package handlers

import (
	"context"
	"net/http"
	"time"

	"stock-user-system/internal/models"
	"stock-user-system/internal/services"

	"github.com/gin-gonic/gin"
	"gorm.io/gorm"
)

var coreIndexSymbols = map[string]bool{
	"000001.SH": true,
	"399001.SZ": true,
	"399006.SZ": true,
	"000688.SH": true,
}

// StockHandler 处理股票看板与同步接口。
type StockHandler struct {
	DB  *gorm.DB
	Svc *services.StockSyncService
}

type stockRow struct {
	Symbol    string  `json:"symbol"`
	Name      string  `json:"name"`
	Close     float64 `json:"close"`
	ChangePct float64 `json:"change_pct"`
	Amount    float64 `json:"amount,omitempty"`
}

type overviewResponse struct {
	LatestTradeDate string        `json:"latest_trade_date"`
	Counts          marketCounts  `json:"counts"`
	AvgChangePct    float64       `json:"avg_change_pct"`
	Indices         []stockRow    `json:"indices"`
	TopGainers      []stockRow    `json:"top_gainers"`
	TopLosers       []stockRow    `json:"top_losers"`
	TurnoverLeaders []stockRow    `json:"turnover_leaders"`
}

type marketCounts struct {
	Up    int64 `json:"up"`
	Down  int64 `json:"down"`
	Flat  int64 `json:"flat"`
	Total int64 `json:"total"`
}

// Overview 返回最新交易日的市场概览。
func (h *StockHandler) Overview(c *gin.Context) {
	ctx := context.Background()

	var latestDate time.Time
	if err := h.DB.WithContext(ctx).Model(&models.StockDailyQuote{}).
		Select("MAX(trade_date)").Scan(&latestDate).Error; err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"success": false, "error": "查询最新交易日失败"})
		return
	}
	if latestDate.IsZero() {
		c.JSON(http.StatusOK, overviewResponse{})
		return
	}

	var counts marketCounts
	if err := h.DB.WithContext(ctx).Model(&models.StockDailyQuote{}).
		Select(`
			COUNT(*) AS total,
			SUM(CASE WHEN change_pct > 0 THEN 1 ELSE 0 END) AS up,
			SUM(CASE WHEN change_pct < 0 THEN 1 ELSE 0 END) AS down,
			SUM(CASE WHEN change_pct = 0 THEN 1 ELSE 0 END) AS flat
		`).
		Where("trade_date = ? AND symbol NOT IN ?", latestDate, indexSymbolsList()).
		Scan(&counts).Error; err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"success": false, "error": "统计涨跌失败"})
		return
	}

	var avgChange float64
	h.DB.WithContext(ctx).Model(&models.StockDailyQuote{}).
		Select("COALESCE(AVG(change_pct), 0)").
		Where("trade_date = ? AND symbol NOT IN ?", latestDate, indexSymbolsList()).
		Scan(&avgChange)

	indices := h.topRows(ctx, latestDate, "symbol IN ?", indexSymbolsList(), 10, false)
	gainers := h.topRows(ctx, latestDate, "symbol NOT IN ?", indexSymbolsList(), 10, true)
	losers := h.topRows(ctx, latestDate, "symbol NOT IN ?", indexSymbolsList(), 10, false)
	turnover := h.topRowsByAmount(ctx, latestDate)

	c.JSON(http.StatusOK, overviewResponse{
		LatestTradeDate: latestDate.Format("2006-01-02"),
		Counts:          counts,
		AvgChangePct:    avgChange,
		Indices:         indices,
		TopGainers:      gainers,
		TopLosers:       losers,
		TurnoverLeaders: turnover,
	})
}

func (h *StockHandler) topRows(ctx context.Context, tradeDate time.Time, condition string, args any, limit int, desc bool) []stockRow {
	var rows []stockRow
	order := "change_pct ASC"
	if desc {
		order = "change_pct DESC"
	}
	h.DB.WithContext(ctx).Model(&models.StockDailyQuote{}).
		Select("symbol, name, close, change_pct").
		Where("trade_date = ?", tradeDate).
		Where(condition, args).
		Order(order).
		Limit(limit).
		Scan(&rows)
	return rows
}

func (h *StockHandler) topRowsByAmount(ctx context.Context, tradeDate time.Time) []stockRow {
	var rows []stockRow
	h.DB.WithContext(ctx).Model(&models.StockDailyQuote{}).
		Select("symbol, name, close, change_pct, amount").
		Where("trade_date = ? AND symbol NOT IN ?", tradeDate, indexSymbolsList()).
		Order("amount DESC").
		Limit(10).
		Scan(&rows)
	return rows
}

// SyncStatus 返回最近一次同步任务状态。
func (h *StockHandler) SyncStatus(c *gin.Context) {
	job, err := h.Svc.LatestJob(c.Request.Context())
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"success": false, "error": "查询同步状态失败"})
		return
	}
	if job == nil {
		c.JSON(http.StatusOK, gin.H{"success": true, "data": nil})
		return
	}
	c.JSON(http.StatusOK, gin.H{"success": true, "data": job})
}

// TriggerSync 手动触发同步（管理员）。
func (h *StockHandler) TriggerSync(c *gin.Context) {
	count, err := h.Svc.Sync(c.Request.Context(), "manual")
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"success": false, "error": err.Error()})
		return
	}
	c.JSON(http.StatusOK, gin.H{"success": true, "records_count": count})
}

func indexSymbolsList() []string {
	list := make([]string, 0, len(coreIndexSymbols))
	for s := range coreIndexSymbols {
		list = append(list, s)
	}
	return list
}