import { InvalidRequest, ServerError, InvalidGrant } from '../../model/error';
import {
  OAuth2,
  OAuth2Client,
  OAuth2Code,
  OAuth2TokenResponse,
} from '../../model/model';
import { createS256, safeCompare } from '../../utils/crypto-tools';

/**
 * Issue an access token by authorization code
 * @param oauth2 - OAuth2 instance
 * @param client - OAuth2 client
 * @param providedCode - Authorization code
 * @returns Access token.
 */
export async function authorizationCode(
  oauth2: OAuth2,
  client: OAuth2Client,
  providedCode: string,
  codeVerifier?: string,
): Promise<OAuth2TokenResponse> {
  const respObj: OAuth2TokenResponse = {
    token_type: 'bearer',
  };

  let code: OAuth2Code | null = null;

  if (!providedCode) {
    throw new InvalidRequest(
      'code is mandatory for authorization_code grant type'
    );
  }

  try {
    code = await oauth2.model.code.fetchByCode(providedCode);
  } catch (err) {
    oauth2.logger.error(err);
    throw new ServerError('Failed to call code.fetchByCode function');
  }

  if (code) {
    if (
      oauth2.model.code.getClientId(code) !== oauth2.model.client.getId(client)
    ) {
      throw new InvalidGrant('Code was issued by another client');
    }

    if (!oauth2.model.code.checkTTL(code)) {
      throw new InvalidGrant('Code has already expired');
    }
  } else {
    throw new InvalidGrant('Code not found');
  }

  oauth2.logger.debug('Code fetched', code);

  const scope = oauth2.model.code.getScope(code);
  const cleanScope = oauth2.model.client.transformScope(scope);
  const userId = oauth2.model.code.getUserId(code);
  const clientId = oauth2.model.code.getClientId(code);

  if (oauth2.model.code.getCodeChallenge) {
    const { challenge, method } = oauth2.model.code.getCodeChallenge(code);

    if (challenge && method) {
      if (!codeVerifier) {
        throw new InvalidGrant('Code verifier is required!');
      }

      if (method === 'plain' && !safeCompare(challenge, codeVerifier)) {
        throw new InvalidGrant('Invalid code verifier!');
      }

      if (method === 'S256' && !safeCompare(createS256(codeVerifier), challenge)) {
        throw new InvalidGrant('Invalid code verifier!');
      }
    }

    oauth2.logger.debug('Code passed PCKE check');
  }

  if (oauth2.model.refreshToken.invalidateOld) {
    try {
      await oauth2.model.refreshToken.removeByUserIdClientId(userId, clientId);
    } catch (err) {
      oauth2.logger.error(err);
      throw new ServerError(
        'Failed to call refreshToken.removeByUserIdClientId function'
      );
    }

    oauth2.logger.debug('Refresh token removed');
  }

  if (!oauth2.model.client.checkGrantType(client, 'refresh_token')) {
    oauth2.logger.debug(
      'Client does not allow grant type refresh_token, skip creation'
    );
  } else {
    try {
      respObj.refresh_token = await oauth2.model.refreshToken.create(
        userId,
        clientId,
        scope
      );
    } catch (err) {
      oauth2.logger.error(err);
      throw new ServerError('Failed to call refreshToken.create function');
    }
  }

  try {
    respObj.access_token = await oauth2.model.accessToken.create(
      userId,
      clientId,
      scope,
      oauth2.model.accessToken.ttl
    );
  } catch (err) {
    oauth2.logger.error(err);
    throw new ServerError('Failed to call accessToken.create function');
  }

  respObj.expires_in = oauth2.model.accessToken.ttl;
  oauth2.logger.debug('Access token saved:', respObj.access_token);

  try {
    await oauth2.model.code.removeByCode(providedCode);
  } catch (err) {
    oauth2.logger.error(err);
    throw new ServerError('Failed to call code.removeByCode function');
  }

  if (cleanScope.includes('openid') && oauth2.model.jwt) {
    const user = await oauth2.model.user.fetchById(
      oauth2.model.code.getUserId(code)
    );

    try {
      respObj.id_token = await oauth2.model.jwt.issueIdToken(
        user,
        client,
        cleanScope,
        code.nonce
      );
    } catch (err) {
      oauth2.logger.error(err);
      throw new ServerError('Failed to issue an ID token');
    }
  }

  return respObj;
}