/*
 * 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.catalina.ant;

import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.net.Authenticator;
import java.net.HttpURLConnection;
import java.net.PasswordAuthentication;
import java.net.URI;
import java.net.URISyntaxException;
import java.net.URLConnection;

import org.apache.catalina.util.IOTools;
import org.apache.tomcat.util.http.Method;
import org.apache.tools.ant.BuildException;
import org.apache.tools.ant.Project;

/**
 * Abstract base class for Ant tasks that interact with the <em>Manager</em> web application for dynamically deploying
 * and undeploying applications. These tasks require Ant 1.4 or later.
 *
 * @since 4.1
 */
public abstract class AbstractCatalinaTask extends BaseRedirectorHelperTask {

    // ----------------------------------------------------- Instance Variables

    /**
     * manager webapp's encoding.
     */
    private static final String CHARSET = "utf-8";


    // ------------------------------------------------------------- Properties

    /**
     * The charset used during URL encoding.
     */
    protected String charset = "ISO-8859-1";

    public String getCharset() {
        return charset;
    }

    public void setCharset(String charset) {
        this.charset = charset;
    }


    /**
     * The login password for the <code>Manager</code> application.
     */
    protected String password = null;

    public String getPassword() {
        return this.password;
    }

    public void setPassword(String password) {
        this.password = password;
    }


    /**
     * The URL of the <code>Manager</code> application to be used.
     */
    protected String url = "http://localhost:8080/manager/text";

    public String getUrl() {
        return this.url;
    }

    public void setUrl(String url) {
        this.url = url;
    }


    /**
     * The login username for the <code>Manager</code> application.
     */
    protected String username = null;

    public String getUsername() {
        return this.username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    /**
     * If set to true - ignore the constraint of the first line of the response message that must be "OK -".
     * <p>
     * When this attribute is set to {@code false} (the default), the first line of server response is expected to start
     * with "OK -". If it does not then the task is considered as failed and the first line is treated as an error
     * message.
     * <p>
     * When this attribute is set to {@code true}, the first line of the response is treated like any other, regardless
     * of its text.
     */
    protected boolean ignoreResponseConstraint = false;

    public boolean isIgnoreResponseConstraint() {
        return ignoreResponseConstraint;
    }

    public void setIgnoreResponseConstraint(boolean ignoreResponseConstraint) {
        this.ignoreResponseConstraint = ignoreResponseConstraint;
    }


    // --------------------------------------------------------- Public Methods

    /**
     * Execute the specified command. This logic only performs the common attribute validation required by all
     * subclasses; it does not perform any functional logic directly.
     *
     * @exception BuildException if a validation error occurs
     */
    @Override
    public void execute() throws BuildException {
        if ((username == null) || (password == null) || (url == null)) {
            throw new BuildException("Must specify all of 'username', 'password', and 'url'");
        }
    }


    /**
     * Execute the specified command, based on the configured properties.
     *
     * @param command Command to be executed
     *
     * @exception BuildException if an error occurs
     */
    public void execute(String command) throws BuildException {
        execute(command, null, null, -1);
    }


    /**
     * Execute the specified command, based on the configured properties. The input stream will be closed upon
     * completion of this task, whether it was executed successfully or not.
     *
     * @param command       Command to be executed
     * @param istream       InputStream to include in an HTTP PUT, if any
     * @param contentType   Content type to specify for the input, if any
     * @param contentLength Content length to specify for the input, if any
     *
     * @exception BuildException if an error occurs
     */
    public void execute(String command, InputStream istream, String contentType, long contentLength)
            throws BuildException {

        InputStreamReader reader = null;
        try {
            // Set up authorization with our credentials
            Authenticator.setDefault(new TaskAuthenticator(username, password));

            // Create a connection for this command
            URI uri = new URI(url + command);
            URLConnection conn = uri.parseServerAuthority().toURL().openConnection();
            HttpURLConnection hconn = (HttpURLConnection) conn;

            // Set up standard connection characteristics
            hconn.setAllowUserInteraction(false);
            hconn.setDoInput(true);
            hconn.setUseCaches(false);
            if (istream != null) {
                preAuthenticate();

                hconn.setDoOutput(true);
                hconn.setRequestMethod(Method.PUT);
                if (contentType != null) {
                    hconn.setRequestProperty("Content-Type", contentType);
                }
                if (contentLength >= 0) {
                    hconn.setRequestProperty("Content-Length", "" + contentLength);

                    hconn.setFixedLengthStreamingMode(contentLength);
                }
            } else {
                hconn.setDoOutput(false);
                hconn.setRequestMethod(Method.GET);
            }
            hconn.setRequestProperty("User-Agent", "Catalina-Ant-Task/1.0");

            // Establish the connection with the server
            hconn.connect();

            // Send the request data (if any)
            if (istream != null) {
                try (istream; OutputStream ostream = hconn.getOutputStream()) {
                    IOTools.flow(istream, ostream);
                }
            }

            // Process the response message
            reader = new InputStreamReader(hconn.getInputStream(), CHARSET);
            StringBuilder buff = new StringBuilder();
            String error = null;
            int msgPriority = Project.MSG_INFO;
            boolean first = true;
            while (true) {
                int ch = reader.read();
                if (ch < 0) {
                    break;
                } else if (ch == '\r' || ch == '\n') {
                    // in Win \r\n would cause handleOutput() to be called
                    // twice, the second time with an empty string,
                    // producing blank lines
                    if (!buff.isEmpty()) {
                        String line = buff.toString();
                        buff.setLength(0);
                        if (!ignoreResponseConstraint && first) {
                            if (!line.startsWith("OK -")) {
                                error = line;
                                msgPriority = Project.MSG_ERR;
                            }
                            first = false;
                        }
                        handleOutput(line, msgPriority);
                    }
                } else {
                    buff.append((char) ch);
                }
            }
            if (!buff.isEmpty()) {
                handleOutput(buff.toString(), msgPriority);
            }
            if (error != null && isFailOnError()) {
                // exception should be thrown only if failOnError == true
                // or error line will be logged twice
                throw new BuildException(error);
            }
        } catch (Exception e) {
            if (isFailOnError()) {
                throw new BuildException(e);
            } else {
                handleErrorOutput(e.getMessage());
            }
        } finally {
            closeRedirector();
            if (reader != null) {
                try {
                    reader.close();
                } catch (IOException ioe) {
                    // Ignore
                }
            }
            if (istream != null) {
                try {
                    istream.close();
                } catch (IOException ioe) {
                    // Ignore
                }
            }
        }
    }


    /*
     * This is a hack. We need to use streaming to avoid OOME on large uploads. We'd like to use
     * Authenticator.setDefault() for authentication as the JRE then provides the DIGEST client implementation. However,
     * the above two are not compatible. When the request is made, the resulting 401 triggers an exception because, when
     * using streams, the InputStream is no longer available to send with the repeated request that now includes the
     * appropriate Authorization header. The hack is to make a simple OPTIONS request- i.e. without a request body. This
     * triggers authentication and the requirement to authenticate for this host is cached and used to provide an
     * appropriate Authorization when the next request is made (that includes a request body).
     */
    private void preAuthenticate() throws IOException, URISyntaxException {

        // Create a connection for this command
        URI uri = new URI(url);
        URLConnection conn = uri.parseServerAuthority().toURL().openConnection();
        HttpURLConnection hconn = (HttpURLConnection) conn;

        // Set up standard connection characteristics
        hconn.setAllowUserInteraction(false);
        hconn.setDoInput(true);
        hconn.setUseCaches(false);
        hconn.setDoOutput(false);
        hconn.setRequestMethod(Method.OPTIONS);
        hconn.setRequestProperty("User-Agent", "Catalina-Ant-Task/1.0");

        // Establish the connection with the server
        hconn.connect();

        // Swallow response message
        try (InputStream is = hconn.getInputStream()) {
            IOTools.flow(is, null);
        }
    }


    private static class TaskAuthenticator extends Authenticator {

        private final String user;
        private final String password;

        private TaskAuthenticator(String user, String password) {
            this.user = user;
            this.password = password;
        }

        @Override
        protected PasswordAuthentication getPasswordAuthentication() {
            return new PasswordAuthentication(user, password.toCharArray());
        }
    }
}
