+const log = Log();
+
+const UI = {
+ addTask: function (description: string): Element {
+ return <Element>log.recordAndApply(`${Date.now()} Create ${description}`);
+ },
+ setPriority: function (createTimestamp: string, priority: number) {
+ return log.recordAndApply(`${Date.now()} Priority ${createTimestamp} ${priority}`);
+ },
+ setState: function (createTimestamp: string, state: string) {
+ return log.recordAndApply(`${Date.now()} State ${createTimestamp} ${state}`);
+ },
+};
+
+const BrowserUI = {
+ addTask: function (event: KeyboardEvent) {
+ const input = <HTMLInputElement>document.getElementById("taskName");
+ if (input.value) {
+ const task = UI.addTask(input.value);
+ input.value = "";
+ if (event.getModifierState("Control")) {
+ this.setPriority(task, null, document.getElementsByClassName("task")[0]);
+ }
+ }
+ },
+
+ 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;
+ },
+
+ moveCursor: function (offset: number): boolean {
+ const active = document.activeElement;
+ if (!active) return false;
+ const dest = this.visibleTaskAtOffset(active, offset);
+ if (dest !== active && dest instanceof HTMLElement) {
+ dest.focus();
+ return true;
+ }
+ return false;
+ },
+
+ moveTask: function (offset: number) {
+ const active = document.activeElement;
+ if (!active) return;
+ const dest = this.visibleTaskAtOffset(active, offset);
+ if (dest === active) return; // Already extremal
+ var onePastDest: Element | null = this.visibleTaskAtOffset(dest, offset / Math.abs(offset));
+ if (onePastDest == dest) onePastDest = null; // Will become extremal
+ if (offset > 0) {
+ this.setPriority(active, dest, onePastDest);
+ } else {
+ this.setPriority(active, onePastDest, dest);
+ }
+ },
+
+ // Change task's priority to be between other tasks a and b.
+ setPriority: function (task: Element, a: Element | null, b: Element | null) {
+ const aPriority = a === null ? 0 : Model.getPriority(a);
+ const bPriority = b === null ? Date.now() : Model.getPriority(b);
+ console.assert(aPriority < bPriority, aPriority, "<", bPriority);
+ const span = bPriority - aPriority;
+ const newPriority = aPriority + 0.1 * span + 0.8 * span * Math.random();
+ console.assert(aPriority < newPriority && newPriority < bPriority, aPriority, "<", newPriority, "<", bPriority);
+ const newPriorityRounded = Math.round(newPriority);
+ const okToRound = aPriority < newPriorityRounded && newPriorityRounded < bPriority;
+ UI.setPriority(task.getAttribute("data-created")!, okToRound ? newPriorityRounded : newPriority);
+ },
+
+ setState: function (state: string) {
+ const createTimestamp = document.activeElement?.getAttribute("data-created");
+ this.moveCursor(1) || this.moveCursor(-1);
+ return UI.setState(createTimestamp!, state);
+ },
+};