class ProjectManager extends Listenable {
	constructor() {
		super();

		this.projectListeners = { };
		this.projects = { };
		
		this.loadProjectsRequest = new Request(TimeCards.REQUEST_URI + "Projects", Request.GET, this.loadedProjects.bind(this), this.projectLoadingError.bind(this));
		this.loadProjectsInterval = setInterval(this.loadProjects.bind(this), 60000);
		this.loadProjects();

		this.deleteProjectRequest = new Request(TimeCards.REQUEST_URI + "Project/Delete", Request.POST, this.deletedProject.bind(this), this.projectDeletionError.bind(this));
		this.createProjectRequest = new Request(TimeCards.REQUEST_URI + "Project/Create", Request.POST, this.createdProject.bind(this), this.projectCreationError.bind(this));
		this.updateProjectRequest = new Request(TimeCards.REQUEST_URI + "Project", Request.POST, this.updatedProject.bind(this), this.projectUpdatingError.bind(this));
	}

	performInitialCalls(eventType, callback) {
		if (eventType == "projectadded") {
			for (var projectId in this.projects) {
				var addedProject = this.projects[projectId];

				var projectAddedEvent = new Event("projectadded");
				projectAddedEvent.project = addedProject;
				callback(projectAddedEvent);
			}
		}
	}

	loadProjects() {
		if (this.loadProjectsRequest.ready) {
			this.loadProjectsRequest.send();
		}
	}

	loadedProjects(projects) {
		//Check for deleted and updated projects.
		for (var projectId in this.projects) {
			var localProject = this.projects[projectId];

			if (!(projectId in projects)) {
				this.callProjectListeners(projectId, null);

				var projectDeletedEvent = new Event("projectremoved");
				projectDeletedEvent.project = localProject;
				this.dispatchEvent(projectDeletedEvent);
				continue;
			}

			var remoteProject = projects[projectId];
			if (!Object.equals(localProject, remoteProject)) {
				this.callProjectListeners(projectId, remoteProject);

				var projectChangedEvent = new Event("projectchanged");
				projectChangedEvent.project = remoteProject;
				this.dispatchEvent(projectChangedEvent);
			}
		}

		//Check for new projects.
		for (var projectId in projects) {
			if (!(projectId in this.projects)) {
				this.callProjectListeners(projectId, projects[projectId]);

				var projectAddedEvent = new Event("projectadded");
				projectAddedEvent.project = projects[projectId];
				this.dispatchEvent(projectAddedEvent);
			}
		}

		this.projects = projects;
	}

	projectLoadingError(request, status, error) {
		alert("Error during the loading of the projects:\r\n\r\n" + JSON.stringify(error, true));
	}

	/**
	 * Attempts to delete the given project on the server side.
	 */
	deleteProject(project) {
		this.deleteProjectRequest.send(project);
	}

	deletedProject(response) {
		this.callProjectListeners(response.project_id, null);

		var projectDeletedEvent = new Event("projectremoved");
		projectDeletedEvent.project = this.projects[response.project_id];
		this.dispatchEvent(projectDeletedEvent);

		delete this.projects[response.project_id];

		//Remove the project from all users locally.
		var roles = TimeCards.userManager.roles;
		for (var roleId in roles) {
			for (var userId in roles[roleId].users) {
				var user = roles[roleId].users[userId];

				if (user.projects && (response.project_id in user.projects)) {
					delete roles[roleId].users[userId].projects[response.project_id];
				}
			}
		}
		TimeCards.userManager.loadedUsers(roles);
	}

	projectDeletionError(request, status, error) {
		alert("Error during the deletion of the project:\r\n\r\n" + JSON.stringify(error, true));
	}

	/**
	 * Attempts to create a project with the given data on the server side.
	 */
	createProject(project) {
		this.createProjectRequest.send(project);
	}

	createdProject(response) {
		this.projects[response.project_id] = response;

		var projectAddedEvent = new Event("projectadded");
		projectAddedEvent.project = response;
		this.dispatchEvent(projectAddedEvent);
	}

	projectCreationError(request, status, error) {
		alert("Error during the creation of the project:\r\n\r\n" + JSON.stringify(error, true));
	}

	/**
	 * Attempts to save the given project data on the server.
	 */
	updateProject(project) {
		this.updateProjectRequest.send(project);
	}

	updatedProject(response) {
		this.projects[response.project_id] = response;

		this.callProjectListeners(response.project_id, response);

		var projectChangedEvent = new Event("projectchanged");
		projectChangedEvent.project = response;
		this.dispatchEvent(projectChangedEvent);
	}

	projectUpdatingError(request, status, error) {
		alert("Error while updating the project:\r\n\r\n" + JSON.stringify(error, true));
	}

	/**
	 * The project listeners are called when a specific project is loaded initially or when it has changed.
	 * The listeners are also called when the project was deleted, but with null instead of the project as a parameter.
	 */
	addProjectListener(projectId, callback) {
		if (!(projectId in this.projectListeners)) {
			this.projectListeners[projectId] = [ ];
		}

		if (this.projectListeners[projectId].indexOf(callback) == -1) {
			this.projectListeners[projectId].push(callback);

			if (projectId in this.projects) {
				callback(this.projects[projectId]);
			}
		}
	}

	removeProjectListener(projectId, callback) {
		if (!(projectId in this.projectListeners)) {
			return;
		}

		var index = this.projectListeners[projectId].indexOf(callback);
		if (index != -1) {
			this.projectListeners[projectId].splice(index, 1);
		}
	}

	callProjectListeners(projectId, projectData) {
		if (!(projectId in this.projectListeners)) {
			return;
		}

		var listeners = this.projectListeners[projectId];
		for (var i = 0; i < listeners.length; i++) {
			listeners[i](projectData);
		}
	}

	getProjectByKey(projectId) {
		if (projectId in this.projects) {
			return this.projects[projectId];
		}

		return null;
	}
}