package handler

import (
	"fmt"
	"net/http"
	"time"

	"github.com/gin-gonic/gin"
	"github.com/xuri/excelize/v2"

	"billai-server/repository"
)

type ExportBillsRequest struct {
	StartDate     string `form:"start_date"`
	EndDate       string `form:"end_date"`
	Category      string `form:"category"`
	Type          string `form:"type"`
	IncomeExpense string `form:"income_expense"`
}

func ExportBills(c *gin.Context) {
	var req ExportBillsRequest
	if err := c.ShouldBindQuery(&req); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{
			"result":  false,
			"message": "参数解析失败: " + err.Error(),
		})
		return
	}

	filter := buildFilterFromRequest(req)

	repo := repository.GetRepository()
	if repo == nil {
		c.JSON(http.StatusInternalServerError, gin.H{
			"result":  false,
			"message": "数据库未连接",
		})
		return
	}

	bills, err := repo.GetCleanedBills(filter)
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{
			"result":  false,
			"message": "查询失败: " + err.Error(),
		})
		return
	}

	f := excelize.NewFile()
	sheet := "账单"
	f.SetSheetName("Sheet1", sheet)

	headers := []string{"时间", "来源", "分类", "交易对方", "商品说明", "收/支", "金额", "支付方式", "状态", "备注"}
	for i, header := range headers {
		cell, _ := excelize.CoordinatesToCellName(i+1, 1)
		f.SetCellValue(sheet, cell, header)
	}

	for idx, bill := range bills {
		row := idx + 2

		f.SetCellValue(sheet, fmt.Sprintf("A%d", row), bill.Time.Time().Format("2006-01-02 15:04:05"))
		f.SetCellValue(sheet, fmt.Sprintf("B%d", row), bill.BillType)
		f.SetCellValue(sheet, fmt.Sprintf("C%d", row), bill.Category)
		f.SetCellValue(sheet, fmt.Sprintf("D%d", row), bill.Merchant)
		f.SetCellValue(sheet, fmt.Sprintf("E%d", row), bill.Description)
		f.SetCellValue(sheet, fmt.Sprintf("F%d", row), bill.IncomeExpense)
		f.SetCellValue(sheet, fmt.Sprintf("G%d", row), bill.Amount)
		f.SetCellValue(sheet, fmt.Sprintf("H%d", row), bill.PayMethod)
		f.SetCellValue(sheet, fmt.Sprintf("I%d", row), bill.Status)
		f.SetCellValue(sheet, fmt.Sprintf("J%d", row), bill.Remark)
	}

	f.SetColWidth(sheet, "A", "A", 20)
	f.SetColWidth(sheet, "B", "B", 8)
	f.SetColWidth(sheet, "C", "C", 12)
	f.SetColWidth(sheet, "D", "D", 20)
	f.SetColWidth(sheet, "E", "E", 30)
	f.SetColWidth(sheet, "F", "F", 8)
	f.SetColWidth(sheet, "G", "G", 12)
	f.SetColWidth(sheet, "H", "H", 15)
	f.SetColWidth(sheet, "I", "I", 10)
	f.SetColWidth(sheet, "J", "J", 20)

	filename := fmt.Sprintf("bills_%s.xlsx", time.Now().Format("20060102_150405"))
	c.Header("Content-Type", "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet")
	c.Header("Content-Disposition", fmt.Sprintf("attachment; filename=%s", filename))
	c.Header("Access-Control-Expose-Headers", "Content-Disposition")

	if err := f.Write(c.Writer); err != nil {
		fmt.Printf("导出 Excel 失败: %v\n", err)
	}
}

func buildFilterFromRequest(req ExportBillsRequest) map[string]interface{} {
	filter := make(map[string]interface{})

	if req.StartDate != "" || req.EndDate != "" {
		timeFilter := make(map[string]interface{})
		if req.StartDate != "" {
			startTime, err := time.ParseInLocation("2006-01-02", req.StartDate, time.Local)
			if err == nil {
				timeFilter["$gte"] = startTime
			}
		}
		if req.EndDate != "" {
			endTime, err := time.ParseInLocation("2006-01-02", req.EndDate, time.Local)
			if err == nil {
				endTime = endTime.Add(24 * time.Hour)
				timeFilter["$lt"] = endTime
			}
		}
		if len(timeFilter) > 0 {
			filter["time"] = timeFilter
		}
	}

	if req.Category != "" {
		filter["category"] = req.Category
	}
	if req.Type != "" {
		filter["bill_type"] = req.Type
	}
	if req.IncomeExpense != "" {
		filter["income_expense"] = req.IncomeExpense
	}

	filter["is_deleted"] = false

	return filter
}