package main

import (
	"encoding/json"
	"flag"
	"fmt"
	"os"
	"path/filepath"

	oci "github.com/opencontainers/image-spec/specs-go/v1"
)

func main() {
	os.Exit(run())
}

func run() int {
	flag.Parse()

	// open and parse the image index json file
	imageLayout := flag.Arg(0)
	imageLayoutAbs, err := filepath.Abs(imageLayout)
	if err != nil {
		fmt.Println(err)
		return 1
	}
	layoutFS := os.DirFS(imageLayoutAbs)
	manifestFile := "manifest_list.new.json"
	file, err := layoutFS.Open(manifestFile)
	if err != nil {
		fmt.Println(err)
		return 1
	}
	defer file.Close()

	dec := json.NewDecoder(file)
	idx := &oci.Index{}
	if err := dec.Decode(idx); err != nil {
		fmt.Println(err)
		return 1
	}

	// search manifest list for all required platforms
	foundPltfs := map[string]bool{
		"linux/amd64": false,
		"linux/arm64": false,
	}
	for _, desc := range idx.Manifests {
		foundPltfs[fmt.Sprintf("%s/%s", desc.Platform.OS, desc.Platform.Architecture)] = true
	}
	for platform, found := range foundPltfs {
		if !found {
			fmt.Printf("failed to find required platform: %s\n", platform)
			os.Exit(1)
		}
	}

	return 0
}