/*******************************************************************************
 * Copyright (c) 2019 Association for Decentralized Information Management in
 * Industry THTH ry.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     Semantum Oy - initial API and implementation
 *******************************************************************************/
package org.simantics.modeling.migration;

import java.io.PrintWriter;
import java.io.StringReader;
import java.util.Collection;
import java.util.HashMap;
import java.util.Map;

import org.eclipse.core.runtime.IProgressMonitor;
import org.simantics.Simantics;
import org.simantics.databoard.Bindings;
import org.simantics.db.ReadGraph;
import org.simantics.db.Resource;
import org.simantics.db.Session;
import org.simantics.db.common.utils.NameUtils;
import org.simantics.db.exception.DatabaseException;
import org.simantics.db.layer0.migration.MigrationState;
import org.simantics.db.layer0.migration.MigrationStateKeys;
import org.simantics.db.layer0.migration.MigrationStep;
import org.simantics.db.layer0.migration.MigrationUtils;
import org.simantics.db.layer0.migration.NullWriter;
import org.simantics.db.request.Read;
import org.simantics.modeling.ModelingResources;
import org.simantics.scl.compiler.commands.CommandSession;
import org.simantics.scl.compiler.types.Types;
import org.simantics.scl.osgi.SCLOsgi;
import org.simantics.scl.runtime.reporting.AbstractSCLReportingHandler;
import org.simantics.scl.runtime.reporting.SCLReportingHandler;

/**
 * Runs the SCL script associated with the migration step.
 * 
 * @author Tuukka Lehtonen
 * @since 1.41.0
 */
public class SCLScriptMigrationStep implements MigrationStep {

    private String scriptId;
    private String script;

    public SCLScriptMigrationStep(ReadGraph graph, Resource step) throws DatabaseException {
        this.scriptId = NameUtils.getSafeName(graph, step);
        this.script = graph.getRelatedValue(
                step,
                ModelingResources.getInstance(graph).Migration_SCLScriptMigrationStep_script,
                Bindings.STRING);
    }

    @Override
    public void applyTo(final IProgressMonitor monitor, Session session, MigrationState state) throws DatabaseException {
        Collection<Resource> roots = state.getProperty(MigrationStateKeys.CURRENT_ROOT_RESOURCES);
        if (!roots.isEmpty()) {
            PrintWriter log = MigrationUtils.getProperty(state, MigrationStateKeys.MESSAGE_LOG_WRITER, NullWriter.PRINT_INSTANCE);
            runScript(monitor, roots, log);
        }
    }

    private static class ReportingHandler extends AbstractSCLReportingHandler {
        PrintWriter log;

        public ReportingHandler(PrintWriter log) {
            this.log = log;
        }

        @Override
        public void print(String text) {
            log.println(text);
        }

        @Override
        public void printError(String error) {
            log.println("ERROR: " + error);
        }
    }

    private void runScript(IProgressMonitor monitor, Collection<Resource> roots, PrintWriter log) throws DatabaseException {
        log.format("## Running SCL Script Migration Step `%s` ##%n", scriptId);
        SCLReportingHandler rh = new ReportingHandler(log);
        Map<Resource, String> rootNames = mapNames(roots);
        for (Resource root : roots) {
            log.format("### Running script for root `%s` ###%n", rootNames.get(root));
            CommandSession session = new CommandSession(SCLOsgi.MODULE_REPOSITORY, rh);
            session.setVariable("root", Types.RESOURCE, root);
            session.execute(new StringReader(script), rh);
        }
    }

    private Map<Resource, String> mapNames(Collection<Resource> roots) throws DatabaseException {
        return Simantics.getSession().syncRequest((Read<Map<Resource, String>>) graph -> mapNames(graph, roots));
    }

    private Map<Resource, String> mapNames(ReadGraph graph, Collection<Resource> roots) throws DatabaseException {
        Map<Resource, String> map = new HashMap<>();
        for (Resource r : roots)
            map.put(r, NameUtils.getSafeName(graph, r));
        return map;
    }

}