package persistence

import (
	entity "RenewCMS/internal/infrastructure/persistence/models"
	"bytes"
	"crypto/sha256"
	"encoding/hex"
	stdimage "image"
	"os"
	"path/filepath"

	_ "golang.org/x/image/webp"
	_ "image/jpeg"
	_ "image/png"

	"gorm.io/gorm"
)

var extensionContentTypes = map[string]string{
	".png":  "image/png",
	".jpg":  "image/jpeg",
	".jpeg": "image/jpeg",
	".webp": "image/webp",
	".svg":  "image/svg+xml",
}

func BackfillImageMetadata(db *gorm.DB, uploadDir string) error {
	var pending []entity.Image
	err := db.Where("filename = '' OR filename IS NULL").Order("id asc").Find(&pending).Error
	if err != nil {
		return err
	}

	for _, row := range pending {
		metadata, ok := readStoredImage(uploadDir, row.Path)
		if !ok {
			continue
		}
		err := db.Model(&entity.Image{}).Where("id = ?", row.ID).UpdateColumns(metadata).Error
		if err != nil {
			return err
		}
	}
	return nil
}

func readStoredImage(uploadDir string, storedPath string) (map[string]any, bool) {
	fileName := filepath.Base(storedPath)
	contentType, known := extensionContentTypes[filepath.Ext(fileName)]
	if !known {
		return nil, false
	}

	data, err := os.ReadFile(filepath.Join(uploadDir, fileName))
	if err != nil {
		return nil, false
	}

	width, height := 0, 0
	if contentType != "image/svg+xml" {
		config, _, err := stdimage.DecodeConfig(bytes.NewReader(data))
		if err != nil {
			return nil, false
		}
		width, height = config.Width, config.Height
	}

	checksum := sha256.Sum256(data)
	return map[string]any{
		"filename":     fileName,
		"size":         int64(len(data)),
		"content_type": contentType,
		"width":        width,
		"height":       height,
		"sha256":       hex.EncodeToString(checksum[:]),
	}, true
}