import { vi } from 'vitest';
import type { StorageItem } from '../../src/generated/storage.js';
import type { CallModuleFunctionClientResponse } from '../../src/generated/modules.js';
import type { CatalogCurrency } from '../../src/generated/catalog.js';

export interface RecordedRequest {
  method: string;
  path: string;
  query: URLSearchParams;
  body: unknown;
  authToken: string | null;
  headers: Headers;
}

export interface FakeGatewayState {
  storage: Map<string, StorageItem>;
  currencies: CatalogCurrency[];
  /** Response per `module/fn`; falls back to `{ result: {} }`. */
  moduleCalls: Map<string, CallModuleFunctionClientResponse>;
}

export interface FakeGateway {
  state: FakeGatewayState;
  recorded: RecordedRequest[];
  install(): void;
}

function json(body: unknown, status = 200): Response {
  return new Response(JSON.stringify(body), {
    status,
    headers: { 'Content-Type': 'application/json' },
  });
}

const noContent = (): Response => new Response(null, { status: 204 });

export function createFakeGateway(seed?: Partial<FakeGatewayState>): FakeGateway {
  const state: FakeGatewayState = {
    storage: seed?.storage ?? new Map(),
    currencies: seed?.currencies ?? [],
    moduleCalls: seed?.moduleCalls ?? new Map(),
  };

  const recorded: RecordedRequest[] = [];

  async function handle(req: RecordedRequest): Promise<Response> {
    const { method, path, query, body } = req;

    if (method === 'POST' && path === '/sdk/v1/authorization/device') {
      const b = body as { deviceId?: string };
      return json({
        accessToken: `access-${b.deviceId ?? 'dev'}`,
        refreshToken: `refresh-${b.deviceId ?? 'dev'}`,
      });
    }

    if (method === 'GET' && path === '/sdk/v1/player/information') {
      return json({ player: null, wallets: [] });
    }

    if (method === 'GET' && path === '/sdk/v1/sync') {
      return json({});
    }

    if (method === 'GET' && path === '/sdk/v1/catalog') {
      return json({ currencies: state.currencies });
    }

    const moduleMatch = path.match(/^\/sdk\/v1\/modules\/([^/]+)\/([^/]+)$/);
    if (method === 'POST' && moduleMatch) {
      return json(state.moduleCalls.get(`${moduleMatch[1]}/${moduleMatch[2]}`) ?? { result: {} });
    }

    if (path === '/sdk/v1/storage') {
      if (method === 'GET') {
        const typeFilter = query.get('types');
        const items = [...state.storage.values()].filter(
          (it) => !typeFilter || it.type === typeFilter,
        );
        return json({ items, nextCursor: '' });
      }
      if (method === 'PUT') {
        const items = (body as { items?: StorageItem[] }).items ?? [];
        for (const item of items) {
          if (item.type) state.storage.set(item.type, { id: `id-${item.type}`, ...item });
        }
        return noContent();
      }
      if (method === 'DELETE') {
        const type = query.get('type');
        if (type) state.storage.delete(type);
        else state.storage.clear();
        return noContent();
      }
    }

    return json({ error: `unhandled route: ${method} ${path}` }, 500);
  }

  function install(): void {
    vi.stubGlobal(
      'fetch',
      vi.fn(async (input: string | URL, init?: RequestInit): Promise<Response> => {
        const url = new URL(typeof input === 'string' ? input : input.toString());
        const headers = new Headers(init?.headers);
        const auth = headers.get('Authorization');
        const req: RecordedRequest = {
          method: (init?.method ?? 'GET').toUpperCase(),
          path: url.pathname,
          query: url.searchParams,
          body: init?.body ? JSON.parse(init.body as string) : undefined,
          authToken: auth ? auth.replace(/^Bearer\s+/, '') : null,
          headers,
        };
        recorded.push(req);
        return handle(req);
      }),
    );
  }

  return {
    state,
    recorded,
    install,
  };
}