fix: transform cobol feature into VSCode extension

.gitignore

@@ -2,4 +2,4 @@ dist/*
 stats.html
 .vscode
 node_modules
-extensions
+/extensions

src/extensions/cobol.ts

@@ -0,0 +1,101 @@
+import { ExtensionHostKind, registerExtension } from 'vscode/extensions'
+import type * as vscode from 'vscode'
+
+const fixedPositions = [0, 6, 7, 11]
+const lastFixedPosition = fixedPositions[fixedPositions.length - 1]!
+
+function findFirstNonSpacePosition (line: string): number {
+  for (let i = 0; i < line.length; i++) {
+    if (line[i] !== ' ') {
+      return i
+    }
+  }
+  return line.length
+}
+
+const { getApi } = registerExtension({
+  name: 'cobol-indent',
+  publisher: 'codingame',
+  version: '1.0.0',
+  engines: {
+    vscode: '*'
+  },
+  contributes: {
+    commands: [{
+      command: 'cobol-indent',
+      title: 'Indent cobol',
+      enablement: 'editorLangId == cobol && !inSnippetMode'
+    }, {
+      command: 'cobol-unindent',
+      title: 'Unindent cobol',
+      enablement: 'editorLangId == cobol && !inSnippetMode'
+    }],
+    keybindings: [{
+      command: 'cobol-indent',
+      key: 'tab',
+      when: 'editorLangId == cobol && !inSnippetMode'
+    }, {
+      command: 'cobol-unindent',
+      key: 'shift+tab',
+      when: 'editorLangId == cobol && !inSnippetMode'
+    }]
+  }
+}, ExtensionHostKind.LocalProcess)
+
+void getApi().then(api => {
+  async function indentEditor (editor: vscode.TextEditor) {
+    await editor.edit(builder => {
+      for (const selection of editor.selections) {
+        for (let lineNumber = selection.start.line; lineNumber <= selection.end.line; lineNumber++) {
+          const line = editor.document.lineAt(lineNumber).text
+          const nonSpacePosition = findFirstNonSpacePosition(line)
+          const nextFixedPosition = fixedPositions.find(p => p > nonSpacePosition)
+
+          let expectedIndent = nextFixedPosition
+          if (expectedIndent == null) {
+            const indentWidth = editor.options.tabSize as number
+            const expectedIndentCount = Math.floor((nonSpacePosition - lastFixedPosition) / indentWidth) + 1
+            expectedIndent = lastFixedPosition + (indentWidth) * expectedIndentCount
+          }
+
+          const toInsert = expectedIndent - nonSpacePosition
+
+          builder.insert(new api.Position(lineNumber, 0), ' '.repeat(toInsert))
+        }
+      }
+    })
+  }
+
+  async function unindentEditor (editor: vscode.TextEditor) {
+    await editor.edit(builder => {
+      for (const selection of editor.selections) {
+        for (let lineNumber = selection.start.line; lineNumber <= selection.end.line; lineNumber++) {
+          const line = editor.document.lineAt(lineNumber).text
+          const nonSpacePosition = findFirstNonSpacePosition(line)
+          const fixedIndentWidth = editor.options.tabSize as number
+          const prevFixedPosition = fixedPositions.slice().reverse().find(p => p < nonSpacePosition) ?? 0
+
+          let expectedIndent = prevFixedPosition
+
+          if (prevFixedPosition === lastFixedPosition) {
+            // Instead of going back to the last fixed position, go to the nearest (prevFixedPosition + tabSize * N) position
+            const expectedIndentCount = Math.floor((nonSpacePosition - lastFixedPosition - 1) / fixedIndentWidth)
+            expectedIndent = lastFixedPosition + fixedIndentWidth * expectedIndentCount
+          }
+
+          const toRemove = nonSpacePosition - expectedIndent
+
+          builder.delete(new api.Range(
+            lineNumber,
+            0,
+            lineNumber,
+            0 + toRemove
+          ))
+        }
+      }
+    })
+  }
+
+  api.commands.registerTextEditorCommand('cobol-indent', indentEditor)
+  api.commands.registerTextEditorCommand('cobol-unindent', unindentEditor)
+})

src/extensions/index.ts

@@ -0,0 +1 @@
+import './cobol'

src/monaco.ts

@@ -3,7 +3,7 @@ import { IReference, ITextFileEditorModel, createConfiguredEditor, errorHandler,
 import { editorOpenHandlerRegistry, initializePromise, isInitialized } from './services'
 import './languages'
 import './worker'
-import setupExtensions from './editor'
+import './extensions'
 import { EditorOpenHandler } from './tools/EditorOpenHandlerRegistry'
 
 errorHandler.setUnexpectedErrorHandler(error => {
@@ -14,11 +14,7 @@ function createEditor (domElement: HTMLElement, options?: monaco.editor.IStandal
   if (!isInitialized()) {
     throw new Error('Monaco not initialized')
   }
-  const editor = createConfiguredEditor(domElement, options)
-
-  setupExtensions(editor)
-
-  return editor
+  return createConfiguredEditor(domElement, options)
 }
 
 async function createModelReference (resource: monaco.Uri, content?: string): Promise<IReference<ITextFileEditorModel>> {