import type { KeycloakConfig, TokenResponse, UserInfo } from '~/utils/types';

export class KeycloakClient {
  private config: KeycloakConfig;

  constructor(config: KeycloakConfig) {
    this.config = config;
  }

  getAuthUrl(state: string): string {
    const params = new URLSearchParams({
      client_id: this.config.clientId,
      redirect_uri: this.config.callbackUrl,
      response_type: 'code',
      scope: 'openid email profile',
      state,
    });

    return `${this.config.issuer}/protocol/openid-connect/auth?${params}`;
  }

  async exchangeCodeForTokens(code: string): Promise<TokenResponse> {
    const response = await fetch(`${this.config.issuer}/protocol/openid-connect/token`, {
      method: 'POST',
      headers: {
        'Content-Type': 'application/x-www-form-urlencoded',
      },
      body: new URLSearchParams({
        grant_type: 'authorization_code',
        client_id: this.config.clientId,
        client_secret: this.config.clientSecret,
        code,
        redirect_uri: this.config.callbackUrl,
      }),
    });

    if (!response.ok) {
      throw new Error(`Token exchange failed: ${response.statusText}`);
    }

    return response.json();
  }

  async getUserInfo(accessToken: string): Promise<UserInfo> {
    const response = await fetch(`${this.config.issuer}/protocol/openid-connect/userinfo`, {
      headers: {
        Authorization: `Bearer ${accessToken}`,
      },
    });

    if (!response.ok) {
      throw new Error(`Failed to get user info: ${response.statusText}`);
    }

    return response.json();
  }

  async refreshToken(refreshToken: string): Promise<TokenResponse> {
    const response = await fetch(`${this.config.issuer}/protocol/openid-connect/token`, {
      method: 'POST',
      headers: {
        'Content-Type': 'application/x-www-form-urlencoded',
      },
      body: new URLSearchParams({
        grant_type: 'refresh_token',
        client_id: this.config.clientId,
        client_secret: this.config.clientSecret,
        refresh_token: refreshToken,
      }),
    });

    if (!response.ok) {
      throw new Error(`Token refresh failed: ${response.statusText}`);
    }

    return response.json();
  }
}

export function createKeycloakClient(): KeycloakClient {
  const config = useRuntimeConfig();
  return new KeycloakClient(config.keycloak);
}