package handler

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

	"github.com/gin-gonic/gin"

	"billai-server/model"
	"billai-server/repository"
)

// UpdateBillRequest 账单更新请求（字段均为可选）
type UpdateBillRequest struct {
	Time          *string  `json:"time,omitempty"`
	Category      *string  `json:"category,omitempty"`
	Merchant      *string  `json:"merchant,omitempty"`
	Description   *string  `json:"description,omitempty"`
	IncomeExpense *string  `json:"income_expense,omitempty"`
	Amount        *float64 `json:"amount,omitempty"`
	PayMethod     *string  `json:"pay_method,omitempty"`
	Status        *string  `json:"status,omitempty"`
	Remark        *string  `json:"remark,omitempty"`
	ReviewLevel   *string  `json:"review_level,omitempty"`
}

type UpdateBillResponse struct {
	Result  bool               `json:"result"`
	Message string             `json:"message,omitempty"`
	Data    *model.CleanedBill `json:"data,omitempty"`
}

func parseBillTime(s string) (time.Time, error) {
	s = strings.TrimSpace(s)
	formats := []string{
		"2006-01-02 15:04:05",
		"2006-01-02T15:04:05Z07:00",
		"2006-01-02T15:04:05Z",
		"2006-01-02",
	}
	for _, f := range formats {
		if t, err := time.ParseInLocation(f, s, time.Local); err == nil {
			return t, nil
		}
	}
	return time.Time{}, fmt.Errorf("unsupported time format")
}

// UpdateBill POST /api/bills/:id 更新清洗后的账单记录
func UpdateBill(c *gin.Context) {
	id := strings.TrimSpace(c.Param("id"))
	if id == "" {
		c.JSON(http.StatusBadRequest, UpdateBillResponse{Result: false, Message: "缺少账单 ID"})
		return
	}

	var req UpdateBillRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, UpdateBillResponse{Result: false, Message: "参数解析失败: " + err.Error()})
		return
	}

	updates := map[string]interface{}{}

	if req.Time != nil {
		t, err := parseBillTime(*req.Time)
		if err != nil {
			c.JSON(http.StatusBadRequest, UpdateBillResponse{Result: false, Message: "时间格式错误"})
			return
		}
		updates["time"] = t
	}

	if req.Category != nil {
		v := strings.TrimSpace(*req.Category)
		if v == "" {
			c.JSON(http.StatusBadRequest, UpdateBillResponse{Result: false, Message: "分类不能为空"})
			return
		}
		updates["category"] = v
	}

	if req.Merchant != nil {
		v := strings.TrimSpace(*req.Merchant)
		if v == "" {
			c.JSON(http.StatusBadRequest, UpdateBillResponse{Result: false, Message: "商家不能为空"})
			return
		}
		updates["merchant"] = v
	}

	if req.Description != nil {
		updates["description"] = strings.TrimSpace(*req.Description)
	}

	if req.IncomeExpense != nil {
		v := strings.TrimSpace(*req.IncomeExpense)
		if v != "" && v != "收入" && v != "支出" {
			c.JSON(http.StatusBadRequest, UpdateBillResponse{Result: false, Message: "income_expense 只能是 收入 或 支出"})
			return
		}
		updates["income_expense"] = v
	}

	if req.Amount != nil {
		updates["amount"] = *req.Amount
	}

	if req.PayMethod != nil {
		updates["pay_method"] = strings.TrimSpace(*req.PayMethod)
	}

	if req.Status != nil {
		updates["status"] = strings.TrimSpace(*req.Status)
	}

	if req.Remark != nil {
		updates["remark"] = strings.TrimSpace(*req.Remark)
	}

	if req.ReviewLevel != nil {
		// 允许设置为空字符串（清除复核等级）或 HIGH/LOW
		v := strings.TrimSpace(*req.ReviewLevel)
		if v != "" && v != "HIGH" && v != "LOW" {
			c.JSON(http.StatusBadRequest, UpdateBillResponse{Result: false, Message: "review_level 只能是空、HIGH 或 LOW"})
			return
		}
		updates["review_level"] = v
	}

	if len(updates) == 0 {
		c.JSON(http.StatusBadRequest, UpdateBillResponse{Result: false, Message: "没有可更新的字段"})
		return
	}
	updates["updated_at"] = time.Now()

	repo := repository.GetRepository()
	if repo == nil {
		c.JSON(http.StatusInternalServerError, UpdateBillResponse{Result: false, Message: "数据库未连接"})
		return
	}

	updated, err := repo.UpdateCleanedBillByID(id, updates)
	if err != nil {
		if err == repository.ErrNotFound {
			c.JSON(http.StatusNotFound, UpdateBillResponse{Result: false, Message: "账单不存在"})
			return
		}
		c.JSON(http.StatusInternalServerError, UpdateBillResponse{Result: false, Message: "更新失败: " + err.Error()})
		return
	}

	c.JSON(http.StatusOK, UpdateBillResponse{Result: true, Message: "更新成功", Data: updated})
}