package handler

import (
	"bytes"
	"fmt"
	"net/http"
	"net/url"
	"strings"
	"time"
	"unicode/utf8"

	"bj_power_wms/ent/inventory"
	"bj_power_wms/ent/material"
	"bj_power_wms/internal/svc"

	"github.com/google/uuid"
	"github.com/xuri/excelize/v2"
)

// xlsxColumn 导出列定义：列名 + 取值函数(返回字符串)
type xlsxColumn struct {
	Title string
	Get   func(map[string]any) string
}

// xlsxFilename 生成导出文件名：{页面名}_{YYYYMMDDHHMMSS}.xlsx（URL 安全，避免中文编码问题）
func xlsxFilename(page string) string {
	return fmt.Sprintf("%s_%s.xlsx", page, time.Now().Format("20060102_150405"))
}

// sendExcel 用 excelize 生成 .xlsx 并写回响应（UTF-8 表头，列宽自适应,冻结首行）
// headers 与 rows 为字符串二维数组；filename 用于 Content-Disposition。
func sendExcel(w http.ResponseWriter, filename string, headers []string, rows [][]any /* any: string|int|int64 */) {
	buf, err := buildXlsx(headers, rows)
	if err != nil {
		fail(w, http.StatusInternalServerError, "生成 Excel 失败: "+err.Error())
		return
	}
	// RFC 5987：中文文件名用 filename*=UTF-8''...（URL 编码），并提供 ASCII 兜底文件名
	asciiName := "export.xlsx"
	encName := ""
	if utf8.ValidString(filename) {
		asciiName = strings.TrimSuffix(filename, ".xlsx") + ".xlsx"
		encName = "filename*=UTF-8''" + url.QueryEscape(filename)
	}
	w.Header().Set("Content-Type", "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet")
	cd := fmt.Sprintf("attachment; filename=\"%s\"", asciiName)
	if encName != "" {
		cd += "; " + encName
	}
	w.Header().Set("Content-Disposition", cd)
	w.Header().Set("X-Excel-Filename", url.QueryEscape(filename))
	w.WriteHeader(http.StatusOK)
	_, _ = w.Write(buf.Bytes())
}

// buildXlsx 生成 xlsx 字节流（含表头样式、列宽自适应）
func buildXlsx(headers []string, rows [][]any) (*bytes.Buffer, error) {
	f := excelize.NewFile()
	defer f.Close()
	sheet := f.GetSheetName(0)

	for i, h := range headers {
		cell, _ := excelize.CoordinatesToCellName(i+1, 1)
		_ = f.SetCellValue(sheet, cell, h)
	}
	style, _ := f.NewStyle(&excelize.Style{
		Font:      &excelize.Font{Bold: true},
		Fill:      excelize.Fill{Type: "pattern", Color: []string{"D9E1F2"}, Pattern: 1},
		Alignment: &excelize.Alignment{Horizontal: "center", Vertical: "center"},
	})
	_ = f.SetRowStyle(sheet, 1, 1, style)

	for r, row := range rows {
		for c, v := range row {
			cell, _ := excelize.CoordinatesToCellName(c+1, r+2)
			_ = f.SetCellValue(sheet, cell, v)
		}
	}

	// 列宽按显示宽度估算（中文=2，ASCII=1，宁宽勿窄）
	widths := make([]float64, len(headers))
	for c := range headers {
		widths[c] = float64(displayWidth(headers[c]) + 2)
	}
	for _, row := range rows {
		for c, v := range row {
			if c >= len(widths) {
				break
			}
			cw := float64(displayWidth(fmt.Sprintf("%v", v)) + 2)
			if cw > widths[c] {
				widths[c] = cw
			}
		}
	}
	for c, wd := range widths {
		col, _ := excelize.ColumnNumberToName(c + 1)
		_ = f.SetColWidth(sheet, col, col, wd)
	}

	return f.WriteToBuffer()
}

// displayWidth 估算字符串在 Excel 中的显示宽度（中文=2，ASCII=1）
func displayWidth(s string) int {
	n := 0
	for _, r := range s {
		if r > 0x2E7F { // 含中文/全角
			n += 2
		} else {
			n++
		}
	}
	return n
}

// manageModeLabel 管理粒度中文名：1=结构件 2=精密件
func manageModeLabel(m int) string {
	if m == 1 {
		return "结构件"
	}
	if m == 2 {
		return "精密件"
	}
	return "-"
}

// unixFmt 把 unix 秒转成 yyyy-MM-dd HH:mm:ss（时间戳<=0 返回空串）
func unixFmt(ts int64) string {
	if ts <= 0 {
		return ""
	}
	return time.Unix(ts, 0).Format("2006-01-02 15:04:05")
}

// inspectionTypeLabel 检验类型中文名
func inspectionTypeLabel(t string) string {
	switch t {
	case "incoming":
		return "来料检"
	case "process":
		return "过程检"
	case "finished":
		return "成品检"
	}
	return t
}

// importErr 单行校验错误（行号 + 物料 + 原因），用于"全失败"时回给前端定位
type importErr struct {
	Row          int    `json:"row"`
	MaterialCode string `json:"materialCode"`
	Message      string `json:"message"`
}

// excelInboundHandler Excel 批量导入入库
// mode=batch(结构件)：列头(首行忽略) 物料编码 | 批次号(可空自动生成) | 数量 | 生产日期 | 供应商 | 区域 | 备注
// mode=sn(精密件)：   列头(首行忽略) 物料编码 | SN | 区域 | 生产日期 | 供应商
//
// 强约束：全成功或全失败（一次性全导入 or 全失败，禁止部分成功）。
// 流程：阶段1 逐行解析+校验(物料存在/数量>0/SN不重复/区域必填) → 任一错则整体拒绝并列出错误行(一行不写)；
// 阶段2 全部通过 → 开启单事务，整体提交，任一步失败整体回滚。
func excelInboundHandler(ctx *svc.ServiceContext) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		if err := r.ParseMultipartForm(20 << 20); err != nil {
			fail(w, http.StatusBadRequest, "文件上传失败: "+err.Error())
			return
		}
		mode := r.FormValue("mode")
		if mode != "sn" {
			mode = "batch"
		}
		f, _, err := r.FormFile("file")
		if err != nil {
			fail(w, http.StatusBadRequest, "缺少 file 字段")
			return
		}
		defer f.Close()

		xl, err := excelize.OpenReader(f)
		if err != nil {
			fail(w, http.StatusBadRequest, "无法解析 Excel: "+err.Error())
			return
		}
		defer xl.Close()
		sheet := xl.GetSheetList()[0]
		rows, err := xl.GetRows(sheet)
		if err != nil {
			fail(w, http.StatusBadRequest, "读取工作表失败: "+err.Error())
			return
		}
		if len(rows) <= 1 {
			fail(w, http.StatusBadRequest, "文件无数据行（首行为表头，需至少一行数据）")
			return
		}

		type planRow struct {
			row      int
			code     string
			batchNo  string
			sn       string
			qty      int
			prodDate string
			supplier string
			zone     string
			remark   string
		}
		plans := make([]planRow, 0, len(rows)-1)
		errs := make([]importErr, 0)

		// ---- 阶段1：解析 + 校验（不落库） ----
		snSeen := map[string]bool{}
		for i, row := range rows {
			if i == 0 {
				continue // 表头
			}
			cell := func(idx int) string {
				if idx < len(row) {
					return strings.TrimSpace(row[idx])
				}
				return ""
			}
			pr := planRow{row: i + 1}
			pr.code = cell(0)
			if mode == "sn" {
				pr.sn = cell(1)
				pr.zone = cell(2) // 精密件模板: 物料编码|SN|区域|生产日期|供应商
				pr.prodDate = cell(3)
				pr.supplier = cell(4)
				pr.remark = cell(4)
			} else {
				pr.batchNo = cell(1)
				pr.qty = atoi(cell(2), 0)
				pr.prodDate = cell(3)
				pr.supplier = cell(4)
				pr.zone = cell(5) // 结构件模板: 物料编码|批次号|数量|生产日期|供应商|区域|备注
				pr.remark = cell(6)
			}

			if pr.code == "" {
				errs = append(errs, importErr{pr.row, pr.code, "物料编码为空"})
				continue
			}
			m, e := ctx.EntClient.Material.Query().Where(material.CodeEQ(pr.code)).Only(ctx0())
			if e != nil {
				errs = append(errs, importErr{pr.row, pr.code, "物料不存在"})
				continue
			}
			if mode == "sn" {
				if m.ManageMode != 2 {
					errs = append(errs, importErr{pr.row, pr.code, "该物料为结构件，SN 导入仅支持精密件(按 SN 管理)"})
					continue
				}
				if pr.sn == "" {
					errs = append(errs, importErr{pr.row, pr.code, "SN 为空"})
					continue
				}
				if snSeen[pr.sn] {
					errs = append(errs, importErr{pr.row, pr.code, "SN 在文件中重复: "+pr.sn})
					continue
				}
				snSeen[pr.sn] = true
				exists, _ := ctx.EntClient.Inventory.Query().
					Where(inventory.ManageModeEQ(2), inventory.SnCodeEQ(pr.sn)).Exist(ctx0())
				if exists {
					errs = append(errs, importErr{pr.row, pr.code, "SN 已存在: "+pr.sn})
					continue
				}
			} else {
				if m.ManageMode != 1 {
					errs = append(errs, importErr{pr.row, pr.code, "该物料为精密件，请使用 SN 导入"})
					continue
				}
				if pr.qty <= 0 {
					errs = append(errs, importErr{pr.row, pr.code, "数量必须大于 0"})
					continue
				}
			}
			if pr.zone == "" {
				errs = append(errs, importErr{pr.row, pr.code, "区域为空（必填）"})
				continue
			}
			plans = append(plans, pr)
		}

		// ---- 阶段2：有错则整体拒绝，一行都不写 ----
		if len(errs) > 0 {
			ok(w, map[string]any{"success": 0, "failed": len(errs), "errors": errs})
			return
		}

		// ---- 阶段3：全部通过 → 单事务整体提交（原子，全成功或全失败） ----
		tx, e := ctx.EntClient.Tx(ctx0())
		if e != nil {
			fail(w, http.StatusInternalServerError, "开启事务失败: "+e.Error())
			return
		}
		committed := false
		defer func() {
			if !committed {
				_ = tx.Rollback()
			}
		}()

		for _, pr := range plans {
			inboundNo := "IB" + uuid.NewString()[:12]
			m, _ := tx.Material.Query().Where(material.CodeEQ(pr.code)).Only(ctx0())
			if mode == "sn" {
				if _, e = tx.Inventory.Create().
					SetManageMode(2).
					SetMaterialCode(pr.code).
					SetNillableMaterialName(strPtr(m.Name)).
					SetSnCode(pr.sn).
					SetQuantity(1).SetLockedQty(0).
					SetQualityStatus("未检").
					SetNillableProductionDate(strPtr(pr.prodDate)).
					SetNillableSupplier(strPtr(pr.supplier)).
					SetNillableZoneCode(strPtr(pr.zone)).
					SetStatus("在库").
					SetInboundNo(inboundNo).
					Save(ctx0()); e != nil {
					fail(w, http.StatusInternalServerError, "创建 SN 库存失败: "+e.Error())
					return
				}
				if _, e = tx.InboundDetail.Create().
					SetInboundNo(inboundNo).SetSnCode(pr.sn).SetMaterialCode(pr.code).SetQuantity(1).
					Save(ctx0()); e != nil {
					fail(w, http.StatusInternalServerError, "创建入库明细失败: "+e.Error())
					return
				}
			} else {
				batchNo := pr.batchNo
				if batchNo == "" {
					// 同一导入内多行空批次需保证批次号唯一，追加行号后缀
					batchNo = genBatchNo(pr.code) + fmt.Sprintf("-%d", pr.row)
				}
				existing, e2 := tx.Inventory.Query().
					Where(inventory.ManageModeEQ(1), inventory.BatchNoEQ(batchNo)).Only(ctx0())
				if e2 == nil {
					if _, e = tx.Inventory.UpdateOneID(existing.ID).
						AddQuantity(pr.qty).
						SetNillableSupplier(strPtr(pr.supplier)).
						Save(ctx0()); e != nil {
						fail(w, http.StatusInternalServerError, "追加批次失败: "+e.Error())
						return
					}
				} else {
					if _, e = tx.Inventory.Create().
						SetManageMode(1).
						SetBatchNo(batchNo).
						SetMaterialCode(pr.code).
						SetNillableMaterialName(strPtr(m.Name)).
						SetQuantity(pr.qty).SetLockedQty(0).
						SetNillableProductionDate(strPtr(pr.prodDate)).
						SetNillableSupplier(strPtr(pr.supplier)).
						SetQualityStatus("未检").
						SetNillableZoneCode(strPtr(pr.zone)).
						SetStatus("在库").
						SetInboundNo(inboundNo).
						Save(ctx0()); e != nil {
						fail(w, http.StatusInternalServerError, "创建库存失败: "+e.Error())
						return
					}
				}
				if _, e = tx.InboundDetail.Create().
					SetInboundNo(inboundNo).SetBatchNo(batchNo).SetMaterialCode(pr.code).SetQuantity(pr.qty).
					Save(ctx0()); e != nil {
					fail(w, http.StatusInternalServerError, "创建入库明细失败: "+e.Error())
					return
				}
			}
			if _, e = tx.InboundOrder.Create().
				SetInboundNo(inboundNo).
				SetNillableInboundType(strPtr("purchase")).
				SetMaterialCode(pr.code).
				SetNillableMaterialName(strPtr(m.Name)).
				SetManageMode(m.ManageMode).
				SetNillableZoneCode(strPtr(pr.zone)).
				SetQuantity(ternary(mode == "sn", 1, pr.qty)).
				SetNillableRemark(strPtr(pr.remark)).
				SetOperator("excel-import").
				Save(ctx0()); e != nil {
				fail(w, http.StatusInternalServerError, "创建入库单失败: "+e.Error())
				return
			}
		}

		if e = tx.Commit(); e != nil {
			fail(w, http.StatusInternalServerError, "提交事务失败: "+e.Error())
			return
		}
		committed = true
		ok(w, map[string]any{"success": len(plans), "failed": 0, "errors": []importErr{}})
	}
}

// ternary 小工具：condition 为真返回 a，否则 b
func ternary(cond bool, a, b int) int {
	if cond {
		return a
	}
	return b
}