/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to you under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.calcite.runtime;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStreamWriter;
import java.io.UnsupportedEncodingException;
import java.io.Writer;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLEncoder;
import java.nio.charset.StandardCharsets;
import java.util.Map;

/**
 * Utilities for connecting to REST services such as Splunk via HTTP.
 */
public class HttpUtils {
  private HttpUtils() {}

  public static HttpURLConnection getURLConnection(String url)
      throws IOException {
    return (HttpURLConnection) new URL(url).openConnection();
  }

  public static void appendURLEncodedArgs(
      StringBuilder out, Map<String, String> args) {
    int i = 0;
    try {
      for (Map.Entry<String, String> me : args.entrySet()) {
        if (i++ != 0) {
          out.append("&");
        }
        out.append(URLEncoder.encode(me.getKey(), "UTF-8"))
            .append("=")
            .append(URLEncoder.encode(me.getValue(), "UTF-8"));
      }
    } catch (UnsupportedEncodingException ignore) {
      // ignore
    }
  }

  public static void appendURLEncodedArgs(
      StringBuilder out, CharSequence... args) {
    if (args.length % 2 != 0) {
      throw new IllegalArgumentException(
          "args should contain an even number of items");
    }
    try {
      int appended = 0;
      for (int i = 0; i < args.length; i += 2) {
        if (args[i + 1] == null) {
          continue;
        }
        if (appended++ > 0) {
          out.append("&");
        }
        out.append(URLEncoder.encode(args[i].toString(), "UTF-8"))
            .append("=")
            .append(URLEncoder.encode(args[i + 1].toString(), "UTF-8"));
      }
    } catch (UnsupportedEncodingException ignore) {
      // ignore
    }
  }

  public static InputStream post(
      String url,
      CharSequence data,
      Map<String, String> headers) throws IOException {
    return post(url, data, headers, 10000, 60000);
  }

  public static InputStream post(
      String url,
      CharSequence data,
      Map<String, String> headers,
      int cTimeout,
      int rTimeout) throws IOException {
    return executeMethod(data == null ? "GET" : "POST", url, data, headers,
        cTimeout, rTimeout);
  }

  public static InputStream executeMethod(
      String method, String url,
      CharSequence data, Map<String, String> headers,
      int cTimeout, int rTimeout) throws IOException {
    // NOTE: do not log "data" or "url"; may contain user name or password.
    final HttpURLConnection conn = getURLConnection(url);
    conn.setRequestMethod(method);
    conn.setReadTimeout(rTimeout);
    conn.setConnectTimeout(cTimeout);

    if (headers != null) {
      for (Map.Entry<String, String> me : headers.entrySet()) {
        conn.setRequestProperty(me.getKey(), me.getValue());
      }
    }
    if (data == null) {
      return conn.getInputStream();
    }
    conn.setDoOutput(true);
    try (Writer w =
             new OutputStreamWriter(conn.getOutputStream(), StandardCharsets.UTF_8)) {
      w.write(data.toString());
      w.flush(); // Get the response
      return conn.getInputStream();
    }
  }
}