package format

import (
	"bytes"
	"errors"
	"fmt"
	"io"
	"log"
	"os"
	"os/exec"
	"path/filepath"
	"strconv"
	"strings"

	"tomatentum.net/svg-templater/pkg/svg"
)

type ConversionParameters struct {
	Format        string
	Width, Height int
}

func ConvertByte(svgblob []byte, param ConversionParameters) ([]byte, error) {
	reader, err := ConvertReader(svgblob, param)
	if err != nil {
		return nil, err
	}
	defer reader.Close()

	result, err := io.ReadAll(reader)
	if err != nil {
		return nil, err
	}
	return result, nil
}

func ConvertReader(svgblob []byte, param ConversionParameters) (io.ReadCloser, error) {
	if param.Format == "svg" {
		return io.NopCloser(bytes.NewReader(svgblob)), nil
	}
	file, err := svg.CreateTemp(bytes.NewReader(svgblob), "svg")
	if err != nil {
		return nil, err
	}
	defer os.Remove(file)

	switch param.Format {
	case "png":
		return convertPNG(file, param)
	}
	return nil, errors.New("Format not supported")
}

func convertPNG(input string, param ConversionParameters) (io.ReadCloser, error) {
	var args []string
	var outExt string

	fontsdir, err := svg.Storage.GetFontsDir()
	if err != nil {
		return nil, err
	}
	args = append(args, "--skip-system-fonts")
	args = append(args, "--use-fonts-dir", fontsdir)

	if param.Width > 0 {
		args = append(args, "-w", strconv.Itoa(param.Width))
	}
	if param.Height > 0 {
		args = append(args, "-h", strconv.Itoa(param.Height))
	}

	outFile := strings.TrimSuffix(input, filepath.Ext(input)) + outExt
	args = append(args, input)
	args = append(args, outFile)

	cmd := exec.Command("resvg", args...)
	cmd.Dir = svg.TempDir

	out, err := cmd.CombinedOutput()
	log.Println(string(out))
	if err != nil {
		return nil, fmt.Errorf("resvg failed: %w: %s", err, string(out))
	}

	file, err := os.Open(outFile)
	if err != nil {
		return nil, err
	}

	return file, nil
}

func CheckResvg() bool {
	_, err := exec.LookPath("resvg")
	return err == nil
}