using Application.Dto.Statistics;
using Service.Transaction;

namespace Application;

/// <summary>
/// 交易统计应用服务接口
/// </summary>
public interface ITransactionStatisticsApplication
{
    // === 新统一接口（推荐使用） ===
    
    /// <summary>
    /// 按日期范围获取每日统计（新统一接口）
    /// </summary>
    Task<List<DailyStatisticsDto>> GetDailyStatisticsByRangeAsync(DateTime startDate, DateTime endDate, string? savingClassify = null);
    
    /// <summary>
    /// 按日期范围获取汇总统计（新统一接口）
    /// </summary>
    Task<MonthlyStatistics> GetSummaryByRangeAsync(DateTime startDate, DateTime endDate);
    
    /// <summary>
    /// 按日期范围获取分类统计（新统一接口）
    /// </summary>
    Task<List<CategoryStatistics>> GetCategoryStatisticsByRangeAsync(DateTime startDate, DateTime endDate, TransactionType type);
    
    /// <summary>
    /// 获取趋势统计数据
    /// </summary>
    Task<List<TrendStatistics>> GetTrendStatisticsAsync(int startYear, int startMonth, int monthCount);
    
    // === 旧接口（保留用于向后兼容，建议迁移到新接口） ===
    
    [Obsolete("请使用 GetDailyStatisticsByRangeAsync")]
    Task<List<BalanceStatisticsDto>> GetBalanceStatisticsAsync(int year, int month);
    
    [Obsolete("请使用 GetDailyStatisticsByRangeAsync")]
    Task<List<DailyStatisticsDto>> GetDailyStatisticsAsync(int year, int month);
    
    [Obsolete("请使用 GetDailyStatisticsByRangeAsync")]
    Task<List<DailyStatisticsDto>> GetWeeklyStatisticsAsync(DateTime startDate, DateTime endDate);
    
    [Obsolete("请使用 GetSummaryByRangeAsync")]
    Task<MonthlyStatistics> GetRangeStatisticsAsync(DateTime startDate, DateTime endDate);
    
    [Obsolete("请使用 GetSummaryByRangeAsync")]
    Task<MonthlyStatistics> GetMonthlyStatisticsAsync(int year, int month);
    
    [Obsolete("请使用 GetCategoryStatisticsByRangeAsync")]
    Task<List<CategoryStatistics>> GetCategoryStatisticsAsync(int year, int month, TransactionType type);
    
    [Obsolete("请使用 GetCategoryStatisticsByRangeAsync")]
    Task<List<CategoryStatistics>> GetCategoryStatisticsByDateRangeAsync(string startDate, string endDate, TransactionType type);
    
    Task<(List<ReasonGroupDto> list, int total)> GetReasonGroupsAsync(int pageIndex, int pageSize);
}

/// <summary>
/// 交易统计应用服务实现
/// </summary>
public class TransactionStatisticsApplication(
    ITransactionStatisticsService statisticsService,
    IConfigService configService
) : ITransactionStatisticsApplication
{
    // === 新统一接口实现 ===
    
    /// <summary>
    /// 按日期范围获取每日统计（新统一接口）
    /// </summary>
    public async Task<List<DailyStatisticsDto>> GetDailyStatisticsByRangeAsync(DateTime startDate, DateTime endDate, string? savingClassify = null)
    {
        // 如果未指定 savingClassify，从配置读取
        savingClassify ??= await configService.GetConfigByKeyAsync<string>("SavingsCategories");
        
        var statistics = await statisticsService.GetDailyStatisticsByRangeAsync(startDate, endDate, savingClassify);

        return statistics.Select(s => new DailyStatisticsDto(
            DateTime.Parse(s.Key).Day,
            s.Value.count,
            s.Value.expense,
            s.Value.income,
            s.Value.saving
        )).ToList();
    }
    
    /// <summary>
    /// 按日期范围获取汇总统计（新统一接口）
    /// </summary>
    public async Task<MonthlyStatistics> GetSummaryByRangeAsync(DateTime startDate, DateTime endDate)
    {
        return await statisticsService.GetSummaryByRangeAsync(startDate, endDate);
    }
    
    /// <summary>
    /// 按日期范围获取分类统计（新统一接口）
    /// </summary>
    public async Task<List<CategoryStatistics>> GetCategoryStatisticsByRangeAsync(DateTime startDate, DateTime endDate, TransactionType type)
    {
        return await statisticsService.GetCategoryStatisticsByDateRangeAsync(startDate, endDate, type);
    }
    
    // === 旧接口实现（保留用于向后兼容） ===
    
    public async Task<List<BalanceStatisticsDto>> GetBalanceStatisticsAsync(int year, int month)
    {
        var savingClassify = await configService.GetConfigByKeyAsync<string>("SavingsCategories");
        var statistics = await statisticsService.GetDailyStatisticsAsync(year, month, savingClassify);

        var sortedStats = statistics.OrderBy(s => DateTime.Parse(s.Key)).ToList();
        var result = new List<BalanceStatisticsDto>();
        decimal cumulativeBalance = 0;

        foreach (var item in sortedStats)
        {
            var dailyBalance = item.Value.income - item.Value.expense;
            cumulativeBalance += dailyBalance;
            result.Add(new BalanceStatisticsDto(DateTime.Parse(item.Key).Day, cumulativeBalance));
        }

        return result;
    }

    public async Task<List<DailyStatisticsDto>> GetDailyStatisticsAsync(int year, int month)
    {
        var savingClassify = await configService.GetConfigByKeyAsync<string>("SavingsCategories");
        var statistics = await statisticsService.GetDailyStatisticsAsync(year, month, savingClassify);

        return statistics.Select(s => new DailyStatisticsDto(
            DateTime.Parse(s.Key).Day, // 从完整日期字符串 "yyyy-MM-dd" 中提取 day
            s.Value.count,
            s.Value.expense,
            s.Value.income,
            s.Value.saving
        )).ToList();
    }

    public async Task<List<DailyStatisticsDto>> GetWeeklyStatisticsAsync(DateTime startDate, DateTime endDate)
    {
        var savingClassify = await configService.GetConfigByKeyAsync<string>("SavingsCategories");
        var statistics = await statisticsService.GetDailyStatisticsByRangeAsync(startDate, endDate, savingClassify);

        return statistics.Select(s => new DailyStatisticsDto(
            DateTime.Parse(s.Key).Day, // 从完整日期字符串 "yyyy-MM-dd" 中提取 day
            s.Value.count,
            s.Value.expense,
            s.Value.income,
            s.Value.saving
        )).ToList();
    }

    public async Task<MonthlyStatistics> GetRangeStatisticsAsync(DateTime startDate, DateTime endDate)
    {
        var records = await statisticsService.GetDailyStatisticsByRangeAsync(startDate, endDate, null);
        
        var totalExpense = records.Sum(r => r.Value.expense);
        var totalIncome = records.Sum(r => r.Value.income);
        var totalCount = records.Sum(r => r.Value.count);
        var expenseCount = records.Count(r => r.Value.expense > 0);
        var incomeCount = records.Count(r => r.Value.income > 0);

        return new MonthlyStatistics
        {
            Year = startDate.Year,
            Month = startDate.Month,
            TotalExpense = totalExpense,
            TotalIncome = totalIncome,
            Balance = totalIncome - totalExpense,
            ExpenseCount = expenseCount,
            IncomeCount = incomeCount,
            TotalCount = totalCount
        };
    }

    public async Task<MonthlyStatistics> GetMonthlyStatisticsAsync(int year, int month)
    {
        return await statisticsService.GetMonthlyStatisticsAsync(year, month);
    }

    public async Task<List<CategoryStatistics>> GetCategoryStatisticsAsync(int year, int month, TransactionType type)
    {
        return await statisticsService.GetCategoryStatisticsAsync(year, month, type);
    }

    public async Task<List<CategoryStatistics>> GetCategoryStatisticsByDateRangeAsync(string startDate, string endDate, TransactionType type)
    {
        var start = DateTime.Parse(startDate);
        var end = DateTime.Parse(endDate);
        return await statisticsService.GetCategoryStatisticsByDateRangeAsync(start, end, type);
    }

    public async Task<List<TrendStatistics>> GetTrendStatisticsAsync(int startYear, int startMonth, int monthCount)
    {
        return await statisticsService.GetTrendStatisticsAsync(startYear, startMonth, monthCount);
    }

    public async Task<(List<ReasonGroupDto> list, int total)> GetReasonGroupsAsync(int pageIndex, int pageSize)
    {
        return await statisticsService.GetReasonGroupsAsync(pageIndex, pageSize);
    }
}