 根据ID获取钱包
func (s *FinanceService) GetWalletByID(ctx context.Context, walletID string) (*entities.Wallet, error) {
	wallet, err := s.walletRepo.GetByID(ctx, walletID)
	if err != nil {
		return nil, fmt.Errorf("钱包不存在: %w", err)
	}
	return &wallet, nil
}

// RechargeWallet 充值钱包
func (s *FinanceService) RechargeWallet(ctx context.Context, userID string, amount float64) error {
	if amount <= 0 {
		return fmt.Errorf("充值金额必须大于0")
	}

	wallet, err := s.walletRepo.GetByUserID(ctx, userID)
	if err != nil {
		return fmt.Errorf("钱包不存在: %w", err)
	}

	// 更新余额
	amountDecimal := decimal.NewFromFloat(amount)
	wallet.AddBalance(amountDecimal)
	
	if err := s.walletRepo.Update(ctx, *wallet); err != nil {
		s.logger.Error("充值失败", zap.Error(err))
		return fmt.Errorf("充值失败: %w", err)
	}

	s.logger.Info("钱包充值成功",
		zap.String("wallet_id", wallet.ID),
		zap.String("user_id", userID),
		zap.Float64("amount", amount),
		zap.String("new_balance", wallet.GetFormattedBalance()),
	)

	return nil
}

// DeductWallet 扣减钱包余额
func (s *FinanceService) DeductWallet(ctx context.Context, userID string, amount float64) error {
	if amount <= 0 {
		return fmt.Errorf("扣减金额必须大于0")
	}

	wallet, err := s.walletRepo.GetByUserID(ctx, userID)
	if err != nil {
		return fmt.Errorf("钱包不存在: %w", err)
	}

	amountDecimal := decimal.NewFromFloat(amount)
	if err := wallet.SubtractBalance(amountDecimal); err != nil {
		return err
	}

	if err := s.walletRepo.Update(ctx, *wallet); err != nil {
		s.logger.Error("扣减失败", zap.Error(err))
		return fmt.Errorf("扣减失败: %w", err)
	}

	s.logger.Info("钱包扣减成功",
		zap.String("wallet_id", wallet.ID),
		zap.String("user_id", userID),
		zap.Float64("amount", amount),
		zap.String("new_balance", wallet.GetFormattedBalance()),
	)

	return nil
}

// GetWalletBalance 获取钱包余额
func (s *FinanceService) GetWalletBalance(ctx context.Context, userID string) (float64, error) {
	wallet, err := s.walletRepo.GetByUserID(ctx, userID)
	if err != nil {
		return 0, fmt.Errorf("钱包不存在: %w", err)
	}
	balance, _ := wallet.Balance.Float64()
	return balance, nil
}

// CheckWalletBalance 检查钱包余额是否足够
func (s *FinanceService) CheckWalletBalance(ctx context.Context, userID string, amount float64) (bool, error) {
	wallet, err := s.walletRepo.GetByUserID(ctx, userID)
	if err != nil {
		return false, fmt.Errorf("钱包不存在: %w", err)
	}
	
	amountDecimal := decimal.NewFromFloat(amount)
	return wallet.HasSufficientBalance(amountDecimal), nil
}