package main

import (
	"bufio"
	"context"
	"io"
	"log"
	"net/http"
	"os"
	"strings"

	"github.com/minio/minio-go/v7"
	"github.com/minio/minio-go/v7/pkg/credentials"
)

func listBucketContents(minioClient *minio.Client, bucketName string) ([]string, error) {
	var contents []string

	// Create a done channel to control the listing
	ctx := context.Background()

	// List all objects from bucket
	for object := range minioClient.ListObjects(ctx, bucketName, minio.ListObjectsOptions{
		Recursive: true,
	}) {
		if object.Err != nil {
			return nil, object.Err
		}
		contents = append(contents, object.Key)
	}

	return contents, nil
}

type IsoInfo struct {
	Url    string
	Hash   string
	Distro string
}

func processStdin() []IsoInfo {
	var isos []IsoInfo
	scanner := bufio.NewScanner(os.Stdin)

	for scanner.Scan() {
		parts := strings.Split(scanner.Text(), " ")
		if len(parts) == 3 {
			iso := IsoInfo{
				Url:    parts[0],
				Hash:   parts[1],
				Distro: parts[2],
			}
			isos = append(isos, iso)
		}
	}

	if err := scanner.Err(); err != nil {
		log.Println("Error reading from stdin:", err)
	}

	return isos
}

func downloadAndUploadIso(minioClient *minio.Client, iso IsoInfo, ch chan int) {
	// Create the destination file path
	destPath := "cache/" + iso.Hash + ".iso"
	// Create cache directory if it doesn't exist
	err := os.MkdirAll("cache", 0755)
	if err != nil {
		log.Fatalln(err)
		ch <- 1
		return
	}

	log.Println("Downloading " + iso.Url)
	// Download the ISO file
	resp, err := http.Get(iso.Url)
	if err != nil {
		log.Fatalln(err)
		ch <- 1
		return
	}
	defer resp.Body.Close()

	// Create the destination file
	destFile, err := os.Create(destPath)
	if err != nil {
		log.Fatalln(err)
		ch <- 1
		return
	}
	defer destFile.Close()

	// Copy the downloaded content to the file
	_, err = io.Copy(destFile, resp.Body)
	if err != nil {
		log.Fatalln(err)
		ch <- 1
		return
	}

	// Reopen file for uploading
	uploadFile, err := os.Open(destPath)
	if err != nil {
		log.Fatalln(err)
		ch <- 1
		return
	}
	defer uploadFile.Close()

	// Get file info for content-length
	fileInfo, err := uploadFile.Stat()
	if err != nil {
		log.Fatalln(err)
		ch <- 1
		return
	}

	log.Println("Uploading " + destPath)
	uploadPath := "cache/" + iso.Distro + "/" + iso.Hash + ".iso"
	// Upload the file to MinIO
	_, err = minioClient.PutObject(context.Background(), "isos", uploadPath, uploadFile, fileInfo.Size(), minio.PutObjectOptions{
		ContentType: "application/x-iso9660-image",
	})
	if err != nil {
		log.Fatalln(err)
		ch <- 1
		return
	}

	log.Println("Done with " + iso.Url)
	ch <- 1
}

func main() {
	endpoint := os.Getenv("STORAGE_URL")
	log.Println("Using endpoint:", endpoint)
	accessKeyID := "root"
	secretAccessKey := os.Getenv("MINIO_SECRET")
	if secretAccessKey == "" {
		log.Fatalln("MINIO_SECRET environment variable not set")
	}
	useSSL := false

	// Initialize minio client
	minioClient, err := minio.New(endpoint, &minio.Options{
		Creds:  credentials.NewStaticV4(accessKeyID, secretAccessKey, ""),
		Secure: useSSL,
	})
	if err != nil {
		log.Fatalln(err)
	}

	// List contents of the "isos" bucket
	contents, err := listBucketContents(minioClient, "isos")
	if err != nil {
		log.Fatalln(err)
	}

	isos := processStdin()

	downloads := 0
	dl_counter := make(chan int)
	for _, iso := range isos {
		// Check if ISO exists in Minio
		isoPath := "cache/" + iso.Distro + "/" + iso.Hash + ".iso"
		exists := false

		for _, item := range contents {
			if item == isoPath {
				exists = true
				break
			}
		}

		if !exists {
			downloads += 1
			go downloadAndUploadIso(minioClient, iso, dl_counter)
		}
	}

	for downloads > 0 {
		if k := <-dl_counter; k == 1 {
			downloads -= 1
		} else {
			log.Println("Received unknown message on channel: ", k)
		}
	}
}