feat(cli): add pull request creation with AI-generated messages (#2)

Add a new `gai pr` subcommand that generates pull request titles and descriptions using AI, then creates the PR via GitHub CLI (`gh`) or Gitea CLI (`tea`). This extends the existing commit-generation system by reusing retry logic and prompt infrastructure, and introduces a `callAI` function that returns raw output (instead of pre-cleaned messages) to support structured PR responses.

Reviewed-on: #2

src/ai.ts

@@ -39,11 +39,10 @@ async function sleep(ms: number) {
   return new Promise((resolve) => setTimeout(resolve, ms));
 }
 
-export async function generateCommitMessage(
+export async function callAI(
   config: Config,
   systemPrompt: string,
   userPrompt: string,
-  retries = MAX_RETRIES,
 ): Promise<string> {
   const url = `${config.apiBase.replace(/\/$/, "")}/chat/completions`;
 
@@ -52,7 +51,7 @@ export async function generateCommitMessage(
     { role: "user", content: userPrompt },
   ];
 
-  for (let attempt = 1; attempt <= retries; attempt++) {
+  for (let attempt = 1; attempt <= MAX_RETRIES; attempt++) {
     try {
       const response = await fetch(url, {
         method: "POST",
@@ -70,7 +69,7 @@ export async function generateCommitMessage(
 
       if (!response.ok) {
         const text = await response.text();
-        if (response.status === 429 && attempt < retries) {
+        if (response.status === 429 && attempt < MAX_RETRIES) {
           await sleep(RETRY_DELAY * attempt);
           continue;
         }
@@ -89,7 +88,7 @@ export async function generateCommitMessage(
       const finishReason = data.choices?.[0]?.finish_reason;
 
       if (raw && raw.trim()) {
-        return cleanMessage(raw);
+        return raw;
       }
 
       if (finishReason === "length") {
@@ -102,22 +101,53 @@ export async function generateCommitMessage(
         throw new Error("Response blocked by content filter.");
       }
 
-      if (attempt < retries) {
+      if (attempt < MAX_RETRIES) {
         await sleep(RETRY_DELAY * attempt);
         continue;
       }
 
       throw new Error(
-        `Empty response from AI after ${retries} attempts. finish_reason: ${finishReason ?? "unknown"}`,
+        `Empty response from AI after ${MAX_RETRIES} attempts. finish_reason: ${finishReason ?? "unknown"}`,
       );
     } catch (err) {
-      if (attempt >= retries) throw err;
+      if (attempt >= MAX_RETRIES) throw err;
       if (err instanceof Error && err.message.startsWith("API error")) throw err;
       if (err instanceof Error && err.message.includes("max_tokens")) throw err;
-      if (err instanceof Error && err.message.includes("content filter")) throw err;
+      if (err instanceof Error && err.message.includes("content filter"))
+        throw err;
       await sleep(RETRY_DELAY * attempt);
     }
   }
 
-  throw new Error("Failed to generate commit message");
+  throw new Error("Failed to generate response");
+}
+
+export async function generateCommitMessage(
+  config: Config,
+  systemPrompt: string,
+  userPrompt: string,
+): Promise<string> {
+  const raw = await callAI(config, systemPrompt, userPrompt);
+  return cleanMessage(raw);
+}
+
+export async function generatePRMessage(
+  config: Config,
+  systemPrompt: string,
+  userPrompt: string,
+): Promise<{ title: string; body: string }> {
+  const raw = await callAI(config, systemPrompt, userPrompt);
+  const cleaned = cleanMessage(raw);
+
+  const lines = cleaned.split("\n");
+  const title = lines[0]?.trim() || "Update";
+  let bodyStart = 1;
+
+  while (bodyStart < lines.length && lines[bodyStart]?.trim() === "") {
+    bodyStart++;
+  }
+
+  const body = lines.slice(bodyStart).join("\n").trim();
+
+  return { title, body };
 }

src/pr.ts

@@ -0,0 +1,184 @@
+export type Platform = "github" | "gitea";
+
+export async function getDefaultBranch(): Promise<string> {
+  try {
+    const result =
+      await Bun.$`git symbolic-ref refs/remotes/origin/HEAD`.quiet().text();
+    return result.trim().replace("refs/remotes/origin/", "");
+  } catch {
+    try {
+      const branches = await Bun.$`git branch -r`.quiet().text();
+      for (const line of branches.split("\n")) {
+        const trimmed = line.trim();
+        if (trimmed === "origin/main" || trimmed === "origin/master") {
+          return trimmed.replace("origin/", "");
+        }
+      }
+    } catch {}
+    return "main";
+  }
+}
+
+export async function getBranchName(): Promise<string> {
+  const result =
+    await Bun.$`git rev-parse --abbrev-ref HEAD`.quiet().text();
+  return result.trim();
+}
+
+export async function getBranchCommits(base: string): Promise<string[]> {
+  try {
+    const result =
+      await Bun.$`git log --oneline origin/${base}..HEAD`.quiet().text();
+    return result.trim().split("\n").filter(Boolean);
+  } catch {
+    try {
+      const result =
+        await Bun.$`git log --oneline ${base}..HEAD`.quiet().text();
+      return result.trim().split("\n").filter(Boolean);
+    } catch {
+      return [];
+    }
+  }
+}
+
+export async function getBranchDiff(base: string): Promise<string> {
+  try {
+    const result =
+      await Bun.$`git diff ${base}...HEAD`.quiet().text();
+    return result.trim();
+  } catch {
+    return "";
+  }
+}
+
+function parseRemoteHostname(url: string): string | null {
+  const hostname = url
+    .trim()
+    .toLowerCase()
+    .replace(/^(https?:\/\/|ssh:\/\/|git:\/\/)/, "")
+    .replace(/^[^@]+@/, "")
+    .split(/[:/]/)[0];
+  return hostname || null;
+}
+
+export async function detectPlatform(): Promise<Platform | null> {
+  try {
+    const url = await Bun.$`git remote get-url origin`.quiet().text();
+    const hostname = parseRemoteHostname(url);
+
+    if (!hostname) return null;
+
+    if (hostname === "github.com") return "github";
+    if (hostname.includes("gitea")) return "gitea";
+    return null;
+  } catch {
+    return null;
+  }
+}
+
+export async function getRemoteHostname(): Promise<string | null> {
+  try {
+    const url = await Bun.$`git remote get-url origin`.quiet().text();
+    return parseRemoteHostname(url);
+  } catch {
+    return null;
+  }
+}
+
+export function checkCLI(platform: Platform): string | null {
+  const bin = platform === "github" ? "gh" : "tea";
+  const path = Bun.which(bin);
+  if (!path) {
+    if (platform === "github") {
+      return "GitHub CLI (gh) not found. Install: brew install gh";
+    }
+    return "Gitea CLI (tea) not found. Install from: https://gitea.com/gitea/tea";
+  }
+  return null;
+}
+
+export async function checkAuth(platform: Platform): Promise<string | null> {
+  if (platform === "github") {
+    try {
+      await Bun.$`gh auth status`.quiet();
+      return null;
+    } catch {
+      return "Not authenticated with GitHub CLI. Run: gh auth login";
+    }
+  }
+
+  try {
+    const result = await Bun.$`tea logins list`.quiet().text();
+    if (result.trim()) return null;
+    return "Not authenticated with Gitea CLI. Run: tea login add";
+  } catch {
+    return "Not authenticated with Gitea CLI. Run: tea login add";
+  }
+}
+
+export async function createPR(
+  platform: Platform,
+  title: string,
+  body: string,
+  base: string,
+  draft: boolean,
+): Promise<string> {
+  if (platform === "github") {
+    const args = [
+      "pr",
+      "create",
+      "--title",
+      title,
+      "--body",
+      body,
+      "--base",
+      base,
+    ];
+    if (draft) args.push("--draft");
+
+    const proc = Bun.spawn(["gh", ...args], {
+      stdout: "pipe",
+      stderr: "pipe",
+    });
+    const exitCode = await proc.exited;
+    const stdout = await new Response(proc.stdout).text();
+    const stderr = await new Response(proc.stderr).text();
+
+    if (exitCode !== 0) {
+      throw new Error(
+        stderr.trim() || `gh pr create failed (exit code ${exitCode})`,
+      );
+    }
+
+    const match = stdout.match(/(https?:\/\/[^\s]+)/);
+    return match ? match[1] : stdout.trim();
+  }
+
+  const args = [
+    "pulls",
+    "create",
+    "--title",
+    title,
+    "--description",
+    body,
+    "--base",
+    base,
+  ];
+
+  const proc = Bun.spawn(["tea", ...args], {
+    stdout: "pipe",
+    stderr: "pipe",
+  });
+  const exitCode = await proc.exited;
+  const stdout = await new Response(proc.stdout).text();
+  const stderr = await new Response(proc.stderr).text();
+
+  if (exitCode !== 0) {
+    throw new Error(
+      stderr.trim() || `tea pulls create failed (exit code ${exitCode})`,
+    );
+  }
+
+  const match = stdout.match(/(https?:\/\/[^\s]+)/);
+  return match ? match[1] : stdout.trim();
+}

src/prompt.ts

@@ -1,4 +1,4 @@
-import type { ProjectContext } from "./types";
+import type { PRContext, ProjectContext } from "./types";
 
 export const SYSTEM_PROMPT = `You are an expert at writing concise, meaningful git commit messages following the Conventional Commits specification.
 
@@ -54,3 +54,65 @@ export function buildPrompt(context: ProjectContext): string {
 
   return parts.join("\n");
 }
+
+export const PR_SYSTEM_PROMPT = `You are an expert at writing clear, concise pull request titles and descriptions.
+
+Format:
+<pr title>
+<blank line>
+<pr body>
+
+Rules:
+1. Title must be under 72 characters, in imperative mood
+2. Follow the Conventional Commits style for the title (e.g., "feat(api): add user authentication")
+3. Body should be 2-3 sentences in plain text explaining WHAT was changed and WHY
+4. Be specific — avoid vague messages
+5. Match the language and style of recent commits if provided
+6. If the branch name hints at the type (e.g., "feat/..." or "fix/..."), reflect that in the title
+7. Output ONLY the PR text — no markdown, no code blocks, no prefixes`;
+
+export function buildPRPrompt(context: PRContext): string {
+  const parts: string[] = [];
+
+  if (
+    context.packageDescription ||
+    context.readme ||
+    context.structure
+  ) {
+    parts.push("## Project Context");
+    if (context.packageDescription) {
+      parts.push(`Description: ${context.packageDescription}`);
+    }
+    if (context.structure) {
+      parts.push(`Structure: ${context.structure}`);
+    }
+    if (context.readme) {
+      parts.push(`README:\n${context.readme}`);
+    }
+    parts.push("");
+  }
+
+  parts.push("## Branch Info");
+  parts.push(`Branch: ${context.branchName}`);
+  parts.push(`Target base: ${context.baseBranch}`);
+  parts.push("");
+
+  if (context.branchCommits.length > 0) {
+    parts.push("## Commits on This Branch");
+    for (const c of context.branchCommits) {
+      parts.push(c);
+    }
+    parts.push("");
+  }
+
+  parts.push("## Changes (diff from base)");
+  parts.push("```diff");
+  parts.push(context.diff);
+  parts.push("```");
+  parts.push("");
+  parts.push(
+    "Generate a pull request title and brief body for the above changes.",
+  );
+
+  return parts.join("\n");
+}

src/types.ts

@@ -19,3 +19,13 @@ export interface ProjectContext {
   recentCommits: string[];
   diff: string;
 }
+
+export interface PRContext {
+  readme: string | null;
+  packageDescription: string | null;
+  structure: string | null;
+  branchName: string;
+  baseBranch: string;
+  branchCommits: string[];
+  diff: string;
+}