/*
 * Copyright (c) 2014 Cisco Systems, Inc. and others.  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
 */
package org.opendaylight.yangtools.yang.parser.repo;

import static org.opendaylight.yangtools.util.concurrent.FluentFutures.immediateFluentFuture;

import com.google.common.base.Function;
import com.google.common.collect.Maps;
import com.google.common.util.concurrent.AsyncFunction;
import com.google.common.util.concurrent.FluentFuture;
import java.io.IOException;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import org.eclipse.jdt.annotation.NonNull;
import org.opendaylight.yangtools.concepts.SemVer;
import org.opendaylight.yangtools.yang.model.api.EffectiveModelContext;
import org.opendaylight.yangtools.yang.model.repo.api.SchemaContextFactoryConfiguration;
import org.opendaylight.yangtools.yang.model.repo.api.SchemaResolutionException;
import org.opendaylight.yangtools.yang.model.repo.api.SemVerSourceIdentifier;
import org.opendaylight.yangtools.yang.model.repo.api.SourceIdentifier;
import org.opendaylight.yangtools.yang.model.repo.api.StatementParserMode;
import org.opendaylight.yangtools.yang.parser.api.YangParser;
import org.opendaylight.yangtools.yang.parser.api.YangParserException;
import org.opendaylight.yangtools.yang.parser.api.YangParserFactory;
import org.opendaylight.yangtools.yang.parser.api.YangSyntaxErrorException;
import org.opendaylight.yangtools.yang.parser.rfc7950.ir.IRSchemaSource;
import org.opendaylight.yangtools.yang.parser.rfc7950.repo.YangModelDependencyInfo;
import org.opendaylight.yangtools.yang.parser.spi.meta.ReactorException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

final class AssembleSources implements AsyncFunction<List<IRSchemaSource>, EffectiveModelContext> {
    private static final Logger LOG = LoggerFactory.getLogger(AssembleSources.class);

    private final @NonNull Function<IRSchemaSource, SourceIdentifier> getIdentifier;
    private final @NonNull SchemaContextFactoryConfiguration config;
    private final @NonNull YangParserFactory parserFactory;

    AssembleSources(final @NonNull YangParserFactory parserFactory,
            final @NonNull SchemaContextFactoryConfiguration config) {
        this.parserFactory = parserFactory;
        this.config = config;
        switch (config.getStatementParserMode()) {
            case SEMVER_MODE:
                this.getIdentifier = AssembleSources::getSemVerIdentifier;
                break;
            default:
                this.getIdentifier = IRSchemaSource::getIdentifier;
        }
    }

    @Override
    public FluentFuture<EffectiveModelContext> apply(final List<IRSchemaSource> sources)
            throws SchemaResolutionException, ReactorException {
        final Map<SourceIdentifier, IRSchemaSource> srcs = Maps.uniqueIndex(sources, getIdentifier);
        final Map<SourceIdentifier, YangModelDependencyInfo> deps =
                Maps.transformValues(srcs, YangModelDependencyInfo::forIR);

        LOG.debug("Resolving dependency reactor {}", deps);

        final StatementParserMode statementParserMode = config.getStatementParserMode();
        final DependencyResolver res = statementParserMode == StatementParserMode.SEMVER_MODE
                ? SemVerDependencyResolver.create(deps) : RevisionDependencyResolver.create(deps);
        if (!res.getUnresolvedSources().isEmpty()) {
            LOG.debug("Omitting models {} due to unsatisfied imports {}", res.getUnresolvedSources(),
                res.getUnsatisfiedImports());
            throw new SchemaResolutionException("Failed to resolve required models",
                    res.getResolvedSources(), res.getUnsatisfiedImports());
        }

        final YangParser parser = parserFactory.createParser(res.parserConfig());
        config.getSupportedFeatures().ifPresent(parser::setSupportedFeatures);
        config.getModulesDeviatedByModules().ifPresent(parser::setModulesWithSupportedDeviations);

        for (final Entry<SourceIdentifier, IRSchemaSource> entry : srcs.entrySet()) {
            try {
                parser.addSource(entry.getValue());
            } catch (YangSyntaxErrorException | IOException e) {
                throw new SchemaResolutionException("Failed to add source " + entry.getKey(), e);
            }
        }

        final EffectiveModelContext schemaContext;
        try {
            schemaContext = parser.buildEffectiveModel();
        } catch (final YangParserException e) {
            if (e.getCause() instanceof ReactorException re) {
                throw new SchemaResolutionException("Failed to resolve required models", re.getSourceIdentifier(), e);
            }
            throw new SchemaResolutionException("Failed to resolve required models", e);
        }

        return immediateFluentFuture(schemaContext);
    }

    private static SemVerSourceIdentifier getSemVerIdentifier(final IRSchemaSource source) {
        final SourceIdentifier identifier = source.getIdentifier();
        final SemVer semver = YangModelDependencyInfo.findSemanticVersion(source.getRootStatement(), identifier);
        if (identifier instanceof SemVerSourceIdentifier && semver == null) {
            return (SemVerSourceIdentifier) identifier;
        }

        return SemVerSourceIdentifier.create(identifier.getName(), identifier.getRevision(), semver);
    }
}