/*
 * Copyright (c) 2003-2004, KNOPFLERFISH project
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following
 * conditions are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 *
 * - Redistributions in binary form must reproduce the above
 *   copyright notice, this list of conditions and the following
 *   disclaimer in the documentation and/or other materials
 *   provided with the distribution.
 *
 * - Neither the name of the KNOPFLERFISH project nor the names of its
 *   contributors may be used to endorse or promote products derived
 *   from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 */

package org.knopflerfish.bundle.basicdriverlocator;

import org.knopflerfish.service.log.LogRef;
import org.osgi.framework.*;
import org.osgi.service.device.*;
import org.osgi.service.log.*;
import java.util.*;
import java.io.*;
import java.net.*;

/**
 * Basic implementation of a DriverLocator.
 *
 * Uses a text-based driver database in Properties format. The driver
 * is named <code>driverDB.props</code> and should reside in the 
 * bundle jar file.
 *
 * <p> 
 * Database file format:
 * <pre>
 *  count=&lt;number of drivers&gt;
 *  &lt;number&gt;.id=&lt;driver id&gt; 
 *  &lt;number&gt;.category=&lt;driver category&gt;
 *  &lt;number&gt;.product=&lt;driver product&gt;
 *  &lt;number&gt;.vendor=&lt;driver vendor&gt;
 *  &lt;number&gt;.url=&lt;driver url&gt; 
 *  &lt;number&gt;.desc=&lt;driver description&gt;
 * </pre>
 *
 *
 */
public class BasicDriverLocator implements DriverLocator {

  /** Context service is running in */
  BundleContext bc                   = null;

  String        dbResourceName       = "/data/driverDB.props";

  // Utility class for logging
  LogRef        log;

  String jarbase = ""; 

  BasicDriverLocator(BundleContext bc) {
    this.bc    = bc;

    // Try to get log service and handle it's life cycle
    log = new LogRef(bc);

    jarbase        = System.getProperty("org.knopflerfish.gosg.jars", "file:");
  }
  
  
  /**
   * Implements DriverLocator.
   *
   * Loads driver DB, then calls match()
   */
  public String[] findDrivers(Dictionary dict) {
    Hashtable drivers = loadDriverDB();

    return match(drivers, dict);
  }


  /**
   * Implements DriverLocator.
   *
   * Load a driver bundle using URL info.
   *
   * @return Stream to driver bundle, null if no driver is found.
   */
  public InputStream loadDriver(String id) throws IOException {
    Hashtable drivers = loadDriverDB();

    DriverInfo      di = (DriverInfo)drivers.get(id);
    InputStream stream = null;

    if(di == null) {
      log.warn("No id" + id);
      throw new IOException("No driver id '" + id + "'"); 
    }
    try {
      String strURL = di.url;
      if(strURL.indexOf(":") == -1) {
	strURL = jarbase + strURL;
      }

      URL url = new URL(strURL);
      
      stream = url.openStream();
    } catch(MalformedURLException e) {
      log.error("bad URL for in " + di, e);
      throw new IOException("Bad driver URL " + e); 
    } catch(IOException e) {
      log.error("can't connect to URL in " + di, e);

      // rethrow exception
      throw e;
    }
    return stream;
  }


  /**
   * Load driver database.
   *
   * @return Hashtable String (driver id) -> DriverInfo
   */
  Hashtable loadDriverDB() {
    Hashtable       d        = new Hashtable();
    InputStream     instream = null;

    try {
      String dbURL = (String)
	System.getProperty("org.osgi.service.basicdriverlocator.dburl");

      // If property exists, try to open URL, otherwise use internal props.
      if(dbURL != null && !dbURL.equals("")) {
	if(dbURL.indexOf(":") == -1) {
	  dbURL = jarbase + dbURL;
	}
	URL url  = new URL(dbURL);
	log.info("read external props file: " + dbURL);
	instream = url.openStream();
      } else {
	log.info("read internal props file: " + dbResourceName);
	instream       = getClass().getResourceAsStream(dbResourceName);
      }

      Properties db  = new Properties();
      
      db.load(instream);
      
      int nCount = Integer.parseInt((String)db.get("count"));
      
      for(int i = 0; i < nCount; i++) {
	try {
	  DriverInfo di = new DriverInfo(db, i);
	  d.put(di.id, di);
	} catch (Exception e) {
	  log.error("Failed to initialize driver entry " + i, e);
	}
      }

    } catch (Exception e) {
      log.error("Can't load driverDB: ", e);
      e.printStackTrace();
    } finally {
      try {
	if(instream != null) instream.close();
      } catch (IOException e2) {
	// silently ignore
      }
    }

    return d;
  }

  /**
   * Check all Drivers in drivers for match agains props.
   *
   * @param drivers String (driver ID) -> DriverInfo
   * @param props Device properties to match
   * @return String array od driver IDs
   */
  String[] match(Hashtable drivers, Dictionary dict) {
    Vector r = new Vector();

    for (Enumeration e = drivers.elements() ; e.hasMoreElements() ;) {
      DriverInfo di = (DriverInfo)e.nextElement();

      if(di.match(dict)) {
	r.addElement(di.id);
      }
    }




    // Create string array, since API says so
    String[] rl = new String[r.size()];

    r.copyInto(rl);

    return rl;
  }
}

/**
 * Utility class for holding driver database
 */
class DriverInfo {
  String   url;
  String   id;
  String   category;
  String   vendor;
  String   product;
  String   desc;

  /**
   * Create from Properties.
   *
   * Values of the form <code>number</code>.key are get() from props to
   * build the DriverInfo.
   *
   * @param p Properties containing driver info
   * @param number count number inte named properties
   */
  DriverInfo(Properties p, int number) {
    id       = (String)p.get("" + number + ".id");
    url      = (String)p.get("" + number + ".url");
    desc     = (String)p.get("" + number + ".desc");
    vendor   = (String)p.get("" + number + ".vendor");
    product  = (String)p.get("" + number + ".product");
    category = (String)p.get("" + number + ".category");
  }


  /**
   * Matching method used by locator. 
   *
   * @return true if DriverInfo matches props, false otherwise
   */
  boolean match(Dictionary props) {
    boolean b =
      cmp(category, (String)props.get("category")) &&
      cmp(product,  (String)props.get("product")) &&
      cmp(vendor,   (String)props.get("vendor"));

    return b;
  }
	
  /**
   * Compare method which allows empty strings and simple wildcards.
   *
   * null, "" and "*" are match-all wildcards.
   *
   * @param s1 string to compare to s2
   * @param s2 string to compare to s1
   * @return true id s1 compares nicely to s2
   */
  boolean cmp(String s1, String s2) {
    return 
      s1 == null || 
      s2 == null || 
      s1.equals("") || 
      s2.equals("") ||
      s1.equals("*") || 
      s2.equals("*") ||
      s1.equalsIgnoreCase(s2);
  }

  /**
   * Convert to string.
   *
   * @return Human-readable string representation
   */
  public String toString() {
    return 
      "id=" + id + 
      ", url=" + url + 
      ", desc=" + desc + 
      ", product=" + product +
      ", vendor=" + vendor;
  }


}