package handlers

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

	"git.mchus.pro/mchus/quoteforge/internal/middleware"
	"git.mchus.pro/mchus/quoteforge/internal/services"
	"github.com/gin-gonic/gin"
)

type ExportHandler struct {
	exportService    *services.ExportService
	configService    services.ConfigurationGetter
	componentService *services.ComponentService
	projectService   *services.ProjectService
}

func NewExportHandler(
	exportService *services.ExportService,
	configService services.ConfigurationGetter,
	componentService *services.ComponentService,
	projectService *services.ProjectService,
) *ExportHandler {
	return &ExportHandler{
		exportService:    exportService,
		configService:    configService,
		componentService: componentService,
		projectService:   projectService,
	}
}

type ExportRequest struct {
	Name         string `json:"name" binding:"required"`
	ProjectName  string `json:"project_name"`
	ProjectUUID  string `json:"project_uuid"`
	Article      string `json:"article"`
	Items        []struct {
		LotName   string  `json:"lot_name" binding:"required"`
		Quantity  int     `json:"quantity" binding:"required,min=1"`
		UnitPrice float64 `json:"unit_price"`
	} `json:"items" binding:"required,min=1"`
	Notes string `json:"notes"`
}

func (h *ExportHandler) ExportCSV(c *gin.Context) {
	var req ExportRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
		return
	}

	data := h.buildExportData(&req)

	// Validate before streaming (can return JSON error)
	if len(data.Items) == 0 {
		c.JSON(http.StatusBadRequest, gin.H{"error": "no items to export"})
		return
	}

	// Get project name if available
	projectName := req.ProjectName
	if projectName == "" && req.ProjectUUID != "" {
		// Try to load project name from database
		username := middleware.GetUsername(c)
		if project, err := h.projectService.GetByUUID(req.ProjectUUID, username); err == nil && project != nil {
			projectName = project.Name
		}
	}
	if projectName == "" {
		projectName = req.Name
	}

	// Set headers before streaming
	exportDate := data.CreatedAt
	articleSegment := sanitizeFilenameSegment(req.Article)
	if articleSegment == "" {
		articleSegment = "BOM"
	}
	filename := fmt.Sprintf("%s (%s) %s %s.csv", exportDate.Format("2006-01-02"), projectName, req.Name, articleSegment)
	c.Header("Content-Type", "text/csv; charset=utf-8")
	c.Header("Content-Disposition", fmt.Sprintf("attachment; filename=\"%s\"", filename))

	// Stream CSV (cannot return JSON after this point)
	if err := h.exportService.ToCSV(c.Writer, data); err != nil {
		c.Error(err) // Log only
		return
	}
}

func (h *ExportHandler) buildExportData(req *ExportRequest) *services.ExportData {
	items := make([]services.ExportItem, len(req.Items))
	var total float64

	for i, item := range req.Items {
		itemTotal := item.UnitPrice * float64(item.Quantity)

		// Получаем информацию о компоненте для заполнения категории и описания
		componentView, err := h.componentService.GetByLotName(item.LotName)
		if err != nil {
			// Если не удалось получить информацию о компоненте, используем только основные данные
			items[i] = services.ExportItem{
				LotName:    item.LotName,
				Quantity:   item.Quantity,
				UnitPrice:  item.UnitPrice,
				TotalPrice: itemTotal,
			}
		} else {
			items[i] = services.ExportItem{
				LotName:     item.LotName,
				Description: componentView.Description,
				Category:    componentView.Category,
				Quantity:    item.Quantity,
				UnitPrice:   item.UnitPrice,
				TotalPrice:  itemTotal,
			}
		}
		total += itemTotal
	}

	return &services.ExportData{
		Name:      req.Name,
		Article:   req.Article,
		Items:     items,
		Total:     total,
		Notes:     req.Notes,
		CreatedAt: time.Now(),
	}
}

func sanitizeFilenameSegment(value string) string {
	if strings.TrimSpace(value) == "" {
		return ""
	}
	replacer := strings.NewReplacer(
		"/", "_",
		"\\", "_",
		":", "_",
		"*", "_",
		"?", "_",
		"\"", "_",
		"<", "_",
		">", "_",
		"|", "_",
	)
	return strings.TrimSpace(replacer.Replace(value))
}

func (h *ExportHandler) ExportConfigCSV(c *gin.Context) {
	username := middleware.GetUsername(c)
	uuid := c.Param("uuid")

	// Get config before streaming (can return JSON error)
	config, err := h.configService.GetByUUID(uuid, username)
	if err != nil {
		c.JSON(http.StatusNotFound, gin.H{"error": err.Error()})
		return
	}

	data := h.exportService.ConfigToExportData(config, h.componentService)

	// Validate before streaming (can return JSON error)
	if len(data.Items) == 0 {
		c.JSON(http.StatusBadRequest, gin.H{"error": "no items to export"})
		return
	}

	// Get project name if configuration belongs to a project
	projectName := config.Name // fallback: use config name if no project
	if config.ProjectUUID != nil && *config.ProjectUUID != "" {
		if project, err := h.projectService.GetByUUID(*config.ProjectUUID, username); err == nil && project != nil {
			projectName = project.Name
		}
	}

	// Set headers before streaming
	// Use price update time if available, otherwise creation time
	exportDate := config.CreatedAt
	if config.PriceUpdatedAt != nil {
		exportDate = *config.PriceUpdatedAt
	}
	filename := fmt.Sprintf("%s (%s) %s BOM.csv", exportDate.Format("2006-01-02"), projectName, config.Name)
	c.Header("Content-Type", "text/csv; charset=utf-8")
	c.Header("Content-Disposition", fmt.Sprintf("attachment; filename=\"%s\"", filename))

	// Stream CSV (cannot return JSON after this point)
	if err := h.exportService.ToCSV(c.Writer, data); err != nil {
		c.Error(err) // Log only
		return
	}
}