package services

import (
	"bytes"
	"encoding/csv"
	"fmt"
	"time"

	"git.mchus.pro/mchus/quoteforge/internal/config"
	"git.mchus.pro/mchus/quoteforge/internal/models"
)

type ExportService struct {
	config config.ExportConfig
}

func NewExportService(cfg config.ExportConfig) *ExportService {
	return &ExportService{config: cfg}
}

type ExportData struct {
	Name      string
	Items     []ExportItem
	Total     float64
	Notes     string
	CreatedAt time.Time
}

type ExportItem struct {
	LotName     string
	Description string
	Category    string
	Quantity    int
	UnitPrice   float64
	TotalPrice  float64
}

func (s *ExportService) ToCSV(data *ExportData) ([]byte, error) {
	var buf bytes.Buffer
	w := csv.NewWriter(&buf)

	// Header
	headers := []string{"Артикул", "Описание", "Категория", "Количество", "Цена за единицу", "Сумма"}
	if err := w.Write(headers); err != nil {
		return nil, err
	}

	// Items
	for _, item := range data.Items {
		row := []string{
			item.LotName,
			item.Description,
			item.Category,
			fmt.Sprintf("%d", item.Quantity),
			fmt.Sprintf("%.2f", item.UnitPrice),
			fmt.Sprintf("%.2f", item.TotalPrice),
		}
		if err := w.Write(row); err != nil {
			return nil, err
		}
	}

	// Total row
	if err := w.Write([]string{"", "", "", "", "ИТОГО:", fmt.Sprintf("%.2f", data.Total)}); err != nil {
		return nil, err
	}

	w.Flush()
	return buf.Bytes(), w.Error()
}

func (s *ExportService) ConfigToExportData(config *models.Configuration) *ExportData {
	items := make([]ExportItem, len(config.Items))
	var total float64

	for i, item := range config.Items {
		itemTotal := item.UnitPrice * float64(item.Quantity)
		items[i] = ExportItem{
			LotName:    item.LotName,
			Quantity:   item.Quantity,
			UnitPrice:  item.UnitPrice,
			TotalPrice: itemTotal,
		}
		total += itemTotal
	}

	return &ExportData{
		Name:      config.Name,
		Items:     items,
		Total:     total,
		Notes:     config.Notes,
		CreatedAt: config.CreatedAt,
	}
}