package org.keycloak.adapters;

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.client.HttpClient;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.message.BasicNameValuePair;
import org.keycloak.adapters.config.RealmConfiguration;
import org.keycloak.representations.AccessTokenResponse;
import org.keycloak.representations.idm.CredentialRepresentation;
import org.keycloak.util.JsonSerialization;
import org.keycloak.util.KeycloakUriBuilder;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;

/**
 * @author <a href="mailto:bill@burkecentral.com">Bill Burke</a>
 * @version $Revision: 1 $
 */
public class TokenGrantRequest {

    public static class HttpFailure extends Exception {
        private int status;
        private String error;

        public HttpFailure(int status, String error) {
            this.status = status;
            this.error = error;
        }

        public int getStatus() {
            return status;
        }

        public String getError() {
            return error;
        }
    }

    public static AccessTokenResponse invoke(RealmConfiguration config, String code, String redirectUri) throws HttpFailure, IOException {
        String codeUrl = config.getCodeUrl();
        String client_id = config.getMetadata().getResourceName();
        Map<String,String> credentials = config.getResourceCredentials();
        HttpClient client = config.getClient();

        return invoke(client, code, codeUrl, redirectUri, client_id, credentials);
    }

    public static AccessTokenResponse invoke(HttpClient client, String code, String codeUrl, String redirectUri, String client_id, Map<String, String> credentials) throws IOException, HttpFailure {
        List<NameValuePair> formparams = new ArrayList<NameValuePair>();
        redirectUri = stripOauthParametersFromRedirect(redirectUri);
        String password = credentials.get("password");
        formparams.add(new BasicNameValuePair("grant_type", "authorization_code"));
        formparams.add(new BasicNameValuePair("code", code));
        formparams.add(new BasicNameValuePair("client_id", client_id));
        formparams.add(new BasicNameValuePair(CredentialRepresentation.PASSWORD, password));
        formparams.add(new BasicNameValuePair("redirect_uri", redirectUri));
        HttpResponse response = null;
        UrlEncodedFormEntity form = new UrlEncodedFormEntity(formparams, "UTF-8");
        HttpPost post = new HttpPost(codeUrl);
        post.setEntity(form);
        response = client.execute(post);
        int status = response.getStatusLine().getStatusCode();
        HttpEntity entity = response.getEntity();
        if (status != 200) {
            error(status, entity);
        }
        if (entity == null) {
            throw new HttpFailure(status, null);
        }
        InputStream is = entity.getContent();
        try {
            return JsonSerialization.readValue(is, AccessTokenResponse.class);
        } finally {
            try {
                is.close();
            } catch (IOException ignored) {

            }
        }
    }


    protected static String readString(InputStream in) throws IOException
    {
        char[] buffer = new char[1024];
        StringBuilder builder = new StringBuilder();
        BufferedReader reader = new BufferedReader(new InputStreamReader(in));
        int wasRead = 0;
        do
        {
            wasRead = reader.read(buffer, 0, 1024);
            if (wasRead > 0)
            {
                builder.append(buffer, 0, wasRead);
            }
        }
        while (wasRead > -1);

        return builder.toString();
    }


    protected static void error(int status, HttpEntity entity) throws HttpFailure, IOException {
       String body = null;
        if (entity != null) {
            InputStream is = entity.getContent();
            try {
                body = readString(is);
            } catch (IOException e) {

            } finally {
                try {
                    is.close();
                } catch (IOException ignored) {

                }
            }
        }
        throw new HttpFailure(status, body);
    }

    protected static String stripOauthParametersFromRedirect(String uri) {
        KeycloakUriBuilder builder = KeycloakUriBuilder.fromUri(uri)
                .replaceQueryParam("code", null)
                .replaceQueryParam("state", null);
        return builder.build().toString();
    }



}
