package com.inexas.jspwikiplugins;

import java.sql.*;
import java.util.*;
import com.ecyrd.jspwiki.*;
import com.ecyrd.jspwiki.plugin.*;

/**
 * Yet another hit count plugin for JSPWiki. A database is used and is fully 
 * configurable through properties in the jspwiki.properties. You should
 * include something like this in the
 * 
 * # HitCounter plugin
 * com.inexas.jspwikiplugins.HitCounter.DbDriver=org.hsqldb.jdbcDriver
 * com.inexas.jspwikiplugins.HitCounter.DbUrl=jdbc:hsqldb:mem:processlab
 * com.inexas.jspwikiplugins.HitCounter.DbUser=sa
 * com.inexas.jspwikiplugins.HitCounter.DbPassword=
 * com.inexas.jspwikiplugins.HitCounter.TestTableSql=SELECT count(*) FROM hitCount
 * com.inexas.jspwikiplugins.HitCounter.CreateTableSql=CREATE TABLE hitCount(pageKey VARCHAR PRIMARY KEY,pageHits INT NOT NULL)
 * com.inexas.jspwikiplugins.HitCounter.ReadHitCountSql=SELECT pageHits FROM hitCount WHERE pageKey=?
 * com.inexas.jspwikiplugins.HitCounter.InsertHitCountSql=INSERT INTO hitCount(pageKey,pageHits)VALUES(?,?)
 * com.inexas.jspwikiplugins.HitCounter.UpdateHitCountSql=UPDATE hitCount SET pageHits=? WHERE pageKey=?
 * 
 * @author Keith Whittingham
 * $Revision: 1.3 $
 */
@SuppressWarnings("unchecked")
public class HitCounter implements WikiPlugin {
	private Connection connection;
	private String readHitCountSql, insertHitCountSql, updateHitCountSql;
	private boolean hide;
	private WikiContext context;
    private Map parameters;
    /** Used for unit tests in place of WikiContext */
    static Map<String,String> testWikiContext;


	/**
	 * This method is called each time a wiki page is shown.
	 * 
	 * @return the HTML to display
	 */
	public String execute(WikiContext wikiContext, Map pluginParameters) throws PluginException {
		try {
	        this.context = wikiContext;
	        this.parameters = pluginParameters;
	        initialize();

	        // Create the key for this page...
	        final String key;
	        if(wikiContext == null) {
	        	// It's a unit test..
	        	key = testWikiContext.get("key");
	        } else {
	        	// We're live
		        final String contextName = wikiContext.getEngine().getApplicationName();
		        final String pageName = wikiContext.getPage().getName();
		        key = contextName + "::" + pageName;
	        }

	        // Read the current hit count value...
	        final int hitCount;
	        final PreparedStatement readPs = connection.prepareStatement(readHitCountSql);
	        readPs.setString(1, key);
	        final ResultSet rs = readPs.executeQuery();
	        if(rs.next()) {
	        	// Count exists, increment it...
	        	hitCount = rs.getInt(1) + 1;
	        	final PreparedStatement updatePs = connection.prepareStatement(updateHitCountSql);
	        	updatePs.setInt(1, hitCount);
	        	updatePs.setString(2, key);
	        	updatePs.executeUpdate();
	        	updatePs.close();
	        } else {
	        	// Hit count doesn't exist yet, create a new one...
	        	hitCount = 1;
	        	final PreparedStatement createPs = connection.prepareStatement(insertHitCountSql);
	        	createPs.setString(1, key);
	        	createPs.setInt(2, hitCount);
	        	createPs.executeUpdate();
	        	createPs.close();
	        }
	        readPs.close();
	        return hide ? "" : Integer.toString(hitCount);
        } catch(final Exception e) {
        	if(connection != null) {
        		try {
	                connection.close();
                } catch(final SQLException e1) {
                	// Ignore it
                }
        		connection = null;
        	}
        	return e.getClass().getName() + ": " + e.getMessage();
        }
	}

	private void initialize() throws Exception {
		// If the connection is null we'll reload everything.... 
		if(connection == null) {
			// Create a connection...
			final String driver = getConfig("com.inexas.jspwikiplugins.HitCounter.DbDriver");
			final String url = getConfig("com.inexas.jspwikiplugins.HitCounter.DbUrl");
			final String user = getConfig("com.inexas.jspwikiplugins.HitCounter.DbUser");
			final String password = getConfig("com.inexas.jspwikiplugins.HitCounter.DbPassword");
			Class.forName(driver);
			connection = DriverManager.getConnection(url, user, password);
			
			// Load the SQL strings
			final String testTable = getConfig("com.inexas.jspwikiplugins.HitCounter.TestTableSql");
			final String createTable = getConfig("com.inexas.jspwikiplugins.HitCounter.CreateTableSql");
			readHitCountSql = getConfig("com.inexas.jspwikiplugins.HitCounter.ReadHitCountSql");
			insertHitCountSql = getConfig("com.inexas.jspwikiplugins.HitCounter.InsertHitCountSql");
			updateHitCountSql = getConfig("com.inexas.jspwikiplugins.HitCounter.UpdateHitCountSql");
			
			// Check the DB table exists, if not create it...
            final Statement statement = connection.createStatement();
			try {
	            statement.execute(testTable);
            } catch(final Exception e) {
            	// Test failed, try and create the table...
            	statement.execute(createTable);
            } finally {
            	statement.close();
            }
			
            // See if the user wants to hide the counter...
			hide = parameters.containsKey("hide");
		}
		
    }

	private String getConfig(String key) throws Exception {
		final String result;
		if(context == null) {
			// It's a unit test...
			result = testWikiContext.get(key);
		} else {
			// We're live..
		    result = context.getEngine().getWikiProperties().getProperty(key);
		}
		if(result == null) {
			throw new Exception("Cannot find parameter in jspwiki.properties: " + key);
		}
		return result;
    }

}