/**
 * 定位一顆工作包的工作樹，不在就重建。
 *
 * 「不在就重建」不是防禦性程式設計，而是最常見的情境：進度完全不寫在本機，換一台機器
 * 或換一個 agent 接手時，工作樹本來就不存在。重建的成本就是一次 `git worktree add`。
 *
 * 重建走的是與 branch-prep 同一套推導與同一套建立方式（`lib` 的 `worktreePath` 與
 * `planWorktree`），所以這裡連帶驗兩件事：算出來的是同一條路徑，而且分支上已經有的
 * 進度會被接上，不是從頭長一棵空的。
 */
import test from 'node:test';
import assert from 'node:assert/strict';
import { existsSync, mkdirSync, mkdtempSync, rmSync, writeFileSync } from 'node:fs';
import { execFileSync } from 'node:child_process';
import { join } from 'node:path';
import { runScript, tmpRoot } from './helpers/run-script.js';
import { makeTempRepoWithRemote } from './helpers/temp-repo.js';

const REPO = 'plugins/tea-sdlc';
const SLUG = 'mine';
const BRANCH = `feat/${SLUG}/main`;

/** 一個有遠端的臨時 repo 與一個空的工作樹家 */
function withRepo(t) {
  const repo = makeTempRepoWithRemote();
  t.after(() => repo.cleanup());
  mkdirSync(tmpRoot, { recursive: true });
  const home = mkdtempSync(join(tmpRoot, 'home-'));
  t.after(() => rmSync(home, { recursive: true, force: true }));
  return { ...repo, home };
}

/** 照正規流程開一棵工作樹，回傳它的路徑——測試不自己算路徑 */
async function prep(repo) {
  const { json } = await runScript(
    'branch-prep.js',
    ['--repo', REPO, '--path', repo.dir, '--source', 'master', '--type', 'feat', '--slug', SLUG],
    { env: { TEA_SDLC_HOME: repo.home } },
  );
  assert.equal(json.ok, true, json.error?.message);
  return json.data.worktree;
}

const run = (repo, args = []) =>
  runScript('worktree-ensure.js', ['--repo', REPO, '--path', repo.dir, '--branch', BRANCH, ...args], {
    env: { TEA_SDLC_HOME: repo.home },
  });

const branchIn = (dir) =>
  execFileSync('git', ['rev-parse', '--abbrev-ref', 'HEAD'], { cwd: dir, encoding: 'utf8' }).trim();

// ── 已經在了就沿用 ─────────────────────────────────────────────────

test('工作樹已經在了就沿用，不碰裡面還沒提交的東西', async (t) => {
  const repo = withRepo(t);
  const worktree = await prep(repo);
  writeFileSync(join(worktree, 'wip.txt'), '做到一半\n');

  const { code, json } = await run(repo);

  assert.equal(code, 0, json.error?.message);
  assert.equal(json.data.worktree, worktree, '推導出的要是 branch-prep 建的那一條');
  assert.equal(json.data.動作, '沿用既有工作樹');
  assert.equal(existsSync(join(worktree, 'wip.txt')), true);
});

// ── 不在就重建 ─────────────────────────────────────────────────────

test('工作樹不在時重建它，分支上的進度跟著回來', async (t) => {
  // 換一台機器接手就是這個情形：進度不寫在本機，工作樹本來就不存在
  const repo = withRepo(t);
  const worktree = await prep(repo);
  writeFileSync(join(worktree, 'done.txt'), '已經提交的進度\n');
  execFileSync('git', ['add', '-A'], { cwd: worktree });
  execFileSync('git', ['commit', '-qm', '分支上的進度'], { cwd: worktree });
  repo.git('worktree', 'remove', worktree);

  const { code, json } = await run(repo);

  assert.equal(code, 0, json.error?.message);
  assert.equal(json.data.worktree, worktree, '同一顆工作包算出來的永遠是同一條路徑');
  assert.equal(json.data.動作, '接上本地既有');
  assert.equal(branchIn(worktree), BRANCH);
  assert.equal(existsSync(join(worktree, 'done.txt')), true, '接上既有分支，不是長一棵空的');
});

test('本機連分支都沒有時，從遠端那一支重建', async (t) => {
  // 真正的新機器：clone 完什麼都沒有，分支只在遠端上
  const repo = withRepo(t);
  repo.pushFromElsewhere(BRANCH, 'theirs.txt', '推上去的進度\n');

  const { code, json } = await run(repo);

  assert.equal(code, 0, json.error?.message);
  assert.equal(json.data.動作, '接上遠端既有');
  assert.equal(existsSync(join(json.data.worktree, 'theirs.txt')), true);
  assert.equal(
    repo.git('for-each-ref', '--format=%(upstream)', `refs/heads/${BRANCH}`),
    '',
    '重建與建立走同一套：一樣不設 upstream',
  );
});

test('中繼資料還在但目錄被砍掉時照樣重建', async (t) => {
  const repo = withRepo(t);
  const worktree = await prep(repo);
  rmSync(worktree, { recursive: true, force: true });

  const { code, json } = await run(repo);

  assert.equal(code, 0, json.error?.message);
  assert.equal(existsSync(worktree), true);
  assert.equal(branchIn(worktree), BRANCH);
});

// ── 擋下來的情況 ───────────────────────────────────────────────────

test('分支在本機與遠端都不存在時明確報錯，不憑空長一棵', async (t) => {
  const repo = withRepo(t);

  const { code, json } = await run(repo);

  assert.equal(code, 1);
  assert.equal(json.error.code, 'BRANCH_NOT_FOUND');
  assert.match(json.error.message, new RegExp(BRANCH));
  assert.equal(existsSync(json.data?.worktree ?? '/nonexistent'), false);
});

test('推導出的路徑上是別的東西時明確報錯，不盲目拿來用', async (t) => {
  const repo = withRepo(t);
  const worktree = await prep(repo);
  repo.git('worktree', 'remove', worktree);
  mkdirSync(worktree, { recursive: true });
  writeFileSync(join(worktree, '別人的東西.txt'), 'x\n');

  const { code, json } = await run(repo);

  assert.equal(code, 1);
  assert.equal(json.error.code, 'WORKTREE_PATH_TAKEN');
  assert.equal(existsSync(join(worktree, '別人的東西.txt')), true, '不是我們建的東西就不碰');
});

test('--path 指向的不是 git repo 時，回可區分的錯誤碼', async (t) => {
  const { json } = await runScript('worktree-ensure.js', [
    '--repo', REPO, '--path', tmpRoot, '--branch', BRANCH,
  ]);

  assert.equal(json.error.code, 'NOT_A_GIT_REPO');
});

test('缺 --branch 時指名缺的是哪一個', async (t) => {
  const repo = withRepo(t);

  const { json } = await runScript('worktree-ensure.js', ['--repo', REPO, '--path', repo.dir], {
    env: { TEA_SDLC_HOME: repo.home },
  });

  assert.equal(json.error.code, 'MISSING_FLAG');
  assert.match(json.error.message, /--branch/);
});

// ── --dry-run ─────────────────────────────────────────────────────

test('--dry-run 印出路徑與將執行的 git 指令，且不建任何東西', async (t) => {
  const repo = withRepo(t);
  repo.pushFromElsewhere(BRANCH, 'theirs.txt', '推上去的進度\n');

  const { code, json } = await run(repo, ['--dry-run']);

  assert.equal(code, 0);
  assert.equal(json.data.dryRun, true);
  assert.match(json.data.worktree, /worktrees\/[0-9a-f]{12}$/);
  assert.deepEqual(json.data.commands, [
    'git fetch origin',
    `git worktree add --no-track -b ${BRANCH} ${json.data.worktree} origin/${BRANCH}`,
  ]);
  assert.equal(existsSync(json.data.worktree), false, '試跑不該真的建');
});

test('--dry-run 在工作樹已經在時說沒事要做', async (t) => {
  const repo = withRepo(t);
  await prep(repo);

  const { json } = await run(repo, ['--dry-run']);

  assert.equal(json.data.動作, '沿用既有工作樹');
  assert.deepEqual(json.data.commands, []);
});

test('--dry-run 也照樣把擋下來的情況說出來', async (t) => {
  const repo = withRepo(t);

  const { json } = await run(repo, ['--dry-run']);

  assert.equal(json.error.code, 'BRANCH_NOT_FOUND');
});