package jmri.jmrit.display.layoutEditor;

import java.util.ArrayList;
import java.util.List;
import jmri.*;
import jmri.NamedBean.BadNameException;

/**
 * The transit creation tool, is designed to be used by higher level tools to
 * create transits between Beans. The higher level tools would already have a
 * valid knowledge of the track layout and Sections, therefore this tool does
 * little validation of sections being added to the transit.
 * <hr>
 * The tool currently only deals with SignalMasts, that have had logic created
 * and also have a section associated between them.
 * <hr>
 * This file is part of JMRI.
 * <p>
 * JMRI is free software; you can redistribute it and/or modify it under the
 * terms of version 2 of the GNU General Public License as published by the Free
 * Software Foundation. See the "COPYING" file for a copy of this license.
 * <p>
 * JMRI is distributed in the hope that it will be useful, but WITHOUT ANY
 * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
 * A PARTICULAR PURPOSE. See the GNU General Public License for more details.
 *
 * @author Kevin Dickerson Copyright (C) 2011
 * @author George Warner Copyright (c) 2017-2018
 */
final public class TransitCreationTool {

    public TransitCreationTool() {
    }

    ArrayList<NamedBean> list = new ArrayList<>();

    public void addNamedBean(NamedBean nb) throws JmriException {
        if (!list.isEmpty()) {
            if (list.get(list.size() - 1) == nb) {
                log.debug("Bean is the same as the last one so will not add or error");
                return;
            }
            //Run through a series of checks that this bean is reachable from the previous
            if ((nb instanceof SignalMast) && (list.get(list.size() - 1) instanceof SignalMast)) {
                SignalMastLogicManager smlm = InstanceManager.getDefault(SignalMastLogicManager.class);
                SignalMastLogic sml = smlm.getSignalMastLogic(((SignalMast) list.get(list.size() - 1)));
                if (sml == null || !sml.isDestinationValid((SignalMast) nb)) {
                    String error = Bundle.getMessage("TCTErrorMastPairsNotValid", nb.getDisplayName(), list.get(list.size() - 1).getDisplayName());
                    log.error("will throw {}", error);
                    throw new JmriException(error);
                }
                if (sml.getAssociatedSection((SignalMast) nb) == null) {
                    String error = Bundle.getMessage("TCTErrorMastPairsNoSection", list.get(list.size() - 1).getDisplayName(), nb.getDisplayName());
                    log.error("will throw {}", error);
                    throw new JmriException(error);
                }
            } else {
                //Need to add the method to get layout block connectivity.  Also work checking that the Layout Block routing has been initialised.
            }
        }
        list.add(nb);
    }

    public Transit createTransit() throws JmriException {
        TransitManager tm = InstanceManager.getDefault(TransitManager.class);
        String transitName = "From " + list.get(0).getDisplayName() + " to " + list.get(list.size() - 1).getDisplayName();
        Transit t;
        try {
            t = tm.createNewTransit(transitName);
        } catch (BadNameException ex) {
            log.error("Unable to create transit {} {}", transitName,ex.getMessage());
            throw new JmriException(Bundle.getMessage("TCTErrorUnableToCreate", transitName) + " " + ex.getLocalizedMessage());
        }
        if (list.get(0) instanceof SignalMast) {
            SignalMastLogicManager smlm = InstanceManager.getDefault(SignalMastLogicManager.class);
            int seqNo = 1;
            // Add stub block section if applicable
            SignalMastLogic smlForFirstMast = smlm.getSignalMastLogic((SignalMast) list.get(0));
            if (smlForFirstMast != null) {
                LayoutBlock layoutBlock = smlForFirstMast.getFacingBlock();
                if (layoutBlock!=null && layoutBlock.getNumberOfNeighbours() == 1) {
                    // A stub track block has one neighbor
                    SectionManager sectionManager = InstanceManager.getDefault(SectionManager.class);
                    for (Section section : sectionManager.getNamedBeanSet()) {
                        // Look for a user defined section that has one block that matches the layout block
                        if (section.getSectionType() == Section.USERDEFINED) {
                            if (section.getNumBlocks() == 1 && layoutBlock.getBlock().equals(section.getEntryBlock())) {
                                t.addTransitSection(new TransitSection(section, seqNo, Section.FORWARD));
                                seqNo++;
                                break;
                            }
                        }
                    }
                    if (seqNo == 1) {
                        log.warn("Unable to find a stub block section for {}", layoutBlock.getDisplayName());
                    }
                }
            }
            for (int i = 1; i <= list.size() - 1; i++) {
                SignalMastLogic sml = smlm.getSignalMastLogic((SignalMast) list.get(i - 1));
                if (sml==null){
                    String error = "Cannot locate SML for SM " + list.get(i - 1).getDisplayName();
                    log.error("will throw {}", error);
                    tm.deregister(t);
                    t.dispose();
                    cancelTransitCreate();
                    throw new JmriException(error);
                }
                Section sec = sml.getAssociatedSection((SignalMast) list.get(i));
                //In theory sec being null would already have been tested when the signal was added.
                if (sec == null) {
                    String error = Bundle.getMessage("TCTErrorMastPairsNoSection", list.get(i - 1).getDisplayName(), list.get(i).getDisplayName());
                    log.error("will throw {}", error);
                    tm.deregister(t);
                    t.dispose();
                    cancelTransitCreate();
                    throw new JmriException(error);
                }
                t.addTransitSection(new TransitSection(sec, seqNo, Section.FORWARD));
                seqNo++;
            }
        }
        //Once created clear the list for a fresh start.
        list = new ArrayList<>();
        return t;
    }

    public void cancelTransitCreate() {
        list = new ArrayList<>();
    }

    public List<NamedBean> getBeans() {
        return list;
    }

    public boolean isToolInUse() {
        return !list.isEmpty();
    }

    private final static org.slf4j.Logger log = org.slf4j.LoggerFactory.getLogger(TransitCreationTool.class);
}