package pi

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

func TestReadPinnedVersionReadsTheSingleDefaultPiArg(t *testing.T) {
	root := t.TempDir()
	writeCoreDockerfile(t, root, "ARG PI_VERSION=0.81.0\nARG PI_VERSION\n")

	got, err := ReadPinnedVersion(root)
	if err != nil {
		t.Fatal(err)
	}
	if got != "0.81.0" {
		t.Fatalf("ReadPinnedVersion() = %q, want 0.81.0", got)
	}
}

func TestReadPinnedVersionRejectsMissingDuplicateAndMalformedPins(t *testing.T) {
	for _, test := range []struct {
		name string
		file string
		want string
	}{
		{name: "missing", file: "# no default\n", want: "one default PI_VERSION"},
		{name: "duplicate", file: "ARG PI_VERSION=0.80.3\nARG PI_VERSION=0.81.0\n", want: "one default PI_VERSION"},
		{name: "malformed", file: "ARG PI_VERSION=latest\n", want: "invalid Pi version"},
	} {
		t.Run(test.name, func(t *testing.T) {
			root := t.TempDir()
			writeCoreDockerfile(t, root, test.file)
			_, err := ReadPinnedVersion(root)
			if err == nil || !strings.Contains(err.Error(), test.want) {
				t.Fatalf("ReadPinnedVersion() error = %v, want %q", err, test.want)
			}
		})
	}
}

func writeCoreDockerfile(t *testing.T, root, contents string) {
	t.Helper()
	if err := os.MkdirAll(filepath.Join(root, "docker"), 0o755); err != nil {
		t.Fatal(err)
	}
	if err := os.WriteFile(filepath.Join(root, "docker", "core.Dockerfile"), []byte(contents), 0o600); err != nil {
		t.Fatal(err)
	}
}