GitHubClient.java

package rabbitescape.ui.swing;

import java.net.UnknownHostException;
import java.util.ArrayList;
import java.util.regex.Pattern;

import static rabbitescape.engine.i18n.Translation.t;

/**
 * @brief retrieval and parsing. no swing.
 */
public class GitHubClient implements GitHubPageFetchNotifier
{
    public final String baseURL = "https://api.github.com/repos/andybalaam/rabbit-escape/issues";
    public final String acceptHeader = "Accept: application/vnd.github.v3+json";
    private ArrayList<GitHubIssue> issues = null;
    private String errMsg = "";
    private int page = 1;
    /** < .../issues?page=number */
    private boolean gotAllPages = false;

    /** < @brief do not query for more pages of issues */

    public GitHubClient()
    {
    }

    public void initialise()
    {
        String jsonIssues = apiCall( "" );
        issues = parseIssues( jsonIssues );
    }

    public void fetchComments( GitHubIssue ghi )
    {
        String jsonComments = apiCall( "/" + ghi.getNumber() + "/comments" );
        String[] commentBodies = GitHubJsonTools
            .getStringValuesFromArrayOfObjects( jsonComments, "body" );

        for ( int i = 0; i < commentBodies.length; i++ )
        {
            ghi.addToBody( commentBodies[i] );
        }
    }

    public String getError()
    {
        return errMsg;
    }

    /**
     * @param GitHubPageFetcher
     *            required in case more issues need fetching. This method can
     *            make a call back to the UI. This is necessary as it may be
     *            time consuming: the user needs a progress bar or something.
     */
    public GitHubIssue getIssue( int index, GitHubPageFetcher ghpf )
    {
        if ( null == issues || index < 0 )
        {
            return null;
        }
        if ( index >= issues.size() )
        {
            if ( gotAllPages )
            {
                return null;
            }
            ghpf.notifyAndFetch( baseURL + "?page=" + ( ++page ),
                acceptHeader,
                t( "Fetching more issues." ),
                this );
            return null; // user waits and requests again
        }
        return issues.get( index );
    }

    public int getIndexOfNumber( int issueNumber )
    {
        for ( int i = 0; i < issues.size(); i++ )
        {
            GitHubIssue ghi = issues.get( i );
            if ( ghi.getNumber() == issueNumber )
            {
                return i;
            }
        }
        return -1;
    }

    private static ArrayList<GitHubIssue> parseIssues( String json )
    { // / @TODO this is extremely crufty: hacking out most of the URL to split
      // on.
      // This leaves the issue number as the first thing in the string.
        Pattern issuePattern = Pattern
            .compile( "\\{\"url\":\"https://api\\.github\\.com/repos/andybalaam/rabbit-escape/issues/" );
        String[] jsonIssuesStrings = issuePattern.split( json );
        ArrayList<GitHubIssue> ret = new ArrayList<GitHubIssue>();
        for ( int i = 0; i < jsonIssuesStrings.length; i++ )
        {
            String jsonIssue = jsonIssuesStrings[i];
            if ( !"0123456789".contains( jsonIssue.substring( 0, 1 ) ) )
            {
                continue;
            }

            GitHubIssue ghi = new GitHubIssue(
                GitHubJsonTools.getIntValue( jsonIssue, "number" ),
                GitHubJsonTools.getStringValue( jsonIssue, "title" ),
                GitHubJsonTools.getStringValue( jsonIssue, "body" ),
                GitHubJsonTools.getStringValuesFromArrayOfObjects( jsonIssue,
                    "labels.name" )
                );
            ret.add( ghi );
        }
        return ret;
    }

    private String apiCall( String endURL )
    {
        try
        {
            return HttpTools.get( baseURL + endURL, acceptHeader );
        }
        catch ( UnknownHostException eUH )
        {
            errMsg = t( "Can't reach github.com." );
        }
        catch ( Exception e )
        {
            e.printStackTrace();
        }
        return null;
    }

    @Override
    public void setPage( String page )
    {
        ArrayList<GitHubIssue> extra = parseIssues( page );
        issues.addAll( extra );
        if ( 0 == extra.size() )
        {
            gotAllPages = true; // Github has no more to give
        }
    }
}