X-Git-Url: http://git.scottworley.com/vopamoi/blobdiff_plain/6d01c40696f0612a6352f21320f417ccf528ab40..e0c49063e71dd24fce0f57a5e9ad1287b8073341:/vopamoi.ts?ds=sidebyside

diff --git a/vopamoi.ts b/vopamoi.ts
index ba5ae85..926a1f0 100644
--- a/vopamoi.ts
+++ b/vopamoi.ts
@@ -13,65 +13,189 @@ function splitN(str: string, delimiter: string, limit: number = MAX_SAFE_INTEGER
   return at === -1 ? [str] : [str.substring(0, at)].concat(splitN(str.substring(at + delimiter.length), delimiter, limit - 1));
 }
 
-const Model = {
-  addTask: function (timestamp: string, description: string): Element {
-    const task = document.createElement("div");
-    task.appendChild(document.createTextNode(description));
-    task.setAttribute("class", "task");
-    task.setAttribute("tabindex", "0");
-    task.setAttribute("data-created", timestamp);
-    document.getElementById("tasks")!.appendChild(task);
-    task.focus();
-    return task;
-  },
-
-  destroyTask: function (createTimestamp: string) {
-    const task = this.getTask(createTimestamp);
-    if (task) {
-      task.parentElement!.removeChild(task);
-    }
-  },
+// A clock that never goes backwards; monotonic.
+function Clock() {
+  var previousNow = Date.now();
+  return {
+    now: function (): number {
+      const now = Date.now();
+      if (now > previousNow) {
+        previousNow = now;
+        return now;
+      }
+      return ++previousNow;
+    },
+  };
+}
+const clock = Clock();
 
-  getPriority: function (task: Element): number {
-    if (task.hasAttribute("data-priority")) {
-      return parseFloat(task.getAttribute("data-priority")!);
-    }
-    return parseFloat(task.getAttribute("data-created")!);
-  },
+// Returns a promise for a hue based on a hash of the string
+function hashHue(str: string) {
+  // Using crypto for this is overkill
+  return crypto.subtle.digest("SHA-256", new TextEncoder().encode(str)).then((buf) => (new Uint16Array(buf)[0] * 360) / 2 ** 16);
+}
+
+function Model() {
+  return {
+    addTask: function (timestamp: string, description: string): Element {
+      const task = document.createElement("div");
+      const desc = document.createElement("span");
+      desc.textContent = description;
+      desc.classList.add("desc");
+      task.appendChild(desc);
+      task.classList.add("task");
+      task.setAttribute("tabindex", "0");
+      task.setAttribute("id", timestamp);
+      task.setAttribute("data-state", "todo");
+      const tasks = document.getElementById("tasks")!;
+      tasks.insertBefore(task, tasks.firstElementChild);
+      return task;
+    },
 
-  getTask: function (createTimestamp: string) {
-    for (const task of document.getElementsByClassName("task")) {
-      if (task.getAttribute("data-created") === createTimestamp) {
-        return task;
+    addTag: function (createTimestamp: string, tagName: string): Element | null {
+      const task = this.getTask(createTimestamp);
+      if (!task) return null;
+      const existingTag = this.hasTag(task, tagName);
+      if (existingTag) return existingTag;
+      const tag = document.createElement("span");
+      tag.appendChild(document.createTextNode(tagName));
+      tag.classList.add("tag");
+      tag.setAttribute("tabindex", "0");
+      hashHue(tagName).then((hue) => (tag.style.backgroundColor = `hsl(${hue},90%,45%)`));
+      for (const child of task.getElementsByClassName("tag")) {
+        if (tagName > child.textContent!) {
+          task.insertBefore(tag, child);
+          return tag;
+        }
       }
-    }
-  },
-
-  setPriority: function (createTimestamp: string, priority: number) {
-    const target = this.getTask(createTimestamp);
-    if (!target) return;
-    target.setAttribute("data-priority", `${priority}`);
-    for (const task of document.getElementsByClassName("task")) {
-      if (task !== target && this.getPriority(task) > priority) {
-        task.parentElement!.insertBefore(target, task);
-        target instanceof HTMLElement && target.focus();
-        return;
+      task.insertBefore(tag, task.getElementsByClassName("desc")[0]!);
+      return tag;
+    },
+
+    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.getElementsByTagName("input")[0]!;
+        if (
+          input.value === target.getAttribute("data-description") &&
+          input.selectionStart === input.value.length &&
+          input.selectionEnd === input.value.length
+        ) {
+          // No local changes have actually been made yet.  Change the contents of the edit box!
+          input.value = newDescription;
+        } 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.getElementsByClassName("desc")[0].textContent = newDescription;
       }
-    }
-    document.getElementById("tasks")!.appendChild(target);
-    target instanceof HTMLElement && target.focus();
-  },
+      return target;
+    },
 
-  setState: function (stateTimestamp: string, createTimestamp: string, state: string) {
-    const task = this.getTask(createTimestamp);
-    if (task) {
-      task.setAttribute(`data-${state}`, stateTimestamp);
-      if (task instanceof HTMLElement) {
-        task.style.display = "none"; // Until view filtering
+    editContent: function (createTimestamp: string, newContent: string): Element | null {
+      const target = this.getTask(createTimestamp);
+      if (!target) return null;
+      if (target.hasAttribute("data-content")) {
+        // Oh no: An edit has arrived from a replica while a local edit is in progress.
+        const input = target.getElementsByTagName("textarea")[0]!;
+        if (
+          input.value === target.getAttribute("data-content") &&
+          input.selectionStart === input.value.length &&
+          input.selectionEnd === input.value.length
+        ) {
+          // No local changes have actually been made yet.  Change the contents of the edit box!
+          input.value = newContent;
+        } 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-content", newContent);
+        }
+      } else {
+        var content = target.getElementsByClassName("content")[0];
+        if (!content) {
+          content = document.createElement("div");
+          content.classList.add("content");
+          target.appendChild(content);
+        }
+        content.textContent = newContent;
       }
-    }
-  },
-};
+      return target;
+    },
+
+    hasTag: function (task: Element, tag: string): Element | null {
+      for (const child of task.getElementsByClassName("tag")) {
+        if (child.textContent === tag) {
+          return child;
+        }
+      }
+      return null;
+    },
+
+    getPriority: function (task: Element): number {
+      if (task.hasAttribute("data-priority")) {
+        return parseFloat(task.getAttribute("data-priority")!);
+      }
+      return parseFloat(task.getAttribute("id")!);
+    },
+
+    getTask: function (createTimestamp: string) {
+      return document.getElementById(createTimestamp);
+    },
+
+    insertInPriorityOrder: function (task: Element, dest: Element) {
+      const priority = this.getPriority(task);
+      for (const t of dest.children) {
+        if (t !== task && this.getPriority(t) < priority) {
+          dest.insertBefore(task, t);
+          return;
+        }
+      }
+      dest.appendChild(task);
+    },
+
+    removeTag: function (createTimestamp: string, tagName: string) {
+      const task = this.getTask(createTimestamp);
+      if (!task) return null;
+      const tag = this.hasTag(task, tagName);
+      if (!tag) return;
+      task.removeChild(tag);
+      if (task instanceof HTMLElement) task.focus();
+    },
+
+    setPriority: function (createTimestamp: string, priority: number): Element | null {
+      const target = this.getTask(createTimestamp);
+      if (!target) return null;
+      target.setAttribute("data-priority", `${priority}`);
+      this.insertInPriorityOrder(target, target.parentElement!);
+      return target;
+    },
+
+    setState: function (stateTimestamp: string, createTimestamp: string, state: string) {
+      const task = this.getTask(createTimestamp);
+      if (!task) return;
+      task.setAttribute("data-state", state);
+      var date = task.getElementsByClassName("statedate")[0];
+      if (state === "todo") {
+        task.removeChild(date);
+        return;
+      }
+      if (!date) {
+        date = document.createElement("span");
+        date.classList.add("statedate");
+        task.insertBefore(date, task.firstChild);
+      }
+      const d = new Date(parseInt(stateTimestamp));
+      date.textContent = `${d.getFullYear()}-${`${d.getMonth() + 1}`.padStart(2, "0")}-${`${d.getDate()}`.padStart(2, "0")}`;
+    },
+  };
+}
+const model = Model();
 
 function Log(prefix: string = "vp-") {
   var next_log_index = 0;
@@ -79,18 +203,31 @@ function Log(prefix: string = "vp-") {
     apply: function (entry: string) {
       const [timestamp, command, data] = splitN(entry, " ", 2);
       if (command == "Create") {
-        return Model.addTask(timestamp, data);
+        return model.addTask(timestamp, data);
       }
-      if (command == "Destroy") {
-        return Model.destroyTask(data.split(" ", 1)[0]);
+      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 == "EditContent") {
+        const [createTimestamp, content] = splitN(data, " ", 1);
+        return model.editContent(createTimestamp, content);
       }
       if (command == "Priority") {
         const [createTimestamp, newPriority] = splitN(data, " ", 1);
-        return Model.setPriority(createTimestamp, parseFloat(newPriority));
+        return model.setPriority(createTimestamp, parseFloat(newPriority));
+      }
+      if (command == "State") {
+        const [createTimestamp, state] = splitN(data, " ", 1);
+        return model.setState(timestamp, createTimestamp, state);
+      }
+      if (command == "Tag") {
+        const [createTimestamp, tag] = splitN(data, " ", 1);
+        return model.addTag(createTimestamp, tag);
+      }
+      if (command == "Untag") {
+        const [createTimestamp, tag] = splitN(data, " ", 1);
+        return model.removeTag(createTimestamp, tag);
       }
     },
 
@@ -104,6 +241,7 @@ function Log(prefix: string = "vp-") {
     },
 
     replay: function () {
+      document.getElementById("tasks")!.style.display = "none";
       while (true) {
         const entry = window.localStorage.getItem(`${prefix}${next_log_index}`);
         if (entry === null) {
@@ -112,125 +250,559 @@ function Log(prefix: string = "vp-") {
         this.apply(entry);
         next_log_index++;
       }
+      document.getElementById("tasks")!.style.display = "";
     },
   };
 }
 const log = Log();
 
-const UI = {
-  addTask: function (description: string): Element {
-    return <Element>log.recordAndApply(`${Date.now()} Create ${description}`);
-  },
-  destroyTask: function (createTimestamp: string) {
-    return log.recordAndApply(`${Date.now()} Destroy ${createTimestamp} ${Model.getTask(createTimestamp)?.textContent}`);
-  },
-  setPriority: function (createTimestamp: string, priority: number) {
-    return log.recordAndApply(`${Date.now()} Priority ${createTimestamp} ${priority}`);
-  },
-  setState: function (createTimestamp: string, state: string) {
-    return log.recordAndApply(`${Date.now()} State ${createTimestamp} ${state}`);
-  },
-};
-
-const BrowserUI = {
-  addTask: function () {
-    const input = <HTMLInputElement>document.getElementById("taskName");
-    if (input.value) {
-      const task = UI.addTask(input.value);
+function UI() {
+  const undoLog: string[][] = [];
+  const redoLog: string[][] = [];
+  function perform(forward: string, reverse: string) {
+    undoLog.push([reverse, forward]);
+    return log.recordAndApply(`${clock.now()} ${forward}`);
+  }
+  return {
+    addTask: function (description: string): Element {
+      const now = clock.now();
+      undoLog.push([`State ${now} deleted`, `State ${now} todo`]);
+      return <Element>log.recordAndApply(`${now} Create ${description}`);
+    },
+    addTag: function (createTimestamp: string, tag: string) {
+      return perform(`Tag ${createTimestamp} ${tag}`, `Untag ${createTimestamp} ${tag}`);
+    },
+    edit: function (createTimestamp: string, newDescription: string, oldDescription: string) {
+      return perform(`Edit ${createTimestamp} ${newDescription}`, `Edit ${createTimestamp} ${oldDescription}`);
+    },
+    editContent: function (createTimestamp: string, newContent: string, oldContent: string) {
+      return perform(`EditContent ${createTimestamp} ${newContent}`, `EditContent ${createTimestamp} ${oldContent}`);
+    },
+    removeTag: function (createTimestamp: string, tag: string) {
+      return perform(`Untag ${createTimestamp} ${tag}`, `Tag ${createTimestamp} ${tag}`);
+    },
+    setPriority: function (createTimestamp: string, newPriority: number, oldPriority: number) {
+      return perform(`Priority ${createTimestamp} ${newPriority}`, `Priority ${createTimestamp} ${oldPriority}`);
+    },
+    setState: function (createTimestamp: string, newState: string, oldState: string) {
+      return perform(`State ${createTimestamp} ${newState}`, `State ${createTimestamp} ${oldState}`);
+    },
+    undo: function () {
+      const entry = undoLog.pop();
+      if (entry) {
+        redoLog.push(entry);
+        return log.recordAndApply(`${clock.now()} ${entry[0]}`);
+      }
+    },
+    redo: function () {
+      const entry = redoLog.pop();
+      if (entry) {
+        undoLog.push(entry);
+        return log.recordAndApply(`${clock.now()} ${entry[1]}`);
+      }
+    },
+  };
+}
+const ui = UI();
+
+enum CommitOrAbort {
+  Commit,
+  Abort,
+}
+
+interface TagFilter {
+  description: string;
+  include: (task: Element) => boolean;
+}
+
+function BrowserUI() {
+  const viewColors: { [key: string]: string } = {
+    all: "Gold",
+    cancelled: "Red",
+    deleted: "Black",
+    done: "LawnGreen",
+    "someday-maybe": "DeepSkyBlue",
+    todo: "White",
+    waiting: "MediumOrchid",
+  };
+  var currentTagFilter: TagFilter | null = null;
+  var currentViewState = "todo";
+  var taskFocusedBeforeJumpingToInput: HTMLElement | null = null;
+  var lastTagNameEntered = "";
+  return {
+    addTask: function (event: KeyboardEvent) {
+      const input = <HTMLInputElement>document.getElementById("taskName");
+      if (input.value.match(/^ *$/)) return;
+      const task = ui.addTask(input.value);
+      if (currentViewState === "todo" || currentViewState === "all") {
+        task instanceof HTMLElement && task.focus();
+      } else if (this.returnFocusAfterInput()) {
+      } else {
+        this.firstVisibleTask()?.focus();
+      }
       input.value = "";
-    }
-  },
-
-  destroyTask: function () {
-    const createTimestamp = document.activeElement?.getAttribute("data-created");
-    this.moveCursor(1) || this.moveCursor(-1);
-    return UI.destroyTask(createTimestamp!);
-  },
-
-  focusTaskNameInput: function (event: any) {
-    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);
-  },
-};
+      if (event.getModifierState("Control")) {
+        this.makeBottomPriority(task);
+      }
+    },
+
+    beginEdit: function (event: Event) {
+      const task = this.currentTask();
+      if (!task) return;
+      const input = document.createElement("input");
+      const desc = task.getElementsByClassName("desc")[0];
+      const oldDescription = desc.textContent!;
+      task.setAttribute("data-description", oldDescription);
+      input.value = oldDescription;
+      input.addEventListener("blur", this.completeEdit, { once: true });
+      desc.textContent = "";
+      task.insertBefore(input, task.firstChild);
+      input.focus();
+      event.preventDefault();
+    },
+
+    beginEditContent: function (event: Event) {
+      const task = this.currentTask();
+      if (!task) return;
+      const input = document.createElement("textarea");
+      const content = task.getElementsByClassName("content")[0];
+      const oldContent = content?.textContent ?? "";
+      task.setAttribute("data-content", oldContent);
+      input.value = oldContent;
+      input.addEventListener("blur", this.completeContentEdit, { once: true });
+      if (content) content.textContent = "";
+      task.appendChild(input);
+      input.focus();
+      event.preventDefault();
+    },
+
+    beginTagEdit: function (event: Event) {
+      const task = this.currentTask();
+      if (!task) return;
+      const input = document.createElement("input");
+      input.classList.add("tag");
+      input.addEventListener("blur", this.completeTagEdit, { once: true });
+      input.value = lastTagNameEntered;
+      task.appendChild(input);
+      input.focus();
+      input.select();
+      event.preventDefault();
+    },
+
+    completeEdit: function (event: Event, resolution: CommitOrAbort = CommitOrAbort.Commit) {
+      const input = event.target as HTMLInputElement;
+      const task = input.parentElement!;
+      const desc = task.getElementsByClassName("desc")[0];
+      const oldDescription = task.getAttribute("data-description")!;
+      const newDescription = input.value;
+      input.removeEventListener("blur", this.completeEdit);
+      task.removeChild(input);
+      task.removeAttribute("data-description");
+      task.focus();
+      if (resolution === CommitOrAbort.Abort || newDescription.match(/^ *$/) || newDescription === oldDescription) {
+        desc.textContent = oldDescription;
+      } else {
+        ui.edit(task.getAttribute("id")!, newDescription, oldDescription);
+      }
+    },
+
+    completeContentEdit: function (event: Event, resolution: CommitOrAbort = CommitOrAbort.Commit) {
+      const input = event.target as HTMLInputElement;
+      const task = input.parentElement!;
+      const content = task.getElementsByClassName("content")[0];
+      const oldContent = task.getAttribute("data-content")!;
+      const newContent = input.value;
+      input.removeEventListener("blur", this.completeContentEdit);
+      task.removeChild(input);
+      task.removeAttribute("data-content");
+      task.focus();
+      if (resolution === CommitOrAbort.Abort || newContent === oldContent) {
+        if (content) content.textContent = oldContent;
+      } else {
+        ui.editContent(task.getAttribute("id")!, newContent, oldContent);
+      }
+    },
+
+    completeTagEdit: function (event: Event, resolution: CommitOrAbort = CommitOrAbort.Commit) {
+      const input = event.target as HTMLInputElement;
+      const task = input.parentElement!;
+      const newTagName = input.value;
+      input.removeEventListener("blur", this.completeTagEdit);
+      task.removeChild(input);
+      task.focus();
+      if (resolution === CommitOrAbort.Commit && !newTagName.match(/^ *$/) && !model.hasTag(task, newTagName)) {
+        ui.addTag(task.getAttribute("id")!, newTagName);
+        lastTagNameEntered = newTagName;
+      }
+    },
+
+    currentTag: function (): Element | null {
+      var target = document.activeElement;
+      if (!target) return null;
+      if (target.classList.contains("task")) {
+        const tags = target.getElementsByClassName("tag");
+        target = tags[tags.length - 1];
+      }
+      if (!target || !target.classList.contains("tag")) return null;
+      return target;
+    },
+
+    currentTask: function (): HTMLElement | null {
+      var target = document.activeElement;
+      if (!target) return null;
+      if (target.classList.contains("tag")) target = target.parentElement!;
+      if (!target.classList.contains("task")) return null;
+      return target as HTMLElement;
+    },
+
+    firstVisibleTask: function (root: Element | null = null) {
+      if (root === null) root = document.body;
+      for (const task of root.getElementsByClassName("task")) {
+        const state = task.getAttribute("data-state");
+        if (
+          task instanceof HTMLElement &&
+          (state === currentViewState || (currentViewState === "all" && state !== "deleted")) &&
+          !task.classList.contains("hide")
+        ) {
+          return task;
+        }
+      }
+    },
+
+    focusTaskNameInput: function (event: Event) {
+      taskFocusedBeforeJumpingToInput = this.currentTask();
+      document.getElementById("taskName")!.focus();
+      window.scroll(0, 0);
+      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;
+        const state = cursor.getAttribute("data-state")!;
+        if (
+          (state === currentViewState || (currentViewState === "all" && state !== "deleted")) &&
+          !cursor.classList.contains("hide")
+        ) {
+          offset -= increment;
+          valid_cursor = cursor;
+        }
+        if (Math.abs(offset) < 0.5) break;
+      }
+      return valid_cursor;
+    },
+
+    jumpCursor: function (position: number) {
+      const first = this.firstVisibleTask();
+      if (!first) return;
+      const dest = this.visibleTaskAtOffset(first, position - 1);
+      if (dest instanceof HTMLElement) dest.focus();
+    },
+
+    makeBottomPriority: function (task: Element | null = null) {
+      if (!task) task = this.currentTask();
+      if (!task) return;
+      this.setPriority(task, document.getElementById("tasks")!.lastElementChild, null);
+    },
+
+    makeTopPriority: function (task: Element | null = null) {
+      if (!task) task = this.currentTask();
+      if (!task) return;
+      ui.setPriority(task.getAttribute("id")!, clock.now(), model.getPriority(task));
+      task instanceof HTMLElement && task.focus();
+    },
+
+    moveCursorLeft: function () {
+      const active = this.currentTask();
+      if (!active) return false;
+      if (active.parentElement!.classList.contains("task")) {
+        active.parentElement!.focus();
+      }
+    },
+
+    moveCursorRight: function () {
+      const active = this.currentTask();
+      if (!active) return false;
+      (this.firstVisibleTask(active) as HTMLElement | null)?.focus();
+    },
+
+    moveCursorVertically: function (offset: number): boolean {
+      let active = this.currentTask();
+      if (!active) {
+        this.firstVisibleTask()?.focus();
+        active = this.currentTask();
+      }
+      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 = this.currentTask();
+      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);
+      }
+    },
+
+    removeTag: function () {
+      const target = this.currentTag();
+      if (!target) return;
+      ui.removeTag(target.parentElement!.getAttribute("id")!, target.textContent!);
+    },
+
+    resetTagView: function () {
+      currentTagFilter = null;
+      this.setTitle();
+      const taskList = document.getElementById("tasks")!;
+      for (const task of Array.from(document.getElementsByClassName("task"))) {
+        task.classList.remove("hide");
+        if (task.parentElement !== taskList) {
+          model.insertInPriorityOrder(task, taskList);
+        }
+      }
+    },
+
+    resetView: function () {
+      this.setView("todo");
+      this.resetTagView();
+    },
+
+    returnFocusAfterInput: function (): boolean {
+      if (taskFocusedBeforeJumpingToInput) {
+        taskFocusedBeforeJumpingToInput.focus();
+        return true;
+      }
+      return false;
+    },
+
+    // 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 ? clock.now() : model.getPriority(a);
+      const bPriority = b === null ? 0 : model.getPriority(b);
+      console.assert(aPriority > bPriority, aPriority, ">", bPriority);
+      const span = aPriority - bPriority;
+      const newPriority = bPriority + 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("id")!, okToRound ? newPriorityRounded : newPriority, model.getPriority(task));
+      task instanceof HTMLElement && task.focus();
+    },
+
+    setState: function (newState: string) {
+      const task = this.currentTask();
+      if (!task) return;
+      const oldState = task.getAttribute("data-state")!;
+      if (newState === oldState) return;
+      const createTimestamp = task.getAttribute("id")!;
+      if (currentViewState !== "all" || newState == "deleted") {
+        this.moveCursorVertically(1) || this.moveCursorVertically(-1);
+      }
+      return ui.setState(createTimestamp, newState, oldState);
+    },
+
+    setTagFilter: function (filter: TagFilter) {
+      if (currentTagFilter !== null) {
+        this.resetTagView();
+      }
+
+      const tasksWithTag = new Map();
+      for (const task of document.getElementsByClassName("task")) {
+        if (filter.include(task)) {
+          tasksWithTag.set(task.getElementsByClassName("desc")[0].textContent, [model.getPriority(task), task]);
+        }
+      }
+
+      function highestPrioritySuperTask(t: Element) {
+        var maxPriority = -1;
+        var superTask = null;
+        for (const child of t.getElementsByClassName("tag")) {
+          const e = tasksWithTag.get(child.textContent);
+          if (e !== undefined && e[0] > maxPriority) {
+            maxPriority = e[0];
+            superTask = e[1];
+          }
+        }
+        return superTask;
+      }
+
+      for (const task of Array.from(document.getElementsByClassName("task"))) {
+        if (filter.include(task)) {
+          task.classList.remove("hide");
+        } else {
+          const superTask = highestPrioritySuperTask(task);
+          if (superTask !== null) {
+            model.insertInPriorityOrder(task, superTask);
+          } else {
+            task.classList.add("hide");
+          }
+        }
+      }
+
+      currentTagFilter = filter;
+      this.setTitle();
+    },
+
+    setTagView: function (tag: string | null = null) {
+      if (tag === null) {
+        const target = this.currentTag();
+        if (!target) return;
+        tag = target.textContent!;
+      }
+      this.setTagFilter({description: tag, include: task => !!model.hasTag(task, tag!)});
+    },
+
+    setTitle: function () {
+      document.title = "Vopamoi: " + currentViewState + (currentTagFilter ? ": " + currentTagFilter.description : "");
+    },
+
+    setView: function (state: string) {
+      const sheet = (document.getElementById("viewStyle") as HTMLStyleElement).sheet!;
+      if (state === "all") {
+        sheet.insertRule(`.task[data-state=deleted] { display: none }`);
+      } else {
+        sheet.insertRule(`.task:not([data-state=${state}]) { display: none }`);
+      }
+      sheet.insertRule(`:root { --view-state-indicator-color: ${viewColors[state]}; }`);
+      sheet.removeRule(2);
+      sheet.removeRule(2);
+      currentViewState = state;
+      this.setTitle();
+      if (this.currentTask()?.getAttribute("data-state") !== state) {
+        this.firstVisibleTask()?.focus();
+      }
+    },
+
+    setUntaggedView: function () {
+      if (currentTagFilter !== null) {
+        this.resetTagView();
+      }
+      for (const task of document.getElementsByClassName("task")) {
+        if (task.getElementsByClassName("tag").length === 0) {
+          task.classList.remove("hide");
+        } else {
+          task.classList.add("hide");
+        }
+      }
+    },
+
+    undo: function () {
+      const ret = ui.undo();
+      if (ret && ret instanceof HTMLElement) ret.focus();
+    },
+    redo: function () {
+      const ret = ui.redo();
+      if (ret && ret instanceof HTMLElement) ret.focus();
+    },
+  };
+}
+const browserUI = BrowserUI();
+
+const scrollIncrement = 60;
+enum InputState {
+  Root,
+  S,
+  V,
+  VS,
+}
+var inputState = InputState.Root;
+var inputCount: number | null = null;
 
 function handleKey(event: any) {
-  if (event.target.tagName === "INPUT") {
-    if (event.key == "Enter") return BrowserUI.addTask();
+  if (["Alt", "Control", "Meta", "Shift"].includes(event.key)) return;
+  if (event.target.tagName === "TEXTAREA") {
+    if (event.key == "Enter" && event.ctrlKey) return browserUI.completeContentEdit(event);
+    if (event.key == "Escape") return browserUI.completeContentEdit(event, CommitOrAbort.Abort);
+  } else if (event.target.tagName === "INPUT") {
+    if (event.target.id === "taskName") {
+      if (event.key == "Enter") return browserUI.addTask(event);
+      if (event.key == "Escape") return browserUI.returnFocusAfterInput();
+    } else if (event.target.classList.contains("tag")) {
+      if (event.key == "Enter") return browserUI.completeTagEdit(event);
+      if (event.key == "Escape") return browserUI.completeTagEdit(event, CommitOrAbort.Abort);
+    } else {
+      if (event.key == "Enter") return browserUI.completeEdit(event);
+      if (event.key == "Escape") return browserUI.completeEdit(event, CommitOrAbort.Abort);
+    }
   } else {
-    if (event.key == "j") return BrowserUI.moveCursor(1);
-    if (event.key == "k") return BrowserUI.moveCursor(-1);
-    if (event.key == "J") return BrowserUI.moveTask(1);
-    if (event.key == "K") return BrowserUI.moveTask(-1);
-    if (event.key == "n") return BrowserUI.focusTaskNameInput(event);
-    if (event.key == "s") return BrowserUI.setState("someday-maybe");
-    if (event.key == "w") return BrowserUI.setState("waiting");
-    if (event.key == "d") return BrowserUI.setState("done");
-    if (event.key == "c") return BrowserUI.setState("cancelled");
-    if (event.key == "X") return BrowserUI.destroyTask();
+    if (inputState === InputState.Root) {
+      if ("0" <= event.key && event.key <= "9") {
+        return (inputCount = (inputCount ?? 0) * 10 + parseInt(event.key));
+      }
+      try {
+        if (event.ctrlKey) {
+          if (event.key == "e") return window.scrollBy(0, (inputCount ?? 1) * scrollIncrement);
+          if (event.key == "y") return window.scrollBy(0, (inputCount ?? 1) * -scrollIncrement);
+        } else {
+          if (event.key == "h") return browserUI.moveCursorLeft();
+          if (event.key == "l") return browserUI.moveCursorRight();
+          if (event.key == "j") return browserUI.moveCursorVertically(inputCount ?? 1);
+          if (event.key == "k") return browserUI.moveCursorVertically(-(inputCount ?? 1));
+          if (event.key == "J") return browserUI.moveTask(inputCount ?? 1);
+          if (event.key == "K") return browserUI.moveTask(-(inputCount ?? 1));
+          if (event.key == "G") return browserUI.jumpCursor(inputCount ?? MAX_SAFE_INTEGER);
+          if (event.key == "T") return browserUI.makeTopPriority();
+          if (event.key == "n") return browserUI.focusTaskNameInput(event);
+          if (event.key == "c") return browserUI.setState("cancelled");
+          if (event.key == "d") return browserUI.setState("done");
+          if (event.key == "q") return browserUI.setState("todo");
+          if (event.key == "s") return (inputState = InputState.S);
+          if (event.key == "w") return browserUI.setState("waiting");
+          if (event.key == "X") return browserUI.setState("deleted");
+          if (event.key == "x") return browserUI.removeTag();
+          if (event.key == "u") return browserUI.undo();
+          if (event.key == "r") return browserUI.redo();
+          if (event.key == "E") return browserUI.beginEditContent(event);
+          if (event.key == "e") return browserUI.beginEdit(event);
+          if (event.key == "t") return browserUI.beginTagEdit(event);
+          if (event.key == "v") return (inputState = InputState.V);
+        }
+      } finally {
+        inputCount = null;
+      }
+    } else if (inputState === InputState.S) {
+      inputState = InputState.Root;
+      if (event.key == "m") return browserUI.setState("someday-maybe");
+    } else if (inputState === InputState.V) {
+      inputState = InputState.Root;
+      if (event.key == "a") return browserUI.setView("all");
+      if (event.key == "c") return browserUI.setView("cancelled");
+      if (event.key == "d") return browserUI.setView("done");
+      if (event.key == "i") return browserUI.setUntaggedView();
+      if (event.key == "p") return browserUI.setTagView("Project");
+      if (event.key == "q") return browserUI.setView("todo");
+      if (event.key == "s") return (inputState = InputState.VS);
+      if (event.key == "T") return browserUI.resetTagView();
+      if (event.key == "t") return browserUI.setTagView();
+      if (event.key == "u") return browserUI.setUntaggedView();
+      if (event.key == "v") return browserUI.resetView();
+      if (event.key == "w") return browserUI.setView("waiting");
+      if (event.key == "x") return browserUI.setView("deleted");
+    } else if (inputState === InputState.VS) {
+      inputState = InputState.Root;
+      if (event.key == "m") return browserUI.setView("someday-maybe");
+    }
   }
 }
 
 function browserInit() {
-  document.body.addEventListener("keydown", handleKey, { capture: false });
   log.replay();
+  browserUI.setTitle();
+  browserUI.firstVisibleTask()?.focus();
+  document.body.addEventListener("keydown", handleKey, { capture: false });
 }