// Cthulhu screen reader.
// Copyright (c) 2026 Storm Dragon
// Authors: Storm Dragon, Angus Kola
//
// This program is free software: you can redistribute it and/or modify it
// under the terms of the GNU 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 General Public License for
// more details.
//
// You should have received a copy of the GNU General Public License along with
// this program. If not, see <https://www.gnu.org/licenses/gpl-3.0.html>.

package lifecycle

import (
	"bytes"
	"context"
	"errors"
	"log/slog"
	"strings"
	"testing"
)

func TestStartAndStopReverseOrder(t *testing.T) {
	var events []string
	runner, err := New(
		Service{
			Name:  "first",
			Start: func(context.Context) error { events = append(events, "start first"); return nil },
			Stop:  func(context.Context) error { events = append(events, "stop first"); return nil },
		},
		Service{
			Name:  "second",
			Start: func(context.Context) error { events = append(events, "start second"); return nil },
			Stop:  func(context.Context) error { events = append(events, "stop second"); return nil },
		},
	)
	if err != nil {
		t.Fatalf("New: %v", err)
	}
	if err := runner.Start(context.Background()); err != nil {
		t.Fatalf("Start: %v", err)
	}
	if runner.State() != StateRunning {
		t.Fatalf("state after start = %s, want %s", runner.State(), StateRunning)
	}
	if err := runner.Stop(context.Background()); err != nil {
		t.Fatalf("Stop: %v", err)
	}
	want := strings.Join([]string{"start first", "start second", "stop second", "stop first"}, ",")
	if got := strings.Join(events, ","); got != want {
		t.Fatalf("events = %q, want %q", got, want)
	}
	if runner.State() != StateStopped {
		t.Fatalf("state after stop = %s, want %s", runner.State(), StateStopped)
	}
}

func TestStartupFailureStopsStartedServices(t *testing.T) {
	startFailure := errors.New("start failed")
	stopFailure := errors.New("stop failed")
	var stopped bool
	runner, err := New(
		Service{
			Name:  "ready",
			Start: func(context.Context) error { return nil },
			Stop: func(context.Context) error {
				stopped = true
				return stopFailure
			},
		},
		Service{
			Name:  "broken",
			Start: func(context.Context) error { return startFailure },
			Stop:  func(context.Context) error { return nil },
		},
	)
	if err != nil {
		t.Fatalf("New: %v", err)
	}

	err = runner.Start(context.Background())
	if !errors.Is(err, startFailure) || !errors.Is(err, stopFailure) {
		t.Fatalf("Start error = %v, want both start and stop failures", err)
	}
	if !stopped {
		t.Fatal("started service was not stopped")
	}
	if runner.State() != StateStopped {
		t.Fatalf("state after failed start = %s, want %s", runner.State(), StateStopped)
	}
}

func TestCanceledStartDoesNotCallService(t *testing.T) {
	ctx, cancel := context.WithCancel(context.Background())
	cancel()
	var called bool
	runner, err := New(Service{
		Name: "service",
		Start: func(context.Context) error {
			called = true
			return nil
		},
		Stop: func(context.Context) error { return nil },
	})
	if err != nil {
		t.Fatalf("New: %v", err)
	}
	err = runner.Start(ctx)
	if !errors.Is(err, context.Canceled) {
		t.Fatalf("Start error = %v, want context.Canceled", err)
	}
	if called {
		t.Fatal("service start was called after cancellation")
	}
	if runner.State() != StateStopped {
		t.Fatalf("state after canceled start = %s, want %s", runner.State(), StateStopped)
	}
}

func TestStopIsIdempotent(t *testing.T) {
	runner, err := New(Service{
		Name:  "service",
		Start: func(context.Context) error { return nil },
		Stop:  func(context.Context) error { return nil },
	})
	if err != nil {
		t.Fatalf("New: %v", err)
	}
	if err := runner.Start(context.Background()); err != nil {
		t.Fatalf("Start: %v", err)
	}
	if err := runner.Stop(context.Background()); err != nil {
		t.Fatalf("first Stop: %v", err)
	}
	if err := runner.Stop(context.Background()); err != nil {
		t.Fatalf("second Stop: %v", err)
	}
}

func TestStopLogsCompletedServiceStages(t *testing.T) {
	var logs bytes.Buffer
	logger := slog.New(slog.NewTextHandler(&logs, &slog.HandlerOptions{Level: slog.LevelDebug}))
	runner, err := NewWithLogger(logger, Service{
		Name:  "service",
		Start: func(context.Context) error { return nil },
		Stop:  func(context.Context) error { return nil },
	})
	if err != nil {
		t.Fatalf("NewWithLogger: %v", err)
	}
	if err := runner.Start(context.Background()); err != nil {
		t.Fatalf("Start: %v", err)
	}
	if err := runner.Stop(context.Background()); err != nil {
		t.Fatalf("Stop: %v", err)
	}

	output := logs.String()
	if !strings.Contains(output, "lifecycle service stopping") ||
		!strings.Contains(output, "lifecycle service stopped") ||
		!strings.Contains(output, "service") {
		t.Fatalf("stop logs = %q, want stopping and stopped records for service", output)
	}
}

func TestNewRejectsInvalidService(t *testing.T) {
	if _, err := New(Service{Name: "invalid"}); err == nil {
		t.Fatal("New accepted a service without functions")
	}
}