//  GNOME Shell Extension TaskBar 2020
//  Copyright (C) 2013-2018 zpydr
//  Copyright (C) 2020 c0ldplasma
//
//  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/>.
//

const Lang = imports.lang;

function Windows(callBackThis, callbackWindowsListChanged, callbackWindowChanged) {
	this.init(callBackThis, callbackWindowsListChanged, callbackWindowChanged);
}

Windows.prototype = {
	workspace: null,
	windowsList: [],
	callBackThis: null,
	callbackWindowsListChanged: null,
	callbackWindowChanged: null,
	workspaceSwitchSignal: null,
	windowAddedSignal: null,
	windowRemovedSignal: null,
	windowsSignals: [],

	init: function(callBackThis, callbackWindowsListChanged, callbackWindowChanged) {
		//Set User Callback
		this.callBackThis = callBackThis;
		this.callbackWindowsListChanged = callbackWindowsListChanged;
		this.callbackWindowChanged = callbackWindowChanged;

		//Init WindowsList
		this.workspaceSignals = new Map();
		this.buildWindowsList();
		this.onWorkspaceChanged();



		//Add window manager signals
		this.workspaceSwitchSignal = global.workspace_manager.connect('workspace-switched', Lang.bind(this, this.buildWindowsList));
		this.nWorkspacesSignal = global.workspace_manager.connect('notify::n-workspaces', Lang.bind(this, this.onWorkspaceChanged));
	},

	destruct: function() {
		//Remove window manager signals
		let numWorkspaces = global.workspace_manager.n_workspaces;
		for (let i = 0; i < numWorkspaces; i++) {
			let workspace = global.workspace_manager.get_workspace_by_index(i);
			let signals = this.workspaceSignals.get(workspace);
			this.workspaceSignals.delete(workspace);
			workspace.disconnect(signals.windowAddedId);
			workspace.disconnect(signals.windowRemovedId);
		}

		//Clean windows list
		this.cleanWindowsList();
	},

	onWorkspaceChanged: function() {
		let numWorkspaces = global.workspace_manager.n_workspaces;
		for (let i = 0; i < numWorkspaces; i++) {
			let workspace = global.workspace_manager.get_workspace_by_index(i);
			if (this.workspaceSignals.has(workspace))
				continue;
			let signals = {
				windowAddedId: 0,
				windowRemovedId: 0
			};
			signals.windowAddedId = workspace.connect_after('window-added', Lang.bind(this, this.buildWindowsList));
			signals.windowRemovedId = workspace.connect('window-removed', Lang.bind(this, this.buildWindowsList));
			this.workspaceSignals.set(workspace, signals);
		}
	},

	buildWindowsList: function() {
		//Clean windows list
		this.cleanWindowsList();

		//Build windows list
		let totalWorkspaces = global.workspace_manager.n_workspaces;
		for (let i = 0; i < totalWorkspaces; i++) {
			let activeWorkspace = global.workspace_manager.get_workspace_by_index(i);
			activeWorkspace.list_windows().sort(this.sortWindowsCompareFunction).forEach(
				function(window) {
					this.addWindowInList(window);
				},
				this
			);
		}

		//Call User Callback
		this.callbackWindowsListChanged.call(this.callBackThis, this.windowsList, 0, null);
	},

	sortWindowsCompareFunction: function(windowA, windowB) {
		return windowA.get_stable_sequence() > windowB.get_stable_sequence();
	},

	onWindowChanged: function(window, object, type) {
		if (type === 0) { //Focus changed
			if (window.appears_focused) {
				this.callbackWindowChanged.call(this.callBackThis, window, 0);
            }
		} else if (type === 1) { //Title changed
			this.callbackWindowChanged.call(this.callBackThis, window, 1);
        } else if (type === 2) { //Minimized
			this.callbackWindowChanged.call(this.callBackThis, window, 2);
        } else if (type === 3) { //Icon
			this.callbackWindowChanged.call(this.callBackThis, window, 3);
        } else if (type === 4) { //Icon
			this.callbackWindowChanged.call(this.callBackThis, window, 4);
        }
	},

	searchWindowInList: function(window) {
		let index = null;
		for (let indexWindow in this.windowsList) {
			if (this.windowsList[indexWindow] === window) {
				index = indexWindow;
				break;
			}
		}
		return index;
	},

	addWindowInList: function(window) {
		let index = this.searchWindowInList(window);
		if (index === null && !window.is_skip_taskbar()) {
			this.windowsList.push(window);

			//Add window signals
			let objectAndSignals = [
				window, [
					window.connect('notify::appears-focused', Lang.bind(this, this.onWindowChanged, 0)),
					window.connect('notify::title', Lang.bind(this, this.onWindowChanged, 1)),
					window.connect('notify::minimized', Lang.bind(this, this.onWindowChanged, 2)),
					window.connect('notify::wm-class', Lang.bind(this, this.onWindowChanged, 3)),
					window.connect('notify::gtk-application-id', Lang.bind(this, this.onWindowChanged, 4))
				]
			];
			this.windowsSignals.push(objectAndSignals);
			return true;
		} else
			return false;
	},

	removeWindowInList: function(window) {
		let index = this.searchWindowInList(window);
		if (index !== null) {
			this.windowsList.splice(index, 1);

			//Remove window signals
			for (let indexSignal in this.windowsSignals) {
				let [object, signals] = this.windowsSignals[indexSignal];
				if (object === window) {
					signals.forEach(
						function(signal) {
							object.disconnect(signal);
						},
						this
					);
					this.windowsSignals.splice(indexSignal, 1);
					break;
				}
			}
			return true;
		} else
			return false;
	},

	cleanWindowsList: function() {
		for (let i = this.windowsList.length - 1; i >= 0; i--)
			this.removeWindowInList(this.windowsList[i]);
	}
}