package memory

import (
	"context"
	"fmt"
	"sync"

	"hyapp/pkg/xerr"
	"hyapp/services/wallet-service/internal/domain/ledger"
)

// Repository 是钱包单元测试用内存账本。
// 它保留幂等命中语义，但不作为生产路径。
type Repository struct {
	mu       sync.Mutex
	balance  map[int64]int64
	receipts map[string]ledger.Receipt
}

// NewRepository 创建内存账本。
func NewRepository() *Repository {
	return &Repository{
		balance:  make(map[int64]int64),
		receipts: make(map[string]ledger.Receipt),
	}
}

// SetBalance 为测试准备用户余额。
func (r *Repository) SetBalance(userID int64, balance int64) {
	r.mu.Lock()
	defer r.mu.Unlock()

	r.balance[userID] = balance
}

// DebitGift 执行内存扣费并按 command_id 幂等返回原始回执。
func (r *Repository) DebitGift(_ context.Context, command ledger.DebitGiftCommand) (ledger.Receipt, error) {
	r.mu.Lock()
	defer r.mu.Unlock()

	if receipt, ok := r.receipts[command.CommandID]; ok {
		return receipt, nil
	}

	total := command.TotalGiftValue()
	current := r.balance[command.SenderUserID]
	if current < total {
		return ledger.Receipt{}, xerr.New(xerr.InsufficientBalance, "insufficient balance")
	}

	receipt := ledger.Receipt{
		BillingReceiptID: fmt.Sprintf("bill_%s", command.CommandID),
		TotalGiftValue:   total,
		BalanceAfter:     current - total,
	}
	r.balance[command.SenderUserID] = receipt.BalanceAfter
	r.receipts[command.CommandID] = receipt

	return receipt, nil
}