roulette/formats/images.go

/*
Copyright © 2023 Seednode <seednode@seedno.de>
*/

package formats

import (
	"errors"
	"fmt"
	"image"
	_ "image/gif"
	_ "image/jpeg"
	_ "image/png"
	"os"

	"github.com/h2non/filetype"
	_ "golang.org/x/image/bmp"
	_ "golang.org/x/image/webp"
)

type Dimensions struct {
	Width  int
	Height int
}

func RegisterImageFormats() *SupportedFormat {
	return &SupportedFormat{
		Title: func(queryParams, fileUri, filePath, fileName, mime string) string {
			dimensions, err := ImageDimensions(filePath)
			if err != nil {
				fmt.Println(err)
			}

			return fmt.Sprintf(`<title>%s (%dx%d)</title>`,
				fileName,
				dimensions.Width,
				dimensions.Height)
		},
		Body: func(queryParams, fileUri, filePath, fileName, mime string) string {
			dimensions, err := ImageDimensions(filePath)
			if err != nil {
				fmt.Println(err)
			}

			return fmt.Sprintf(`<a href="/%s"><img src="%s" width="%d" height="%d" type="%s" alt="Roulette selected: %s"></a>`,
				queryParams,
				fileUri,
				dimensions.Width,
				dimensions.Height,
				mime,
				fileName)
		},
		Extensions: []string{
			`.bmp`,
			`.gif`,
			`.jpeg`,
			`.jpg`,
			`.png`,
			`.webp`,
		},
		validator: func(head []byte) bool {
			return filetype.IsImage(head)
		},
	}
}

func ImageDimensions(path string) (*Dimensions, error) {
	file, err := os.Open(path)
	switch {
	case errors.Is(err, os.ErrNotExist):
		fmt.Printf("File %s does not exist\n", path)
		return &Dimensions{}, nil
	case err != nil:
		fmt.Printf("File %s open returned error: %s\n", path, err)
		return &Dimensions{}, err
	}
	defer file.Close()

	myImage, _, err := image.DecodeConfig(file)
	switch {
	case errors.Is(err, image.ErrFormat):
		fmt.Printf("File %s has invalid image format\n", path)
		return &Dimensions{Width: 0, Height: 0}, nil
	case err != nil:
		fmt.Printf("File %s decode returned error: %s\n", path, err)
		return &Dimensions{}, err
	}

	return &Dimensions{Width: myImage.Width, Height: myImage.Height}, nil
}