import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
import Database from 'better-sqlite3';
import {
  RedditAccountEstablishmentRepository,
  RedditAccountsRepository,
} from '../src/database/account-repositories.js';
import { runMigrations } from '../src/database/client.js';
import {
  AccountEstablishmentService,
  evaluateAccountProfile,
  isUnestablishedFailure,
  type AccountEstablishmentSettings,
} from '../src/services/account-establishment.js';
import { RedditAccountsService } from '../src/services/reddit-accounts.js';
import type { RedditAccountProfile } from '../src/reddit/api.js';
import { RedditRateLimitError } from '../src/reddit/api.js';
import { createMockLogger } from './mockLogger.js';

const DAY_MS = 24 * 60 * 60_000;
const NOW = 1_700_000_000_000;
const ACCOUNT_ID = '@t2_new:reddit.com';

const settings: AccountEstablishmentSettings = {
  enabled: true,
  profileCheckIntervalMs: 6 * 60 * 60_000,
  minAccountAgeDays: 7,
  minTotalKarma: 20,
  minCommentKarma: 5,
  requireVerifiedEmail: false,
  probeRetryBaseMs: 4 * 60 * 60_000,
  probeRetryMaxMs: 48 * 60 * 60_000,
};

function profile(overrides: Partial<RedditAccountProfile> = {}): RedditAccountProfile {
  return {
    createdAt: NOW - 30 * DAY_MS,
    linkKarma: 100,
    commentKarma: 50,
    totalKarma: 150,
    hasVerifiedEmail: true,
    isSuspended: false,
    ...overrides,
  };
}

describe('unestablished failure classification', () => {
  it('recognises the Reddit codes and messages that mean the account is too new', () => {
    expect(isUnestablishedFailure(null, 'rate.invitation_limit_new_account')).toBe(true);
    expect(isUnestablishedFailure(null, 'rate.invitation_limit_immature_account')).toBe(true);
    expect(isUnestablishedFailure('Your account is too new to start chats', null)).toBe(true);
    expect(isUnestablishedFailure('You need more karma to message this user', null)).toBe(true);
    expect(isUnestablishedFailure('Please verify your email address first', null)).toBe(true);
    expect(isUnestablishedFailure('New accounts cannot start chats', null)).toBe(true);
  });

  it('leaves ordinary throttles and recipient-side refusals alone', () => {
    // This code is the throttle applied to accounts that *are* established.
    expect(isUnestablishedFailure(
      'Reddit is throttling new chat invitations; replies in existing chats can continue.',
      'rate.invitation_limit_mature_account',
    )).toBe(false);
    expect(isUnestablishedFailure('Recipient does not accept chat requests', null)).toBe(false);
    expect(isUnestablishedFailure('Reddit user is unavailable', null)).toBe(false);
    expect(isUnestablishedFailure('Reddit chat invitation failed temporarily', 'rate.room_creation_limit')).toBe(false);
    expect(isUnestablishedFailure(null, null)).toBe(false);
  });
});

describe('profile evaluation', () => {
  it('reports every threshold the account falls short of', () => {
    const verdict = evaluateAccountProfile({
      accountCreatedAt: NOW - 2 * DAY_MS,
      linkKarma: 1,
      commentKarma: 1,
      totalKarma: 2,
      hasVerifiedEmail: false,
    }, { ...settings, requireVerifiedEmail: true }, NOW);

    expect(verdict.established).toBe(false);
    expect(verdict.reasons).toEqual([
      'Account is 2 days old (below the configured floor of 7 days)',
      'Total karma is 2 (below the configured floor of 20)',
      'Comment karma is 1 (below the configured floor of 5)',
      'Email address is not verified',
    ]);
  });

  it('passes an account that clears every threshold', () => {
    const verdict = evaluateAccountProfile({
      accountCreatedAt: NOW - 30 * DAY_MS,
      linkKarma: 100,
      commentKarma: 50,
      totalKarma: 150,
      hasVerifiedEmail: true,
    }, settings, NOW);

    expect(verdict).toEqual({ established: true, reasons: [] });
  });

  it('never counts a missing value against the account', () => {
    const verdict = evaluateAccountProfile({
      accountCreatedAt: null,
      linkKarma: null,
      commentKarma: null,
      totalKarma: null,
      hasVerifiedEmail: null,
    }, { ...settings, requireVerifiedEmail: true }, NOW);

    expect(verdict).toEqual({ established: true, reasons: [] });
  });
});

describe('AccountEstablishmentService', () => {
  let db: Database.Database;
  let repository: RedditAccountEstablishmentRepository;
  let now: number;

  function createService(
    getAccountProfile: (username: string) => Promise<RedditAccountProfile | null>,
    overrides: Partial<AccountEstablishmentSettings> = {},
  ) {
    return new AccountEstablishmentService(
      ACCOUNT_ID,
      'new-account',
      { getAccountProfile },
      repository,
      { ...settings, ...overrides },
      createMockLogger(),
      { isFullyAuthenticated: () => true, invalidate: () => undefined },
      () => now,
    );
  }

  beforeEach(() => {
    now = NOW;
    db = new Database(':memory:');
    db.pragma('foreign_keys = ON');
    runMigrations(db);
    new RedditAccountsRepository(db).upsertVerified({
      accountId: ACCOUNT_ID,
      redditUsername: 'new-account',
      matrixUserId: ACCOUNT_ID,
      cookiesJson: '[]',
      matrixCredentialsJson: '{}',
      now: NOW,
    });
    repository = new RedditAccountEstablishmentRepository(db);
  });

  afterEach(() => db.close());

  it('allows sending until something says otherwise', () => {
    const service = createService(async () => profile());

    expect(service.isSendable()).toBe(true);
    expect(service.snapshot()).toBeNull();
  });

  it('flags a brand new account from its profile and stores the evidence', async () => {
    const service = createService(async () => profile({
      createdAt: NOW - DAY_MS,
      linkKarma: 0,
      commentKarma: 0,
      totalKarma: 0,
    }));

    const record = await service.checkNow();

    expect(record).toMatchObject({
      state: 'unestablished',
      accountCreatedAt: NOW - DAY_MS,
      linkKarma: 0,
      commentKarma: 0,
      totalKarma: 0,
      hasVerifiedEmail: true,
      profileCheckedAt: NOW,
      probeFailureCount: 0,
    });
    expect(record!.reasons).toContain('Account is 1 day old (below the configured floor of 7 days)');
    // A guessed threshold must never hold the account back: it has to be
    // allowed to try, or Reddit's authoritative answer can never arrive.
    expect(record!.retryAt).toBeNull();
    expect(service.isSendable()).toBe(true);
  });

  it('clears the flag once the account has aged and earned karma', async () => {
    let current = profile({ createdAt: NOW - DAY_MS, linkKarma: 0, commentKarma: 0, totalKarma: 0 });
    const service = createService(async () => current);

    expect(await service.checkNow()).toMatchObject({ state: 'unestablished' });

    now = NOW + 10 * DAY_MS;
    current = profile({ createdAt: NOW - DAY_MS, commentKarma: 30, totalKarma: 60 });
    const record = await service.checkNow();

    expect(record).toMatchObject({ state: 'established', reasons: [] });
    expect(service.isSendable()).toBe(true);
  });

  it('holds the account out of sending when Reddit rejects an invitation as too new', () => {
    const service = createService(async () => profile());

    const record = service.recordSendFailure(
      'Reddit chat invitation failed temporarily',
      'rate.invitation_limit_new_account',
    );

    expect(record).toMatchObject({ state: 'unestablished', probeFailureCount: 1 });
    expect(record!.retryAt).toBe(NOW + settings.probeRetryBaseMs);
    expect(record!.lastProbeFailure).toContain('rate.invitation_limit_new_account');
    expect(service.isSendable()).toBe(false);

    now = NOW + settings.probeRetryBaseMs;
    expect(service.isSendable()).toBe(true);
  });

  it('ignores failures that are not about how established the account is', () => {
    const service = createService(async () => profile());

    expect(service.recordSendFailure('Recipient does not accept chat requests', null)).toBeNull();
    expect(service.snapshot()).toBeNull();
    expect(service.isSendable()).toBe(true);
  });

  it('backs off further on each repeated rejection, up to the configured ceiling', () => {
    const service = createService(async () => profile(), { probeRetryMaxMs: 6 * 60 * 60_000 });

    expect(service.recordSendFailure('account is too new')!.retryAt).toBe(NOW + 4 * 60 * 60_000);
    expect(service.recordSendFailure('account is too new')!.retryAt).toBe(NOW + 6 * 60 * 60_000);
    expect(service.recordSendFailure('account is too new')).toMatchObject({
      probeFailureCount: 3,
      retryAt: NOW + 6 * 60 * 60_000,
    });
  });

  it('treats a delivered invitation as proof the account is established', () => {
    const service = createService(async () => profile());
    service.recordSendFailure('account is too new');

    const record = service.recordSendSuccess();

    expect(record).toMatchObject({
      state: 'established',
      reasons: [],
      probeFailureCount: 0,
      retryAt: null,
      lastProbeFailure: null,
    });
    expect(service.isSendable()).toBe(true);
  });

  it('keeps a rejected account held even when its profile now looks acceptable', async () => {
    const service = createService(async () => profile());
    service.recordSendFailure('account is too new');

    now = NOW + 60_000;
    const record = await service.checkNow();

    expect(record).toMatchObject({ state: 'unestablished', retryAt: NOW + settings.probeRetryBaseMs });
    expect(record!.totalKarma).toBe(150);
    expect(service.isSendable()).toBe(false);
  });

  it('leaves the stored verdict untouched when Reddit rate-limits the profile lookup', async () => {
    const service = createService(async () => { throw new RedditRateLimitError(60_000); });

    expect(await service.checkNow()).toBeNull();
    expect(service.snapshot()).toBeNull();
    expect(service.isSendable()).toBe(true);
  });

  it('does nothing at all when establishment tracking is disabled', async () => {
    const getAccountProfile = vi.fn(async () => profile({ createdAt: NOW }));
    const service = createService(getAccountProfile, { enabled: false });

    service.start();
    expect(await service.checkNow()).toBeNull();
    expect(service.recordSendFailure('account is too new')).toBeNull();
    expect(getAccountProfile).not.toHaveBeenCalled();
    expect(service.isSendable()).toBe(true);
    service.stop();
  });

  it('publishes the stored evidence through the account listing the dashboard reads', async () => {
    const accounts = new RedditAccountsService(
      new RedditAccountsRepository(db),
      {} as never,
      { getSnapshot: () => ({ accountId: ACCOUNT_ID }) } as never,
      undefined,
      undefined,
      repository,
    );

    expect(accounts.list()[0].establishment).toBeNull();

    // Age is reported relative to the wall clock the dashboard renders in.
    await createService(async () => profile({
      createdAt: Date.now() - 3 * DAY_MS,
      linkKarma: 1,
      commentKarma: 2,
      totalKarma: 3,
      hasVerifiedEmail: false,
    })).checkNow();

    expect(accounts.list()[0].establishment).toMatchObject({
      state: 'unestablished',
      // Below our thresholds, but nothing Reddit has refused — so not held.
      sendingHeld: false,
      accountAgeDays: 3,
      linkKarma: 1,
      commentKarma: 2,
      totalKarma: 3,
      hasVerifiedEmail: false,
      profileCheckedAt: NOW,
      retryAt: null,
    });
    expect(accounts.list()[0].establishment!.reasons.length).toBeGreaterThan(0);
  });

  it('marks sending as held only while a Reddit rejection is still in force', () => {
    const accounts = new RedditAccountsService(
      new RedditAccountsRepository(db),
      {} as never,
      { getSnapshot: () => ({ accountId: ACCOUNT_ID }) } as never,
      undefined,
      undefined,
      repository,
    );
    // The listing derives the hold against the wall clock the dashboard renders
    // in, so this account's rejection is recorded there too.
    now = Date.now();
    const service = createService(async () => profile());

    service.recordSendFailure('account is too new');
    expect(accounts.list()[0].establishment).toMatchObject({ state: 'unestablished', sendingHeld: true });

    service.recordSendSuccess();
    expect(accounts.list()[0].establishment).toMatchObject({ state: 'established', sendingHeld: false });
  });

  it('skips the check while the account session is not authenticated', async () => {
    const getAccountProfile = vi.fn(async () => profile());
    const service = new AccountEstablishmentService(
      ACCOUNT_ID,
      'new-account',
      { getAccountProfile },
      repository,
      settings,
      createMockLogger(),
      { isFullyAuthenticated: () => false, invalidate: () => undefined },
      () => now,
    );

    expect(await service.checkNow()).toBeNull();
    expect(getAccountProfile).not.toHaveBeenCalled();
  });
});