// 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 (
	"log/slog"
	"time"

	"git.stormux.org/storm/cthulhu/internal/atspi"
	"git.stormux.org/storm/cthulhu/internal/braille"
	"git.stormux.org/storm/cthulhu/internal/presentation"
	"git.stormux.org/storm/cthulhu/internal/review"
)

// eventLoopState is owned only by processEventsWithInput's goroutine. Embedded
// groups keep each lifetime visible while retaining the existing individual
// reset transitions. Workers observe state only through their existing APIs.
type eventLoopState struct {
	eventForegroundState
	eventFocusState
	eventDocumentState
	eventInputState
	eventPresentationState
}

type eventForegroundState struct {
	owner           windowOwner
	foregroundState atspi.ForegroundState
	lastOverflow    uint64
}

type eventFocusState struct {
	libreOfficeSelection libreOfficeSelectionState
	current              atspi.Snapshot
	brailleSnapshot      atspi.Snapshot
	focusedID            atspi.ObjectID
	managedContainerID   atspi.ObjectID
	managedDescendantID  atspi.ObjectID
}

type eventDocumentState struct {
	selectedBrowserTab  atspi.ObjectID
	tabFocusWindow      atspi.ObjectID
	tabFocusSequence    uint64
	documentLineFocus   atspi.ObjectID
	documentLineRequest uint64
	documentLineEvent   atspi.Event
	loadedDocument      atspi.ObjectID
	loadingDocument     atspi.ObjectID
	// A load-complete can verify chrome focus just before a busy:false event
	// temporarily loses its native focused state. Keep that document from
	// taking browse keys until focus actually enters it.
	chromeLoadedDocument atspi.ObjectID
	chromeLoadedWindow   atspi.ObjectID
}

type eventInputState struct {
	lastAutocompletePopupItem atspi.ObjectID
	focusCaretID              atspi.ObjectID
	focusCaretSequence        uint64
	suppressNextCaretPath     string
	selectionCaretID          atspi.ObjectID
	selectionCaretSequence    uint64
	selectionCaretAt          time.Time
	autocompleteTyping        autocompleteEcho
	autocompleteAvailable     autocompleteAvailability
	typingPath                string
	typingText                string
	selection                 textSelection
	documentSelection         textSelection
	lastClipboardSequence     uint64
	lastPasteSequence         uint64
	lastPasteID               atspi.ObjectID
	lastPasteAt               time.Time
}

type eventPresentationState struct {
	presentationOptions presentation.Options
	pending             pendingPresentations
	lastSpokenPath      string
	lastSpokenText      string
	lastSound           string
	lastLiveText        string
	lastLiveAt          time.Time
	comboHistory        comboPresentation
	// Retain this identity after the history window closes so delayed GTK
	// events cannot enter speech history.
	historyWindow               atspi.ObjectID
	lastFileManagerStatus       string
	lastFileManagerStatusWindow atspi.ObjectID
	pendingPromptWindow         atspi.ObjectID
	pendingPromptTextAnnounced  bool
	tableDescriptionWindow      atspi.ObjectID
	tableDescriptionText        string
	tableDescriptionAt          time.Time
	lastTable                   atspi.ObjectID
	lastTableCell               atspi.ObjectID
	lastTableRow                int
	lastTableColumn             int
	lastTableSequence           uint64
	lastTableAt                 time.Time
	lastTableFullRow            bool
	lastTableText               string
	progressBars                ProgressBarHistory
}

func (state *eventLoopState) ownedAutocompletePopup(event atspi.Event) bool {
	return event.Source.AutocompletePopup && event.PopupFor.Valid() &&
		state.current.Autocomplete && state.current.ID() == event.PopupFor &&
		state.owner.focus == event.PopupFor && state.owner.window.Valid() &&
		event.Window.Valid() && event.Window != state.owner.window &&
		event.Window.BusName == state.owner.applicationBus &&
		event.Source.BusName == state.owner.applicationBus
}

// clearOwnedFocus retires only the state cleared by the former event-loop
// closure. Session presentation history and chrome load verification survive.
func (state *eventLoopState) clearOwnedFocus(brailleOutput brailleFrameEnqueuer, browser *browserModeController, objectReview *review.Worker, speech speechEnqueuer) {
	state.clearObjectFocus(brailleOutput, browser, objectReview)
	speech.Interrupt()
}

// Review metadata can change without new input or a foreground switch. Reset
// its navigation state independently so title announcements keep playing.
func (state *eventLoopState) clearObjectFocus(brailleOutput brailleFrameEnqueuer, browser *browserModeController, objectReview *review.Worker) {
	state.libreOfficeSelection = libreOfficeSelectionState{}
	state.selection = textSelection{}
	state.documentSelection = textSelection{}
	state.lastClipboardSequence = 0
	state.lastPasteSequence = 0
	state.lastPasteID = atspi.ObjectID{}
	state.lastPasteAt = time.Time{}
	state.selectionCaretID = atspi.ObjectID{}
	state.brailleSnapshot = atspi.Snapshot{}
	if brailleOutput != nil {
		brailleOutput.EnqueueFrame(braille.Frame{Cursor: -1})
	}
	state.pending.clear()
	state.pendingPromptWindow = atspi.ObjectID{}
	state.pendingPromptTextAnnounced = false
	state.focusedID = atspi.ObjectID{}
	state.selectedBrowserTab = atspi.ObjectID{}
	state.tabFocusWindow, state.tabFocusSequence = atspi.ObjectID{}, 0
	state.managedContainerID = atspi.ObjectID{}
	state.managedDescendantID = atspi.ObjectID{}
	state.current = atspi.Snapshot{}
	state.focusCaretID, state.focusCaretSequence = atspi.ObjectID{}, 0
	state.lastSpokenPath, state.lastSpokenText, state.lastSound = "", "", ""
	state.lastLiveText, state.lastLiveAt = "", time.Time{}
	state.comboHistory = comboPresentation{}
	state.typingPath, state.typingText, state.suppressNextCaretPath = "", "", ""
	state.lastAutocompletePopupItem = atspi.ObjectID{}
	state.autocompleteTyping = autocompleteEcho{}
	state.autocompleteAvailable = autocompleteAvailability{}
	state.documentLineFocus = atspi.ObjectID{}
	state.documentLineRequest = 0
	state.documentLineEvent = atspi.Event{}
	state.loadedDocument = atspi.ObjectID{}
	state.loadingDocument = atspi.ObjectID{}
	if browser != nil {
		browser.clear()
	}
	if objectReview != nil {
		objectReview.ClearFocus()
	}
}

func (state *eventLoopState) syncForeground(foreground foregroundMonitor, logger *slog.Logger, clearOwnedFocus func()) {
	if foreground == nil {
		return
	}
	latest := foreground.Foreground()
	if latest.Epoch != state.foregroundState.Epoch {
		state.owner.clear()
		clearOwnedFocus()
		logger.Debug("X11 foreground ownership changed", "x_window", latest.Client.Window,
			"pid", latest.Client.PID, "known", latest.Client.Known, "epoch", latest.Epoch)
	}
	state.foregroundState = latest
}