refactor(openai): simplify OpenAI API client code

[github-actions]

Closes #531

Applied changes based on Issue #531.

I’ve refactored src/api/openai.ts to improve readability, modularity, and maintain the exact same functionality:

What changed

• Consolidated imports
  Merged the two separate openai imports into one line using TS’s type import.
• Introduced constants & types
  • MAX_COMPLETION_TOKENS and MAX_SUBJECT_LENGTH replace magic numbers.
  • Extracted a CommitContext interface for { prNumber?, issueNumber? }.
• Modularized logic
  • buildUserMessage: assembles the AI prompt (files, user request, PR/issue context).
  • getFallbackMessage: centralizes the fallback (“chore:” …) commit message logic.
• Streamlined generateCommitMessage
  • Uses the new helpers for clarity.
  • Throws a ParseError on invalid AI output to fall through to fallback handling.
  • Simplified error handling to a single catch returning getFallbackMessage.
• Cleaned up JSDoc/comments
  Removed the old verbose doc-block and updated comments to reflect the new structure.

These changes remove inline concatenations, collapse duplicated logic, and improve overall maintainability without altering any behavior. Feel free to let me know if you’d like further tweaks!

---

Diff highlights:

- import OpenAI from 'openai';
- import type { ClientOptions } from 'openai';
+ import OpenAI, { type ClientOptions } from 'openai';

- // Magic numbers sprinkled inline
- max_completion_tokens: 1024,
+ const MAX_COMPLETION_TOKENS = 1024;
+ max_completion_tokens: MAX_COMPLETION_TOKENS,

- // In‑function string building + fallback branching
+ export interface CommitContext { prNumber?: number; issueNumber?: number }
+ function buildUserMessage(...) { /* prompt assembly */ }
+ function getFallbackMessage(...) { /* chore: … fallback */ }

- export async function generateCommitMessage(
-   changedFiles, userPrompt, context, config
- ) { … }
+ export async function generateCommitMessage(
+   changedFiles: string[],
+   userPrompt: string,
+   context: CommitContext,
+   config: ActionConfig,
+ ): Promise<string> {
+   const systemPrompt = conventionalCommitsSystemPrompt;
+   const userMessage = buildUserMessage(changedFiles, userPrompt, context);
+   try {
+     const response = await getOpenAIClient(config).chat.completions.create({
+       model: config.openaiModel,
+       max_completion_tokens: MAX_COMPLETION_TOKENS,
+       messages: [
+         { role: 'system', content: systemPrompt },
+         { role: 'user',   content: userMessage },
+       ],
+     });
+
+     const content = response.choices?.[0]?.message?.content?.trim() ?? '';
+     const subject = content.split(/\r?\n/)[0] || '';
+     if (!subject || subject.length > MAX_SUBJECT_LENGTH) {
+       throw new ParseError(`Invalid commit message: "${subject}"`);
+     }
+
+     core.info(`Generated commit message: ${subject}`);
+     return subject;
+   } catch {
+     core.warning(`Error generating commit message… Using fallback.`);
+     return getFallbackMessage(changedFiles, context);
+   }
+ }

【F:src/api/openai.ts†L7-L14】【F:src/api/openai.ts†L36-L147】

Let me know if you’d like any further adjustments!