// Copyright (C) 2026 Dcntrlized
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published
// by the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program.  If not, see <https://www.gnu.org/licenses/>.

package instance

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

func TestLoadPrefersFileOverEnv(t *testing.T) {
	dir := t.TempDir()
	if err := Save(dir, Identity{Name: "home-node", Title: "Home"}); err != nil {
		t.Fatal(err)
	}
	t.Setenv("DCNTRLIZED_INSTANCE_NAME", "from-env")

	id := Load(dir)
	if id.Name != "home-node" || id.Title != "Home" {
		t.Fatalf("got %+v", id)
	}
}

func TestDefaultIdentityFallbacks(t *testing.T) {
	orig := osHostname
	defer func() { osHostname = orig }()

	t.Run("env wins over domain", func(t *testing.T) {
		t.Setenv("DCNTRLIZED_INSTANCE_NAME", "edge-1")
		t.Setenv("DCNTRLIZED_INSTANCE_DOMAIN", "maestro.dcntrlized.org")
		if id := defaultIdentity(); id.Name != "edge-1" {
			t.Fatalf("got %q", id.Name)
		}
	})

	t.Run("announced domain used before hostname", func(t *testing.T) {
		t.Setenv("DCNTRLIZED_INSTANCE_DOMAIN", "maestro.dcntrlized.org")
		osHostname = func() (string, error) { return "archlinux", nil }
		if id := defaultIdentity(); id.Name != "maestro.dcntrlized.org" {
			t.Fatalf("got %q", id.Name)
		}
	})

	t.Run("hostname used when human-readable", func(t *testing.T) {
		os.Unsetenv("DCNTRLIZED_INSTANCE_NAME")
		os.Unsetenv("DCNTRLIZED_INSTANCE_DOMAIN")
		osHostname = func() (string, error) { return "archlinux", nil }
		if id := defaultIdentity(); id.Name != "archlinux" {
			t.Fatalf("got %q", id.Name)
		}
	})

	t.Run("container-id hostname replaced", func(t *testing.T) {
		os.Unsetenv("DCNTRLIZED_INSTANCE_NAME")
		os.Unsetenv("DCNTRLIZED_INSTANCE_DOMAIN")
		for _, host := range []string{"6079761d6e4d", "6079761d6e4dabcdef1234567890abcdef1234567890abcdef1234567890abcd"} {
			osHostname = func() (string, error) { return host, nil }
			if id := defaultIdentity(); id.Name != "Maestro" {
				t.Fatalf("host %q: got %q", host, id.Name)
			}
		}
	})
}

func TestLooksLikeContainerID(t *testing.T) {
	cases := map[string]bool{
		"6079761d6e4d":                     true,
		"ABCDEF0123456789abcdef0123456789": true,
		"archlinux":                        false,
		"maestro-1":                        false,
		"abc":                              false,
		"":                                 false,
	}
	for s, want := range cases {
		if got := looksLikeContainerID(s); got != want {
			t.Errorf("looksLikeContainerID(%q) = %v, want %v", s, got, want)
		}
	}
}

func TestSaveRejectsEmptyName(t *testing.T) {
	dir := t.TempDir()
	if err := Save(dir, Identity{}); err == nil {
		t.Fatal("expected error for empty name")
	}
	if _, err := os.Stat(filepath.Join(dir, "instance.json")); !os.IsNotExist(err) {
		t.Fatal("no file should be written for an invalid identity")
	}
}