feat: initial project setup with gai tool

src/config.ts

@@ -0,0 +1,48 @@
+import { existsSync, mkdirSync } from "node:fs";
+import { join } from "node:path";
+import { homedir } from "node:os";
+import type { Config } from "./types";
+
+const DEFAULT_CONFIG: Config = {
+  apiKey: "",
+  apiBase: "https://api.openai.com/v1",
+  model: "gpt-4o",
+  maxTokens: 500,
+  temperature: 0.7,
+};
+
+const CONFIG_DIR = join(homedir(), ".config", "gai");
+const CONFIG_PATH = join(CONFIG_DIR, "config.json");
+
+export async function loadConfig(): Promise<Config> {
+  let config = { ...DEFAULT_CONFIG };
+
+  if (existsSync(CONFIG_PATH)) {
+    try {
+      const file = Bun.file(CONFIG_PATH);
+      const json = (await file.json()) as Partial<Config>;
+      config = { ...config, ...json };
+    } catch {}
+  }
+
+  if (process.env.GAI_API_KEY) config.apiKey = process.env.GAI_API_KEY;
+  if (process.env.GAI_API_BASE) config.apiBase = process.env.GAI_API_BASE;
+  if (process.env.GAI_MODEL) config.model = process.env.GAI_MODEL;
+  if (process.env.GAI_MAX_TOKENS)
+    config.maxTokens = parseInt(process.env.GAI_MAX_TOKENS);
+  if (process.env.GAI_TEMPERATURE)
+    config.temperature = parseFloat(process.env.GAI_TEMPERATURE);
+
+  return config;
+}
+
+export async function saveConfig(partial: Partial<Config>): Promise<void> {
+  if (!existsSync(CONFIG_DIR)) {
+    mkdirSync(CONFIG_DIR, { recursive: true });
+  }
+
+  const current = await loadConfig();
+  const merged = { ...current, ...partial };
+
+  await Bun.write(CONFIG_PATH, JSON.stringify(merged, null, 2));
+}