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

namespace AssetManager.Infrastructure.Services;

/// <summary>
/// 市场数据服务实现（基于 Tiingo）
/// </summary>
public class MarketDataService : IMarketDataService
{
    private readonly ILogger<MarketDataService> _logger;
    private readonly HttpClient _httpClient;
    private readonly string _tiingoApiKey;

    /// <summary>
    /// 构造函数
    /// </summary>
    /// <param name="logger">日志记录器</param>
    /// <param name="httpClientFactory">HTTP 客户端工厂</param>
    public MarketDataService(ILogger<MarketDataService> logger, IHttpClientFactory httpClientFactory)
    {
        _logger = logger;
        _httpClient = httpClientFactory.CreateClient();
        // TODO: 从配置读取 Tiingo API Key
        _tiingoApiKey = Environment.GetEnvironmentVariable("TIINGO_API_KEY") ?? "bd00fee76d3012b047473078904001b33322cb46";
        _httpClient.DefaultRequestHeaders.Add("Authorization", $"Token {_tiingoApiKey}");
    }

    /// <summary>
    /// 获取股票实时价格
    /// </summary>
    /// <param name="symbol">股票代码</param>
    /// <returns>股票价格信息</returns>
    public async Task<MarketPriceResponse> GetStockPriceAsync(string symbol)
    {
        try
        {
            _logger.LogInformation($"Requesting stock price for symbol: {symbol}");

            // Tiingo 日线最新价格端点（取最近1条）
            var url = $"https://api.tiingo.com/tiingo/daily/{symbol}/prices?token={_tiingoApiKey}";
            var response = await _httpClient.GetFromJsonAsync<List<TiingoDailyResponse>>(url);

            if (response == null || response.Count == 0)
            {
                throw new Exception($"No data found for {symbol}");
            }

            var latest = response[^1];
            decimal? prevClose = response.Count >= 2 ? response[^2].close : null;

            return new MarketPriceResponse
            {
                Symbol = symbol,
                Price = latest.close ?? 0,
                PreviousClose = prevClose ?? 0,
                Timestamp = latest.date ?? DateTime.UtcNow,
                AssetType = "Stock"
            };
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, $"Error getting stock price for {symbol}");
            throw;
        }
    }

    /// <summary>
    /// 获取加密货币实时价格
    /// </summary>
    /// <param name="symbol">加密货币代码（如 BTCUSD）</param>
    /// <returns>加密货币价格信息</returns>
    public async Task<MarketPriceResponse> GetCryptoPriceAsync(string symbol)
    {
        try
        {
            _logger.LogInformation($"Requesting crypto price for symbol: {symbol}");

            // Tiingo 加密货币最新价格端点
            var url = $"https://api.tiingo.com/tiingo/crypto/prices?tickers={symbol}&token={_tiingoApiKey}";
            var response = await _httpClient.GetFromJsonAsync<List<TiingoCryptoPriceResponse>>(url);

            if (response == null || response.Count == 0 || response[0].priceData == null || response[0].priceData.Count == 0)
            {
                throw new Exception($"No data found for {symbol}");
            }

            var latest = response[0].priceData[0];
            return new MarketPriceResponse
            {
                Symbol = symbol,
                Price = latest.close ?? 0,
                PreviousClose = 0, // Tiingo crypto 端点没有 prevClose，暂时用 0
                Timestamp = latest.date ?? DateTime.UtcNow,
                AssetType = "Crypto"
            };
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, $"Error getting crypto price for {symbol}");
            throw;
        }
    }

    /// <summary>
    /// 获取股票历史数据
    /// </summary>
    /// <param name="symbol">股票代码</param>
    /// <param name="timeframe">时间周期</param>
    /// <param name="limit">数据点数量</param>
    /// <returns>历史数据列表</returns>
    public async Task<List<MarketDataResponse>> GetStockHistoricalDataAsync(string symbol, string timeframe, int limit)
    {
        try
        {
            _logger.LogInformation($"Requesting stock historical data for symbol: {symbol}, timeframe: {timeframe}, limit: {limit}");

            var endDate = DateTime.UtcNow;
            var startDate = CalculateStartDate(endDate, timeframe, limit);
            var resampleFreq = GetTiingoResampleFreq(timeframe);

            // Tiingo 历史数据端点
            var url = $"https://api.tiingo.com/tiingo/daily/{symbol}/prices?startDate={startDate:yyyy-MM-dd}&endDate={endDate:yyyy-MM-dd}&resampleFreq={resampleFreq}&token={_tiingoApiKey}";
            var response = await _httpClient.GetFromJsonAsync<List<TiingoDailyResponse>>(url);

            if (response == null)
            {
                return new List<MarketDataResponse>();
            }

            // 取最近 limit 条
            var result = response
                .OrderByDescending(x => x.date)
                .Take(limit)
                .OrderBy(x => x.date)
                .Select(x => new MarketDataResponse
                {
                    Symbol = symbol,
                    Open = x.open ?? 0,
                    High = x.high ?? 0,
                    Low = x.low ?? 0,
                    Close = x.close ?? 0,
                    Volume = x.volume ?? 0,
                    Timestamp = x.date ?? DateTime.UtcNow,
                    AssetType = "Stock"
                })
                .ToList();

            return result;
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, $"Error getting stock historical data for {symbol}");
            throw;
        }
    }

    /// <summary>
    /// 获取加密货币历史数据
    /// </summary>
    /// <param name="symbol">加密货币代码</param>
    /// <param name="timeframe">时间周期</param>
    /// <param name="limit">数据点数量</param>
    /// <returns>历史数据列表</returns>
    public async Task<List<MarketDataResponse>> GetCryptoHistoricalDataAsync(string symbol, string timeframe, int limit)
    {
        try
        {
            _logger.LogInformation($"Requesting crypto historical data for symbol: {symbol}, timeframe: {timeframe}, limit: {limit}");

            var endDate = DateTime.UtcNow;
            var startDate = CalculateStartDate(endDate, timeframe, limit);
            var resampleFreq = GetTiingoResampleFreq(timeframe);

            // Tiingo 加密货币历史数据端点
            var url = $"https://api.tiingo.com/tiingo/crypto/prices?tickers={symbol}&startDate={startDate:yyyy-MM-dd}&endDate={endDate:yyyy-MM-dd}&resampleFreq={resampleFreq}&token={_tiingoApiKey}";
            var response = await _httpClient.GetFromJsonAsync<List<TiingoCryptoPriceResponse>>(url);

            if (response == null || response.Count == 0 || response[0].priceData == null)
            {
                return new List<MarketDataResponse>();
            }

            // 取最近 limit 条
            var result = response[0].priceData!
                .OrderByDescending(x => x.date)
                .Take(limit)
                .OrderBy(x => x.date)
                .Select(x => new MarketDataResponse
                {
                    Symbol = symbol,
                    Open = x.open ?? 0,
                    High = x.high ?? 0,
                    Low = x.low ?? 0,
                    Close = x.close ?? 0,
                    Volume = x.volume ?? 0,
                    Timestamp = x.date ?? DateTime.UtcNow,
                    AssetType = "Crypto"
                })
                .ToList();

            return result;
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, $"Error getting crypto historical data for {symbol}");
            throw;
        }
    }

    /// <summary>
    /// 转换为 Tiingo 的 resampleFreq
    /// </summary>
    private string GetTiingoResampleFreq(string timeframe)
    {
        return timeframe.ToLower() switch
        {
            "1min" => "1min",
            "5min" => "5min",
            "15min" => "15min",
            "1h" => "1hour",
            "1d" => "daily",
            "1w" => "weekly",
            "1m" => "monthly",
            _ => "daily"
        };
    }

    /// <summary>
    /// 计算开始日期
    /// </summary>
    private DateTime CalculateStartDate(DateTime endDate, string timeframe, int limit)
    {
        return timeframe.ToLower() switch
        {
            "1min" => endDate.AddMinutes(-limit),
            "5min" => endDate.AddMinutes(-limit * 5),
            "15min" => endDate.AddMinutes(-limit * 15),
            "1h" => endDate.AddHours(-limit),
            "1d" => endDate.AddDays(-limit),
            "1w" => endDate.AddDays(-limit * 7),
            "1m" => endDate.AddMonths(-limit),
            _ => endDate.AddDays(-limit)
        };
    }
}

// Tiingo 响应模型
internal class TiingoPriceResponse
{
    public decimal? tngoLast { get; set; }
    public decimal? close { get; set; }
    public decimal? prevClose { get; set; }
    public DateTime? date { get; set; }
}

internal class TiingoDailyResponse
{
    public decimal? open { get; set; }
    public decimal? high { get; set; }
    public decimal? low { get; set; }
    public decimal? close { get; set; }
    public decimal? volume { get; set; }
    public DateTime? date { get; set; }
}

internal class TiingoCryptoPriceResponse
{
    public List<TiingoCryptoBar>? priceData { get; set; }
}

internal class TiingoCryptoBar
{
    public decimal? open { get; set; }
    public decimal? high { get; set; }
    public decimal? low { get; set; }
    public decimal? close { get; set; }
    public decimal? volume { get; set; }
    public DateTime? date { get; set; }
}