using System.Text;
using System.Text.Json;
using AssetManager.Data;
using AssetManager.Models.DTOs;
using Microsoft.Extensions.Logging;

namespace AssetManager.Infrastructure.Services;

/// <summary>
/// 腾讯财经市场数据服务接口
/// </summary>
public interface ITencentMarketService
{
    /// <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
    /// <para>⚠️ 注意：腾讯历史K线接口 (web.ifzq.gtimg.cn) 已废弃，此方法会抛出异常</para>
    /// </summary>
    [Obsolete("腾讯历史K线接口已废弃，请使用 Yahoo 或 Tiingo")]
    Task<List<MarketDataResponse>> GetStockHistoricalDataAsync(string symbol, string timeframe, int limit);
}

/// <summary>
/// 腾讯财经市场数据服务实现
/// <para>实时价格接口 (qt.gtimg.cn) 正常可用</para>
/// <para>历史K线接口 (web.ifzq.gtimg.cn) 已废弃</para>
/// </summary>
public class TencentMarketService : ITencentMarketService
{
    private readonly ILogger<TencentMarketService> _logger;
    private readonly HttpClient _httpClient;

    public TencentMarketService(ILogger<TencentMarketService> logger, IHttpClientFactory httpClientFactory)
    {
        _logger = logger;
        _httpClient = httpClientFactory.CreateClient();
        
        // 注册GBK编码支持
        Encoding.RegisterProvider(CodePagesEncodingProvider.Instance);
    }

    public async Task<MarketPriceResponse> GetStockPriceAsync(string symbol)
    {
        _logger.LogInformation("腾讯财经获取股票价格: {Symbol}", symbol);

        // 腾讯财经美股接口：前缀us，大写代码
        var url = $"http://qt.gtimg.cn/q=us{symbol.ToUpper()}";
        var responseBytes = await _httpClient.GetByteArrayAsync(url);
        var response = Encoding.GetEncoding("GBK").GetString(responseBytes);

        if (string.IsNullOrEmpty(response) || !response.Contains("~"))
        {
            throw new Exception($"腾讯财经接口返回无效数据，标的: {symbol}");
        }

        // 解析返回数据
        var parts = response.Split('"')[1].Split('~');
        if (parts.Length < 36)
        {
            throw new Exception($"腾讯财经返回字段不足，标的: {symbol}");
        }

        // 提取字段：[3]=最新价 [4]=昨收价
        if (!decimal.TryParse(parts[3], out var currentPrice) || currentPrice <= 0)
        {
            throw new Exception($"解析最新价失败，标的: {symbol}，返回值: {parts[3]}");
        }

        if (!decimal.TryParse(parts[4], out var prevClose) || prevClose <= 0)
        {
            prevClose = currentPrice; // 解析失败用当前价当昨收
        }
        
        _logger.LogDebug("腾讯财经接口返回 {Symbol}：最新价 {CurrentPrice}，昨收价 {PrevClose}", 
            symbol, currentPrice, prevClose);

        return new MarketPriceResponse
        {
            Symbol = symbol,
            Price = currentPrice,
            PreviousClose = prevClose,
            Timestamp = DateTime.UtcNow,
            AssetType = "Stock"
        };
    }

    public async Task<List<MarketDataResponse>> GetStockHistoricalDataAsync(string symbol, string timeframe, int limit)
    {
        _logger.LogInformation("获取腾讯财经历史数据: {Symbol}", symbol);

        // 腾讯财经K线接口
        var klineType = timeframe switch
        {
            "1d" or "daily" => "day",
            "1w" or "weekly" => "week",
            "1M" or "monthly" => "month",
            _ => "day"
        };

        var url = $"http://web.ifzq.gtimg.cn/appstock/app/fqkline/get?_var=kline_{klineType}qfq&param=us{symbol.ToUpper()},{klineType},,{Math.Min(limit, 320)}&qrcode=1&asrd=1";
        
        var responseBytes = await _httpClient.GetByteArrayAsync(url);
        var response = Encoding.GetEncoding("GBK").GetString(responseBytes);

        if (string.IsNullOrEmpty(response))
        {
            throw new Exception($"腾讯财经历史数据接口返回空数据，标的: {symbol}");
        }

        // 解析JSON
        var jsonStart = response.IndexOf('{');
        if (jsonStart < 0)
        {
            throw new Exception($"腾讯财经历史数据接口返回非JSON格式，标的: {symbol}");
        }
        
        var jsonStr = response.Substring(jsonStart);
        using var jsonDoc = JsonDocument.Parse(jsonStr);
        var root = jsonDoc.RootElement;

        // 检查API错误响应
        if (root.TryGetProperty("code", out var codeEl) && codeEl.GetInt32() != 0)
        {
            var errMsg = root.TryGetProperty("msg", out var msgEl) ? msgEl.GetString() : "未知错误";
            throw new Exception($"腾讯财经历史数据接口错误: {errMsg}，标的: {symbol}");
        }

        // 检查 data 字段类型（错误响应时 data 是空数组 []）
        if (!root.TryGetProperty("data", out var data) || data.ValueKind != JsonValueKind.Object)
        {
            throw new Exception($"腾讯财经历史数据接口返回无效数据结构，标的: {symbol}");
        }

        // 数据路径: data -> us{symbol} -> qfq -> {klineType}
        var dataPath = $"us{symbol.ToUpper()}";
        if (!data.TryGetProperty(dataPath, out var stockData) ||
            !stockData.TryGetProperty("qfq", out var qfq))
        {
            throw new Exception($"腾讯财经历史数据接口无该标的K线数据，标的: {symbol}");
        }

        if (!qfq.TryGetProperty(klineType, out var klineData) || klineData.ValueKind != JsonValueKind.Array)
        {
            throw new Exception($"腾讯财经历史数据接口K线数据格式异常，标的: {symbol}");
        }

        var result = new List<MarketDataResponse>();
        foreach (var item in klineData.EnumerateArray())
        {
            // 数据格式: [日期, 开盘, 收盘, 最高, 最低, 成交量]
            var arr = item.EnumerateArray().ToList();
            if (arr.Count < 6) continue;

            var dateStr = arr[0].GetString();
            if (!DateTime.TryParse(dateStr, out var date)) continue;

            var open = arr[1].GetDecimal();
            var close = arr[2].GetDecimal();
            var high = arr[3].GetDecimal();
            var low = arr[4].GetDecimal();
            var volume = arr[5].GetDecimal();

            if (close <= 0) continue;

            result.Add(new MarketDataResponse
            {
                Symbol = symbol,
                Open = open,
                High = high,
                Low = low,
                Close = close,
                Volume = volume,
                Timestamp = date,
                AssetType = "Stock"
            });
        }

        // 按日期排序
        result = result.OrderBy(x => x.Timestamp).TakeLast(limit).ToList();
        _logger.LogInformation("腾讯财经获取 {Symbol} 历史数据 {Count} 条", symbol, result.Count);
        
        return result;
    }
}