import type { AuthInfo } from '@modelcontextprotocol/server';

import { createMcpHandler, withMcpAuth } from 'mcp-handler';

import { MemoryAuditStore, TrustEngine } from '../packages/core/src/index.js';

import {

  OPENCLASP_MCP_INSTRUCTIONS,

  registerOpenClaspTools,

} from '../packages/mcp-server/src/server.js';

import { HostedRepository } from '../packages/persistence/src/hosted.js';

import { verifyAuth0Token } from './auth0.js';

import { oauthStore } from './oauth-store.js';

const repository = process.env.DATABASE_URL

  ? new HostedRepository(process.env.DATABASE_URL)

  : undefined;

const engines = new Map<string, Promise<TrustEngine>>();

function engineFor(context: { http?: { authInfo?: { extra?: Record<string, unknown> } } }) {

  const operatorId =

    context.http?.authInfo?.extra?.operatorId ?? context.http?.authInfo?.extra?.userId;

  if (typeof operatorId !== 'string' || !repository) return Promise.resolve(new TrustEngine());

  let pending = engines.get(operatorId);

  if (!pending) {

    pending = repository.list(operatorId).then((rows) => {

      const store = new MemoryAuditStore();

      for (const row of rows) {

        if (row.kind !== 'interaction') store.append(row.kind, row.recordId, row.payload);

      }

      return new TrustEngine(store);

    });

    engines.set(operatorId, pending);

  }

  return pending;

}

const mcp = createMcpHandler(

  (server) =>

    registerOpenClaspTools(

      server,

      engineFor,

      repository

        ? (operatorId, kind, recordId, value) =>

            repository.upsert(operatorId, kind, recordId, value)

        : undefined,

      repository,

      repository,

    ),

  {

    serverInfo: { name: 'openclasp', version: '0.1.0' },

    instructions: OPENCLASP_MCP_INSTRUCTIONS,

  },

);

async function verifyToken(_request: Request, bearerToken?: string): Promise<AuthInfo | undefined> {

  if (!bearerToken) return undefined;

  if (bearerToken.startsWith('oc_oat_')) {

    const authentication = await oauthStore().verifyAccessToken(bearerToken);

    if (!authentication || !authentication.scopes.includes('mcp:access'))

      throw new Error('OpenClasp OAuth token is invalid or missing the MCP scope');

    return {

      token: bearerToken,

      clientId: authentication.clientId,

      scopes: authentication.scopes,

      expiresAt: Math.floor(Date.parse(authentication.expiresAt) / 1000),

      extra: {

        operatorId: authentication.operatorId,

        credentialType: 'oauth_access_token',

      },

    };

  }

  if (bearerToken.startsWith('oc_at_')) {

    if (!repository) throw new Error('Agent access tokens are not configured');

    const authentication = await repository.verifyAgentAccessToken(bearerToken);

    if (!authentication.scopes.includes('mcp:access'))

      throw new Error('Agent access token is missing the MCP scope');

    return {

      token: bearerToken,

      clientId: authentication.clientId,

      scopes: authentication.scopes,

      expiresAt: Math.floor(Date.parse(authentication.expiresAt) / 1000),

      extra: {

        operatorId: authentication.operatorId,

        boundAgentId: authentication.agentId,

        credentialType: 'agent_access_token',

      },

    };

  }

  const authentication = await verifyAuth0Token(bearerToken, {

    dashboard: false,

    requiredScopes: ['mcp:access'],

  });

  return {

    token: bearerToken,

    clientId: authentication.clientId,

    scopes: authentication.scopes,

    ...(typeof authentication.payload.exp === 'number'

      ? { expiresAt: authentication.payload.exp }

      : {}),

    extra: { operatorId: authentication.payload.sub },

  };

}

const resourceMetadataPath = '/.well-known/oauth-protected-resource/mcp';

const authenticatedHandler = withMcpAuth(mcp, verifyToken, {

  required: true,

  resourceMetadataPath,

  ...(process.env.OPENCLASP_MCP_URL

    ? { resourceUrl: new URL(process.env.OPENCLASP_MCP_URL).origin }

    : {}),

});

async function handler(request: Request): Promise<Response> {

  const response = await authenticatedHandler(request);

  if (response.status !== 401 || request.headers.get('authorization')?.trim()) return response;

  // A missing credential is an authentication discovery challenge, not an invalid token.

  // Cursor's V2 MCP client treats `invalid_token` while auth is still unknown as a

  // transient connection failure instead of starting OAuth.

  const configuredResource = process.env.OPENCLASP_MCP_URL;

  const publicOrigin = configuredResource

    ? new URL(configuredResource).origin

    : new URL(request.url).origin;

  const headers = new Headers(response.headers);

  headers.set(

    'www-authenticate',

    `Bearer resource_metadata="${new URL(resourceMetadataPath, publicOrigin).href}", scope="mcp:access"`,

  );

  headers.set('cache-control', 'no-store');

  headers.delete('content-length');

  headers.delete('content-type');

  return new Response(null, {

    status: response.status,

    statusText: response.statusText,

    headers,

  });

}

export { handler as GET, handler as POST };