package org.apache.maven.scm.provider.git.repository;

/*
 * 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.
 */

import org.apache.maven.scm.ScmException;
import org.apache.maven.scm.provider.ScmProviderRepository;
import org.apache.maven.scm.provider.ScmProviderRepositoryWithHost;

import java.net.URI;
import java.net.URISyntaxException;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

/**
 * @author <a href="mailto:evenisse@apache.org">Emmanuel Venisse</a>
 * @author <a href="mailto:struberg@apache.org">Mark Struberg</a>
 *
 */
public class GitScmProviderRepository
    extends ScmProviderRepositoryWithHost
{

    /**
     * sequence used to delimit the fetch URL
     */
    public static final String URL_DELIMITER_FETCH = "[fetch=]";

    /**
     * sequence used to delimit the push URL
     */
    public static final String URL_DELIMITER_PUSH = "[push=]";

    /**
     * this trails every protocol
     */
    public static final String PROTOCOL_SEPARATOR = "://";

    /**
     * use local file as transport
     */
    public static final String PROTOCOL_FILE = "file";

    /**
     * use gits internal protocol
     */
    public static final String PROTOCOL_GIT = "git";

    /**
     * use secure shell protocol
     */
    public static final String PROTOCOL_SSH = "ssh";

    /**
     * use the standard port 80 http protocol
     */
    public static final String PROTOCOL_HTTP = "http";

    /**
     * use the standard port 443 https protocol
     */
    public static final String PROTOCOL_HTTPS = "https";

    /**
     * use rsync for retrieving the data
     * TODO implement!
     */
    public static final String PROTOCOL_RSYNC = "rsync";

    private static final Pattern HOST_AND_PORT_EXTRACTOR =
        Pattern.compile( "([^:/\\\\~]*)(?::(\\d*))?(?:([:/\\\\~])(.*))?" );

    /**
     * No special protocol specified. Git will either use git://
     * or ssh:// depending on whether we work locally or over the network
     */
    public static final String PROTOCOL_NONE = "";

    /**
     * this may either 'git' or 'jgit' depending on the underlying implementation being used
     */
    private String provider;

    /**
     * the URL used to fetch from the upstream repository
     */
    private RepositoryUrl fetchInfo;

    /**
     * the URL used to push to the upstream repository
     */
    private RepositoryUrl pushInfo;

    public GitScmProviderRepository( String url )
        throws ScmException
    {
        if ( url == null )
        {
            throw new ScmException( "url must not be null" );
        }

        if ( url.startsWith( URL_DELIMITER_FETCH ) )
        {
            String fetch = url.substring( URL_DELIMITER_FETCH.length() );

            int indexPushDelimiter = fetch.indexOf( URL_DELIMITER_PUSH );
            if ( indexPushDelimiter >= 0 )
            {
                String push = fetch.substring( indexPushDelimiter + URL_DELIMITER_PUSH.length() );
                pushInfo = parseUrl( push );

                fetch = fetch.substring( 0, indexPushDelimiter );
            }

            fetchInfo = parseUrl( fetch );

            if ( pushInfo == null )
            {
                pushInfo = fetchInfo;
            }
        }
        else if ( url.startsWith( URL_DELIMITER_PUSH ) )
        {
            String push = url.substring( URL_DELIMITER_PUSH.length() );

            int indexFetchDelimiter = push.indexOf( URL_DELIMITER_FETCH );
            if ( indexFetchDelimiter >= 0 )
            {
                String fetch = push.substring( indexFetchDelimiter + URL_DELIMITER_FETCH.length() );
                fetchInfo = parseUrl( fetch );

                push = push.substring( 0, indexFetchDelimiter );
            }

            pushInfo = parseUrl( push );

            if ( fetchInfo == null )
            {
                fetchInfo = pushInfo;
            }
        }
        else
        {
            fetchInfo = pushInfo = parseUrl( url );
        }

        // set the default values for backward compatibility from the push url
        // because it's more likely that the push URL contains 'better' credentials
        setUser( pushInfo.getUserName() );
        setPassword( pushInfo.getPassword() );
        setHost( pushInfo.getHost() );
        if ( pushInfo.getPort() != null && pushInfo.getPort().length() > 0 )
        {
            setPort( Integer.parseInt( pushInfo.getPort() ) );
        }
    }

    public GitScmProviderRepository( String url, String user, String password )
        throws ScmException
    {
        this( url );

        setUser( user );

        setPassword( password );
    }

    /**
     * @return either 'git' or 'jgit' depending on the underlying implementation being used
     */
    public String getProvider()
    {
        return provider;
    }

    public RepositoryUrl getFetchInfo()
    {
        return fetchInfo;
    }

    public RepositoryUrl getPushInfo()
    {
        return pushInfo;
    }


    /**
     * @return the URL used to fetch from the upstream repository
     */
    public String getFetchUrl()
    {
        return getUrl( fetchInfo );
    }

    /**
     * @return the URL used to push to the upstream repository
     */
    public String getPushUrl()
    {
        return getUrl( pushInfo );
    }


    /**
     * Parse the given url string and store all the extracted
     * information in a {@code RepositoryUrl}
     *
     * @param url to parse
     * @return filled with the information from the given URL
     * @throws ScmException
     */
    private RepositoryUrl parseUrl( String url )
        throws ScmException
    {
        RepositoryUrl repoUrl = new RepositoryUrl();

        url = parseProtocol( repoUrl, url );
        url = parseUserInfo( repoUrl, url );
        url = parseHostAndPort( repoUrl, url );
        // the rest of the url must be the path to the repository on the server
        repoUrl.setPath( url );
        return repoUrl;
    }


    /**
     * @param repoUrl
     * @return
     */
    private String getUrl( RepositoryUrl repoUrl )
    {
        StringBuilder urlSb = new StringBuilder( repoUrl.getProtocol() );
        boolean urlSupportsUserInformation = false;

        if ( PROTOCOL_SSH.equals( repoUrl.getProtocol() ) || PROTOCOL_RSYNC.equals( repoUrl.getProtocol() )
            || PROTOCOL_GIT.equals( repoUrl.getProtocol() ) || PROTOCOL_HTTP.equals( repoUrl.getProtocol() )
            || PROTOCOL_HTTPS.equals( repoUrl.getProtocol() ) || PROTOCOL_NONE.equals( repoUrl.getProtocol() ) )
        {
            urlSupportsUserInformation = true;
        }

        if ( repoUrl.getProtocol() != null && repoUrl.getProtocol().length() > 0 )
        {
            urlSb.append( "://" );
        }

        // add user information if given and allowed for the protocol
        if ( urlSupportsUserInformation )
        {
            String userName = repoUrl.getUserName();
            // if specified on the commandline or other configuration, we take this.
            if ( getUser() != null && getUser().length() > 0 )
            {
                userName = getUser();
            }

            String password = repoUrl.getPassword();
            if ( getPassword() != null && getPassword().length() > 0 )
            {
                password = getPassword();
            }

            if ( userName != null && userName.length() > 0 )
            {
                String userInfo = userName;
                if ( password != null && password.length() > 0 )
                {
                    userInfo +=  ":" + password;
                }

                try
                {
                    URI uri = new URI( null, userInfo, "localhost", -1, null, null, null );
                    urlSb.append( uri.getRawUserInfo() );
                }
                catch ( URISyntaxException e )
                {
                    // Quite impossible...
                    // Otherwise throw a RTE since this method is also used by toString()
                    e.printStackTrace();
                }

                urlSb.append( '@' );
            }
        }

        // add host and port information
        urlSb.append( repoUrl.getHost() );
        if ( repoUrl.getPort() != null && repoUrl.getPort().length() > 0 )
        {
            urlSb.append( ':' ).append( repoUrl.getPort() );
        }

        // finaly we add the path to the repo on the host
        urlSb.append( repoUrl.getPath() );

        return urlSb.toString();
    }

    /**
     * Parse the protocol from the given url and fill it into the given RepositoryUrl.
     *
     * @param repoUrl
     * @param url
     * @return the given url with the protocol parts removed
     */
    private String parseProtocol( RepositoryUrl repoUrl, String url )
        throws ScmException
    {
        // extract the protocol
        if ( url.startsWith( PROTOCOL_FILE + PROTOCOL_SEPARATOR ) )
        {
            repoUrl.setProtocol( PROTOCOL_FILE );
        }
        else if ( url.startsWith( PROTOCOL_HTTPS + PROTOCOL_SEPARATOR ) )
        {
            repoUrl.setProtocol( PROTOCOL_HTTPS );
        }
        else if ( url.startsWith( PROTOCOL_HTTP + PROTOCOL_SEPARATOR ) )
        {
            repoUrl.setProtocol( PROTOCOL_HTTP );
        }
        else if ( url.startsWith( PROTOCOL_SSH + PROTOCOL_SEPARATOR ) )
        {
            repoUrl.setProtocol( PROTOCOL_SSH );
        }
        else if ( url.startsWith( PROTOCOL_GIT + PROTOCOL_SEPARATOR ) )
        {
            repoUrl.setProtocol( PROTOCOL_GIT );
        }
        else if ( url.startsWith( PROTOCOL_RSYNC + PROTOCOL_SEPARATOR ) )
        {
            repoUrl.setProtocol( PROTOCOL_RSYNC );
        }
        else
        {
            // when no protocol is specified git will pick either ssh:// or git://
            // depending on whether we work locally or over the network
            repoUrl.setProtocol( PROTOCOL_NONE );
            return url;
        }

        url = url.substring( repoUrl.getProtocol().length() + 3 );

        return url;
    }

    /**
     * Parse the user information from the given url and fill
     * user name and password into the given RepositoryUrl.
     *
     * @param repoUrl
     * @param url
     * @return the given url with the user parts removed
     */
    private String parseUserInfo( RepositoryUrl repoUrl, String url )
        throws ScmException
    {
        // extract user information
        int indexAt = url.lastIndexOf( '@' );
        if ( indexAt >= 0 )
        {
            String userInfo = url.substring( 0, indexAt );
            int indexPwdSep = userInfo.indexOf( ':' );
            if ( indexPwdSep < 0 )
            {
                repoUrl.setUserName( userInfo );
            }
            else
            {
                repoUrl.setUserName( userInfo.substring( 0, indexPwdSep ) );
                repoUrl.setPassword( userInfo.substring( indexPwdSep + 1 ) );
            }

            url = url.substring( indexAt + 1 );
        }
        return url;
    }

    /**
     * Parse server and port from the given url and fill it into the
     * given RepositoryUrl.
     *
     * @param repoUrl
     * @param url
     * @return the given url with the server parts removed
     * @throws ScmException
     */
    private String parseHostAndPort( RepositoryUrl repoUrl, String url )
        throws ScmException
    {

        repoUrl.setPort( "" );
        repoUrl.setHost( "" );

        if ( PROTOCOL_FILE.equals( repoUrl.getProtocol() ) )
        {
            // a file:// URL doesn't need any further parsing as it cannot contain a port, etc
            return url;
        }
        else
        {

            Matcher hostAndPortMatcher = HOST_AND_PORT_EXTRACTOR.matcher( url );
            if ( hostAndPortMatcher.matches() )
            {
                if ( hostAndPortMatcher.groupCount() > 1 && hostAndPortMatcher.group( 1 ) != null )
                {
                    repoUrl.setHost( hostAndPortMatcher.group( 1 ) );
                }
                if ( hostAndPortMatcher.groupCount() > 2 && hostAndPortMatcher.group( 2 ) != null )
                {
                    repoUrl.setPort( hostAndPortMatcher.group( 2 ) );
                }

                StringBuilder computedUrl = new StringBuilder();
                if ( hostAndPortMatcher.group( hostAndPortMatcher.groupCount() - 1 ) != null )
                {
                    computedUrl.append( hostAndPortMatcher.group( hostAndPortMatcher.groupCount() - 1 ) );
                }
                if ( hostAndPortMatcher.group( hostAndPortMatcher.groupCount() ) != null )
                {
                    computedUrl.append( hostAndPortMatcher.group( hostAndPortMatcher.groupCount() ) );
                }
                return computedUrl.toString();
            }
            else
            {
                // Pattern doesn't match, let's return the original url
                return url;
            }
        }
    }


    /**
     * {@inheritDoc}
     */
    public String getRelativePath( ScmProviderRepository ancestor )
    {
        if ( ancestor instanceof GitScmProviderRepository )
        {
            GitScmProviderRepository gitAncestor = (GitScmProviderRepository) ancestor;

            //X TODO review!
            String url = getFetchUrl();
            String path = url.replaceFirst( gitAncestor.getFetchUrl() + "/", "" );

            if ( !path.equals( url ) )
            {
                return path;
            }
        }
        return null;
    }

    /**
     * {@inheritDoc}
     */
    public String toString()
    {
        // yes we really like to check if those are the exact same instance!
        if ( fetchInfo == pushInfo )
        {
            return getUrl( fetchInfo );
        }
        return URL_DELIMITER_FETCH + getUrl( fetchInfo ) + URL_DELIMITER_PUSH + getUrl( pushInfo );
    }

}