using Microsoft.Extensions.Logging;

namespace AssetManager.Infrastructure.Services;

/// <summary>
/// Mock 汇率服务（占位实现，后续接入真实汇率源）
/// </summary>
public class MockExchangeRateService : IExchangeRateService
{
    private readonly ILogger<MockExchangeRateService> _logger;

    // 固定的 Mock 汇率（以 2026 年初为基准）
    private readonly Dictionary<string, decimal> _mockRates = new()
    {
        { "CNY-USD", 0.14m },
        { "USD-CNY", 7.10m },
        { "CNY-HKD", 1.09m },
        { "HKD-CNY", 0.92m },
        { "USD-HKD", 7.75m },
        { "HKD-USD", 0.13m },
        { "CNY-CNY", 1.00m },
        { "USD-USD", 1.00m },
        { "HKD-HKD", 1.00m }
    };

    public MockExchangeRateService(ILogger<MockExchangeRateService> logger)
    {
        _logger = logger;
    }

    public Task<decimal> GetExchangeRateAsync(string fromCurrency, string toCurrency)
    {
        _logger.LogInformation("Mock 获取汇率: {FromCurrency} -> {ToCurrency}", fromCurrency, toCurrency);

        string key = $"{fromCurrency}-{toCurrency}";
        if (_mockRates.TryGetValue(key, out decimal rate))
        {
            return Task.FromResult(rate);
        }

        // 默认返回 1（同币种或不支持的币种）
        return Task.FromResult(1.00m);
    }

    public Task<decimal> ConvertAmountAsync(decimal amount, string fromCurrency, string toCurrency)
    {
        _logger.LogInformation("Mock 转换金额: {Amount} {FromCurrency} -> {ToCurrency}", amount, fromCurrency, toCurrency);

        if (fromCurrency == toCurrency)
        {
            return Task.FromResult(amount);
        }

        return GetExchangeRateAsync(fromCurrency, toCurrency)
            .ContinueWith(t => amount * t.Result);
    }
}