// Copyright (c) 2009 The Chromium Authors. All rights reserved.

// Use of this source code is governed by a BSD-style license that can be

// found in the LICENSE file.

package org.chromium.sdk;

import java.util.ArrayList;

import java.util.Arrays;

import java.util.Collections;

import java.util.List;

/**

 * An object that describes the numeric part of version.

 */

public class Version implements Comparable<Version> {

  private final List<Integer> components;

  /**

   * Constructs an immutable Version instance given the numeric components of version.

   */

  public Version(Integer ... components) {

    this(Arrays.asList(components));

  }

  /**

   * Constructs an immutable Version instance given the numeric components of version.

   */

  public Version(List<Integer> components) {

    this.components = Collections.unmodifiableList(new ArrayList<Integer>(components));

  }

  /**

   * @return numeric components of version in form of list of integers

   */

  public List<Integer> getComponents() {

    return components;

  }

  @Override

  public boolean equals(Object obj) {

    if (obj == null || !(obj instanceof Version)) {

      return false;

    }

    Version that = (Version) obj;

    return this.components.equals(that.components);

  }

  @Override

  public int hashCode() {

    return components.hashCode();

  }

  public int compareTo(Version other) {

    for (int i = 0; i < this.components.size(); i++) {

      if (other.components.size() <= i) {

        // shorter version is less

        return +1;

      }

      int res = this.components.get(i).compareTo(other.components.get(i));

      if (res != 0) {

        return res;

      }

    }

    if (this.components.size() < other.components.size()) {

      return -1;

    } else {

      return 0;

    }

  }

  @Override

  public String toString() {

    return components.toString();

  }

  /**

   * Parses string as version as far as it is dot-delimited integer numbers.

   * @param text string representation of version; not null

   * @return new instance of version or null if text is not version.

   */

  public static Version parseString(String text) {

    int i = 0;

    List<Integer> components = new ArrayList<Integer>(4);

    while (i < text.length()) {

      int num = Character.digit(text.charAt(i), 10);

      if (num < 0) {

        break;

      }

      i++;

      while (i < text.length() && Character.digit(text.charAt(i), 10) >= 0) {

        num = num * 10 + Character.digit(text.charAt(i), 10);

        i++;

      }

      components.add(num);

      if (i < text.length() && text.charAt(i) == '.') {

        i++;

        continue;

      } else {

        break;

      }

    }

    if (components.isEmpty()) {

      return null;

    }

    return new Version(components);

  }

}