feat: initial project setup with gai tool

src/ai.ts

@@ -0,0 +1,55 @@
+import type { Config } from "./types";
+
+interface ChatMessage {
+  role: "system" | "user" | "assistant";
+  content: string;
+}
+
+interface ChatCompletionResponse {
+  choices?: Array<{
+    message?: {
+      content?: string;
+    };
+  }>;
+}
+
+export async function generateCommitMessage(
+  config: Config,
+  systemPrompt: string,
+  userPrompt: string,
+): Promise<string> {
+  const url = `${config.apiBase.replace(/\/$/, "")}/chat/completions`;
+
+  const messages: ChatMessage[] = [
+    { role: "system", content: systemPrompt },
+    { role: "user", content: userPrompt },
+  ];
+
+  const response = await fetch(url, {
+    method: "POST",
+    headers: {
+      "Content-Type": "application/json",
+      Authorization: `Bearer ${config.apiKey}`,
+    },
+    body: JSON.stringify({
+      model: config.model,
+      max_tokens: config.maxTokens,
+      temperature: config.temperature,
+      messages,
+    }),
+  });
+
+  if (!response.ok) {
+    const text = await response.text();
+    throw new Error(`API request failed (${response.status}): ${text}`);
+  }
+
+  const data = (await response.json()) as ChatCompletionResponse;
+  const message = data.choices?.[0]?.message?.content?.trim();
+
+  if (!message) {
+    throw new Error("Empty response from AI");
+  }
+
+  return message;
+}