/*
 * 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.version;

import java.util.Objects;

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;

/**
 * A version range inspired by mathematical range syntax. For example, "[1.0,2.0)", "[1.0,)" or "[1.0]".
 * <p>
 * Despite its name, this class is generic in a sense it works with any {@link Version}
 */
public final class GenericVersionRange implements VersionRange {
    private final VersionScheme versionScheme;

    private final Bound lowerBound;

    private final Bound upperBound;

    /**
     * Creates a version range from the specified range specification.
     *
     * @param range the range specification to parse, must not be {@code null}
     * @throws InvalidVersionSpecificationException if the range could not be parsed
     */
    GenericVersionRange(VersionScheme versionScheme, String range) throws InvalidVersionSpecificationException {
        this.versionScheme = requireNonNull(versionScheme, "versionScheme cannot be null");
        String process = requireNonNull(range, "version range cannot be null");

        boolean lowerBoundInclusive, upperBoundInclusive;
        Version lowerBound, upperBound;

        if (range.startsWith("[")) {
            lowerBoundInclusive = true;
        } else if (range.startsWith("(")) {
            lowerBoundInclusive = false;
        } else {
            throw new InvalidVersionSpecificationException(
                    range, "Invalid version range " + range + ", a range must start with either [ or (");
        }

        if (range.endsWith("]")) {
            upperBoundInclusive = true;
        } else if (range.endsWith(")")) {
            upperBoundInclusive = false;
        } else {
            throw new InvalidVersionSpecificationException(
                    range, "Invalid version range " + range + ", a range must end with either [ or (");
        }

        process = process.substring(1, process.length() - 1);

        int index = process.indexOf(",");

        if (index < 0) {
            if (!lowerBoundInclusive || !upperBoundInclusive) {
                throw new InvalidVersionSpecificationException(
                        range, "Invalid version range " + range + ", single version must be surrounded by []");
            }

            String version = process.trim();
            if (version.endsWith(".*")) {
                String prefix = version.substring(0, version.length() - 1);
                lowerBound = parse(prefix + "min");
                upperBound = parse(prefix + "max");
            } else {
                lowerBound = parse(version);
                upperBound = lowerBound;
            }
        } else {
            String parsedLowerBound = process.substring(0, index).trim();
            String parsedUpperBound = process.substring(index + 1).trim();

            // more than two bounds, e.g. (1,2,3)
            if (parsedUpperBound.contains(",")) {
                throw new InvalidVersionSpecificationException(
                        range, "Invalid version range " + range + ", bounds may not contain additional ','");
            }

            lowerBound = !parsedLowerBound.isEmpty() ? parse(parsedLowerBound) : null;
            upperBound = !parsedUpperBound.isEmpty() ? parse(parsedUpperBound) : null;

            if (upperBound != null && lowerBound != null) {
                if (upperBound.compareTo(lowerBound) < 0) {
                    throw new InvalidVersionSpecificationException(
                            range,
                            "Invalid version range " + range + ", lower bound must not be greater than upper bound");
                }
            }
        }

        this.lowerBound = (lowerBound != null) ? new Bound(lowerBound, lowerBoundInclusive) : null;
        this.upperBound = (upperBound != null) ? new Bound(upperBound, upperBoundInclusive) : null;
    }

    private Version parse(String version) throws InvalidVersionSpecificationException {
        return versionScheme.parseVersion(version);
    }

    @Override
    public Bound getLowerBound() {
        return lowerBound;
    }

    @Override
    public Bound getUpperBound() {
        return upperBound;
    }

    @Override
    public boolean containsVersion(Version version) {
        if (lowerBound != null) {
            int comparison = lowerBound.getVersion().compareTo(version);

            if (comparison == 0 && !lowerBound.isInclusive()) {
                return false;
            }
            if (comparison > 0) {
                return false;
            }
        }

        if (upperBound != null) {
            int comparison = upperBound.getVersion().compareTo(version);

            if (comparison == 0 && !upperBound.isInclusive()) {
                return false;
            }
            if (comparison < 0) {
                return false;
            }
        }

        return true;
    }

    @Override
    public boolean equals(Object obj) {
        if (obj == this) {
            return true;
        } else if (obj == null || !getClass().equals(obj.getClass())) {
            return false;
        }

        VersionRange that = (VersionRange) obj;

        return Objects.equals(upperBound, that.getUpperBound()) && Objects.equals(lowerBound, that.getLowerBound());
    }

    @Override
    public int hashCode() {
        int hash = 17;
        hash = hash * 31 + hash(upperBound);
        hash = hash * 31 + hash(lowerBound);
        return hash;
    }

    private static int hash(Object obj) {
        return obj != null ? obj.hashCode() : 0;
    }

    @Override
    public String toString() {
        StringBuilder buffer = new StringBuilder(64);
        if (lowerBound != null) {
            buffer.append(lowerBound.isInclusive() ? '[' : '(');
            buffer.append(lowerBound.getVersion());
        } else {
            buffer.append('(');
        }
        buffer.append(',');
        if (upperBound != null) {
            buffer.append(upperBound.getVersion());
            buffer.append(upperBound.isInclusive() ? ']' : ')');
        } else {
            buffer.append(')');
        }
        return buffer.toString();
    }
}