package beast.util;

import beast.app.util.Version;

/**
 * Note: this class has a natural ordering that is not necessarily
 * consistent with equals(). The definition of equals() tests for
 * equality of version strings, while (for example) compareTo() returns
 * 0 for versions with version strings "2.0" and "2".
 *
 * @author Tim Vaughan <tgvaughan@gmail.com>
 */
public class PackageVersion extends Version implements Comparable<PackageVersion> {

    String versionString;

    public PackageVersion(String versionString) {
        this.versionString = versionString;
    }

    @Override
    public String getVersion() {
        return versionString;
    }

    @Override
    public String getVersionString() {
        return versionString;
    }

    @Override
    public String getDateString() {
        return null;
    }

    @Override
    public String[] getCredits() {
        return null;
    }

    @Override
    public String toString() {
        return versionString;
    }

    @Override
    public int compareTo(PackageVersion otherVersion) {
        return compareVersionStrings(this.versionString, otherVersion.versionString);
    }

    /**
     * Compare package version strings.
     *
     * @param versionA first version string
     * @param versionB second version string
     * @return -1, 0 or 1 if versionA is less than, equal to or greater than versionB
     */
    private int compareVersionStrings(String versionA, String versionB) {

        String[] partsA = versionA.split("\\.");
        String[] partsB = versionB.split("\\.");

        int n = Math.max(partsA.length, partsB.length);

        for (int i=0; i<n; i++) {
            int partAint, partBint;
            String partAstr, partBstr;

            if (i<partsA.length) {
                partAint = Integer.parseInt("0" + partsA[i].replaceAll("(^[0-9]*).*$", "$1"));
                partAstr = partsA[i].replaceAll("^[0-9]*(.*)$", "$1");
            } else {
                partAint = 0;
                partAstr = "";
            }

            if (i<partsB.length) {
                partBint = Integer.parseInt("0" + partsB[i].replaceAll("(^[0-9]*).*$", "$1"));
                partBstr = partsB[i].replaceAll("^[0-9]*(.*)$", "$1");
            } else {
                partBint = 0;
                partBstr = "";
            }

            if (partAint<partBint)
                return -1;

            if (partAint>partBint)
                return 1;

            // 1.0 > 1.0-alpha
            if (partAstr.isEmpty() && !partBstr.isEmpty())
                return 1;

            // 1.0-alpha < 1.0
            if (!partAstr.isEmpty() && partBstr.isEmpty())
                return -1;

            int strComp = partAstr.compareTo(partBstr);
            if (strComp != 0)
                return strComp;
        }

        return 0;
    }

    /**
     * Compare with object o.
     *
     * @param o object with which to test for equality.
     * @return true iff the version strings are exactly equal.
     */
    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;

        PackageVersion that = (PackageVersion) o;

        return versionString.equals(that.versionString);

    }

    @Override
    public int hashCode() {
        return versionString.hashCode();
    }
}