// 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 app

import (
	"context"
	"log/slog"

	"git.stormux.org/storm/cthulhu/internal/config"
	"git.stormux.org/storm/cthulhu/internal/lifecycle"
	"git.stormux.org/storm/cthulhu/internal/platform/xorg"
	"git.stormux.org/storm/cthulhu/internal/sound"
)

// runtimeBackends carries constructed backends only between assembly and Run.
// The lifecycle runner owns their start/stop order after construction.
type runtimeBackends struct {
	speechOutput    speechEnqueuer
	brailleOutput   *brailleWorker
	speechMessages  *speechWorker
	history         *speechHistory
	settingsUpdater any
	inputListener   InputListener
	copyChanges     <-chan struct{}
	sounds          soundService
	services        []lifecycle.Service
}

// newRuntimeBackends registers sound, speech, speech worker, input, and the
// optional clipboard monitor in that order. The speech worker has a lifetime
// independent of the event-loop context so farewell can be delivered.
func newRuntimeBackends(options *Options, settings config.Settings, logger *slog.Logger, adapter Adapter) (*runtimeBackends, error) {
	var speechOutput speechEnqueuer = discardSpeech{}
	brailleOutput, err := newBrailleWorker(logger)
	if err != nil {
		return nil, err
	}
	brailleOutput.router, _ = adapter.(brailleRouter)
	brailleOutput.SetContraction(settings.EnableContractedBraille, settings.BrailleContractionTable)
	brailleOutput.SetWordWrap(settings.Braille.WordWrap)
	backends := &runtimeBackends{
		speechOutput:  speechOutput,
		brailleOutput: brailleOutput,
		services:      make([]lifecycle.Service, 0, 5),
	}
	if options.newSound != nil {
		backends.sounds = options.newSound()
	} else {
		backends.sounds = sound.New(logger, sound.NativePlayer{Sink: settings.SoundSink}, settings.SoundTheme, settings.SoundVolume)
	}
	if updater, ok := backends.sounds.(soundSettingsUpdater); ok {
		updater.Configure(soundConfiguration(settings))
	}
	backends.services = append(backends.services, lifecycle.Service{Name: "sound", Start: backends.sounds.Start, Stop: func(context.Context) error {
		soundContext, cancelSound := context.WithTimeout(context.Background(), soundStopTimeout)
		defer cancelSound()
		logger.Debug("playing shutdown sound")
		if err := backends.sounds.Stop(soundContext); err != nil {
			logger.Warn("stop sound service", "error", err)
			return err
		}
		logger.Debug("shutdown sound completed")
		return nil
	}})
	if options.newSpeaker == nil {
		options.newSpeaker = func() Speaker {
			return newConfiguredSpeaker(options.SpeechSocket, settings)
		}
	}
	speaker := options.newSpeaker()
	backends.settingsUpdater = speaker
	backends.speechMessages = newSpeechWorker(logger, speaker)
	backends.speechMessages.SetEnabled(settings.EnableSpeech)
	if beeper, ok := backends.sounds.(interface{ SpeechBeep(context.Context) error }); ok {
		backends.speechMessages.beep = beeper.SpeechBeep
	}
	backends.history = newSpeechHistory(settings.SpeechHistoryLimit)
	backends.speechMessages.history = backends.history
	backends.speechOutput = backends.speechMessages
	if options.newInput == nil {
		options.newInput = func() InputListener { return xorg.New() }
	}
	backends.inputListener = options.newInput()
	backends.services = append(backends.services,
		lifecycle.Service{Name: "speech", Start: func(ctx context.Context) error {
			if !settings.EnableSpeech {
				return nil
			}
			return speaker.Connect(ctx)
		}, Stop: speaker.Close},
		lifecycle.Service{Name: "speech worker", Start: func(context.Context) error {
			// The runner owns this worker's lifetime. Keeping it independent of
			// the event-loop context lets graceful shutdown queue its farewell.
			return backends.speechMessages.Start(context.Background())
		}, Stop: backends.speechMessages.Stop},
	)
	backends.services = append(backends.services,
		desktopInputService("X11 listener", backends.inputListener, logger),
	)
	if _, native := backends.inputListener.(*xorg.Listener); native {
		clipboardMonitor := xorg.NewClipboardMonitor()
		backends.services = append(backends.services, lifecycle.Service{
			Name: "clipboard changes",
			Start: func(ctx context.Context) error {
				if err := clipboardMonitor.Start(ctx); err != nil {
					logger.Warn("copy feedback unavailable", "error", err)
					return nil
				}
				backends.copyChanges = clipboardMonitor.Changes()
				return nil
			},
			Stop: clipboardMonitor.Stop,
		})
	}
	return backends, nil
}