using NodaTime;
using YahooQuotesApi;
using AssetManager.Data;
using AssetManager.Models.DTOs;
using Microsoft.Extensions.Logging;
using System.Collections.Immutable;

namespace AssetManager.Infrastructure.Services;


/// <summary>
/// Yahoo财经市场数据服务接口
/// </summary>
public interface IYahooMarketService
{
    /// <summary>
    /// 获取股票实时价格
    /// </summary>
    Task<MarketPriceResponse> GetStockPriceAsync(string symbol);
    
    /// <summary>
    /// 获取股票历史K线数据
    /// </summary>
    Task<List<MarketDataResponse>> GetStockHistoricalDataAsync(string symbol, string timeframe, int limit);
}
/// <summary>
/// Yahoo财经市场数据服务实现
/// </summary>
public class YahooMarketService : IYahooMarketService
{
    private readonly ILogger<YahooMarketService> _logger;

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

    /// <summary>
    /// 转换股票代码为 Yahoo Finance 格式
    /// <para>BRK.B → BRK-B（伯克希尔B类股）</para>
    /// <para>BRK.A → BRK-A（伯克希尔A类股）</para>
    /// </summary>
    private string ConvertToYahooSymbol(string symbol)
    {
        if (string.IsNullOrEmpty(symbol))
            return symbol;
        
        // Yahoo Finance 用连字符表示类别股，而非点号
        // BRK.B → BRK-B, BRK.A → BRK-A
        return symbol.ToUpper().Replace(".", "-");
    }

    /// <summary>
    /// 根据 timeframe 和 limit 计算需要的开始日期
    /// </summary>
    private DateTime CalculateStartDate(string timeframe, int limit)
    {
        var now = DateTime.UtcNow;
        
        // 根据周期类型计算需要的天数，预留缓冲
        return timeframe.ToLower() switch
        {
            "1d" or "daily" or "day" => now.AddDays(-limit * 1.5),       // 日线：limit * 1.5 天
            "1w" or "weekly" or "week" => now.AddDays(-limit * 8),       // 周线：limit * 8 天
            "1m" or "monthly" or "month" => now.AddDays(-limit * 35),    // 月线：limit * 35 天
            _ => now.AddDays(-Math.Max(limit * 2, 365))                  // 默认：至少365天
        };
    }

    public async Task<MarketPriceResponse> GetStockPriceAsync(string symbol)
    {
        var yahooSymbol = ConvertToYahooSymbol(symbol);
        _logger.LogInformation("Yahoo获取股票价格: {Symbol} -> {YahooSymbol}", symbol, yahooSymbol);
        
        // 实时价格不需要历史数据，使用最小范围
        var yahooQuotes = new YahooQuotesBuilder()
            .WithHistoryStartDate(Instant.FromDateTimeUtc(DateTime.UtcNow.AddDays(-7)))
            .Build();
        
        Snapshot? snapshot = await yahooQuotes.GetSnapshotAsync(yahooSymbol);
        if (snapshot is null)
            throw new InvalidOperationException($"Yahoo未知标的: {symbol}");
        
        decimal price = snapshot.RegularMarketPrice;
        if (price <= 0)
            throw new InvalidOperationException($"Yahoo获取价格失败，标的: {symbol}");
        
        decimal previousClose = snapshot.RegularMarketPreviousClose;
        if (previousClose <= 0)
            previousClose = price;
        
        _logger.LogDebug("Yahoo接口返回 {Symbol}：最新价 {CurrentPrice}，昨收价 {PrevClose}", 
            symbol, price, previousClose);

        return new MarketPriceResponse
        {
            Symbol = symbol, // 返回原始代码
            Price = price,
            PreviousClose = previousClose,
            Timestamp = DateTime.UtcNow,
            AssetType = "Stock"
        };
    }

    public async Task<List<MarketDataResponse>> GetStockHistoricalDataAsync(string symbol, string timeframe, int limit)
    {
        var yahooSymbol = ConvertToYahooSymbol(symbol);
        _logger.LogInformation("Yahoo获取历史数据: {Symbol} -> {YahooSymbol}, {Timeframe}, {Limit}", symbol, yahooSymbol, timeframe, limit);
        
        // 根据请求参数动态计算开始日期
        var startDate = CalculateStartDate(timeframe, limit);
        _logger.LogDebug("历史数据开始日期: {StartDate}", startDate.ToString("yyyy-MM-dd"));
        
        var yahooQuotes = new YahooQuotesBuilder()
            .WithHistoryStartDate(Instant.FromDateTimeUtc(startDate))
            .Build();
        
        Result<History> result = await yahooQuotes.GetHistoryAsync(yahooSymbol);
        if (result.Value == null)
            throw new InvalidOperationException($"Yahoo获取历史数据失败，标的: {symbol}");
        
        History history = result.Value;
        var ticks = history.Ticks;
        
        var marketDataList = new List<MarketDataResponse>();
        
        foreach (var tick in ticks)
        {
            marketDataList.Add(new MarketDataResponse
            {
                Symbol = symbol, // 返回原始代码
                Timestamp = tick.Date.ToDateTimeUtc(),
                Open = (decimal)tick.Open,
                High = (decimal)tick.High,
                Low = (decimal)tick.Low,
                Close = (decimal)tick.Close,
                Volume = (decimal)tick.Volume,
                AssetType = "Stock"
            });
        }
        
        // 按时间戳排序并取最近的limit条
        var sortedData = marketDataList
            .OrderBy(x => x.Timestamp)
            .TakeLast(limit)
            .ToList();
        
        _logger.LogInformation("Yahoo获取 {Symbol} 历史数据 {Count} 条（请求 {Limit} 条）", symbol, sortedData.Count, limit);
        
        return sortedData;
    }
}