// Fenrir console screen reader.
// Copyright (c) 2026 Storm Dragon
// SPDX-License-Identifier: GPL-3.0-or-later
//
// 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"
	"sync"
	"time"

	"git.stormux.org/storm/fenrir/internal/config"
	"git.stormux.org/storm/fenrir/internal/i18n"
	"git.stormux.org/storm/fenrir/internal/notifications"
	"git.stormux.org/storm/fenrir/internal/preferences"
	"git.stormux.org/storm/fenrir/internal/presentation"
	"git.stormux.org/storm/fenrir/internal/prompt"
	"git.stormux.org/storm/fenrir/internal/reader"
	"git.stormux.org/storm/fenrir/internal/screen"
	"git.stormux.org/storm/fenrir/internal/speech"
	"git.stormux.org/storm/fenrir/internal/terminal"
)

// application owns mutable reader state. Its methods run only on the event
// loop; asynchronous services return results rather than changing this state.
type application struct {
	ctx       context.Context
	source    Source
	keyboards Keyboards
	voice     *echoSpeaker
	cues      SoundPlayer
	options   RunOptions

	engine        *reader.Reader
	ui            *internalUI
	clipboards    *clipboardHost
	spellMenu     *spellcheckMenu
	prompts       *prompt.Detector
	settings      applicationSettings
	quick         *quickSettings
	notifications []notification
	saver         *settingsSaver
	speechPending bool
	speechResults chan speechChangeResult
	overrideLoads chan func()
	speechChoices chan preferences.Discovery
	prepareSpeech func(config.Speech) (speech.Transport, error)

	notificationSound   notificationSoundGate
	notificationHistory *notifications.Client
	notificationClosers sync.WaitGroup

	muted, temporarySilence bool
	quitting, quitAfterSave bool

	scriptGeneration, spellSession, spellFeedback uint64

	lastTerminal                                             int
	lastActive                                               bool
	lastGeneration                                           uint64
	lastRows, lastCols                                       int
	lastNumLock                                              bool
	lastSnapshot                                             screen.Snapshot
	overrides                                                map[int]*applicationOverride
	overrideCurrent                                          *applicationOverride
	overrideFailed                                           *applicationOverride
	overrideTransition, overrideRestoreFailed, overrideDirty bool
}

func new_application(ctx context.Context, source Source, keyboards Keyboards, voice Speaker, options RunOptions) (*application, error) {
	prompts, err := prompt.New(options.Settings.Prompt.ExactMatches, options.Settings.Prompt.CustomPatterns)
	if err != nil {
		return nil, err
	}
	a := &application{
		ctx: ctx, source: source, keyboards: keyboards, options: options,
		voice: &echoSpeaker{Speaker: voice}, cues: options.Sounds,
		engine: reader.New(), prompts: prompts,
		settings: applicationSettings{
			live: options.Settings, saveDraft: options.Settings, resetBase: options.Settings,
			remoteFields:    make(map[string]uint64),
			speechAvailable: options.Settings.Presentation.Speech.Enabled,
		},
		muted: !options.Settings.Presentation.Speech.Enabled,
		quick: new_quick_settings(options.Settings.Presentation.Speech.Driver), saver: &settingsSaver{results: make(chan error, 1)},
	}
	if options.EffectiveSpeech != nil {
		copy_speech_selection(&a.settings.live.Presentation.Speech, *options.EffectiveSpeech)
	}
	a.voice.punctuation, a.voice.punctuationLevel = options.Punctuation, options.Settings.Reading.PunctuationLevel
	a.voice.settings, a.voice.play = &a.settings.live, a.play
	a.ui = new_internal_ui(ctx, keyboards, a.voice)
	a.ui.gridSettings = func() config.InternalUI { return a.settings.live.InternalUI }
	a.ui.previewSpelling = a.preview_spelling
	a.ui.discoverChoices, a.ui.saveSettings = options.SettingsChoices, a.save_menu_settings
	a.speechResults = make(chan speechChangeResult, 1)
	a.overrideLoads = make(chan func(), 1)
	a.speechChoices = make(chan preferences.Discovery, 1)
	a.prepareSpeech = prepare_speech
	a.quick.selectSpeech = func(target config.Speech, done func(error, bool)) {
		session, feedback, uiGeneration := a.spellSession, a.spellFeedback, a.ui.generation
		a.change_speech(target, func(err error) {
			done(err, a.spellSession == session && a.spellFeedback == feedback && a.ui.generation == uiGeneration && !a.quitting)
		})
	}
	a.ui.catalog = func(discovery preferences.Discovery) {
		if discovery.Driver == "" || discovery.Driver == a.settings.live.Presentation.Speech.Driver {
			a.quick.discovery = discovery
		}
	}
	if options.SettingsChoices != nil {
		go func() {
			discovery := options.SettingsChoices(options.Settings)
			select {
			case a.speechChoices <- discovery:
			case <-ctx.Done():
			}
		}()
	}
	a.configure_reader()
	a.clipboards = new_clipboard(options.Settings.Clipboard, a.engine, options.Clipboard, a.present, func() string { return a.voice.last })
	a.clipboards.historyStore = options.ClipboardHistory
	a.restore_clipboard()
	a.spellMenu = &spellcheckMenu{ui: a.ui, service: options.Spellcheck, clipboards: a.clipboards}
	if session, ok := source.(*terminal.Session); ok {
		a.clipboards.queuePaste = session.Queue_paste
	}
	return a, nil
}

func (a *application) restore_clipboard() {
	if a.options.ClipboardHistory == nil {
		return
	}
	if a.settings.live.Clipboard.Persistent {
		if err := a.options.ClipboardHistory.LoadErr; err != nil {
			slog.Warn("clipboard history load failed", "error", err, "at", time.Now())
			a.present(i18n.T("Clipboard import failed"), presentation.Error)
		} else if err := a.clipboards.history.Restore(a.options.ClipboardHistory.Initial); err != nil {
			slog.Warn("clipboard history load failed", "error", err, "at", time.Now())
			a.present(i18n.T("Clipboard import failed"), presentation.Error)
		} else if len(a.options.ClipboardHistory.Initial.Entries) > a.settings.live.Clipboard.NumberOfClipboards {
			a.options.ClipboardHistory.Resize(a.settings.live.Clipboard.NumberOfClipboards)
		}
		if a.options.ClipboardHistory.LoadErr == nil {
			a.clipboards.settings.Persistent = a.options.ClipboardHistory.InitialEnabled
			a.settings.live.Clipboard.Persistent = a.options.ClipboardHistory.InitialEnabled
			a.settings.saveDraft.Clipboard.Persistent = a.options.ClipboardHistory.InitialEnabled
		}
	}
}