/*
 * 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.
 */
package org.eclipse.aether.util.filter;

import java.util.Arrays;
import java.util.Collection;
import java.util.HashSet;
import java.util.List;
import java.util.Objects;
import java.util.Set;

import org.eclipse.aether.artifact.Artifact;
import org.eclipse.aether.graph.Dependency;
import org.eclipse.aether.graph.DependencyFilter;
import org.eclipse.aether.graph.DependencyNode;
import org.eclipse.aether.version.InvalidVersionSpecificationException;
import org.eclipse.aether.version.Version;
import org.eclipse.aether.version.VersionRange;
import org.eclipse.aether.version.VersionScheme;

import static java.util.Objects.requireNonNull;

/**
 */
class AbstractPatternDependencyFilter implements DependencyFilter {

    private final Set<String> patterns = new HashSet<>();

    private final VersionScheme versionScheme;

    /**
     * Creates a new filter using the specified patterns.
     *
     * @param patterns The include patterns, may be {@code null} or empty to include no artifacts.
     */
    AbstractPatternDependencyFilter(final String... patterns) {
        this(null, patterns);
    }

    /**
     * Creates a new filter using the specified patterns.
     *
     * @param versionScheme To be used for parsing versions/version ranges. If {@code null} and pattern specifies a
     *            range no artifact will be included.
     * @param patterns The include patterns, may be {@code null} or empty to include no artifacts.
     */
    AbstractPatternDependencyFilter(final VersionScheme versionScheme, final String... patterns) {
        this(versionScheme, patterns == null ? null : Arrays.asList(patterns));
    }

    /**
     * Creates a new filter using the specified patterns.
     *
     * @param patterns The include patterns, may be {@code null} or empty to include no artifacts.
     */
    AbstractPatternDependencyFilter(final Collection<String> patterns) {
        this(null, patterns);
    }

    /**
     * Creates a new filter using the specified patterns and {@link VersionScheme} .
     *
     * @param versionScheme To be used for parsing versions/version ranges. If {@code null} and pattern specifies a
     *            range no artifact will be included.
     * @param patterns The include patterns, may be {@code null} or empty to include no artifacts.
     */
    AbstractPatternDependencyFilter(final VersionScheme versionScheme, final Collection<String> patterns) {
        if (patterns != null) {
            this.patterns.addAll(patterns);
        }
        this.versionScheme = versionScheme;
    }

    public boolean accept(final DependencyNode node, List<DependencyNode> parents) {
        requireNonNull(node, "node cannot be null");
        requireNonNull(parents, "parents cannot be null");
        final Dependency dependency = node.getDependency();
        if (dependency == null) {
            return true;
        }
        return accept(dependency.getArtifact());
    }

    protected boolean accept(final Artifact artifact) {
        for (final String pattern : patterns) {
            final boolean matched = accept(artifact, pattern);
            if (matched) {
                return true;
            }
        }
        return false;
    }

    private boolean accept(final Artifact artifact, final String pattern) {
        final String[] tokens = new String[] {
            artifact.getGroupId(), artifact.getArtifactId(), artifact.getExtension(), artifact.getBaseVersion()
        };

        final String[] patternTokens = pattern.split(":");

        // fail immediately if pattern tokens outnumber tokens to match
        boolean matched = (patternTokens.length <= tokens.length);

        for (int i = 0; matched && i < patternTokens.length; i++) {
            matched = matches(tokens[i], patternTokens[i]);
        }

        return matched;
    }

    private boolean matches(final String token, final String pattern) {
        boolean matches;

        // support full wildcard and implied wildcard
        if ("*".equals(pattern) || pattern.length() == 0) {
            matches = true;
        }
        // support contains wildcard
        else if (pattern.startsWith("*") && pattern.endsWith("*")) {
            final String contains = pattern.substring(1, pattern.length() - 1);

            matches = (token.contains(contains));
        }
        // support leading wildcard
        else if (pattern.startsWith("*")) {
            final String suffix = pattern.substring(1);

            matches = token.endsWith(suffix);
        }
        // support trailing wildcard
        else if (pattern.endsWith("*")) {
            final String prefix = pattern.substring(0, pattern.length() - 1);

            matches = token.startsWith(prefix);
        }
        // support versions range
        else if (pattern.startsWith("[") || pattern.startsWith("(")) {
            matches = isVersionIncludedInRange(token, pattern);
        }
        // support exact match
        else {
            matches = token.equals(pattern);
        }

        return matches;
    }

    private boolean isVersionIncludedInRange(final String version, final String range) {
        if (versionScheme == null) {
            return false;
        } else {
            try {
                final Version parsedVersion = versionScheme.parseVersion(version);
                final VersionRange parsedRange = versionScheme.parseVersionRange(range);

                return parsedRange.containsVersion(parsedVersion);
            } catch (final InvalidVersionSpecificationException e) {
                return false;
            }
        }
    }

    @Override
    public boolean equals(final Object obj) {
        if (this == obj) {
            return true;
        }

        if (obj == null || !getClass().equals(obj.getClass())) {
            return false;
        }

        final AbstractPatternDependencyFilter that = (AbstractPatternDependencyFilter) obj;

        return Objects.equals(this.patterns, that.patterns) && Objects.equals(this.versionScheme, that.versionScheme);
    }

    @Override
    public int hashCode() {
        int hash = 17;
        hash = hash * 31 + patterns.hashCode();
        hash = hash * 31 + ((versionScheme == null) ? 0 : versionScheme.hashCode());
        return hash;
    }
}
