import { test } from 'node:test';
import assert from 'node:assert/strict';
import { fetchDiff } from '../src/lib/review.js';

function giteaStub() {
  const calls = [];
  return {
    calls,
    getPrDiff: (o, r, i) => { calls.push(['pr', o, r, i]); return Promise.resolve('PRDIFF'); },
    getCommitDiff: (o, r, sha) => { calls.push(['commit', o, r, sha]); return Promise.resolve('HEADDIFF'); },
    getCompareDiff: (o, r, before, after) => { calls.push(['compare', o, r, before, after]); return Promise.resolve('RANGEDIFF'); }
  };
}

const HEAD = 'a'.repeat(40);
const BEFORE = 'b'.repeat(40);

test('PR jobs use the PR diff', async () => {
  const g = giteaStub();
  const out = await fetchDiff({ gitea: g, job: { owner: 'o', repo: 'r', prIndex: 5, sha: HEAD, before: null } });
  assert.equal(out, 'PRDIFF');
  assert.deepEqual(g.calls, [['pr', 'o', 'r', 5]]);
});

test('push uses ONE compare diff over the full before...after range', async () => {
  const g = giteaStub();
  const out = await fetchDiff({
    gitea: g,
    job: {
      owner: 'o', repo: 'r', prIndex: null, sha: HEAD, before: BEFORE,
      // 25 commits in the payload: must NOT fall back to per-commit slicing
      commitShas: Array.from({ length: 25 }, (_, i) => String(i).padStart(40, '0'))
    }
  });
  assert.equal(out, 'RANGEDIFF');
  assert.deepEqual(g.calls, [['compare', 'o', 'r', BEFORE, HEAD]]);
});

test('new-branch push (before = zero sha) falls back to head commit diff', async () => {
  const g = giteaStub();
  const out = await fetchDiff({
    gitea: g,
    job: { owner: 'o', repo: 'r', prIndex: null, sha: HEAD, before: '0'.repeat(40), commitShas: [HEAD] }
  });
  assert.equal(out, 'HEADDIFF');
  assert.deepEqual(g.calls, [['commit', 'o', 'r', HEAD]]);
});

test('missing before also falls back to head commit diff', async () => {
  const g = giteaStub();
  const out = await fetchDiff({
    gitea: g,
    job: { owner: 'o', repo: 'r', prIndex: null, sha: HEAD, before: null, commitShas: [HEAD] }
  });
  assert.equal(out, 'HEADDIFF');
  assert.deepEqual(g.calls, [['commit', 'o', 'r', HEAD]]);
});

test('compare failure propagates (no silent placeholder diff)', async () => {
  const g = giteaStub();
  g.getCompareDiff = () => Promise.reject(new Error('boom 500'));
  await assert.rejects(
    () => fetchDiff({ gitea: g, job: { owner: 'o', repo: 'r', prIndex: null, sha: HEAD, before: BEFORE } }),
    /boom 500/
  );
});