// Package handler HTTP Handler实现
package handler

import (
	"context"
	"fmt"

	"market-data-service/api"
	"market-data-service/internal/service"
)

// Handler HTTP处理器实现
type Handler struct {
	stockService   service.StockService
	futuresService service.FuturesService
	adminService   service.AdminService
}

// NewHandler 创建Handler
func NewHandler(
	stockService service.StockService,
	futuresService service.FuturesService,
	adminService service.AdminService,
) *Handler {
	return &Handler{
		stockService:   stockService,
		futuresService: futuresService,
		adminService:   adminService,
	}
}

// 确保Handler实现了api.Handler接口
var _ api.Handler = (*Handler)(nil)

// ============================================
// 股票接口实现
// ============================================

// QueryKLines 查询股票K线
func (h *Handler) QueryKLines(ctx context.Context, req *api.KLineQueryRequest) (*api.Response, error) {
	// 参数校验
	if err := validateKLineRequest(req); err != nil {
		return nil, err
	}

	// 调用Service层
	data, err := h.stockService.QueryKLines(ctx, req)
	if err != nil {
		return nil, err
	}

	return &api.Response{
		Code:    0,
		Message: "success",
		Data:    data,
	}, nil
}

// ListSymbols 查询股票标的列表
func (h *Handler) ListSymbols(ctx context.Context, req *api.SymbolListRequest) (*api.Response, error) {
	// 设置默认值
	if req.Page <= 0 {
		req.Page = 1
	}
	if req.Size <= 0 {
		req.Size = 20
	}
	if req.Size > 100 {
		req.Size = 100
	}

	data, err := h.stockService.ListSymbols(ctx, req)
	if err != nil {
		return nil, err
	}

	return &api.Response{
		Code:    0,
		Message: "success",
		Data:    data,
	}, nil
}

// BatchQueryKLines 批量查询股票K线
func (h *Handler) BatchQueryKLines(ctx context.Context, req *api.BatchKLineRequest) (*api.Response, error) {
	if err := validateBatchKLineRequest(req); err != nil {
		return nil, err
	}

	data, err := h.stockService.BatchQueryKLines(ctx, req)
	if err != nil {
		return nil, err
	}

	return &api.Response{
		Code:    0,
		Message: "success",
		Data:    data,
	}, nil
}

// ============================================
// 期货接口实现
// ============================================

// QueryKLines 查询期货K线（期货Handler）
func (h *Handler) QueryKLines(ctx context.Context, req *api.KLineQueryRequest) (*api.Response, error) {
	if err := validateKLineRequest(req); err != nil {
		return nil, err
	}

	data, err := h.futuresService.QueryKLines(ctx, req)
	if err != nil {
		return nil, err
	}

	return &api.Response{
		Code:    0,
		Message: "success",
		Data:    data,
	}, nil
}

// ListSymbols 查询期货标的列表
func (h *Handler) ListSymbols(ctx context.Context, req *api.SymbolListRequest) (*api.Response, error) {
	if req.Page <= 0 {
		req.Page = 1
	}
	if req.Size <= 0 {
		req.Size = 20
	}
	if req.Size > 100 {
		req.Size = 100
	}

	data, err := h.futuresService.ListSymbols(ctx, req)
	if err != nil {
		return nil, err
	}

	return &api.Response{
		Code:    0,
		Message: "success",
		Data:    data,
	}, nil
}

// BatchQueryKLines 批量查询期货K线
func (h *Handler) BatchQueryKLines(ctx context.Context, req *api.BatchKLineRequest) (*api.Response, error) {
	if err := validateBatchKLineRequest(req); err != nil {
		return nil, err
	}

	data, err := h.futuresService.BatchQueryKLines(ctx, req)
	if err != nil {
		return nil, err
	}

	return &api.Response{
		Code:    0,
		Message: "success",
		Data:    data,
	}, nil
}

// QueryContinuousKLines 查询主力连续合约K线（预留）
func (h *Handler) QueryContinuousKLines(ctx context.Context, underlying string, req *api.KLineQueryRequest) (*api.Response, error) {
	// TODO: 首期返回空数据或错误提示
	return &api.Response{
		Code:    0,
		Message: "success",
		Data: &api.KLineData{
			Symbol:  underlying + ".MAIN",
			Name:    underlying + "主力连续",
			Freq:    req.Freq,
			Count:   0,
			Items:   []api.KLineItem{},
		},
	}, nil
}

// ============================================
// 管理接口实现
// ============================================

// GetDataSourceStatus 获取数据源状态
func (h *Handler) GetDataSourceStatus(ctx context.Context) (*api.Response, error) {
	data, err := h.adminService.GetDataSourceStatus(ctx)
	if err != nil {
		return nil, err
	}

	return &api.Response{
		Code:    0,
		Message: "success",
		Data:    data,
	}, nil
}

// SwitchDataSource 切换数据源
func (h *Handler) SwitchDataSource(ctx context.Context, req *api.SourceSwitchRequest) (*api.Response, error) {
	if err := h.adminService.SwitchDataSource(ctx, req); err != nil {
		return nil, err
	}

	return &api.Response{
		Code:    0,
		Message: "数据源切换成功",
		Data:    nil,
	}, nil
}

// BackfillData 历史数据补录
func (h *Handler) BackfillData(ctx context.Context, req *api.BackfillRequest) (*api.Response, error) {
	// 异步启动补录任务
	taskID, err := h.adminService.BackfillData(ctx, req)
	if err != nil {
		return nil, err
	}

	return &api.Response{
		Code:    0,
		Message: "补录任务已启动",
		Data: map[string]string{
			"task_id": taskID,
		},
	}, nil
}

// HealthCheck 健康检查
func (h *Handler) HealthCheck(ctx context.Context) (*api.HealthResponse, error) {
	// TODO: 检查数据库连接、数据源连通性等
	return h.adminService.HealthCheck(ctx)
}

// ============================================
// 新增接口：交易日历和期货合约
// ============================================

// GetTradingDates 获取股票交易日历
func (h *Handler) GetTradingDates(ctx context.Context, req *api.TradingDatesRequest) (*api.Response, error) {
	if err := validateTradingDatesRequest(req); err != nil {
		return nil, err
	}

	// 通过请求路径判断是股票还是期货，这里简化处理
	// 实际可以通过gin的context或其他方式判断
	data, err := h.stockService.GetTradingDates(ctx, req)
	if err != nil {
		return nil, err
	}

	return &api.Response{
		Code:    0,
		Message: "success",
		Data:    data,
	}, nil
}

// GetContractsByUnderlying 根据品种获取可交易合约
func (h *Handler) GetContractsByUnderlying(ctx context.Context, req *api.FuturesContractsRequest) (*api.Response, error) {
	if req.Underlying == "" {
		return nil, fmt.Errorf("underlying不能为空")
	}

	data, err := h.futuresService.GetContractsByUnderlying(ctx, req)
	if err != nil {
		return nil, err
	}

	return &api.Response{
		Code:    0,
		Message: "success",
		Data:    data,
	}, nil
}

// ============================================
// 私有辅助函数
// ============================================

func validateKLineRequest(req *api.KLineQueryRequest) error {
	if req.Symbol == "" {
		return fmt.Errorf("symbol不能为空")
	}
	if req.Start == "" || len(req.Start) != 8 {
		return fmt.Errorf("start日期格式错误，应为YYYYMMDD")
	}
	if req.End == "" || len(req.End) != 8 {
		return fmt.Errorf("end日期格式错误，应为YYYYMMDD")
	}
	if req.Freq == "" {
		req.Freq = api.Freq1D
	}
	return nil
}

func validateBatchKLineRequest(req *api.BatchKLineRequest) error {
	if len(req.Symbols) == 0 {
		return fmt.Errorf("symbols不能为空")
	}
	if len(req.Symbols) > 100 {
		return fmt.Errorf("单次查询标的数不能超过100")
	}
	if req.Start == "" || len(req.Start) != 8 {
		return fmt.Errorf("start日期格式错误，应为YYYYMMDD")
	}
	if req.End == "" || len(req.End) != 8 {
		return fmt.Errorf("end日期格式错误，应为YYYYMMDD")
	}
	if req.Freq == "" {
		req.Freq = api.Freq1D
	}
	return nil
}

func validateTradingDatesRequest(req *api.TradingDatesRequest) error {
	if req.Start == "" || len(req.Start) != 8 {
		return fmt.Errorf("start日期格式错误，应为YYYYMMDD")
	}
	if req.End == "" || len(req.End) != 8 {
		return fmt.Errorf("end日期格式错误，应为YYYYMMDD")
	}
	return nil
}