From 43adb13fb2400ac82b2ef76925936521832b5416 Mon Sep 17 00:00:00 2001
From: Zef Hemel <zef@zef.me>
Date: Fri, 26 Jan 2024 11:10:35 +0100
Subject: [PATCH] Fixes #330

---
 plug-api/silverbullet-syscall/editor.ts |  8 +++++++
 plugs/tasks/task.ts                     | 32 +++++++++++++++++++++++++
 plugs/tasks/tasks.plug.yaml             |  7 +++++-
 web/cm_plugins/task.ts                  |  6 +++--
 web/syscalls/cm_util.ts                 | 23 ++++++++++++++++++
 web/syscalls/editor.ts                  |  8 +++++++
 6 files changed, 81 insertions(+), 3 deletions(-)
 create mode 100644 web/syscalls/cm_util.ts

diff --git a/plug-api/silverbullet-syscall/editor.ts b/plug-api/silverbullet-syscall/editor.ts
index 5f1b91e1..c80bb0c1 100644
--- a/plug-api/silverbullet-syscall/editor.ts
+++ b/plug-api/silverbullet-syscall/editor.ts
@@ -15,6 +15,14 @@ export function getText(): Promise<string> {
   return syscall("editor.getText");
 }
 
+/**
+ * This updates the editor text, but in a minimal-diff way:
+ * it compares the current editor text with the new text, and only sends the changes to the editor, thereby preserving cursor location
+ */
+export function setText(newText: string) {
+  return syscall("editor.setText", newText);
+}
+
 export function getCursor(): Promise<number> {
   return syscall("editor.getCursor");
 }
diff --git a/plugs/tasks/task.ts b/plugs/tasks/task.ts
index f280cb97..3f8b7086 100644
--- a/plugs/tasks/task.ts
+++ b/plugs/tasks/task.ts
@@ -5,6 +5,7 @@ import { editor, markdown, space, sync } from "$sb/syscalls.ts";
 import {
   addParentPointers,
   collectNodesMatching,
+  findNodeMatching,
   findNodeOfType,
   findParentMatching,
   nodeAtPos,
@@ -337,3 +338,34 @@ export async function postponeCommand() {
     },
   });
 }
+
+export async function removeCompletedTasksCommand() {
+  const tree = await markdown.parseMarkdown(await editor.getText());
+  addParentPointers(tree);
+
+  // Taking this ugly approach because the tree is modified in place
+  // Just finding and removing one task at a time and then repeating until nothing changes
+  while (true) {
+    const completedTaskNode = findNodeMatching(tree, (node) => {
+      return node.type === "Task" &&
+        ["x", "X"].includes(node.children![0].children![1].text!);
+    });
+    if (completedTaskNode) {
+      // Ok got one, let's remove it
+      const listItemNode = completedTaskNode.parent!;
+      const bulletListNode = listItemNode.parent!;
+      // Remove the list item
+      const listItemIdx = bulletListNode.children!.indexOf(listItemNode);
+      let removeItems = 1;
+      if (bulletListNode.children![listItemIdx + 1]?.text === "\n") {
+        removeItems++;
+      }
+      bulletListNode.children!.splice(listItemIdx, removeItems);
+    } else {
+      // No completed tasks left, we're done
+      break;
+    }
+  }
+
+  await editor.setText(renderToText(tree));
+}
diff --git a/plugs/tasks/tasks.plug.yaml b/plugs/tasks/tasks.plug.yaml
index 1b776475..d8ca28fa 100644
--- a/plugs/tasks/tasks.plug.yaml
+++ b/plugs/tasks/tasks.plug.yaml
@@ -32,4 +32,9 @@ functions:
   taskComplete:
     path: ./complete.ts:completeTaskState
     events:
-    - editor:complete
\ No newline at end of file
+    - editor:complete
+
+  removeCompletedTasksCommand:
+    path: task.ts:removeCompletedTasksCommand
+    command:
+      name: "Task: Remove Completed"
\ No newline at end of file
diff --git a/web/cm_plugins/task.ts b/web/cm_plugins/task.ts
index 60a2915d..a0cca4ef 100644
--- a/web/cm_plugins/task.ts
+++ b/web/cm_plugins/task.ts
@@ -19,9 +19,11 @@ class CheckboxWidget extends WidgetType {
     checkbox.type = "checkbox";
     checkbox.checked = this.checked;
     checkbox.addEventListener("click", (e) => {
-      // Let the click handler handle this
       e.stopPropagation();
-
+      e.preventDefault();
+    });
+    checkbox.addEventListener("mouseup", (e) => {
+      e.stopPropagation();
       this.clickCallback(this.pos);
     });
     wrap.appendChild(checkbox);
diff --git a/web/syscalls/cm_util.ts b/web/syscalls/cm_util.ts
new file mode 100644
index 00000000..7c9af6cd
--- /dev/null
+++ b/web/syscalls/cm_util.ts
@@ -0,0 +1,23 @@
+import diff, { DELETE, INSERT } from "https://esm.sh/fast-diff@1.3.0";
+import type { ChangeSpec } from "@codemirror/state";
+
+export function diffAndPrepareChanges(
+  oldString: string,
+  newString: string,
+): ChangeSpec[] {
+  // Use the fast-diff library to compute the changes
+  const diffs = diff(oldString, newString);
+
+  // Convert the diffs to CodeMirror transactions
+  let startIndex = 0;
+  const changes: ChangeSpec[] = [];
+  for (const part of diffs) {
+    if (part[0] === INSERT) {
+      changes.push({ from: startIndex, insert: part[1] });
+    } else if (part[0] === DELETE) {
+      changes.push({ from: startIndex, to: startIndex + part[1].length });
+    }
+    startIndex += part[1].length;
+  }
+  return changes;
+}
diff --git a/web/syscalls/editor.ts b/web/syscalls/editor.ts
index 760cc297..b91a50f7 100644
--- a/web/syscalls/editor.ts
+++ b/web/syscalls/editor.ts
@@ -15,6 +15,7 @@ import type { FilterOption } from "../types.ts";
 import { UploadFile } from "../../plug-api/types.ts";
 import { PageRef } from "$sb/lib/page.ts";
 import { openSearchPanel } from "../deps.ts";
+import { diffAndPrepareChanges } from "./cm_util.ts";
 
 export function editorSyscalls(client: Client): SysCallMapping {
   const syscalls: SysCallMapping = {
@@ -24,6 +25,13 @@ export function editorSyscalls(client: Client): SysCallMapping {
     "editor.getText": () => {
       return client.editorView.state.sliceDoc();
     },
+    "editor.setText": (_ctx, newText: string) => {
+      const currentText = client.editorView.state.sliceDoc();
+      const allChanges = diffAndPrepareChanges(currentText, newText);
+      client.editorView.dispatch({
+        changes: allChanges,
+      });
+    },
     "editor.getCursor": (): number => {
       return client.editorView.state.selection.main.from;
     },