import Database from 'better-sqlite3';
import { afterEach, describe, expect, it } from 'vitest';
import { backfill } from '../src/backfill.js';
import { createAppViewStore } from '../src/store.js';

const COLLECTION = 'dev.pdsjs.git.pull';
const REPO = 'dev.pdsjs.git.repo';
const OWNER = 'did:plc:owner';
const STRANGER = 'did:plc:stranger';
const PDS = 'https://pds.example.com';

/**
 * A fetch that plays the relay, the PLC directory and the PDS, each against
 * its own origin.
 * @param {Record<string, any>} routes
 */
function fakeFetch(routes) {
  /** @type {import('../src/backfill.js').FetchLike} */
  return async (input) => {
    const url = String(input);
    for (const [match, body] of Object.entries(routes)) {
      if (url.includes(match)) {
        return Response.json(typeof body === 'function' ? body(url) : body);
      }
    }
    return new Response('not found', { status: 404 });
  };
}

const didDoc = {
  alsoKnownAs: ['at://owner.example.com'],
  service: [
    {
      id: '#atproto_pds',
      type: 'AtprotoPersonalDataServer',
      serviceEndpoint: PDS,
    },
  ],
};

describe('backfill', () => {
  /** @type {import('node:http').Server|undefined} */
  let server;

  afterEach(() => {
    server?.close();
  });

  it('walks the relay listing and indexes what each account holds', async () => {
    const store = createAppViewStore(new Database(':memory:'));
    let listed = 0;
    await backfill({
      store,
      collections: [COLLECTION],
      fetch: fakeFetch({
        '/xrpc/com.atproto.sync.listReposByCollection': () => {
          listed += 1;
          return listed === 1
            ? { repos: [{ did: STRANGER }, { did: OWNER }] }
            : { repos: [] };
        },
        '/did:plc:stranger/data': {
          service: [{ id: '#atproto_pds', serviceEndpoint: PDS }],
        },
        '/did:plc:owner/data': didDoc,
        '/xrpc/com.atproto.repo.listRecords': (/** @type {string} */ url) => {
          // Only the stranger holds pull records; the owner holds none.
          const repo = new URL(url).searchParams.get('repo');
          return repo === STRANGER
            ? {
                records: [
                  {
                    uri: `at://${STRANGER}/${COLLECTION}/3kpull`,
                    cid: 'bafypull',
                    value: {
                      subject: { uri: `at://${OWNER}/${REPO}/proj` },
                    },
                  },
                ],
              }
            : { records: [] };
        },
      }),
    });

    const found = store.about(`at://${OWNER}/${REPO}/proj`, COLLECTION);
    expect(found).toHaveLength(1);
    expect(found[0].did).toBe(STRANGER);
    // The handle from the DID document rode along.
    expect(store.handleOf(OWNER)).toBe('owner.example.com');
    // The walk finished: no cursor is stored past the end.
    expect(store.textCursor(`backfill:${COLLECTION}`)).toBeUndefined();
  });

  it('resumes from the stored pagination cursor', async () => {
    const store = createAppViewStore(new Database(':memory:'));
    store.setTextCursor(`backfill:${COLLECTION}`, 'page-two');
    /** @type {string[]} */
    const cursors = [];
    await backfill({
      store,
      collections: [COLLECTION],
      fetch: fakeFetch({
        '/xrpc/com.atproto.sync.listReposByCollection': (
          /** @type {string} */ url,
        ) => {
          cursors.push(new URL(url).searchParams.get('cursor') ?? '');
          return { repos: [] };
        },
      }),
    });
    expect(cursors).toEqual(['page-two']);
  });

  it('skips an account whose DID document does not resolve', async () => {
    const store = createAppViewStore(new Database(':memory:'));
    await backfill({
      store,
      collections: [COLLECTION],
      fetch: fakeFetch({
        '/xrpc/com.atproto.sync.listReposByCollection': {
          repos: [{ did: 'did:plc:missing' }, { did: OWNER }],
          cursor: '',
        },
        '/did:plc:owner/data': didDoc,
        '/xrpc/com.atproto.repo.listRecords': {
          records: [
            {
              uri: `at://${OWNER}/${COLLECTION}/3kpull`,
              cid: 'bafyowner',
              value: {},
            },
          ],
        },
      }),
    });
    expect(store.getRecord(`at://${OWNER}/${COLLECTION}/3kpull`)).not.toBe(
      null,
    );
    expect(store.getRecord('at://did:plc:missing/anything/1')).toBe(null);
  });

  it('stops with a notice when the relay refuses to answer', async () => {
    const store = createAppViewStore(new Database(':memory:'));
    /** @type {string[]} */
    const notices = [];
    await backfill({
      store,
      collections: [COLLECTION],
      fetch: fakeFetch({}),
      onNotice: (message) => notices.push(message),
    });
    expect(notices.some((message) => message.includes('answered 404'))).toBe(
      true,
    );
    expect(store.listRecords(COLLECTION)).toEqual([]);
  });
});