package main

import (
	"os"
	"path/filepath"
	"reflect"
	"testing"
)

func catalogue(t *testing.T, manifests map[string]string) string {
	t.Helper()
	root := t.TempDir()
	for name, body := range manifests {
		dir := filepath.Join(root, "modules", name)
		if err := os.MkdirAll(dir, 0o755); err != nil {
			t.Fatal(err)
		}
		if err := os.WriteFile(filepath.Join(dir, "module.json"), []byte(body), 0o644); err != nil {
			t.Fatal(err)
		}
	}
	return root
}

const buildah = `{"module":"buildah","provides":[{"name":"rootless-image-build","reach":"machine"}]}`

func TestOnlyBuildahProvidesTheRootlessImageBuild(t *testing.T) {
	root := catalogue(t, map[string]string{"buildah": buildah, "go": `{"module":"go","provides":[{"name":"go-toolchain"}]}`})
	got, err := Check(root)
	if err != nil {
		t.Fatal(err)
	}
	if len(got) != 0 {
		t.Errorf("found %v, want none", got)
	}
}

func TestDockerAndAnySecondProviderAreRefused(t *testing.T) {
	root := catalogue(t, map[string]string{
		"buildah": buildah,
		"docker":  `{"module":"docker","provides":[{"name":"rootless-image-build"}]}`,
		"other":   `{"module":"other","provides":[{"name":"x"},{"name":"rootless-image-build"}]}`,
	})
	got, err := Check(root)
	if err != nil {
		t.Fatal(err)
	}
	want := []Finding{{Module: "docker"}, {Module: "other"}}
	if !reflect.DeepEqual(got, want) {
		t.Errorf("found %v, want %v", got, want)
	}
}

func TestBuildahMustProvideIt(t *testing.T) {
	root := catalogue(t, map[string]string{"buildah": `{"module":"buildah"}`})
	got, err := Check(root)
	if err != nil {
		t.Fatal(err)
	}
	if want := []Finding{{Module: "buildah"}}; !reflect.DeepEqual(got, want) {
		t.Errorf("found %v, want %v", got, want)
	}
}

// The catalogue as it stands: this is the check itself, run here too.
func TestTheCatalogueGivesTheProvisionToBuildahAlone(t *testing.T) {
	got, err := Check("../..")
	if err != nil {
		t.Fatal(err)
	}
	if len(got) != 0 {
		t.Errorf("the catalogue's providers of rootless-image-build are wrong: %v", got)
	}
}