#!/usr/bin/env node

import process from "node:process";
import {
  ROOT_DIR,
  assertNonEmpty,
  confirmPrompt,
  fail,
  logInfo,
  logSuccess,
  run,
  runCaptureOutput,
  tryRun,
  usage,
} from "./lib.mjs";

const issueId = process.argv[2] ?? "";
const base = process.argv[3] ?? "";
const usageMessage = usage(process.argv[1], "<issue ID> <target branch>");

assertNonEmpty(issueId, "Issue ID is empty", usageMessage);
assertNonEmpty(base, "Target branch is empty", usageMessage);

if (!/^\d+$/.test(issueId)) {
  fail("Issue ID must be an integer.");
}

const branchSuffix = `issue-${issueId}`;
const hotfixBranch = `hotfix/${branchSuffix}`;

function branchExistsOnOrigin(branch) {
  return tryRun("git", [
    "ls-remote",
    "--exit-code",
    "--heads",
    "origin",
    branch,
  ]).ok;
}

function createOrCheckoutBranch(checkoutBranch, baseBranch) {
  if (branchExistsOnOrigin(checkoutBranch)) {
    logInfo(
      `Branch ${checkoutBranch} exists. Checking out and merging ${baseBranch}...`,
    );
    run("git", ["checkout", checkoutBranch]);
    run("git", ["pull", "origin", checkoutBranch]);
    run("git", ["merge", baseBranch]);
  } else {
    logInfo(`Creating hotfix branch for issue ${issueId}...`);
    run("git", ["checkout", baseBranch]);
    run("git", ["checkout", "-b", checkoutBranch]);
    run("git", ["merge", baseBranch]);
  }
}

function commitIfNeeded(message) {
  run("git", ["add", "."]);
  const commit = tryRun("git", ["commit", "-m", message]);
  if (commit.ok) {
    return;
  }

  const combined = `${commit.stdout}\n${commit.stderr}`;
  if (/nothing to commit|no changes added to commit/i.test(combined)) {
    logSuccess("No local changes to commit.");
    return;
  }

  process.stderr.write(commit.stderr);
  process.exit(commit.status ?? 1);
}

function pushChanges(fixType, syncBranch, syncBase) {
  const message = `${fixType}: resolve critical production issue in #${issueId}`;
  commitIfNeeded(message);

  const prUrl = runCaptureOutput("gh", [
    "pr",
    "list",
    "--head",
    syncBranch,
    "--base",
    syncBase,
    "--state",
    "open",
    "--json",
    "url",
    "--jq",
    ".[0].url",
  ]);

  if (prUrl) {
    logSuccess(`PR already exists: ${prUrl}`);
  } else {
    logInfo("No PR found. Creating new PR...");
    run("gh", [
      "pr",
      "create",
      "--head",
      syncBranch,
      "--base",
      syncBase,
      "--title",
      message,
    ]);
  }

  logInfo(`Pushing changes from ${syncBase} to ${syncBranch}...`);
  run("git", ["push", "origin", syncBranch]);
}

async function main() {
  createOrCheckoutBranch(hotfixBranch, base);

  await confirmPrompt(
    "Edit files and confirm to continue. This can always be rerun to pickup where you left off. Continue?",
  );

  pushChanges("fix", hotfixBranch, base);

  const syncBranch = `sync/staging-${branchSuffix}`;
  createOrCheckoutBranch(syncBranch, hotfixBranch);
  pushChanges("sync", syncBranch, "staging");
}

main().catch((error) => {
  fail(error instanceof Error ? error.message : String(error));
});