/*******************************************************************************
 * Copyright (c) 2008-2010 Sonatype, Inc.
 * 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
 *
 * Contributors:
 *      Sonatype, Inc. - initial API and implementation
 *******************************************************************************/

package org.eclipse.m2e.scm.spi;

import java.io.File;
import java.io.InputStream;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IConfigurationElement;
import org.eclipse.core.runtime.IExecutableExtension;
import org.eclipse.core.runtime.IProgressMonitor;

import org.eclipse.m2e.scm.MavenProjectScmInfo;


/**
 * An SCM handler base class
 * 
 * @author Eugene Kuleshov
 */
public abstract class ScmHandler implements Comparable<ScmHandler>, IExecutableExtension {
  private static final Logger log = LoggerFactory.getLogger(ScmHandler.class);

  public static final String ATTR_CLASS = "class"; //$NON-NLS-1$

  public static final String ATTR_TYPE = "type"; //$NON-NLS-1$

  public static final String ATTR_PRIORITY = "priority"; //$NON-NLS-1$

  private String type;

  private int priority;

  public String getType() {
    return type;
  }

  public int getPriority() {
    return priority;
  }

  /**
   * Opens resource from SCM
   * 
   * @param url an url in maven-scm format for the resource to open
   * @param revision a resource revision to open
   * @throws CoreException when selected resource can't be open
   * @see http://maven.apache.org/scm/scm-url-format.html
   */
  public InputStream open(String url, String revision) throws CoreException {
    return null;
  }

  /**
   * @param info
   * @param location
   * @param monitor
   */
  public abstract void checkoutProject(MavenProjectScmInfo info, //
      File location, IProgressMonitor monitor) throws CoreException, InterruptedException;

  // IExecutableExtension  

  public void setInitializationData(IConfigurationElement config, String propertyName, Object data) {
    String handlerClass = config.getAttribute(propertyName);
    String type = config.getAttribute(ATTR_TYPE);
    String priority = config.getAttribute(ATTR_PRIORITY);

    this.type = type;

    if(priority != null) {
      try {
        this.priority = Integer.parseInt(priority);
      } catch(Exception ex) {
        log.error("Unable to parse priority for " + handlerClass, ex);
      }
    }
  }

  // Comparable

  public int compareTo(ScmHandler o) {
    if(o != null) {
      ScmHandler handler = o;
      int res = getType().compareTo(handler.getType());
      if(res == 0) {
        res = getPriority() - handler.getPriority();
      }
      return res;
    }
    return -1;
  }

  public int hashCode() {
    final int prime = 31;
    int result = prime + this.priority;
    return prime * result + ((this.type == null) ? 0 : this.type.hashCode());
  }

  public boolean equals(Object obj) {
    if(this == obj) {
      return true;
    }
    if(obj == null) {
      return false;
    }
    if(getClass() != obj.getClass()) {
      return false;
    }
    ScmHandler other = (ScmHandler) obj;
    if(this.priority != other.priority) {
      return false;
    }
    if(this.type == null) {
      if(other.type != null) {
        return false;
      }
    } else if(!this.type.equals(other.type)) {
      return false;
    }
    return true;
  }

}