import { assertEquals } from "https://deno.land/std@0.224.0/testing/asserts.ts";

/**
 * Generation 2 Proof of Concept: Git Storage (Notes)
 *
 * This module demonstrates interacting with Git Notes in a completely
 * isolated, real Git environment using Deno.Command. It sets up a local
 * Git repository on the fly to avoid polluting the main project repo,
 * thereby proving production-readiness of the local-first storage mechanism.
 */

async function runGitCmd(args: string[], cwd?: string): Promise<string> {
  const cmd = new Deno.Command("git", {
    args,
    cwd,
    stdout: "piped",
    stderr: "piped",
  });
  const output = await cmd.output();
  const stdout = new TextDecoder().decode(output.stdout).trim();
  const stderr = new TextDecoder().decode(output.stderr).trim();

  if (!output.success) {
    throw new Error(`Git command failed: git ${args.join(" ")}\n${stderr}`);
  }
  return stdout;
}

export async function addGitNote(
  cwd: string,
  ref: string,
  message: string,
  targetRef: string = "HEAD",
) {
  await runGitCmd([
    "notes",
    "--ref",
    ref,
    "add",
    "-f",
    "-m",
    message,
    targetRef,
  ], cwd);
}

export async function readGitNote(
  cwd: string,
  ref: string,
  targetRef: string = "HEAD",
): Promise<string> {
  try {
    return await runGitCmd(["notes", "--ref", ref, "show", targetRef], cwd);
  } catch (error: any) {
    if (
      error.message.includes("No note found") ||
      error.message.includes("does not exist")
    ) {
      return "";
    }
    throw error;
  }
}

if (import.meta.main) {
  console.log("Running Gen 2 Git Storage PoC tests...");

  // Setup an isolated Git repository
  const tempDir = await Deno.makeTempDir({ prefix: "agent-forum-git-poc-" });
  console.log(`Created isolated Git repo at ${tempDir}`);

  try {
    await runGitCmd(["init"], tempDir);
    await runGitCmd(["config", "user.email", "poc@example.com"], tempDir);
    await runGitCmd(["config", "user.name", "PoC Tester"], tempDir);

    // Create an initial commit so we have a HEAD
    const dummyFile = `${tempDir}/README.md`;
    await Deno.writeTextFile(dummyFile, "# Dummy");
    await runGitCmd(["add", "README.md"], tempDir);
    await runGitCmd(["commit", "-m", "Initial commit"], tempDir);

    const customRef = "forum/test-reasoning";
    const testMessage = JSON.stringify({
      agent: "poc-g2-agent",
      risk: "low",
      thought: "This is a hidden thought stored in an isolated git note.",
    });

    console.log(`Adding note to current HEAD under ref ${customRef}...`);
    await addGitNote(tempDir, customRef, testMessage);

    console.log(`Reading note back...`);
    const readMessage = await readGitNote(tempDir, customRef);

    assertEquals(readMessage, testMessage);
    console.log(
      "✅ Gen 2 Git Storage PoC successful: Read/Write worked securely in an isolated Git environment.",
    );
  } catch (err) {
    console.error("❌ Gen 2 Git Storage PoC failed:", err);
    Deno.exit(1);
  } finally {
    console.log(`Cleaning up isolated Git repo...`);
    await Deno.remove(tempDir, { recursive: true });
  }
}