package services

import (
	"encoding/json"
	"fmt"

	"git.mchus.pro/mchus/priceforge/internal/models"
	"gorm.io/gorm"
)

// ImportFormatService manages qt_import_formats records.
type ImportFormatService struct {
	db *gorm.DB
}

func NewImportFormatService(db *gorm.DB) *ImportFormatService {
	return &ImportFormatService{db: db}
}

// List returns all active import formats.
func (s *ImportFormatService) List() ([]models.ImportFormat, error) {
	var formats []models.ImportFormat
	if err := s.db.Where("is_active = ?", true).Order("name").Find(&formats).Error; err != nil {
		return nil, fmt.Errorf("list import formats: %w", err)
	}
	return formats, nil
}

// GetByCode returns an import format by format_code.
func (s *ImportFormatService) GetByCode(code string) (*models.ImportFormat, error) {
	var f models.ImportFormat
	if err := s.db.Where("format_code = ?", code).First(&f).Error; err != nil {
		return nil, fmt.Errorf("get import format %q: %w", code, err)
	}
	return &f, nil
}

// Save creates or updates an import format.
func (s *ImportFormatService) Save(f *models.ImportFormat) error {
	if f.FormatCode == "" {
		return fmt.Errorf("format_code is required")
	}
	if err := s.db.Save(f).Error; err != nil {
		return fmt.Errorf("save import format: %w", err)
	}
	return nil
}

// Delete marks an import format as inactive.
func (s *ImportFormatService) Delete(code string) error {
	return s.db.Model(&models.ImportFormat{}).
		Where("format_code = ?", code).
		Update("is_active", false).Error
}

// ParseColumnMapping decodes the column_mapping JSON from a format into
// a CompetitorColumnMapping struct (shared format for all sources).
func (s *ImportFormatService) ParseColumnMapping(f *models.ImportFormat) (*models.CompetitorColumnMapping, error) {
	if len(f.ColumnMapping) == 0 {
		return &models.CompetitorColumnMapping{}, nil
	}
	var m models.CompetitorColumnMapping
	if err := json.Unmarshal(f.ColumnMapping, &m); err != nil {
		return nil, fmt.Errorf("parse column_mapping for format %q: %w", f.FormatCode, err)
	}
	return &m, nil
}