namespace WebApi.Controllers;

[ApiController]
[Route("api/[controller]/[action]")]
public class TransactionRecordController(
    ITransactionRecordRepository transactionRepository,
    ITransactionCategoryRepository categoryRepository,
    IOpenAiService openAiService,
    ILogger<TransactionRecordController> logger
) : ControllerBase
{
    /// <summary>
    /// 获取交易记录列表（分页）
    /// </summary>
    [HttpGet]
    public async Task<PagedResponse<Entity.TransactionRecord>> GetListAsync(
        [FromQuery] DateTime? lastOccurredAt = null,
        [FromQuery] long? lastId = null,
        [FromQuery] string? searchKeyword = null
    )
    {
        try
        {
            var (list, lastTime, lastIdResult) = await transactionRepository.GetPagedListAsync(lastOccurredAt, lastId, 20, searchKeyword);
            var total = await transactionRepository.GetTotalCountAsync();

            return new PagedResponse<Entity.TransactionRecord>
            {
                Success = true,
                Data = list.ToArray(),
                Total = (int)total,
                LastId = lastIdResult,
                LastTime = lastTime
            };
        }
        catch (Exception ex)
        {
            logger.LogError(ex, "获取交易记录列表失败，时间: {LastTime}, ID: {LastId}", lastOccurredAt, lastId);
            return PagedResponse<Entity.TransactionRecord>.Fail($"获取交易记录列表失败: {ex.Message}");
        }
    }

    /// <summary>
    /// 根据ID获取交易记录详情
    /// </summary>
    [HttpGet("{id}")]
    public async Task<BaseResponse<Entity.TransactionRecord>> GetByIdAsync(long id)
    {
        try
        {
            var transaction = await transactionRepository.GetByIdAsync(id);
            if (transaction == null)
            {
                return BaseResponse<Entity.TransactionRecord>.Fail("交易记录不存在");
            }

            return new BaseResponse<Entity.TransactionRecord>
            {
                Success = true,
                Data = transaction
            };
        }
        catch (Exception ex)
        {
            logger.LogError(ex, "获取交易记录详情失败，交易ID: {TransactionId}", id);
            return BaseResponse<Entity.TransactionRecord>.Fail($"获取交易记录详情失败: {ex.Message}");
        }
    }

    /// <summary>
    /// 根据邮件ID获取交易记录列表
    /// </summary>
    [HttpGet("{emailId}")]
    public async Task<BaseResponse<List<Entity.TransactionRecord>>> GetByEmailIdAsync(long emailId)
    {
        try
        {
            var transactions = await transactionRepository.GetByEmailIdAsync(emailId);
            return new BaseResponse<List<Entity.TransactionRecord>>
            {
                Success = true,
                Data = transactions
            };
        }
        catch (Exception ex)
        {
            logger.LogError(ex, "获取邮件交易记录失败，邮件ID: {EmailId}", emailId);
            return BaseResponse<List<Entity.TransactionRecord>>.Fail($"获取邮件交易记录失败: {ex.Message}");
        }
    }

    /// <summary>
    /// 创建交易记录
    /// </summary>
    [HttpPost]
    public async Task<BaseResponse> CreateAsync([FromBody] CreateTransactionDto dto)
    {
        try
        {
            // 解析日期字符串
            if (!DateTime.TryParse(dto.OccurredAt, out var occurredAt))
            {
                return BaseResponse.Fail("交易时间格式不正确");
            }

            var transaction = new Entity.TransactionRecord
            {
                OccurredAt = occurredAt,
                Reason = dto.Reason ?? string.Empty,
                Amount = dto.Amount,
                Type = dto.Type,
                Classify = dto.Classify ?? string.Empty,
                SubClassify = dto.SubClassify ?? string.Empty,
                ImportFrom = "手动录入",
                EmailMessageId = 0 // 手动录入的记录，EmailMessageId 设为 0
            };

            var result = await transactionRepository.AddAsync(transaction);
            if (result)
            {
                return new BaseResponse
                {
                    Success = true
                };
            }
            else
            {
                return BaseResponse.Fail("创建交易记录失败");
            }
        }
        catch (Exception ex)
        {
            logger.LogError(ex, "创建交易记录失败，交易信息: {@TransactionDto}", dto);
            return BaseResponse.Fail($"创建交易记录失败: {ex.Message}");
        }
    }

    /// <summary>
    /// 更新交易记录
    /// </summary>
    [HttpPost]
    public async Task<BaseResponse> UpdateAsync([FromBody] UpdateTransactionDto dto)
    {
        try
        {
            var transaction = await transactionRepository.GetByIdAsync(dto.Id);
            if (transaction == null)
            {
                return BaseResponse.Fail("交易记录不存在");
            }

            // 更新可编辑字段
            transaction.Reason = dto.Reason ?? string.Empty;
            transaction.Amount = dto.Amount;
            transaction.Balance = dto.Balance;
            transaction.Type = dto.Type;
            transaction.Classify = dto.Classify ?? string.Empty;
            transaction.SubClassify = dto.SubClassify ?? string.Empty;

            var success = await transactionRepository.UpdateAsync(transaction);
            if (success)
            {
                return new BaseResponse
                {
                    Success = true
                };
            }
            else
            {
                return BaseResponse.Fail("更新交易记录失败");
            }
        }
        catch (Exception ex)
        {
            logger.LogError(ex, "更新交易记录失败，交易ID: {TransactionId}, 交易信息: {@TransactionDto}", dto.Id, dto);
            return BaseResponse.Fail($"更新交易记录失败: {ex.Message}");
        }
    }

    /// <summary>
    /// 删除交易记录
    /// </summary>
    [HttpPost]
    public async Task<BaseResponse> DeleteByIdAsync([FromQuery] long id)
    {
        try
        {
            var success = await transactionRepository.DeleteAsync(id);
            if (success)
            {
                return new BaseResponse
                {
                    Success = true
                };
            }
            else
            {
                return BaseResponse.Fail("删除交易记录失败，记录不存在");
            }
        }
        catch (Exception ex)
        {
            logger.LogError(ex, "删除交易记录失败，交易ID: {TransactionId}", id);
            return BaseResponse.Fail($"删除交易记录失败: {ex.Message}");
        }
    }

    /// <summary>
    /// 获取指定月份每天的消费统计
    /// </summary>
    [HttpGet]
    public async Task<BaseResponse<List<DailyStatisticsDto>>> GetDailyStatisticsAsync(
        [FromQuery] int year,
        [FromQuery] int month
    )
    {
        try
        {
            var statistics = await transactionRepository.GetDailyStatisticsAsync(year, month);
            var result = statistics.Select(s => new DailyStatisticsDto(s.Key, s.Value.count, s.Value.amount)).ToList();

            return new BaseResponse<List<DailyStatisticsDto>>
            {
                Success = true,
                Data = result
            };
        }
        catch (Exception ex)
        {
            logger.LogError(ex, "获取日历统计数据失败，年份: {Year}, 月份: {Month}", year, month);
            return BaseResponse<List<DailyStatisticsDto>>.Fail($"获取日历统计数据失败: {ex.Message}");
        }
    }

    /// <summary>
    /// 获取指定日期的交易记录
    /// </summary>
    [HttpGet]
    public async Task<BaseResponse<List<Entity.TransactionRecord>>> GetByDateAsync(
        [FromQuery] string date
    )
    {
        try
        {
            if (!DateTime.TryParse(date, out var targetDate))
            {
                return BaseResponse<List<Entity.TransactionRecord>>.Fail("日期格式不正确");
            }

            // 获取当天的开始和结束时间
            var startDate = targetDate.Date;
            var endDate = startDate.AddDays(1);

            var records = await transactionRepository.GetByDateRangeAsync(startDate, endDate);

            return new BaseResponse<List<Entity.TransactionRecord>>
            {
                Success = true,
                Data = records
            };
        }
        catch (Exception ex)
        {
            logger.LogError(ex, "获取指定日期的交易记录失败，日期: {Date}", date);
            return BaseResponse<List<Entity.TransactionRecord>>.Fail($"获取指定日期的交易记录失败: {ex.Message}");
        }
    }

    /// <summary>
    /// 获取未分类的账单数量
    /// </summary>
    [HttpGet]
    public async Task<BaseResponse<int>> GetUnclassifiedCountAsync()
    {
        try
        {
            var count = await transactionRepository.GetUnclassifiedCountAsync();
            return new BaseResponse<int>
            {
                Success = true,
                Data = count
            };
        }
        catch (Exception ex)
        {
            logger.LogError(ex, "获取未分类账单数量失败");
            return BaseResponse<int>.Fail($"获取未分类账单数量失败: {ex.Message}");
        }
    }

    /// <summary>
    /// 获取未分类的账单列表
    /// </summary>
    [HttpGet]
    public async Task<BaseResponse<List<Entity.TransactionRecord>>> GetUnclassifiedAsync([FromQuery] int pageSize = 10)
    {
        try
        {
            var records = await transactionRepository.GetUnclassifiedAsync(pageSize);
            return new BaseResponse<List<Entity.TransactionRecord>>
            {
                Success = true,
                Data = records
            };
        }
        catch (Exception ex)
        {
            logger.LogError(ex, "获取未分类账单列表失败");
            return BaseResponse<List<Entity.TransactionRecord>>.Fail($"获取未分类账单列表失败: {ex.Message}");
        }
    }

    /// <summary>
    /// 智能分类 - 使用AI对账单进行分类（流式响应）
    /// </summary>
    [HttpPost]
    public async Task SmartClassifyAsync([FromBody] SmartClassifyRequest request)
    {
        Response.ContentType = "text/event-stream";
        Response.Headers.Append("Cache-Control", "no-cache");
        Response.Headers.Append("Connection", "keep-alive");

        try
        {
            // 获取要分类的账单
            var records = await transactionRepository.GetUnclassifiedAsync(request.PageSize);
            if (records.Count == 0)
            {
                await WriteEventAsync("error", "没有需要分类的账单");
                return;
            }

            // 获取所有分类
            var categories = await categoryRepository.GetAllAsync();
            
            // 构建分类信息
            var categoryInfo = string.Join("\n", categories
                .Select(c =>
                {
                    var children = categories.Where(x => x.ParentId == c.Id).ToList();
                    var childrenStr = children.Count > 0 
                        ? $"，子分类：{string.Join("、", children.Select(x => x.Name))}" 
                        : "";
                    return $"- {c.Name} ({(c.Type == TransactionType.Expense ? "支出" : "收入")}){childrenStr}";
                }));

            // 构建账单信息
            var billsInfo = string.Join("\n", records.Select((r, i) => 
                $"{i + 1}. ID={r.Id}, 摘要={r.Reason}, 金额={r.Amount}, 类型={GetTypeName(r.Type)}"));

            var systemPrompt = $@"你是一个专业的账单分类助手。请根据提供的账单信息和分类列表，为每个账单选择最合适的分类。

可用的分类列表：
{categoryInfo}

分类规则：
1. 根据账单的摘要和金额，选择最匹配的一级分类
2. 如果有合适的子分类，也要指定子分类
3. 如果无法确定分类，可以选择""其他""

请对每个账单进行分类，每次输出一个账单的分类结果，格式如下：
{{""id"": 账单ID, ""classify"": ""一级分类"", ""subClassify"": ""子分类""}}

只输出JSON，不要有其他文字说明。";

            var userPrompt = $@"请为以下账单进行分类：

{billsInfo}

请逐个输出分类结果。";

            // 流式调用AI
            await WriteEventAsync("start", $"开始分类 {records.Count} 条账单");

            await foreach (var chunk in openAiService.ChatStreamAsync(systemPrompt, userPrompt))
            {
                await WriteEventAsync("data", chunk);
            }

            await WriteEventAsync("end", "分类完成");
        }
        catch (Exception ex)
        {
            logger.LogError(ex, "智能分类失败");
            await WriteEventAsync("error", $"智能分类失败: {ex.Message}");
        }
    }

    /// <summary>
    /// 批量更新账单分类
    /// </summary>
    [HttpPost]
    public async Task<BaseResponse> BatchUpdateClassifyAsync([FromBody] List<BatchUpdateClassifyItem> items)
    {
        try
        {
            var successCount = 0;
            var failCount = 0;

            foreach (var item in items)
            {
                var record = await transactionRepository.GetByIdAsync(item.Id);
                if (record != null)
                {
                    record.Classify = item.Classify ?? string.Empty;
                    record.SubClassify = item.SubClassify ?? string.Empty;
                    var success = await transactionRepository.UpdateAsync(record);
                    if (success)
                        successCount++;
                    else
                        failCount++;
                }
                else
                {
                    failCount++;
                }
            }

            return new BaseResponse
            {
                Success = true,
                Message = $"批量更新完成，成功 {successCount} 条，失败 {failCount} 条"
            };
        }
        catch (Exception ex)
        {
            logger.LogError(ex, "批量更新分类失败");
            return BaseResponse.Fail($"批量更新分类失败: {ex.Message}");
        }
    }

    private async Task WriteEventAsync(string eventType, string data)
    {
        var message = $"event: {eventType}\ndata: {data}\n\n";
        await Response.WriteAsync(message);
        await Response.Body.FlushAsync();
    }

    private static string GetTypeName(TransactionType type)
    {
        return type switch
        {
            TransactionType.Expense => "支出",
            TransactionType.Income => "收入",
            TransactionType.None => "不计入收支",
            _ => "未知"
        };
    }


}

/// <summary>
/// 创建交易记录DTO
/// </summary>
public record CreateTransactionDto(
    string OccurredAt,
    string? Reason,
    decimal Amount,
    TransactionType Type,
    string? Classify,
    string? SubClassify
);

/// <summary>
/// 更新交易记录DTO
/// </summary>
public record UpdateTransactionDto(
    long Id,
    string? Reason,
    decimal Amount,
    decimal Balance,
    TransactionType Type,
    string? Classify,
    string? SubClassify
);

/// <summary>
/// 日历统计响应DTO
/// </summary>
public record DailyStatisticsDto(
    string Date,
    int Count,
    decimal Amount
);

/// <summary>
/// 智能分类请求DTO
/// </summary>
public record SmartClassifyRequest(
    int PageSize = 10
);

/// <summary>
/// 批量更新分类项DTO
/// </summary>
public record BatchUpdateClassifyItem(
    long Id,
    string? Classify,
    string? SubClassify
);