+ edit: function (createTimestamp: string, newDescription: string): Element | null {
+ const target = this.getTask(createTimestamp);
+ if (!target) return null;
+ if (target.hasAttribute("data-description")) {
+ // Oh no: An edit has arrived from a replica while a local edit is in progress.
+ const input = target.children[0] as HTMLInputElement;
+ if (
+ input.value === target.getAttribute("data-description") &&
+ input.selectionStart === 0 &&
+ input.selectionEnd === input.value.length
+ ) {
+ // No local changes have actually been made yet. Change the contents of the edit box!
+ input.value = newDescription;
+ input.select();
+ } else {
+ // No great options.
+ // Prefer not to interrupt the local user's edit.
+ // The remote edit is mostly lost; this mostly becomes last-write-wins.
+ target.setAttribute("data-description", newDescription);
+ }
+ } else {
+ target.textContent = newDescription;
+ }
+ return target;
+ },
+
+ getPriority: function (task: Element): number {
+ if (task.hasAttribute("data-priority")) {
+ return parseFloat(task.getAttribute("data-priority")!);
+ }
+ return parseFloat(task.getAttribute("data-created")!);
+ },
+
+ getState: function (task: Element): string {
+ return task.getAttribute("data-state") ?? "todo";
+ },
+
+ getTask: function (createTimestamp: string) {
+ for (const task of document.getElementsByClassName("task")) {
+ if (task.getAttribute("data-created") === createTimestamp) {
+ return task;
+ }
+ }
+ },
+
+ setPriority: function (createTimestamp: string, priority: number): Element | null {
+ const target = this.getTask(createTimestamp);
+ if (!target) return null;
+ target.setAttribute("data-priority", `${priority}`);
+ for (const task of document.getElementsByClassName("task")) {
+ if (task !== target && this.getPriority(task) > priority) {
+ task.parentElement!.insertBefore(target, task);
+ return target;
+ }
+ }
+ document.getElementById("tasks")!.appendChild(target);
+ return target;
+ },
+
+ setState: function (stateTimestamp: string, createTimestamp: string, state: string) {
+ const task = this.getTask(createTimestamp);
+ if (task) {
+ task.setAttribute("data-state", state);
+ if (task instanceof HTMLElement) {
+ task.style.display = state == "todo" ? "block" : "none"; // Until view filtering
+ }
+ }
+ },
+};
+
+function Log(prefix: string = "vp-") {
+ var next_log_index = 0;
+ return {
+ apply: function (entry: string) {
+ const [timestamp, command, data] = splitN(entry, " ", 2);
+ if (command == "Create") {
+ return Model.addTask(timestamp, data);
+ }
+ if (command == "Edit") {
+ const [createTimestamp, description] = splitN(data, " ", 1);
+ return Model.edit(createTimestamp, description);
+ }
+ if (command == "State") {
+ const [createTimestamp, state] = splitN(data, " ", 1);
+ return Model.setState(timestamp, createTimestamp, state);
+ }
+ if (command == "Priority") {
+ const [createTimestamp, newPriority] = splitN(data, " ", 1);
+ return Model.setPriority(createTimestamp, parseFloat(newPriority));
+ }
+ },
+
+ record: function (entry: string) {
+ window.localStorage.setItem(`${prefix}${next_log_index++}`, entry);
+ },
+
+ recordAndApply: function (entry: string) {
+ this.record(entry);
+ return this.apply(entry);
+ },
+
+ replay: function () {
+ while (true) {
+ const entry = window.localStorage.getItem(`${prefix}${next_log_index}`);
+ if (entry === null) {
+ break;
+ }
+ this.apply(entry);
+ next_log_index++;
+ }
+ },
+ };
+}
+const log = Log();
+
+const undoLog: string[] = [];
+
+const UI = {
+ addTask: function (description: string): Element {
+ const now = Date.now();
+ undoLog.push(`State ${now} deleted`);
+ return <Element>log.recordAndApply(`${now} Create ${description}`);
+ },
+ edit: function (createTimestamp: string, newDescription: string, oldDescription: string) {
+ undoLog.push(`Edit ${createTimestamp} ${oldDescription}`);
+ return log.recordAndApply(`${Date.now()} Edit ${createTimestamp} ${newDescription}`);
+ },
+ setPriority: function (createTimestamp: string, newPriority: number, oldPriority: number) {
+ undoLog.push(`Priority ${createTimestamp} ${oldPriority}`);
+ return log.recordAndApply(`${Date.now()} Priority ${createTimestamp} ${newPriority}`);
+ },
+ setState: function (createTimestamp: string, newState: string, oldState: string) {
+ undoLog.push(`State ${createTimestamp} ${oldState}`);
+ return log.recordAndApply(`${Date.now()} State ${createTimestamp} ${newState}`);
+ },
+ undo: function () {
+ if (undoLog.length > 0) {
+ return log.recordAndApply(`${Date.now()} ${undoLog.pop()}`);
+ }
+ },
+};
+
+const BrowserUI = {
+ addTask: function (event: KeyboardEvent) {
+ const input = <HTMLInputElement>document.getElementById("taskName");
+ if (input.value) {
+ const task = UI.addTask(input.value);
+ if (task && task instanceof HTMLElement) task.focus();
+ input.value = "";
+ if (event.getModifierState("Control")) {
+ this.setPriority(task, null, document.getElementsByClassName("task")[0]);
+ }
+ }
+ },
+
+ beginEdit: function (event: Event) {
+ const task = document.activeElement;
+ if (!task) return;
+ const input = document.createElement("input");
+ const oldDescription = task.textContent!;
+ task.setAttribute("data-description", oldDescription);
+ input.value = oldDescription;
+ input.addEventListener("blur", BrowserUI.completeEdit, { once: true });
+ task.textContent = "";
+ task.appendChild(input);
+ input.focus();
+ input.select();
+ event.preventDefault();
+ },
+
+ completeEdit: function (event: Event) {
+ const input = event.target as HTMLInputElement;
+ const task = input.parentElement!;
+ const oldDescription = task.getAttribute("data-description")!;
+ const newDescription = input.value;
+ input.removeEventListener("blur", BrowserUI.completeEdit);
+ task.removeChild(task.children[0]);
+ task.removeAttribute("data-description");
+ task.focus();
+ if (newDescription === oldDescription) {
+ task.textContent = oldDescription;
+ } else {
+ UI.edit(task.getAttribute("data-created")!, newDescription, oldDescription);
+ }
+ },
+
+ firstVisibleTask: function () {
+ for (const task of document.getElementsByClassName("task")) {
+ if (task instanceof HTMLElement && task.style.display !== "none") {
+ return task;
+ }
+ }
+ },
+
+ focusTaskNameInput: function (event: Event) {
+ document.getElementById("taskName")!.focus();
+ event.preventDefault();
+ },
+
+ visibleTaskAtOffset(task: Element, offset: number): Element {
+ var cursor: Element | null = task;
+ var valid_cursor = cursor;
+ const increment = offset / Math.abs(offset);
+ while (true) {
+ cursor = increment > 0 ? cursor.nextElementSibling : cursor.previousElementSibling;
+ if (!cursor || !(cursor instanceof HTMLElement)) break;
+ if (cursor.style.display !== "none") {
+ offset -= increment;
+ valid_cursor = cursor;
+ }
+ if (Math.abs(offset) < 0.5) break;
+ }
+ return valid_cursor;