// NOTE: kept OUT of src/database/migrations/ on purpose — the TypeORM migrations glob
// (`migrations/*{.ts,.js}`) would otherwise load this spec as a migration under ts-node
// (the CLI datasource / start:dev) and crash on `describe`.
import { QueryRunner } from 'typeorm';
import { AddUuidDefaultsForPostgres1779235200000 } from './migrations/1779235200000-AddUuidDefaultsForPostgres';

const ALL_TABLES = ['sessions', 'webhooks', 'messages', 'message_batches'];

interface RunnerOpts {
  versionNum?: number; // server_version_num, e.g. 150000 (PG 15) or 120000 (PG 12)
  extInstalled?: boolean; // is pgcrypto already present in pg_extension?
  createExtensionThrows?: boolean; // does CREATE EXTENSION fail (unprivileged role)?
}

function makeQueryRunner(type: string, existingTables: Set<string>, opts: RunnerOpts = {}) {
  const { versionNum = 150000, extInstalled = false, createExtensionThrows = false } = opts;
  const query = jest.fn((sql: string) => {
    const s = String(sql);
    if (/server_version_num/i.test(s)) return Promise.resolve([{ num: versionNum }]);
    if (/pg_extension/i.test(s)) return Promise.resolve(extInstalled ? [{ ok: 1 }] : []);
    if (/CREATE EXTENSION/i.test(s) && createExtensionThrows) {
      return Promise.reject(new Error('permission denied to create extension "pgcrypto"'));
    }
    return Promise.resolve(undefined);
  });
  return {
    dataSource: { options: { type } },
    hasTable: jest.fn((t: string) => Promise.resolve(existingTables.has(t))),
    query,
  };
}

const sqlOf = (qr: ReturnType<typeof makeQueryRunner>): string[] =>
  qr.query.mock.calls.map(call => String((call as unknown[])[0]));

describe('AddUuidDefaultsForPostgres migration', () => {
  const migration = new AddUuidDefaultsForPostgres1779235200000();

  it('is a no-op on SQLite — issues no query and never probes tables', async () => {
    const qr = makeQueryRunner('sqlite', new Set(ALL_TABLES));
    await migration.up(qr as unknown as QueryRunner);
    await migration.down(qr as unknown as QueryRunner);
    expect(qr.query).not.toHaveBeenCalled();
    expect(qr.hasTable).not.toHaveBeenCalled();
  });

  it('on PG 13+ does NOT touch pgcrypto (core gen_random_uuid), only sets the DEFAULTs', async () => {
    const qr = makeQueryRunner('postgres', new Set(ALL_TABLES), { versionNum: 150000 });
    await migration.up(qr as unknown as QueryRunner);

    const calls = sqlOf(qr);
    expect(calls.some(q => /CREATE EXTENSION/i.test(q))).toBe(false);
    expect(calls.some(q => /pg_extension/i.test(q))).toBe(false); // no need to probe the catalog on 13+
    // version probe + one ALTER per existing table.
    expect(qr.query).toHaveBeenCalledTimes(1 + ALL_TABLES.length);
    expect(qr.query).toHaveBeenCalledWith(
      'ALTER TABLE "sessions" ALTER COLUMN "id" SET DEFAULT gen_random_uuid()::varchar',
    );
  });

  it('on PG <= 12 with pgcrypto missing, creates it BEFORE any gen_random_uuid() default', async () => {
    const qr = makeQueryRunner('postgres', new Set(ALL_TABLES), { versionNum: 120000, extInstalled: false });
    await migration.up(qr as unknown as QueryRunner);

    const calls = sqlOf(qr);
    const extIdx = calls.findIndex(q => /CREATE EXTENSION IF NOT EXISTS pgcrypto/i.test(q));
    const firstAlterIdx = calls.findIndex(q => /gen_random_uuid\(\)/i.test(q));
    expect(extIdx).toBeGreaterThanOrEqual(0);
    expect(extIdx).toBeLessThan(firstAlterIdx);
  });

  it('on PG <= 12 with pgcrypto already installed, does NOT attempt CREATE EXTENSION', async () => {
    const qr = makeQueryRunner('postgres', new Set(ALL_TABLES), { versionNum: 120000, extInstalled: true });
    await migration.up(qr as unknown as QueryRunner);

    const calls = sqlOf(qr);
    expect(calls.some(q => /CREATE EXTENSION/i.test(q))).toBe(false);
    expect(calls.some(q => /gen_random_uuid/i.test(q))).toBe(true); // DEFAULTs still applied
  });

  it('on PG <= 12 where the role cannot create pgcrypto, throws a clear error and sets no DEFAULT', async () => {
    const qr = makeQueryRunner('postgres', new Set(ALL_TABLES), {
      versionNum: 120000,
      extInstalled: false,
      createExtensionThrows: true,
    });
    await expect(migration.up(qr as unknown as QueryRunner)).rejects.toThrow(/pgcrypto/i);
    // Aborted before any ALTER — no half-applied default.
    expect(sqlOf(qr).some(q => /gen_random_uuid/i.test(q))).toBe(false);
  });

  it('skips tables that do not exist', async () => {
    const qr = makeQueryRunner('postgres', new Set(['sessions', 'messages']), { versionNum: 150000 });
    await migration.up(qr as unknown as QueryRunner);
    // version probe + 2 ALTERs (only the two existing tables).
    expect(qr.query).toHaveBeenCalledTimes(1 + 2);
  });

  it('on Postgres down() drops the DEFAULT on every existing table', async () => {
    const qr = makeQueryRunner('postgres', new Set(ALL_TABLES));
    await migration.down(qr as unknown as QueryRunner);

    expect(qr.query).toHaveBeenCalledTimes(ALL_TABLES.length);
    expect(qr.query).toHaveBeenCalledWith('ALTER TABLE "message_batches" ALTER COLUMN "id" DROP DEFAULT');
  });
});