From ce70e64b9c32df49066382e3c07dc6030f8ffe00 Mon Sep 17 00:00:00 2001
From: Tom MacWright <tmcw@users.noreply.github.com>
Date: Tue, 14 May 2024 16:36:04 -0400
Subject: [PATCH] feat: Add shouldComplete option (#27)

- Adds some more JSDoc documentation
- Adds a new option `shouldComplete`, that accepts a `CompletionContext` and lets you decide whether to complete at a particular part of the document
---
 demo/index.ts              |  7 +++++++
 src/completionRequester.ts | 14 +++++++++++++-
 src/config.ts              | 19 +++++++++++++++++++
 src/plugin.ts              | 19 ++++++++++++++++++-
 4 files changed, 57 insertions(+), 2 deletions(-)

diff --git a/demo/index.ts b/demo/index.ts
index 1049c48..421bb67 100644
--- a/demo/index.ts
+++ b/demo/index.ts
@@ -35,6 +35,13 @@ const hiddenValue = "https://macwright.com/"`,
     }),
     copilotPlugin({
       apiKey: "d49954eb-cfba-4992-980f-d8fb37f0e942",
+      shouldComplete(context) {
+        if (context.tokenBefore(["String"])) {
+          return true;
+        }
+        let match = context.matchBefore(/(@(?:\w*))(?:[./](\w*))?/);
+        return !match;
+      },
     }),
   ],
   parent: document.querySelector("#editor")!,
diff --git a/src/completionRequester.ts b/src/completionRequester.ts
index 500e96b..a5623df 100644
--- a/src/completionRequester.ts
+++ b/src/completionRequester.ts
@@ -1,4 +1,4 @@
-import { completionStatus } from "@codemirror/autocomplete";
+import { CompletionContext, completionStatus } from "@codemirror/autocomplete";
 import { ChangeSet, Transaction } from "@codemirror/state";
 import { EditorView, ViewUpdate } from "@codemirror/view";
 import {
@@ -77,6 +77,18 @@ export function completionRequester() {
     // Get the current position and source
     const state = update.state;
     const pos = state.selection.main.head;
+
+    // If we've configured a custom rule for when to show completions
+    // and that rule says no, don't offer completions.
+    if (
+      config.shouldComplete &&
+      !config.shouldComplete(
+        new CompletionContext(update.view.state, pos, false),
+      )
+    ) {
+      return;
+    }
+
     const source = state.doc.toString();
 
     // Set a new timeout to request completion
diff --git a/src/config.ts b/src/config.ts
index 78b283a..4a106e7 100644
--- a/src/config.ts
+++ b/src/config.ts
@@ -2,12 +2,17 @@ import { Facet, combineConfig } from "@codemirror/state";
 import { Language } from "./api/proto/exa/codeium_common_pb/codeium_common_pb.js";
 import { Document } from "./api/proto/exa/language_server_pb/language_server_pb.js";
 import { type PartialMessage } from "@bufbuild/protobuf";
+import { type CompletionContext } from "@codemirror/autocomplete";
 
 export interface CodeiumConfig {
   /**
    * Codeium API key
    */
   apiKey: string;
+
+  /**
+   * The programming language of the given document.
+   */
   language?: Language;
   /**
    * Time in millseconds after typing to fetch
@@ -16,6 +21,15 @@ export interface CodeiumConfig {
   timeout?: number;
 
   authSource?: number;
+
+  /**
+   * An optional method that lets you decide whether Codeium
+   * should be triggered at a particular place in a document.
+   *
+   * Might be useful for if you're fighting with overlapping
+   * autocomplete sources.
+   */
+  shouldComplete?: (context: CompletionContext) => boolean;
 }
 
 export const codeiumConfig = Facet.define<
@@ -40,6 +54,11 @@ export interface CodeiumOtherDocumentsConfig {
   override?: () => Promise<OtherDocuments> | OtherDocuments;
 }
 
+/**
+ * Configuration for other documents included with the completion
+ * request. Adding other documents helps you get more accurate
+ * suggestions by adding context.
+ */
 export const codeiumOtherDocumentsConfig = Facet.define<
   CodeiumOtherDocumentsConfig,
   Required<CodeiumOtherDocumentsConfig>
diff --git a/src/plugin.ts b/src/plugin.ts
index 01db495..25cacb0 100644
--- a/src/plugin.ts
+++ b/src/plugin.ts
@@ -16,7 +16,11 @@ import {
 import { Language } from "./api/proto/exa/codeium_common_pb/codeium_common_pb.js";
 import { copilotIgnore } from "./annotations.js";
 
-function isDecorationClicked(view: EditorView) {
+/**
+ * Clicking a completion accepts it. This figures out
+ * whether a given click event is within the completion's area.
+ */
+function isDecorationClicked(view: EditorView): boolean {
   let inRange = false;
   const head = view.state.selection.asSingle().ranges.at(0)?.head;
   const stateField = view.state.field(completionDecoration);
@@ -29,6 +33,15 @@ function isDecorationClicked(view: EditorView) {
   return false;
 }
 
+/**
+ * Handles the behavior in which if you have a completion like
+ *
+ * foo|bar
+ *
+ * (the cursor is at |) and you type an x, it rejects
+ * the completion because that isn't part of the suggested
+ * code.
+ */
 function completionPlugin() {
   return EditorView.domEventHandlers({
     keydown(event, view) {
@@ -53,6 +66,10 @@ function completionPlugin() {
   });
 }
 
+/**
+ * Changing the editor's focus - blurring it by clicking outside -
+ * rejects the suggestion
+ */
 function viewCompletionPlugin() {
   return EditorView.updateListener.of((update) => {
     if (update.focusChanged) {