// Copyright (c) 2026 Storm Dragon
// Authors: Storm Dragon, Angus Kola
// SPDX-License-Identifier: GPL-3.0-or-later

package atspi

import (
	"errors"
	"sync"
)

// Choices contain only identities and coordinates, never provider objects or
// cell text. They survive focus/lock/tab changes and expire on document/window
// destruction, sheet topology/name changes and shutdown. A fixed limit bounds
// missed deaths. Calc recreates its table objects on every sheet switch.
type libreOfficeHeaderKey struct {
	window, document ObjectID
	sheet            string
}

type libreOfficeHeaderChoice struct {
	row, column       int
	rowSet, columnSet bool
}

type libreOfficeHeaderStore struct {
	mutex   sync.Mutex
	choices map[libreOfficeHeaderKey]libreOfficeHeaderChoice
}

func libreOfficeHeaderIdentity(snapshot Snapshot, window ObjectID) (libreOfficeHeaderKey, bool) {
	context := snapshot.LibreOffice
	key := libreOfficeHeaderKey{window: window}
	if context != nil {
		key.document = context.Document
		key.sheet = context.SheetName
	}
	valid := IsLibreOfficeProcess(snapshot.ApplicationProcess) && !snapshot.Defunct &&
		snapshot.Role == "table cell" && context != nil && context.InSpreadsheet && context.Cell &&
		snapshot.TablePositionKnown && snapshot.TableRowIndex >= 0 && snapshot.TableColumnIndex >= 0 &&
		key.window.Valid() && key.document.Valid() && key.sheet != "" && snapshot.TablePath != "" &&
		key.window.BusName == snapshot.BusName && key.document.BusName == snapshot.BusName
	return key, valid
}

// ConfigureLibreOfficeHeader is called only for the event loop's owned cell.
// It copies a choice without querying AT-SPI or waiting for the GLib thread.
// columnHeaders selects the row that supplies column headings; otherwise the
// current column supplies row headings. clear removes only that axis.
func (adapter *Adapter) ConfigureLibreOfficeHeader(snapshot Snapshot, window ObjectID, columnHeaders, clear bool) error {
	key, valid := libreOfficeHeaderIdentity(snapshot, window)
	if !valid || adapter.secure.Load() {
		return errors.New("Not in a Calc cell.")
	}
	store := &adapter.libreOfficeHeaders
	store.mutex.Lock()
	defer store.mutex.Unlock()
	choice, exists := store.choices[key]
	if !exists && !clear && len(store.choices) >= 64 {
		return errors.New("Header choices are full. Clear a sheet's headers first.")
	}
	if columnHeaders {
		choice.row, choice.rowSet = snapshot.TableRowIndex, !clear
	} else {
		choice.column, choice.columnSet = snapshot.TableColumnIndex, !clear
	}
	if !choice.rowSet && !choice.columnSet {
		delete(store.choices, key)
		return nil
	}
	if store.choices == nil {
		store.choices = make(map[libreOfficeHeaderKey]libreOfficeHeaderChoice)
	}
	store.choices[key] = choice
	return nil
}

func (store *libreOfficeHeaderStore) get(key libreOfficeHeaderKey) libreOfficeHeaderChoice {
	store.mutex.Lock()
	defer store.mutex.Unlock()
	return store.choices[key]
}

func (store *libreOfficeHeaderStore) forget(id ObjectID) {
	store.mutex.Lock()
	defer store.mutex.Unlock()
	for key := range store.choices {
		if id == key.window || id == key.document {
			delete(store.choices, key)
		}
	}
}

func (store *libreOfficeHeaderStore) hasBus(bus string) bool {
	store.mutex.Lock()
	defer store.mutex.Unlock()
	for key := range store.choices {
		if key.window.BusName == bus {
			return true
		}
	}
	return false
}

func (store *libreOfficeHeaderStore) reset() {
	store.mutex.Lock()
	defer store.mutex.Unlock()
	store.choices = nil
}