package main

import (
	"fmt"
	"io"
	"net/http"
	"os"
	"path/filepath"
	"strings"
)

func downloadImage(config *Config) error {
	filename := getFilenameFromURL(config.ImageURL)
	filepath := filepath.Join("/tmp", filename)

	if _, err := os.Stat(filepath); err == nil {
		fmt.Printf("Image already exists at %s, skipping download\n", filepath)
		config.ImageURL = filepath
		return nil
	}

	fmt.Printf("Downloading image from %s...\n", config.ImageURL)

	resp, err := http.Get(config.ImageURL)
	if err != nil {
		return fmt.Errorf("failed to download image: %w", err)
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		return fmt.Errorf("bad status: %s", resp.Status)
	}

	out, err := os.Create(filepath)
	if err != nil {
		return fmt.Errorf("failed to create file: %w", err)
	}
	defer out.Close()

	counter := &WriteCounter{Total: resp.ContentLength}
	_, err = io.Copy(out, io.TeeReader(resp.Body, counter))
	if err != nil {
		return fmt.Errorf("failed to save image: %w", err)
	}

	fmt.Println("\nDownload completed!")
	config.ImageURL = filepath
	return nil
}

func getFilenameFromURL(url string) string {
	parts := strings.Split(url, "/")
	return parts[len(parts)-1]
}

type WriteCounter struct {
	Total      int64
	Downloaded int64
}

func (wc *WriteCounter) Write(p []byte) (int, error) {
	n := len(p)
	wc.Downloaded += int64(n)
	wc.printProgress()
	return n, nil
}

func (wc *WriteCounter) printProgress() {
	fmt.Printf("\r")
	if wc.Total > 0 {
		percent := float64(wc.Downloaded) / float64(wc.Total) * 100
		fmt.Printf("Downloading... %.0f%% (%d/%d MB)", percent, wc.Downloaded/1024/1024, wc.Total/1024/1024)
	} else {
		fmt.Printf("Downloading... %d MB", wc.Downloaded/1024/1024)
	}
}