From 68fa996072de972c395b312affd13e212b59f034 Mon Sep 17 00:00:00 2001
From: Harry Vince <harryavince@gmail.com>
Date: Thu, 9 Jan 2025 23:53:31 +0000
Subject: [PATCH 1/6] fix: editor markdown not incrementing in a numbered list

---
 web_src/js/features/comp/EditorMarkdown.test.ts | 6 +++---
 web_src/js/features/comp/EditorMarkdown.ts      | 8 ++++++--
 2 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/web_src/js/features/comp/EditorMarkdown.test.ts b/web_src/js/features/comp/EditorMarkdown.test.ts
index 7b4b44e83cb56..af1fa48cd4709 100644
--- a/web_src/js/features/comp/EditorMarkdown.test.ts
+++ b/web_src/js/features/comp/EditorMarkdown.test.ts
@@ -32,10 +32,10 @@ test('EditorMarkdown', () => {
   testInput({value: '1. \n2. ', pos: 3}, {value: '\n2. ', pos: 0});
 
   testInput('- x', '- x\n- ');
-  testInput('1. foo', '1. foo\n1. ');
-  testInput({value: '1. a\n2. b\n3. c', pos: 4}, {value: '1. a\n1. \n2. b\n3. c', pos: 8});
+  testInput('1. foo', '1. foo\n2. ');
+  testInput({value: '1. a\n2. b\n3. c', pos: 4}, {value: '1. a\n2. \n2. b\n3. c', pos: 8});
   testInput('- [ ]', '- [ ]\n- ');
   testInput('- [ ] foo', '- [ ] foo\n- [ ] ');
   testInput('* [x] foo', '* [x] foo\n* [ ] ');
-  testInput('1. [x] foo', '1. [x] foo\n1. [ ] ');
+  testInput('1. [x] foo', '1. [x] foo\n2. [ ] ');
 });
diff --git a/web_src/js/features/comp/EditorMarkdown.ts b/web_src/js/features/comp/EditorMarkdown.ts
index 5e2ef121f5297..f9aa5dab1f201 100644
--- a/web_src/js/features/comp/EditorMarkdown.ts
+++ b/web_src/js/features/comp/EditorMarkdown.ts
@@ -96,8 +96,12 @@ function handleNewline(textarea: HTMLTextAreaElement, e: Event) {
   } else {
     // start a new line with the same indention and prefix
     let newPrefix = prefix;
-    // a simple approach, otherwise it needs to parse the lines after the current line
-    if (/^\d+\./.test(prefix)) newPrefix = `1. ${newPrefix.slice(newPrefix.indexOf('.') + 2)}`;
+    const digitMatch = /^\d+/.exec(prefix);
+    if (digitMatch) {
+      const number = parseInt(digitMatch[0]);
+      const incremented = number + 1;
+      newPrefix = `${incremented}. ${newPrefix.slice(newPrefix.indexOf('.') + 2)}`;
+    }
     newPrefix = newPrefix.replace('[x]', '[ ]');
     const newLine = `\n${indention}${newPrefix}`;
     textarea.value = value.slice(0, selStart) + newLine + value.slice(selEnd);

From a17c3e84481f21a0c0abf410080a090d49fa08e3 Mon Sep 17 00:00:00 2001
From: wxiaoguang <wxiaoguang@gmail.com>
Date: Fri, 10 Jan 2025 12:53:49 +0800
Subject: [PATCH 2/6] make code easier to test

---
 .../js/features/comp/EditorMarkdown.test.ts   |  7 ++-
 web_src/js/features/comp/EditorMarkdown.ts    | 54 +++++++++++++------
 2 files changed, 44 insertions(+), 17 deletions(-)

diff --git a/web_src/js/features/comp/EditorMarkdown.test.ts b/web_src/js/features/comp/EditorMarkdown.test.ts
index af1fa48cd4709..455cf4e2443a2 100644
--- a/web_src/js/features/comp/EditorMarkdown.test.ts
+++ b/web_src/js/features/comp/EditorMarkdown.test.ts
@@ -1,4 +1,4 @@
-import {initTextareaMarkdown} from './EditorMarkdown.ts';
+import {initTextareaMarkdown, markdownHandleListNumbers} from './EditorMarkdown.ts';
 
 test('EditorMarkdown', () => {
   const textarea = document.createElement('textarea');
@@ -33,9 +33,12 @@ test('EditorMarkdown', () => {
 
   testInput('- x', '- x\n- ');
   testInput('1. foo', '1. foo\n2. ');
-  testInput({value: '1. a\n2. b\n3. c', pos: 4}, {value: '1. a\n2. \n2. b\n3. c', pos: 8});
+  testInput({value: '1. a\n2. b\n3. c', pos: 4}, {value: '1. a\n2. \n3. b\n4. c', pos: 8});
   testInput('- [ ]', '- [ ]\n- ');
   testInput('- [ ] foo', '- [ ] foo\n- [ ] ');
   testInput('* [x] foo', '* [x] foo\n* [ ] ');
   testInput('1. [x] foo', '1. [x] foo\n2. [ ] ');
+
+  // TODO: test separately
+  markdownHandleListNumbers({value: '1.', selStart: 1, selEnd: 2});
 });
diff --git a/web_src/js/features/comp/EditorMarkdown.ts b/web_src/js/features/comp/EditorMarkdown.ts
index f9aa5dab1f201..d21bc65056137 100644
--- a/web_src/js/features/comp/EditorMarkdown.ts
+++ b/web_src/js/features/comp/EditorMarkdown.ts
@@ -14,7 +14,13 @@ export function textareaInsertText(textarea, value) {
   triggerEditorContentChanged(textarea);
 }
 
-function handleIndentSelection(textarea, e) {
+type TextareaValueSelection = {
+  value: string;
+  selStart: number;
+  selEnd: number;
+}
+
+function handleIndentSelection(textarea: HTMLTextAreaElement, e) {
   const selStart = textarea.selectionStart;
   const selEnd = textarea.selectionEnd;
   if (selEnd === selStart) return; // do not process when no selection
@@ -56,18 +62,21 @@ function handleIndentSelection(textarea, e) {
   triggerEditorContentChanged(textarea);
 }
 
-function handleNewline(textarea: HTMLTextAreaElement, e: Event) {
-  const selStart = textarea.selectionStart;
-  const selEnd = textarea.selectionEnd;
-  if (selEnd !== selStart) return; // do not process when there is a selection
+type MarkdownHandleListNumbersResult = {
+  handled: boolean;
+  valueSelection?: TextareaValueSelection;
+}
 
-  const value = textarea.value;
+export function markdownHandleListNumbers(tvs: TextareaValueSelection): MarkdownHandleListNumbersResult {
+  const ret: MarkdownHandleListNumbersResult = {handled: false};
+  if (tvs.selEnd !== tvs.selStart) return ret; // do not process when there is a selection
 
+  const value = tvs.value;
   // find the current line
   // * if selStart is 0, lastIndexOf(..., -1) is the same as lastIndexOf(..., 0)
   // * if lastIndexOf reruns -1, lineStart is 0 and it is still correct.
-  const lineStart = value.lastIndexOf('\n', selStart - 1) + 1;
-  let lineEnd = value.indexOf('\n', selStart);
+  const lineStart = value.lastIndexOf('\n', tvs.selStart - 1) + 1;
+  let lineEnd = value.indexOf('\n', tvs.selStart);
   lineEnd = lineEnd < 0 ? value.length : lineEnd;
   let line = value.slice(lineStart, lineEnd);
   if (!line) return; // if the line is empty, do nothing, let the browser handle it
@@ -82,17 +91,20 @@ function handleNewline(textarea: HTMLTextAreaElement, e: Event) {
   let prefix = '';
   if (prefixMatch) {
     prefix = prefixMatch[0];
-    if (lineStart + prefix.length > selStart) prefix = ''; // do not add new line if cursor is at prefix
+    if (lineStart + prefix.length > tvs.selStart) prefix = ''; // do not add new line if cursor is at prefix
   }
 
   line = line.slice(prefix.length);
-  if (!indention && !prefix) return; // if no indention and no prefix, do nothing, let the browser handle it
+  if (!indention && !prefix) return ret; // if no indention and no prefix, do nothing, let the browser handle it
 
-  e.preventDefault();
+  ret.handled = true;
   if (!line) {
     // clear current line if we only have i.e. '1. ' and the user presses enter again to finish creating a list
-    textarea.value = value.slice(0, lineStart) + value.slice(lineEnd);
-    textarea.setSelectionRange(selStart - prefix.length, selStart - prefix.length);
+    ret.valueSelection = {
+      value: value.slice(0, lineStart) + value.slice(lineEnd),
+      selStart: tvs.selStart - prefix.length,
+      selEnd: tvs.selStart - prefix.length,
+    };
   } else {
     // start a new line with the same indention and prefix
     let newPrefix = prefix;
@@ -104,9 +116,21 @@ function handleNewline(textarea: HTMLTextAreaElement, e: Event) {
     }
     newPrefix = newPrefix.replace('[x]', '[ ]');
     const newLine = `\n${indention}${newPrefix}`;
-    textarea.value = value.slice(0, selStart) + newLine + value.slice(selEnd);
-    textarea.setSelectionRange(selStart + newLine.length, selStart + newLine.length);
+    ret.valueSelection = {
+      value: value.slice(0, tvs.selStart) + newLine + value.slice(tvs.selEnd),
+      selStart: tvs.selStart + newLine.length,
+      selEnd: tvs.selStart + newLine.length,
+    };
   }
+  return ret;
+}
+
+function handleNewline(textarea: HTMLTextAreaElement, e: Event) {
+  const ret = markdownHandleListNumbers({value: textarea.value, selStart: textarea.selectionStart, selEnd: textarea.selectionEnd});
+  if (!ret.handled) return;
+  e.preventDefault();
+  textarea.value = ret.valueSelection.value;
+  textarea.setSelectionRange(ret.valueSelection.selStart, ret.valueSelection.selEnd);
   triggerEditorContentChanged(textarea);
 }
 

From c6da950ca7986a5419bee6c01728398beab0a84a Mon Sep 17 00:00:00 2001
From: wxiaoguang <wxiaoguang@gmail.com>
Date: Fri, 10 Jan 2025 14:09:27 +0800
Subject: [PATCH 3/6] improve

---
 .../js/features/comp/EditorMarkdown.test.ts   | 68 ++++++++++++++++-
 web_src/js/features/comp/EditorMarkdown.ts    | 73 ++++++++++++++-----
 2 files changed, 117 insertions(+), 24 deletions(-)

diff --git a/web_src/js/features/comp/EditorMarkdown.test.ts b/web_src/js/features/comp/EditorMarkdown.test.ts
index 455cf4e2443a2..b3ac1314bdb71 100644
--- a/web_src/js/features/comp/EditorMarkdown.test.ts
+++ b/web_src/js/features/comp/EditorMarkdown.test.ts
@@ -1,4 +1,67 @@
-import {initTextareaMarkdown, markdownHandleListNumbers} from './EditorMarkdown.ts';
+import {initTextareaMarkdown, markdownHandleListNumbers, textareaSplitLines} from './EditorMarkdown.ts';
+
+test('textareaSplitLines', () => {
+  let ret = textareaSplitLines('a\nbc\nd', 0);
+  expect(ret).toEqual({lines: ['a', 'bc', 'd'], lengthBeforePosLine: 0, posLineIndex: 0, inlinePos: 0});
+
+  ret = textareaSplitLines('a\nbc\nd', 1);
+  expect(ret).toEqual({lines: ['a', 'bc', 'd'], lengthBeforePosLine: 0, posLineIndex: 0, inlinePos: 1});
+
+  ret = textareaSplitLines('a\nbc\nd', 2);
+  expect(ret).toEqual({lines: ['a', 'bc', 'd'], lengthBeforePosLine: 2, posLineIndex: 1, inlinePos: 0});
+
+  ret = textareaSplitLines('a\nbc\nd', 3);
+  expect(ret).toEqual({lines: ['a', 'bc', 'd'], lengthBeforePosLine: 2, posLineIndex: 1, inlinePos: 1});
+
+  ret = textareaSplitLines('a\nbc\nd', 4);
+  expect(ret).toEqual({lines: ['a', 'bc', 'd'], lengthBeforePosLine: 2, posLineIndex: 1, inlinePos: 2});
+
+  ret = textareaSplitLines('a\nbc\nd', 5);
+  expect(ret).toEqual({lines: ['a', 'bc', 'd'], lengthBeforePosLine: 5, posLineIndex: 2, inlinePos: 0});
+
+  ret = textareaSplitLines('a\nbc\nd', 6);
+  expect(ret).toEqual({lines: ['a', 'bc', 'd'], lengthBeforePosLine: 5, posLineIndex: 2, inlinePos: 1});
+});
+
+test('markdownHandleListNumbers', () => {
+  const testInput = (input: string, expected: string) => {
+    const inputPos = input.indexOf('|');
+    input = input.replace('|', '');
+    const ret = markdownHandleListNumbers({value: input, selStart: inputPos, selEnd: inputPos});
+
+    const expectedPos = expected.indexOf('|');
+    expected = expected.replace('|', '');
+    expect(ret).toEqual({handled: true, valueSelection: {value: expected, selStart: expectedPos, selEnd: expectedPos}});
+  };
+
+  testInput(`
+1. a
+2. |
+`, `
+1. a
+|
+`);
+
+  testInput(`
+1. a
+1. b|
+`, `
+1. a
+2. b
+3. |
+`);
+
+  testInput(`
+1. a
+2. b|
+3. c
+`, `
+1. a
+2. b
+3. |
+4. c
+`);
+});
 
 test('EditorMarkdown', () => {
   const textarea = document.createElement('textarea');
@@ -38,7 +101,4 @@ test('EditorMarkdown', () => {
   testInput('- [ ] foo', '- [ ] foo\n- [ ] ');
   testInput('* [x] foo', '* [x] foo\n* [ ] ');
   testInput('1. [x] foo', '1. [x] foo\n2. [ ] ');
-
-  // TODO: test separately
-  markdownHandleListNumbers({value: '1.', selStart: 1, selEnd: 2});
 });
diff --git a/web_src/js/features/comp/EditorMarkdown.ts b/web_src/js/features/comp/EditorMarkdown.ts
index d21bc65056137..1c7aeff3e87c6 100644
--- a/web_src/js/features/comp/EditorMarkdown.ts
+++ b/web_src/js/features/comp/EditorMarkdown.ts
@@ -67,6 +67,45 @@ type MarkdownHandleListNumbersResult = {
   valueSelection?: TextareaValueSelection;
 }
 
+type TextLinesBuffer = {
+  lines: string[];
+  lengthBeforePosLine: number;
+  posLineIndex: number;
+  inlinePos: number
+}
+
+export function textareaSplitLines(value: string, pos: number): TextLinesBuffer {
+  const lines = value.split('\n');
+  let lengthBeforePosLine = 0, inlinePos = 0, posLineIndex = 0;
+  for (; posLineIndex < lines.length; posLineIndex++) {
+    const lineLength = lines[posLineIndex].length + 1;
+    if (lengthBeforePosLine + lineLength > pos) {
+      inlinePos = pos - lengthBeforePosLine;
+      break;
+    }
+    lengthBeforePosLine += lineLength;
+  }
+  return {lines, lengthBeforePosLine, posLineIndex, inlinePos};
+}
+
+function markdownReformatListNumbers(linesBuf: TextLinesBuffer, indention: string) {
+  const re = new RegExp(`^${indention}([0-9]+)\\.`);
+  let firstLineIdx = 0;
+  for (firstLineIdx = linesBuf.posLineIndex - 1; firstLineIdx >= 0; firstLineIdx--) {
+    if (!re.test(linesBuf.lines[firstLineIdx])) break;
+  }
+  firstLineIdx++;
+  for (let i = firstLineIdx; i < linesBuf.lines.length; i++) {
+    if (!re.test(linesBuf.lines[i])) break;
+    linesBuf.lines[i] = `${indention}${i - firstLineIdx + 1}.${linesBuf.lines[i].replace(re, '')}`;
+  }
+  linesBuf.lengthBeforePosLine = 0;
+  for (let i = 0; i < linesBuf.posLineIndex; i++) {
+    linesBuf.lengthBeforePosLine += linesBuf.lines[i].length + 1;
+  }
+  linesBuf.posLineIndex = linesBuf.lines[linesBuf.posLineIndex].length;
+}
+
 export function markdownHandleListNumbers(tvs: TextareaValueSelection): MarkdownHandleListNumbersResult {
   const ret: MarkdownHandleListNumbersResult = {handled: false};
   if (tvs.selEnd !== tvs.selStart) return ret; // do not process when there is a selection
@@ -97,32 +136,26 @@ export function markdownHandleListNumbers(tvs: TextareaValueSelection): Markdown
   line = line.slice(prefix.length);
   if (!indention && !prefix) return ret; // if no indention and no prefix, do nothing, let the browser handle it
 
-  ret.handled = true;
+  const linesBuf = textareaSplitLines(value, tvs.selStart);
   if (!line) {
     // clear current line if we only have i.e. '1. ' and the user presses enter again to finish creating a list
-    ret.valueSelection = {
-      value: value.slice(0, lineStart) + value.slice(lineEnd),
-      selStart: tvs.selStart - prefix.length,
-      selEnd: tvs.selStart - prefix.length,
-    };
+    linesBuf.lines[linesBuf.posLineIndex] = '';
+    linesBuf.inlinePos = 0;
   } else {
-    // start a new line with the same indention and prefix
+    // start a new line with the same indention
     let newPrefix = prefix;
-    const digitMatch = /^\d+/.exec(prefix);
-    if (digitMatch) {
-      const number = parseInt(digitMatch[0]);
-      const incremented = number + 1;
-      newPrefix = `${incremented}. ${newPrefix.slice(newPrefix.indexOf('.') + 2)}`;
-    }
+    if (/^\d+\./.test(prefix)) newPrefix = `1. ${newPrefix.slice(newPrefix.indexOf('.') + 2)}`;
     newPrefix = newPrefix.replace('[x]', '[ ]');
-    const newLine = `\n${indention}${newPrefix}`;
-    ret.valueSelection = {
-      value: value.slice(0, tvs.selStart) + newLine + value.slice(tvs.selEnd),
-      selStart: tvs.selStart + newLine.length,
-      selEnd: tvs.selStart + newLine.length,
-    };
+
+    const newLine = `${indention}${newPrefix}`;
+    linesBuf.lengthBeforePosLine += linesBuf.lines[linesBuf.posLineIndex].length;
+    linesBuf.lines.splice(linesBuf.posLineIndex + 1, 0, newLine);
+    linesBuf.posLineIndex++;
+    linesBuf.inlinePos = newLine.length;
   }
-  return ret;
+  markdownReformatListNumbers(linesBuf, indention);
+  const newPos = linesBuf.lengthBeforePosLine + linesBuf.inlinePos;
+  return {handled: true, valueSelection: {value: linesBuf.lines.join('\n'), selStart: newPos, selEnd: newPos}};
 }
 
 function handleNewline(textarea: HTMLTextAreaElement, e: Event) {

From b5197e8f88d20904f5d6b43b71f3adde8b3aee45 Mon Sep 17 00:00:00 2001
From: wxiaoguang <wxiaoguang@gmail.com>
Date: Fri, 10 Jan 2025 14:45:28 +0800
Subject: [PATCH 4/6] fix more edge cases

---
 .../js/features/comp/EditorMarkdown.test.ts   | 79 +++++++++++++++++--
 web_src/js/features/comp/EditorMarkdown.ts    | 42 +++++-----
 2 files changed, 96 insertions(+), 25 deletions(-)

diff --git a/web_src/js/features/comp/EditorMarkdown.test.ts b/web_src/js/features/comp/EditorMarkdown.test.ts
index b3ac1314bdb71..ed3427e9243f3 100644
--- a/web_src/js/features/comp/EditorMarkdown.test.ts
+++ b/web_src/js/features/comp/EditorMarkdown.test.ts
@@ -24,14 +24,20 @@ test('textareaSplitLines', () => {
 });
 
 test('markdownHandleListNumbers', () => {
-  const testInput = (input: string, expected: string) => {
+  const testInput = (input: string, expected?: string) => {
     const inputPos = input.indexOf('|');
     input = input.replace('|', '');
     const ret = markdownHandleListNumbers({value: input, selStart: inputPos, selEnd: inputPos});
-
-    const expectedPos = expected.indexOf('|');
-    expected = expected.replace('|', '');
-    expect(ret).toEqual({handled: true, valueSelection: {value: expected, selStart: expectedPos, selEnd: expectedPos}});
+    if (expected === null) {
+      expect(ret).toEqual({handled: false});
+    } else {
+      const expectedPos = expected.indexOf('|');
+      expected = expected.replace('|', '');
+      expect(ret).toEqual({
+        handled: true,
+        valueSelection: {value: expected, selStart: expectedPos, selEnd: expectedPos},
+      });
+    }
   };
 
   testInput(`
@@ -42,6 +48,10 @@ test('markdownHandleListNumbers', () => {
 |
 `);
 
+  testInput(`
+|1. a
+`, null); // let browser handle it
+
   testInput(`
 1. a
 1. b|
@@ -49,6 +59,36 @@ test('markdownHandleListNumbers', () => {
 1. a
 2. b
 3. |
+`);
+
+  testInput(`
+2. a
+2. b|
+
+1. x
+1. y
+`, `
+1. a
+2. b
+3. |
+
+1. x
+1. y
+`);
+
+  testInput(`
+2. a
+2. b
+
+1. x|
+1. y
+`, `
+2. a
+2. b
+
+1. x
+2. |
+3. y
 `);
 
   testInput(`
@@ -60,6 +100,35 @@ test('markdownHandleListNumbers', () => {
 2. b
 3. |
 4. c
+`);
+
+  testInput(`
+1. a
+  1. b
+  2. b
+  3. b
+  4. b
+1. c|
+`, `
+1. a
+  1. b
+  2. b
+  3. b
+  4. b
+2. c
+3. |
+`);
+
+  // this is a special case, it's difficult to re-format the parent level at the moment, so leave it to the future
+  testInput(`
+1. a
+  2. b|
+3. c
+`, `
+1. a
+  1. b
+  2. |
+3. c
 `);
 });
 
diff --git a/web_src/js/features/comp/EditorMarkdown.ts b/web_src/js/features/comp/EditorMarkdown.ts
index 1c7aeff3e87c6..40f9d4e8ed5d0 100644
--- a/web_src/js/features/comp/EditorMarkdown.ts
+++ b/web_src/js/features/comp/EditorMarkdown.ts
@@ -89,15 +89,23 @@ export function textareaSplitLines(value: string, pos: number): TextLinesBuffer
 }
 
 function markdownReformatListNumbers(linesBuf: TextLinesBuffer, indention: string) {
-  const re = new RegExp(`^${indention}([0-9]+)\\.`);
-  let firstLineIdx = 0;
+  const reDeeperIndention = new RegExp(`^${indention}\\s+`);
+  const reSameLevel = new RegExp(`^${indention}([0-9]+)\\.`);
+  let firstLineIdx: number;
   for (firstLineIdx = linesBuf.posLineIndex - 1; firstLineIdx >= 0; firstLineIdx--) {
-    if (!re.test(linesBuf.lines[firstLineIdx])) break;
+    const line = linesBuf.lines[firstLineIdx];
+    if (!reDeeperIndention.test(line) && !reSameLevel.test(line)) break;
   }
   firstLineIdx++;
+  let num = 1;
   for (let i = firstLineIdx; i < linesBuf.lines.length; i++) {
-    if (!re.test(linesBuf.lines[i])) break;
-    linesBuf.lines[i] = `${indention}${i - firstLineIdx + 1}.${linesBuf.lines[i].replace(re, '')}`;
+    const line = linesBuf.lines[i];
+    const sameLevel = reSameLevel.test(line);
+    if (!sameLevel && !reDeeperIndention.test(line)) break;
+    if (sameLevel) {
+      linesBuf.lines[i] = `${indention}${num}.${line.replace(reSameLevel, '')}`;
+      num++;
+    }
   }
   linesBuf.lengthBeforePosLine = 0;
   for (let i = 0; i < linesBuf.posLineIndex; i++) {
@@ -107,22 +115,17 @@ function markdownReformatListNumbers(linesBuf: TextLinesBuffer, indention: strin
 }
 
 export function markdownHandleListNumbers(tvs: TextareaValueSelection): MarkdownHandleListNumbersResult {
-  const ret: MarkdownHandleListNumbersResult = {handled: false};
-  if (tvs.selEnd !== tvs.selStart) return ret; // do not process when there is a selection
-
-  const value = tvs.value;
-  // find the current line
-  // * if selStart is 0, lastIndexOf(..., -1) is the same as lastIndexOf(..., 0)
-  // * if lastIndexOf reruns -1, lineStart is 0 and it is still correct.
-  const lineStart = value.lastIndexOf('\n', tvs.selStart - 1) + 1;
-  let lineEnd = value.indexOf('\n', tvs.selStart);
-  lineEnd = lineEnd < 0 ? value.length : lineEnd;
-  let line = value.slice(lineStart, lineEnd);
-  if (!line) return; // if the line is empty, do nothing, let the browser handle it
+  const unhandled: MarkdownHandleListNumbersResult = {handled: false};
+  if (tvs.selEnd !== tvs.selStart) return unhandled; // do not process when there is a selection
+
+  const linesBuf = textareaSplitLines(tvs.value, tvs.selStart);
+  let line = linesBuf.lines[linesBuf.posLineIndex] ?? '';
+  if (!line) return unhandled; // if the line is empty, do nothing, let the browser handle it
 
   // parse the indention
   const indention = /^\s*/.exec(line)[0];
   line = line.slice(indention.length);
+  if (linesBuf.inlinePos <= indention.length) return unhandled; // if cursor is at the indention, do nothing, let the browser handle it
 
   // parse the prefixes: "1. ", "- ", "* ", there could also be " [ ] " or " [x] " for task lists
   // there must be a space after the prefix because none of "1.foo" / "-foo" is a list item
@@ -130,13 +133,12 @@ export function markdownHandleListNumbers(tvs: TextareaValueSelection): Markdown
   let prefix = '';
   if (prefixMatch) {
     prefix = prefixMatch[0];
-    if (lineStart + prefix.length > tvs.selStart) prefix = ''; // do not add new line if cursor is at prefix
+    if (prefix.length > linesBuf.inlinePos) prefix = ''; // do not add new line if cursor is at prefix
   }
 
   line = line.slice(prefix.length);
-  if (!indention && !prefix) return ret; // if no indention and no prefix, do nothing, let the browser handle it
+  if (!indention && !prefix) return unhandled; // if no indention and no prefix, do nothing, let the browser handle it
 
-  const linesBuf = textareaSplitLines(value, tvs.selStart);
   if (!line) {
     // clear current line if we only have i.e. '1. ' and the user presses enter again to finish creating a list
     linesBuf.lines[linesBuf.posLineIndex] = '';

From 4628e8d956bd56527c41b514d7b1e67b4ab43d3d Mon Sep 17 00:00:00 2001
From: wxiaoguang <wxiaoguang@gmail.com>
Date: Fri, 10 Jan 2025 14:57:26 +0800
Subject: [PATCH 5/6] fix more edge cases

---
 .../js/features/comp/EditorMarkdown.test.ts   | 17 ++++++---
 web_src/js/features/comp/EditorMarkdown.ts    | 37 ++++++++++++-------
 2 files changed, 35 insertions(+), 19 deletions(-)

diff --git a/web_src/js/features/comp/EditorMarkdown.test.ts b/web_src/js/features/comp/EditorMarkdown.test.ts
index ed3427e9243f3..063f314f93266 100644
--- a/web_src/js/features/comp/EditorMarkdown.test.ts
+++ b/web_src/js/features/comp/EditorMarkdown.test.ts
@@ -1,4 +1,4 @@
-import {initTextareaMarkdown, markdownHandleListNumbers, textareaSplitLines} from './EditorMarkdown.ts';
+import {initTextareaMarkdown, markdownHandleIndention, textareaSplitLines} from './EditorMarkdown.ts';
 
 test('textareaSplitLines', () => {
   let ret = textareaSplitLines('a\nbc\nd', 0);
@@ -23,11 +23,11 @@ test('textareaSplitLines', () => {
   expect(ret).toEqual({lines: ['a', 'bc', 'd'], lengthBeforePosLine: 5, posLineIndex: 2, inlinePos: 1});
 });
 
-test('markdownHandleListNumbers', () => {
+test('markdownHandleIndention', () => {
   const testInput = (input: string, expected?: string) => {
     const inputPos = input.indexOf('|');
     input = input.replace('|', '');
-    const ret = markdownHandleListNumbers({value: input, selStart: inputPos, selEnd: inputPos});
+    const ret = markdownHandleIndention({value: input, selStart: inputPos, selEnd: inputPos});
     if (expected === null) {
       expect(ret).toEqual({handled: false});
     } else {
@@ -40,6 +40,13 @@ test('markdownHandleListNumbers', () => {
     }
   };
 
+  testInput(`
+  a|b
+`, `
+  a
+  |b
+`);
+
   testInput(`
 1. a
 2. |
@@ -54,11 +61,11 @@ test('markdownHandleListNumbers', () => {
 
   testInput(`
 1. a
-1. b|
+1. b|c
 `, `
 1. a
 2. b
-3. |
+3. |c
 `);
 
   testInput(`
diff --git a/web_src/js/features/comp/EditorMarkdown.ts b/web_src/js/features/comp/EditorMarkdown.ts
index 40f9d4e8ed5d0..ec73d3ad9109a 100644
--- a/web_src/js/features/comp/EditorMarkdown.ts
+++ b/web_src/js/features/comp/EditorMarkdown.ts
@@ -62,7 +62,7 @@ function handleIndentSelection(textarea: HTMLTextAreaElement, e) {
   triggerEditorContentChanged(textarea);
 }
 
-type MarkdownHandleListNumbersResult = {
+type MarkdownHandleIndentionResult = {
   handled: boolean;
   valueSelection?: TextareaValueSelection;
 }
@@ -107,39 +107,44 @@ function markdownReformatListNumbers(linesBuf: TextLinesBuffer, indention: strin
       num++;
     }
   }
+  recalculateLengthBeforeLine(linesBuf);
+  linesBuf.posLineIndex = linesBuf.lines[linesBuf.posLineIndex].length;
+}
+
+function recalculateLengthBeforeLine(linesBuf: TextLinesBuffer) {
   linesBuf.lengthBeforePosLine = 0;
   for (let i = 0; i < linesBuf.posLineIndex; i++) {
     linesBuf.lengthBeforePosLine += linesBuf.lines[i].length + 1;
   }
-  linesBuf.posLineIndex = linesBuf.lines[linesBuf.posLineIndex].length;
 }
 
-export function markdownHandleListNumbers(tvs: TextareaValueSelection): MarkdownHandleListNumbersResult {
-  const unhandled: MarkdownHandleListNumbersResult = {handled: false};
+export function markdownHandleIndention(tvs: TextareaValueSelection): MarkdownHandleIndentionResult {
+  const unhandled: MarkdownHandleIndentionResult = {handled: false};
   if (tvs.selEnd !== tvs.selStart) return unhandled; // do not process when there is a selection
 
   const linesBuf = textareaSplitLines(tvs.value, tvs.selStart);
-  let line = linesBuf.lines[linesBuf.posLineIndex] ?? '';
+  const line = linesBuf.lines[linesBuf.posLineIndex] ?? '';
   if (!line) return unhandled; // if the line is empty, do nothing, let the browser handle it
 
   // parse the indention
-  const indention = /^\s*/.exec(line)[0];
-  line = line.slice(indention.length);
+  let lineContent = line;
+  const indention = /^\s*/.exec(lineContent)[0];
+  lineContent = lineContent.slice(indention.length);
   if (linesBuf.inlinePos <= indention.length) return unhandled; // if cursor is at the indention, do nothing, let the browser handle it
 
   // parse the prefixes: "1. ", "- ", "* ", there could also be " [ ] " or " [x] " for task lists
   // there must be a space after the prefix because none of "1.foo" / "-foo" is a list item
-  const prefixMatch = /^([0-9]+\.|[-*])(\s\[([ x])\])?\s/.exec(line);
+  const prefixMatch = /^([0-9]+\.|[-*])(\s\[([ x])\])?\s/.exec(lineContent);
   let prefix = '';
   if (prefixMatch) {
     prefix = prefixMatch[0];
     if (prefix.length > linesBuf.inlinePos) prefix = ''; // do not add new line if cursor is at prefix
   }
 
-  line = line.slice(prefix.length);
+  lineContent = lineContent.slice(prefix.length);
   if (!indention && !prefix) return unhandled; // if no indention and no prefix, do nothing, let the browser handle it
 
-  if (!line) {
+  if (!lineContent) {
     // clear current line if we only have i.e. '1. ' and the user presses enter again to finish creating a list
     linesBuf.lines[linesBuf.posLineIndex] = '';
     linesBuf.inlinePos = 0;
@@ -149,19 +154,23 @@ export function markdownHandleListNumbers(tvs: TextareaValueSelection): Markdown
     if (/^\d+\./.test(prefix)) newPrefix = `1. ${newPrefix.slice(newPrefix.indexOf('.') + 2)}`;
     newPrefix = newPrefix.replace('[x]', '[ ]');
 
-    const newLine = `${indention}${newPrefix}`;
-    linesBuf.lengthBeforePosLine += linesBuf.lines[linesBuf.posLineIndex].length;
+    const inlinePos = linesBuf.inlinePos;
+    linesBuf.lines[linesBuf.posLineIndex] = line.substring(0, inlinePos);
+    const newLineLeft = `${indention}${newPrefix}`;
+    const newLine = `${newLineLeft}${line.substring(inlinePos)}`;
     linesBuf.lines.splice(linesBuf.posLineIndex + 1, 0, newLine);
     linesBuf.posLineIndex++;
-    linesBuf.inlinePos = newLine.length;
+    linesBuf.inlinePos = newLineLeft.length;
+    recalculateLengthBeforeLine(linesBuf);
   }
+
   markdownReformatListNumbers(linesBuf, indention);
   const newPos = linesBuf.lengthBeforePosLine + linesBuf.inlinePos;
   return {handled: true, valueSelection: {value: linesBuf.lines.join('\n'), selStart: newPos, selEnd: newPos}};
 }
 
 function handleNewline(textarea: HTMLTextAreaElement, e: Event) {
-  const ret = markdownHandleListNumbers({value: textarea.value, selStart: textarea.selectionStart, selEnd: textarea.selectionEnd});
+  const ret = markdownHandleIndention({value: textarea.value, selStart: textarea.selectionStart, selEnd: textarea.selectionEnd});
   if (!ret.handled) return;
   e.preventDefault();
   textarea.value = ret.valueSelection.value;

From a5261422a6c66b7ffcfc98bad7a9eeab414ab36b Mon Sep 17 00:00:00 2001
From: wxiaoguang <wxiaoguang@gmail.com>
Date: Fri, 10 Jan 2025 15:09:30 +0800
Subject: [PATCH 6/6] fix more edge cases

---
 .../js/features/comp/EditorMarkdown.test.ts   | 23 +++++++++++++++++++
 web_src/js/features/comp/EditorMarkdown.ts    | 16 +++++++++----
 2 files changed, 34 insertions(+), 5 deletions(-)

diff --git a/web_src/js/features/comp/EditorMarkdown.test.ts b/web_src/js/features/comp/EditorMarkdown.test.ts
index 063f314f93266..9f34d77348228 100644
--- a/web_src/js/features/comp/EditorMarkdown.test.ts
+++ b/web_src/js/features/comp/EditorMarkdown.test.ts
@@ -124,6 +124,29 @@ test('markdownHandleIndention', () => {
   4. b
 2. c
 3. |
+`);
+
+  testInput(`
+1. a
+2. a
+3. a
+4. a
+5. a
+6. a
+7. a
+8. a
+9. b|c
+`, `
+1. a
+2. a
+3. a
+4. a
+5. a
+6. a
+7. a
+8. a
+9. b
+10. |c
 `);
 
   // this is a special case, it's difficult to re-format the parent level at the moment, so leave it to the future
diff --git a/web_src/js/features/comp/EditorMarkdown.ts b/web_src/js/features/comp/EditorMarkdown.ts
index ec73d3ad9109a..d3ed492396fef 100644
--- a/web_src/js/features/comp/EditorMarkdown.ts
+++ b/web_src/js/features/comp/EditorMarkdown.ts
@@ -99,16 +99,22 @@ function markdownReformatListNumbers(linesBuf: TextLinesBuffer, indention: strin
   firstLineIdx++;
   let num = 1;
   for (let i = firstLineIdx; i < linesBuf.lines.length; i++) {
-    const line = linesBuf.lines[i];
-    const sameLevel = reSameLevel.test(line);
-    if (!sameLevel && !reDeeperIndention.test(line)) break;
+    const oldLine = linesBuf.lines[i];
+    const sameLevel = reSameLevel.test(oldLine);
+    if (!sameLevel && !reDeeperIndention.test(oldLine)) break;
     if (sameLevel) {
-      linesBuf.lines[i] = `${indention}${num}.${line.replace(reSameLevel, '')}`;
+      const newLine = `${indention}${num}.${oldLine.replace(reSameLevel, '')}`;
+      linesBuf.lines[i] = newLine;
       num++;
+      if (linesBuf.posLineIndex === i) {
+        // need to correct the cursor inline position if the line length changes
+        linesBuf.inlinePos += newLine.length - oldLine.length;
+        linesBuf.inlinePos = Math.max(0, linesBuf.inlinePos);
+        linesBuf.inlinePos = Math.min(newLine.length, linesBuf.inlinePos);
+      }
     }
   }
   recalculateLengthBeforeLine(linesBuf);
-  linesBuf.posLineIndex = linesBuf.lines[linesBuf.posLineIndex].length;
 }
 
 function recalculateLengthBeforeLine(linesBuf: TextLinesBuffer) {