✨ grammar checker

src/main/grammarService.ts

@@ -0,0 +1,74 @@
+import https from 'https'
+import querystring from 'querystring'
+
+export interface GrammarMatch {
+  offset: number
+  length: number
+  message: string
+  shortMessage: string
+  replacement: string | null
+  ruleId: string
+  categoryId: string
+}
+
+const IGNORED_RULE_IDS = new Set([
+  'WHITESPACE_RULE',
+  'UNPAIRED_BRACKETS',
+  'EN_QUOTES',
+  'DASH_RULE',
+  'WORD_CONTAINS_UNDERSCORE',
+])
+
+export async function checkGrammar(text: string, language = 'en-US'): Promise<GrammarMatch[]> {
+  return new Promise((resolve, reject) => {
+    const body = querystring.stringify({ text, language, enabledOnly: 'false' })
+    const req = https.request(
+      {
+        hostname: 'api.languagetool.org',
+        path: '/v2/check',
+        method: 'POST',
+        headers: {
+          'Content-Type': 'application/x-www-form-urlencoded',
+          'Content-Length': Buffer.byteLength(body),
+          'Accept': 'application/json',
+        },
+      },
+      (res) => {
+        let data = ''
+        res.on('data', (chunk) => { data += chunk })
+        res.on('end', () => {
+          try {
+            const parsed = JSON.parse(data) as {
+              matches: Array<{
+                offset: number
+                length: number
+                message: string
+                shortMessage: string
+                replacements: Array<{ value: string }>
+                rule: { id: string; category: { id: string } }
+              }>
+            }
+            const matches: GrammarMatch[] = parsed.matches
+              .filter((m) => !IGNORED_RULE_IDS.has(m.rule.id))
+              .map((m) => ({
+                offset: m.offset,
+                length: m.length,
+                message: m.message,
+                shortMessage: m.shortMessage || m.message,
+                replacement: m.replacements[0]?.value ?? null,
+                ruleId: m.rule.id,
+                categoryId: m.rule.category.id,
+              }))
+            resolve(matches)
+          } catch (e) {
+            reject(new Error(`LanguageTool parse error: ${String(e)}`))
+          }
+        })
+      }
+    )
+    req.on('error', reject)
+    req.setTimeout(15000, () => { req.destroy(); reject(new Error('Grammar check timed out')) })
+    req.write(body)
+    req.end()
+  })
+}