package main

import (
	"archive/zip"
	"flag"
	"fmt"
	"io"
	"os"
	"os/exec"
	"path/filepath"

	"github.com/fatih/color"
)

var (
	FlagOutputFile = flag.String("o", "output.pdf", "output file name")
	ColorRed       = color.New(color.FgRed)
)

func main() {
	flag.Parse()

	if _, err := exec.LookPath("img2pdf"); err != nil {
		ColorRed.Fprintln(os.Stderr, "img2pdf not installed")
		os.Exit(1)
	}

	inputFilePath := flag.Arg(0)
	if inputFilePath == "" {
		ColorRed.Fprintln(os.Stderr, "please provide an input file path")
		os.Exit(1)
	}

	inputFile, err := os.Open(inputFilePath)
	if err != nil {
		ColorRed.Fprintf(os.Stderr, "input file path could not be read: %s\n", err.Error())
		os.Exit(1)
	}
	defer inputFile.Close()

	fi, err := inputFile.Stat()
	if err != nil {
		ColorRed.Fprintf(os.Stderr, "input file path could not be read: %s\n", err.Error())
		os.Exit(1)
	}

	zipr, err := zip.NewReader(inputFile, fi.Size())
	if err != nil {
		ColorRed.Fprintf(os.Stderr, "input file path could not be read: %s\n", err.Error())
		os.Exit(1)
	}

	tempFiles := make([]string, 0, len(zipr.File))
	for _, file := range zipr.File {
		ext := filepath.Ext(file.Name)
		tempFile, err := os.CreateTemp("", fmt.Sprintf("*%s", ext))
		if err != nil {
			ColorRed.Fprintf(os.Stderr, "temporary file could not be created: %s\n", err.Error())
			os.Exit(1)
		}
		defer os.Remove(tempFile.Name())
		defer tempFile.Close()
		tempFiles = append(tempFiles, tempFile.Name())

		imgFile, err := file.Open()
		if err != nil {
			ColorRed.Fprintf(os.Stderr, "compressed file could not be read: %s\n", err.Error())
			os.Exit(1)
		}
		defer imgFile.Close()

		if _, err := io.Copy(tempFile, imgFile); err != nil {
			ColorRed.Fprintf(os.Stderr, "coud not create image file: %s\n", err.Error())
			os.Exit(1)
		}

		tempFile.Close()
	}

	args := append([]string{"--output", *FlagOutputFile}, tempFiles...)
	img2pdf := exec.Command("img2pdf", args...)

	if err := img2pdf.Start(); err != nil {
		ColorRed.Fprintf(os.Stderr, "img2pdf could not be started: %s\n", err.Error())
		os.Exit(1)
	}

	if err := img2pdf.Wait(); err != nil {
		ColorRed.Fprintf(os.Stderr, "img2pdf returned an error: %s\n", err.Error())
		os.Exit(1)
	}
}