/**
 * Billing / Subscription client — thin wrapper over @bytelyst/subscription-client.
 *
 * Delegates subscription operations to the shared package.
 * Keeps ChronoMind-specific usage API as a local fetch call.
 * Client-side only — uses the stored auth token for authorization.
 */

import { createSubscriptionClient } from '@bytelyst/subscription-client';
import type { SubscriptionDoc } from '@bytelyst/subscription-client';
import { PRODUCT_ID, getBaseUrl, getAuthClient } from './auth-api';

// ── Shared client ──────────────────────────────────────────────────

let _client: ReturnType<typeof createSubscriptionClient> | null = null;

function getClient() {
  if (!_client) {
    _client = createSubscriptionClient({
      baseUrl: `${getBaseUrl()}/api`,
      productId: PRODUCT_ID,
      userId: 'me',
      getAccessToken: () => getAuthClient().getAccessToken() ?? '',
    });
  }
  return _client;
}

// ── Types (backwards-compatible) ───────────────────────────────────

export interface Subscription {
  id: string;
  productId: string;
  userId: string;
  plan: 'free' | 'pro';
  status: 'active' | 'cancelled' | 'past_due' | 'trialing';
  currentPeriodStart: string;
  currentPeriodEnd: string;
  cancelAtPeriodEnd: boolean;
  stripeCustomerId?: string;
  stripeSubscriptionId?: string;
  createdAt: string;
  updatedAt: string;
}

function toSubscription(doc: SubscriptionDoc): Subscription {
  return {
    id: doc.id,
    productId: doc.productId ?? PRODUCT_ID,
    userId: doc.userId,
    plan: doc.plan as Subscription['plan'],
    status: doc.status as Subscription['status'],
    currentPeriodStart: doc.currentPeriodStart,
    currentPeriodEnd: doc.currentPeriodEnd,
    cancelAtPeriodEnd: doc.cancelAtPeriodEnd,
    stripeCustomerId: doc.stripeCustomerId,
    stripeSubscriptionId: doc.stripeSubscriptionId,
    createdAt: doc.createdAt,
    updatedAt: doc.updatedAt,
  };
}

// ── Subscription API ───────────────────────────────────────────────

export async function getMySubscription(_userId?: string): Promise<Subscription | null> {
  try {
    const doc = await getClient().getMySubscription();
    return doc ? toSubscription(doc) : null;
  } catch {
    return null;
  }
}

export async function cancelSubscription(_userId?: string): Promise<Subscription | null> {
  try {
    const doc = await getClient().cancelSubscription();
    return toSubscription(doc);
  } catch {
    return null;
  }
}

// ── Usage API (ChronoMind-specific, not in shared client) ──────────

export interface UsageSummary {
  timersCreated: number;
  routinesCompleted: number;
  focusMinutes: number;
}

export async function getUsageSummary(userId: string, days = 30): Promise<UsageSummary | null> {
  try {
    const token = getAuthClient().getAccessToken();
    const res = await fetch(`${getBaseUrl()}/usage/summary?userId=${userId}&days=${days}`, {
      headers: {
        'Content-Type': 'application/json',
        'x-product-id': PRODUCT_ID,
        ...(token ? { Authorization: `Bearer ${token}` } : {}),
      },
    });
    if (!res.ok) return null;
    const data = await res.json() as { summary: UsageSummary };
    return data.summary;
  } catch {
    return null;
  }
}