// 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"
	"errors"
	"log/slog"
	"time"

	"git.stormux.org/storm/cthulhu/internal/lifecycle"
)

// runtimeShutdown owns the ordered teardown after the event loop returns.
// The worker channels must close before preferences, braille, and speech stop.
type runtimeShutdown struct {
	tentacles   *tentacleRuntime
	ocr         *ocrSession
	logger      *slog.Logger
	cancel      context.CancelFunc
	workers     *runtimeWorkers
	preferences *preferencesWorker
	braille     *brailleWorker
	speech      *speechWorker
	focusGate   *focusGate
	services    *lifecycle.Runner
}

func stopRuntime(runtime runtimeShutdown) error {
	runtime.cancel()
	var tentacleError error
	if runtime.tentacles != nil {
		ctx, cancel := context.WithTimeout(context.Background(), 6*time.Second)
		tentacleError = runtime.tentacles.Stop(ctx)
		cancel()
	}
	<-runtime.workers.commandDone
	if runtime.workers.internalUIDone != nil {
		<-runtime.workers.internalUIDone
	}
	<-runtime.workers.clipboardDone
	<-runtime.workers.inputDone
	<-runtime.workers.copyDone
	<-runtime.workers.autoClipboardDone
	if runtime.ocr != nil {
		ocrContext, cancelOCR := context.WithTimeout(context.Background(), 5*time.Second)
		if err := runtime.ocr.Stop(ocrContext); err != nil {
			runtime.logger.Warn("stop OCR", "error", err)
		}
		cancelOCR()
	}
	// Join settings work before farewell and backend shutdown. The preferences
	// service also remains in the runner so failed cleanup is retried there.
	if runtime.preferences != nil {
		preferencesContext, cancelPreferences := context.WithTimeout(context.Background(), 7*time.Second)
		if err := runtime.preferences.Stop(preferencesContext); err != nil {
			runtime.logger.Warn("stop preferences", "error", err)
		}
		cancelPreferences()
	}
	brailleContext, cancelBraille := context.WithTimeout(context.Background(), shutdownTimeout)
	if err := runtime.braille.Stop(brailleContext); err != nil {
		runtime.logger.Warn("stop braille", "error", err)
	}
	cancelBraille()
	if runtime.speech != nil && !runtime.focusGate.Locked() {
		farewellContext, cancelFarewell := context.WithTimeout(context.Background(), farewellTimeout)
		runtime.speech.InterruptForUser()
		farewellError := runtime.speech.EnqueueAndWait(farewellContext, speechRequest{
			Text:  random_string(shutdownMessages),
			Role:  "system",
			Cause: "shutdown",
		})
		cancelFarewell()
		if farewellError != nil {
			runtime.logger.Warn("deliver shutdown message", "error", farewellError)
		} else {
			runtime.logger.Debug("shutdown message accepted")
		}
	}
	shutdownContext, cancelShutdown := context.WithTimeout(context.Background(), shutdownTimeout)
	defer cancelShutdown()
	runtime.logger.Debug("stopping runtime services")
	stopError := runtime.services.Stop(shutdownContext)
	if stopError != nil {
		runtime.logger.Warn("runtime services stopped with an error", "error", stopError)
	} else {
		runtime.logger.Debug("runtime services stopped")
	}
	return errors.Join(tentacleError, stopError)
}