using AssetManager.Data;
using AssetManager.Models.DTOs;
using AssetManager.Infrastructure.Services;
using SqlSugar;
using Microsoft.Extensions.Logging;

namespace AssetManager.Services;

/// <summary>
/// 组合净值历史服务实现
/// </summary>
public class PortfolioNavService : IPortfolioNavService
{
    private readonly ISqlSugarClient _db;
    private readonly IMarketDataService _marketDataService;
    private readonly IExchangeRateService _exchangeRateService;
    private readonly ILogger<PortfolioNavService> _logger;

    public PortfolioNavService(
        ISqlSugarClient db,
        IMarketDataService marketDataService,
        IExchangeRateService exchangeRateService,
        ILogger<PortfolioNavService> logger)
    {
        _db = db;
        _marketDataService = marketDataService;
        _exchangeRateService = exchangeRateService;
        _logger = logger;
    }

    public async Task<NavHistoryResponse> GetNavHistoryAsync(string portfolioId, string userId, NavHistoryRequest request)
    {
        // 验证权限
        var portfolio = await _db.Queryable<Portfolio>()
            .Where(p => p.Id == portfolioId && p.UserId == userId)
            .FirstAsync();

        if (portfolio == null)
        {
            throw new Exception("Portfolio not found or access denied");
        }

        // 设置默认日期范围（最近30天）
        var endDate = request.EndDate ?? DateTime.Today;
        var startDate = request.StartDate ?? endDate.AddDays(-30);

        // 检查是否有历史数据，没有则自动回填
        var existingCount = await _db.Queryable<PortfolioNavHistory>()
            .Where(n => n.PortfolioId == portfolioId)
            .CountAsync();

        if (existingCount == 0)
        {
            _logger.LogInformation("组合 {PortfolioId} 无净值历史数据，自动开始回填", portfolioId);
            await BackfillNavHistoryInternalAsync(portfolioId, portfolio);
        }
        else
        {
            // 有历史数据，检查是否需要计算今日净值
            var today = DateTime.Today;
            var todayNavExists = await _db.Queryable<PortfolioNavHistory>()
                .Where(n => n.PortfolioId == portfolioId && n.NavDate == today)
                .AnyAsync();
            
            if (!todayNavExists)
            {
                _logger.LogInformation("组合 {PortfolioId} 今日净值不存在，自动计算", portfolioId);
                try
                {
                    await CalculateAndSaveDailyNavAsync(portfolioId);
                }
                catch (Exception ex)
                {
                    _logger.LogWarning(ex, "组合 {PortfolioId} 今日净值计算失败，将使用历史数据", portfolioId);
                }
            }
        }

        // 查询净值历史
        var navHistory = await _db.Queryable<PortfolioNavHistory>()
            .Where(n => n.PortfolioId == portfolioId)
            .Where(n => n.NavDate >= startDate && n.NavDate <= endDate)
            .OrderBy(n => n.NavDate)
            .ToListAsync();

        // 如果没有历史数据
        if (!navHistory.Any())
        {
            return new NavHistoryResponse
            {
                PortfolioId = portfolioId,
                Currency = portfolio.Currency,
                NavHistory = new List<NavHistoryItem>(),
                Statistics = new NavStatistics()
            };
        }

        // 计算统计指标
        var returns = navHistory.Select(n => (double)n.DailyReturn).Where(r => r != 0).ToList();
        var statistics = CalculateStatistics(returns, navHistory);

        return new NavHistoryResponse
        {
            PortfolioId = portfolioId,
            Currency = portfolio.Currency,
            NavHistory = navHistory.Select(n => new NavHistoryItem
            {
                Date = n.NavDate.ToString("yyyy-MM-dd"),
                Nav = (double)n.Nav,
                TotalValue = (double)n.TotalValue,
                TotalCost = (double)n.TotalCost,
                DailyReturn = (double)n.DailyReturn,
                CumulativeReturn = (double)n.CumulativeReturn
            }).ToList(),
            Statistics = statistics
        };
    }

    public async Task<bool> CalculateAndSaveDailyNavAsync(string portfolioId)
    {
        var portfolio = await _db.Queryable<Portfolio>()
            .Where(p => p.Id == portfolioId)
            .FirstAsync();

        if (portfolio == null) return false;

        var today = DateTime.Today;

        // 检查是否已存在当日净值
        var existingNav = await _db.Queryable<PortfolioNavHistory>()
            .Where(n => n.PortfolioId == portfolioId && n.NavDate == today)
            .FirstAsync();

        if (existingNav != null)
        {
            _logger.LogInformation("组合 {PortfolioId} 当日净值已存在，跳过计算", portfolioId);
            return true;
        }

        // 获取持仓
        var positions = await _db.Queryable<Position>()
            .Where(pos => pos.PortfolioId == portfolioId)
            .ToListAsync();

        if (!positions.Any())
        {
            _logger.LogInformation("组合 {PortfolioId} 无持仓，跳过净值计算", portfolioId);
            return false;
        }

        string targetCurrency = portfolio.Currency ?? "CNY";
        decimal totalValue = 0;

        // 计算总市值
        foreach (var pos in positions)
        {
            if (pos.StockCode == null || pos.Currency == null) continue;

            decimal currentPrice = pos.AvgPrice;
            try
            {
                var priceResponse = await _marketDataService.GetPriceAsync(pos.StockCode, pos.AssetType ?? "Stock");
                if (priceResponse.Price > 0)
                {
                    currentPrice = priceResponse.Price;
                }
            }
            catch (Exception ex)
            {
                _logger.LogWarning(ex, "获取 {StockCode} 价格失败，使用成本价", pos.StockCode);
            }

            decimal positionValue = pos.Shares * currentPrice;
            decimal positionValueInTarget = await _exchangeRateService.ConvertAmountAsync(
                positionValue, pos.Currency, targetCurrency);
            totalValue += positionValueInTarget;
        }

        // 获取昨日净值
        var yesterdayNav = await _db.Queryable<PortfolioNavHistory>()
            .Where(n => n.PortfolioId == portfolioId && n.NavDate < today)
            .OrderByDescending(n => n.NavDate)
            .FirstAsync();

        // 计算累计投入成本（从交易记录汇总，卖出时按比例减少成本）
        var transactions = await _db.Queryable<Transaction>()
            .Where(t => t.PortfolioId == portfolioId && t.TransactionTime.Date <= today)
            .OrderBy(t => t.TransactionTime)
            .ToListAsync();

        decimal totalCost = 0;
        var holdingsCost = new Dictionary<string, decimal>(); // 每个标的的累计成本
        
        foreach (var tx in transactions)
        {
            if (tx.StockCode == null) continue;
            
            if (tx.Type == "buy")
            {
                decimal txAmount = tx.TotalAmount;
                decimal txAmountInTarget = await _exchangeRateService.ConvertAmountAsync(
                    txAmount, tx.Currency, targetCurrency);
                totalCost += txAmountInTarget;
                
                // 更新该标的的累计成本
                if (holdingsCost.ContainsKey(tx.StockCode))
                {
                    holdingsCost[tx.StockCode] += txAmountInTarget;
                }
                else
                {
                    holdingsCost[tx.StockCode] = txAmountInTarget;
                }
            }
            else if (tx.Type == "sell")
            {
                // 卖出时按比例减少该标的的累计成本
                if (holdingsCost.ContainsKey(tx.StockCode) && tx.Amount > 0)
                {
                    // 需要知道当时该标的的总数量来计算比例
                    // 从 Position 表获取当前持仓数量（不精确，但作为近似）
                    var position = positions.FirstOrDefault(p => p.StockCode == tx.StockCode);
                    if (position != null && position.Shares > 0)
                    {
                        // 近似：用当前持仓数量 + 卖出数量 作为原来数量
                        decimal originalShares = position.Shares + tx.Amount;
                        decimal soldRatio = tx.Amount / originalShares;
                        decimal costToReduce = holdingsCost[tx.StockCode] * soldRatio;
                        holdingsCost[tx.StockCode] -= costToReduce;
                        totalCost -= costToReduce;
                    }
                }
            }
        }

        // 计算净值
        decimal nav = totalCost > 0 ? totalValue / totalCost : 1.0m;
        decimal dailyReturn = 0;
        decimal cumulativeReturn = totalCost > 0 ? (totalValue - totalCost) / totalCost * 100 : 0;

        if (yesterdayNav != null && yesterdayNav.TotalValue > 0)
        {
            dailyReturn = (totalValue - yesterdayNav.TotalValue) / yesterdayNav.TotalValue * 100;
        }

        // 保存净值记录
        var navRecord = new PortfolioNavHistory
        {
            Id = "nav-" + Guid.NewGuid().ToString().Substring(0, 8),
            PortfolioId = portfolioId,
            NavDate = today,
            TotalValue = totalValue,
            TotalCost = totalCost,
            Nav = nav,
            DailyReturn = dailyReturn,
            CumulativeReturn = cumulativeReturn,
            Currency = targetCurrency,
            PositionCount = positions.Count,
            Source = "calculated",
            CreatedAt = DateTime.Now
        };

        await _db.Insertable(navRecord).ExecuteCommandAsync();
        _logger.LogInformation("组合 {PortfolioId} 净值计算完成: NAV={Nav}, 日收益={DailyReturn}%",
            portfolioId, nav, dailyReturn);

        return true;
    }

    public async Task<int> CalculateAllPortfoliosDailyNavAsync()
    {
        var portfolios = await _db.Queryable<Portfolio>()
            .Where(p => p.Status == "运行中")
            .ToListAsync();

        int successCount = 0;
        foreach (var portfolio in portfolios)
        {
            try
            {
                var result = await CalculateAndSaveDailyNavAsync(portfolio.Id);
                if (result) successCount++;
            }
            catch (Exception ex)
            {
                _logger.LogError(ex, "组合 {PortfolioId} 净值计算失败", portfolio.Id);
            }
        }

        _logger.LogInformation("批量净值计算完成: 成功 {Success}/{Total}", successCount, portfolios.Count);
        return successCount;
    }

    public async Task<BackfillNavResponse> BackfillNavHistoryAsync(string portfolioId, string userId, bool force = false)
    {
        // 验证权限
        var portfolio = await _db.Queryable<Portfolio>()
            .Where(p => p.Id == portfolioId && p.UserId == userId)
            .FirstAsync();

        if (portfolio == null)
        {
            throw new Exception("Portfolio not found or access denied");
        }

        return await BackfillNavHistoryInternalAsync(portfolioId, portfolio, force);
    }

    /// <summary>
    /// 内部回填方法（已验证权限）
    /// </summary>
    private async Task<BackfillNavResponse> BackfillNavHistoryInternalAsync(string portfolioId, Portfolio portfolio, bool force = false)
    {
        // 获取所有交易记录，按时间排序
        var transactions = await _db.Queryable<Transaction>()
            .Where(t => t.PortfolioId == portfolioId)
            .OrderBy(t => t.TransactionTime)
            .ToListAsync();

        if (!transactions.Any())
        {
            return new BackfillNavResponse
            {
                PortfolioId = portfolioId,
                RecordsCreated = 0,
                Message = "无交易记录，无法计算净值历史"
            };
        }

        // 确定起始日期（最早交易日期）
        var startDate = transactions.Min(t => t.TransactionTime).Date;
        var endDate = DateTime.Today;
        string targetCurrency = portfolio.Currency ?? "CNY";

        _logger.LogInformation("开始回填净值历史: {PortfolioId}, 日期范围: {StartDate} ~ {EndDate}",
            portfolioId, startDate, endDate);

        // 如果强制重新计算，先删除所有历史记录
        if (force)
        {
            await _db.Deleteable<PortfolioNavHistory>()
                .Where(n => n.PortfolioId == portfolioId)
                .ExecuteCommandAsync();
        }

        // 持仓快照：股票代码 -> (数量, 成本)
        var holdings = new Dictionary<string, (decimal shares, decimal cost, string? currency, string? assetType)>();

        // 累计投入成本
        decimal cumulativeCost = 0;

        // 记录创建数量
        int recordsCreated = 0;

        // 遍历每个交易日
        for (var date = startDate; date <= endDate; date = date.AddDays(1))
        {
            // 检查是否已存在该日期的净值记录（非强制模式）
            if (!force)
            {
                var existingNav = await _db.Queryable<PortfolioNavHistory>()
                    .Where(n => n.PortfolioId == portfolioId && n.NavDate == date)
                    .FirstAsync();

                if (existingNav != null) continue;
            }

            // 处理当天的所有交易
            var todayTransactions = transactions.Where(t => t.TransactionTime.Date == date).ToList();
            foreach (var tx in todayTransactions)
            {
                if (tx.StockCode == null) continue;

                if (tx.Type == "buy")
                {
                    if (holdings.ContainsKey(tx.StockCode))
                    {
                        var existing = holdings[tx.StockCode];
                        decimal newShares = existing.shares + tx.Amount;
                        decimal newCost = existing.cost + tx.TotalAmount;
                        holdings[tx.StockCode] = (newShares, newCost, tx.Currency, tx.AssetType);
                    }
                    else
                    {
                        holdings[tx.StockCode] = (tx.Amount, tx.TotalAmount, tx.Currency, tx.AssetType);
                    }

                    // 累计投入成本（转换为目标币种）
                    decimal txAmountInTarget = await _exchangeRateService.ConvertAmountAsync(
                        tx.TotalAmount, tx.Currency, targetCurrency);
                    cumulativeCost += txAmountInTarget;
                }
                else if (tx.Type == "sell")
                {
                    if (holdings.ContainsKey(tx.StockCode))
                    {
                        var existing = holdings[tx.StockCode];
                        decimal soldRatio = tx.Amount / existing.shares;
                        decimal remainingShares = existing.shares - tx.Amount;
                        decimal remainingCost = existing.cost * (1 - (decimal)soldRatio);

                        if (remainingShares <= 0)
                        {
                            holdings.Remove(tx.StockCode);
                        }
                        else
                        {
                            holdings[tx.StockCode] = (remainingShares, remainingCost, existing.currency, existing.assetType);
                        }

                        // 按比例减少累计投入成本（关键修复：不再用卖出金额）
                        decimal costToReduce = cumulativeCost * (decimal)soldRatio;
                        cumulativeCost -= costToReduce;
                    }
                }
            }

            // 如果没有持仓，跳过
            if (!holdings.Any()) continue;

            // 计算当日市值
            decimal totalValue = 0;
            bool hasValidPrice = true;
            List<string> failedSymbols = new List<string>();
            
            foreach (var (stockCode, (shares, cost, currency, assetType)) in holdings)
            {
                var priceResult = await GetHistoricalPriceAsync(stockCode, assetType ?? "Stock", date);
                if (priceResult == null || priceResult <= 0)
                {
                    hasValidPrice = false;
                    failedSymbols.Add(stockCode);
                    continue;
                }
                
                decimal price = priceResult.Value;
                decimal positionValue = shares * price;
                decimal positionValueInTarget = await _exchangeRateService.ConvertAmountAsync(
                    positionValue, currency ?? targetCurrency, targetCurrency);
                totalValue += positionValueInTarget;
            }

            // 如果有任何持仓价格获取失败，跳过该日期，不写入错误数据
            if (!hasValidPrice)
            {
                _logger.LogWarning("跳过日期 {Date}，以下持仓价格获取失败: {Symbols}", 
                    date.ToString("yyyy-MM-dd"), string.Join(", ", failedSymbols));
                continue;
            }

            // 计算净值
            decimal nav = cumulativeCost > 0 ? totalValue / cumulativeCost : 1.0m;
            decimal cumulativeReturn = cumulativeCost > 0 ? (totalValue - cumulativeCost) / cumulativeCost * 100 : 0;

            // 获取昨日净值以计算日收益率
            var yesterdayNav = await _db.Queryable<PortfolioNavHistory>()
                .Where(n => n.PortfolioId == portfolioId && n.NavDate < date)
                .OrderByDescending(n => n.NavDate)
                .FirstAsync();

            decimal dailyReturn = 0;
            if (yesterdayNav != null && yesterdayNav.TotalValue > 0)
            {
                dailyReturn = (totalValue - yesterdayNav.TotalValue) / yesterdayNav.TotalValue * 100;
            }

            // 保存净值记录
            var navRecord = new PortfolioNavHistory
            {
                Id = "nav-" + Guid.NewGuid().ToString().Substring(0, 8),
                PortfolioId = portfolioId,
                NavDate = date,
                TotalValue = totalValue,
                TotalCost = cumulativeCost,
                Nav = nav,
                DailyReturn = dailyReturn,
                CumulativeReturn = cumulativeReturn,
                Currency = targetCurrency,
                PositionCount = holdings.Count,
                Source = "backfill",
                CreatedAt = DateTime.Now
            };

            await _db.Insertable(navRecord).ExecuteCommandAsync();
            recordsCreated++;

            // 每100条记录输出一次进度
            if (recordsCreated % 100 == 0)
            {
                _logger.LogInformation("回填进度: {Count} 条记录已创建", recordsCreated);
            }
        }

        _logger.LogInformation("净值历史回填完成: {PortfolioId}, 共创建 {Count} 条记录", portfolioId, recordsCreated);

        return new BackfillNavResponse
        {
            PortfolioId = portfolioId,
            RecordsCreated = recordsCreated,
            StartDate = startDate,
            EndDate = endDate,
            Message = $"成功回填 {recordsCreated} 条净值记录"
        };
    }

    public async Task<int> DeleteNavHistoryAfterDateAsync(string portfolioId, DateTime date)
    {
        var deleted = await _db.Deleteable<PortfolioNavHistory>()
            .Where(n => n.PortfolioId == portfolioId && n.NavDate >= date)
            .ExecuteCommandAsync();

        _logger.LogInformation("删除净值记录: PortfolioId={PortfolioId}, Date>={Date}, Count={Count}",
            portfolioId, date, deleted);

        return deleted;
    }

    /// <summary>
    /// 获取历史价格（优先从缓存读取）
    /// </summary>
    private async Task<decimal?> GetHistoricalPriceAsync(string symbol, string assetType, DateTime date)
    {
        try
        {
            // 1. 先从缓存表查特定日期的价格
            var cachedPrice = await _db.Queryable<MarketKlineCache>()
                .Where(k => k.Symbol == symbol.ToUpper() 
                         && k.AssetType == assetType.ToUpper()
                         && k.Timeframe == "1D"
                         && k.Timestamp.Date == date.Date)
                .FirstAsync();

            if (cachedPrice != null && cachedPrice.Close > 0)
            {
                _logger.LogDebug("缓存命中: {Symbol} {Date}, 价格: {Price}", symbol, date.ToString("yyyy-MM-dd"), cachedPrice.Close);
                return cachedPrice.Close;
            }

            // 2. 缓存未命中，尝试获取该日期附近的历史数据
            var historicalData = await _marketDataService.GetHistoricalDataAsync(symbol, assetType, "1d", 30);
            
            // 精确匹配日期
            var priceOnDate = historicalData.FirstOrDefault(d => d.Timestamp.Date == date.Date);
            if (priceOnDate != null && priceOnDate.Close > 0)
            {
                return priceOnDate.Close;
            }

            // 找最近的交易日价格
            var nearestPrice = historicalData
                .Where(d => d.Timestamp.Date <= date.Date)
                .OrderByDescending(d => d.Timestamp)
                .FirstOrDefault();

            if (nearestPrice != null && nearestPrice.Close > 0)
            {
                _logger.LogDebug("使用最近交易日价格: {Symbol} {Date} → {ActualDate}", 
                    symbol, date.ToString("yyyy-MM-dd"), nearestPrice.Timestamp.ToString("yyyy-MM-dd"));
                return nearestPrice.Close;
            }

            // 3. 最后尝试获取实时价格
            var currentPrice = await _marketDataService.GetPriceAsync(symbol, assetType);
            if (currentPrice != null && currentPrice.Price > 0)
            {
                return currentPrice.Price;
            }

            _logger.LogWarning("无法获取有效价格: {Symbol}, {Date}", symbol, date);
            return null;
        }
        catch (Exception ex)
        {
            _logger.LogWarning(ex, "获取历史价格失败: {Symbol}, {Date}", symbol, date);
            return null;
        }
    }

    /// <summary>
    /// 计算统计指标
    /// </summary>
    private NavStatistics CalculateStatistics(List<double> returns, List<PortfolioNavHistory> history)
    {
        if (!history.Any()) return new NavStatistics();

        var maxReturn = returns.Any() ? returns.Max() : 0;
        var minReturn = returns.Any() ? returns.Min() : 0;

        // 计算最大回撤（修复：用第一条记录的 Nav 作为初始 peak）
        double maxDrawdown = 0;
        var orderedHistory = history.OrderBy(h => h.NavDate).ToList();
        double peak = (double)orderedHistory.First().Nav;
        foreach (var item in orderedHistory)
        {
            var nav = (double)item.Nav;
            if (nav > peak) peak = nav;
            var drawdown = (peak - nav) / peak * 100;
            if (drawdown > maxDrawdown) maxDrawdown = drawdown;
        }

        // 计算夏普比率（修复：收益率从百分比转为小数）
        double sharpeRatio = 0;
        double volatility = 0;
        if (returns.Any())
        {
            // 收益率从百分比形式转换为小数形式（如 0.5% -> 0.005）
            var decimalReturns = returns.Select(r => r / 100.0).ToList();
            var avgReturn = decimalReturns.Average();
            var stdDev = Math.Sqrt(decimalReturns.Sum(r => Math.Pow(r - avgReturn, 2)) / decimalReturns.Count);
            
            // 年化
            double annualizedReturn = avgReturn * 252;
            double annualizedVol = stdDev * Math.Sqrt(252);
            volatility = annualizedVol * 100; // 转回百分比形式显示
            sharpeRatio = annualizedVol > 0 ? (annualizedReturn - 0.03) / annualizedVol : 0; // 3% 无风险利率
        }

        // 总收益率
        var totalReturn = history.Any() 
            ? (double)(history.Last().CumulativeReturn) 
            : 0;

        return new NavStatistics
        {
            MaxReturn = Math.Round(maxReturn, 2),
            MinReturn = Math.Round(minReturn, 2),
            MaxDrawdown = Math.Round(maxDrawdown, 2),
            SharpeRatio = Math.Round(sharpeRatio, 2),
            Volatility = Math.Round(volatility, 2),
            TotalReturn = Math.Round(totalReturn, 2),
            TradingDays = history.Count
        };
    }
}