package org.kuali.core.db.torque;

 import static java.sql.Types.CLOB;

 import static java.sql.Types.DATE;

 import static java.sql.Types.TIMESTAMP;

 import static org.kuali.db.JDBCUtils.closeQuietly;

 import java.io.File;

 import java.io.FileNotFoundException;

 import java.io.FileOutputStream;

 import java.io.IOException;

 import java.io.PrintWriter;

 import java.io.Reader;

 import java.io.Writer;

 import java.sql.Clob;

 import java.sql.Connection;

 import java.sql.DatabaseMetaData;

 import java.sql.ResultSet;

 import java.sql.ResultSetMetaData;

 import java.sql.SQLException;

 import java.sql.Statement;

 import java.sql.Timestamp;

 import java.text.SimpleDateFormat;

 import java.util.ArrayList;

 import java.util.Date;

 import java.util.List;

 import java.util.Set;

 import java.util.TreeSet;

 import org.apache.commons.io.IOUtils;

 import org.apache.commons.lang.StringUtils;

 import org.apache.tools.ant.BuildException;

 import org.apache.tools.ant.Project;

 import org.apache.torque.engine.database.model.Column;

 import org.apache.torque.engine.database.model.Table;

 import org.apache.torque.engine.platform.Platform;

 import org.apache.torque.engine.platform.PlatformFactory;

 import org.apache.xerces.dom.DocumentImpl;

 import org.apache.xerces.dom.DocumentTypeImpl;

 import org.apache.xerces.util.XMLChar;

 import org.apache.xml.serialize.Method;

 import org.apache.xml.serialize.OutputFormat;

 import org.apache.xml.serialize.XMLSerializer;

 import org.w3c.dom.Element;

 /**

  * This task exports tables from a JDBC accessible database to XML

  */

 public class KualiTorqueDataDumpTask extends DumpTask {

     Utils utils = new Utils();

     private static final String FS = System.getProperty("file.separator");

     /**

      * The directory where XML files will be written

      */

     private File dataXMLDir;

     /**

      * The format to use for dates/timestamps

      */

     private String dateFormat = "yyyyMMddHHmmss z";

     /**

      * The formatter that will do the formatting of dates;

      */

     private SimpleDateFormat dateFormatter;

     @Override

     protected void showConfiguration() {

         super.showConfiguration();

         log("Exporting to: " + getDataXMLDir().getAbsolutePath());

         log("Date format: \"" + dateFormat + "\" - " + dateFormatter.format(new Date()));

     }

     @Override

     protected void updateConfiguration(final Platform platform) {

         super.updateConfiguration(platform);

         dateFormatter = new SimpleDateFormat(dateFormat);

     }

     /**

      * Dump the data to XML files

      */

     @Override

     public void execute() throws BuildException {

         try {

             log("--------------------------------------");

             log("Impex - Data Export");

             log("--------------------------------------");

             Platform platform = PlatformFactory.getPlatformFor(targetDatabase);

             updateConfiguration(platform);

             showConfiguration();

             // Generate the XML

             generateXML(platform);

         } catch (Exception e) {

             throw new BuildException(e);

         }

     }

     /**

      * Generate a SQL statement that selects all data from the table

      */

     protected String getDataSelectStatement(final TableHelper helper, final String tableName) throws SQLException {

         StringBuffer sb = new StringBuffer("SELECT * FROM ");

         sb.append(tableName);

         sb.append(" ORDER BY 'x'");

         List<String> pkFields = helper.getPlatform().getPrimaryKeys(helper.getDbMetaData(), getSchema(), tableName);

         for (String field : pkFields) {

             sb.append(", ").append(field);

         }

         return sb.toString();

     }

     /**

      * Generate an array of Column objects from the result set metadata

      */

     protected Column[] getColumns(final ResultSetMetaData md) throws SQLException {

         Column[] columns = new Column[md.getColumnCount() + 1];

         for (int i = 1; i <= md.getColumnCount(); i++) {

             Column column = new Column();

             column.setName(md.getColumnName(i));

             column.setJdbcType(md.getColumnType(i));

             columns[i] = column;

         }

         return columns;

     }

     /**

      * Extract a column value from the result set, converting as needed

      */

     protected Object getColumnValue(final ResultSet rs, final int index, final Column column, final int rowCount,

             final String tableName) {

         // Extract a raw object

         Object columnValue = null;

         try {

             columnValue = rs.getObject(index);

             // If it is null we're done

             if (columnValue == null) {

                 return null;

             }

             // Handle special types

             switch (column.getJdbcType()) {

             case (CLOB):

                 // Extract a CLOB

                 return getClob((Clob) columnValue);

             case (DATE):

             case (TIMESTAMP):

                 // Extract dates and timestamps

                 return getDate(rs, index);

             default:

                 // Otherwise return the raw object

                 return columnValue;

             }

         } catch (Exception e) {

             // Don't let an issue extracting a value from one column in one row

             // stop the process

             // Log the row/column and continue

             log("Problem reading row " + rowCount + " column " + column.getName() + " from " + tableName,

                     Project.MSG_ERR);

             log(e.getClass().getName() + " : " + e.getMessage(), Project.MSG_ERR);

         }

         return null;

     }

     /**

      * Convert a JDBC Timestamp into a java.util.Date using the specified format

      */

     protected String getDate(final ResultSet rs, final int index) throws SQLException {

         Timestamp date = rs.getTimestamp(index);

         return dateFormatter.format(date);

     }

     /**

      * Convert a CLOB to a String

      */

     protected String getClob(final Clob clob) throws SQLException {

         Reader r = null;

         StringBuffer sb = new StringBuffer();

         try {

             r = clob.getCharacterStream();

             char[] buffer = new char[4096];

             int len;

             while ((len = r.read(buffer)) != -1) {

                 sb.append(buffer, 0, len);

             }

         } catch (IOException e) {

             throw new SQLException(e);

         } finally {

             IOUtils.closeQuietly(r);

         }

         return sb.toString();

     }

     /**

      * Convert a row from the result set into an Element

      */

     protected Element getRow(final DocumentImpl doc, final String tableName, final ResultSetMetaData md,

             final ResultSet rs, final Column[] columns, final int rowCount) throws SQLException {

         // Generate a row object

         Element row = doc.createElement(tableName);

         // Cycle through the columns

         for (int i = 1; i <= md.getColumnCount(); i++) {

             // Extract a column value

             Object columnValue = getColumnValue(rs, i, columns[i], rowCount, tableName);

             // Null values can be omitted from the XML

             if (columnValue == null) {

                 continue;

             }

             // Otherwise, escape the String and add it to the row Element

             row.setAttribute(columns[i].getName(), xmlEscape(columnValue.toString()));

         }

         // Return an Element representing one row of data from the ResultSet

         return row;

     }

     /**

      * Generate and return the dataset Element

      */

     protected Element getDatasetNode(final TableHelper helper, final DocumentImpl document, final String tableName)

             throws SQLException {

         Element datasetNode = document.createElement("dataset");

         Statement stmt = null;

         ResultSet rs = null;

         try {

             // This query selects everything from the table

             String query = getDataSelectStatement(helper, tableName);

             stmt = helper.getConnection().createStatement(ResultSet.TYPE_FORWARD_ONLY, ResultSet.CONCUR_READ_ONLY);

             rs = stmt.executeQuery(query);

             ResultSetMetaData md = rs.getMetaData();

             Column[] columns = getColumns(md);

             int count = 0;

             // Process the ResultSet

             while (rs.next()) {

                 count++;

                 log("Processing row " + count + " of " + tableName, Project.MSG_DEBUG);

                 Element row = getRow(document, tableName, md, rs, columns, count);

                 datasetNode.appendChild(row);

             }

             helper.setRowCount(count);

             // Keep track of how many rows we found

             if (count == 0) {

                 log("No data found in table " + tableName, Project.MSG_DEBUG);

                 return null;

             }

         } catch (Exception e) {

             throw new SQLException(e);

         } finally {

             // Clean up

             closeQuietly(rs);

             closeQuietly(stmt);

         }

         return datasetNode;

     }

     /**

      * Return the systemId to use

      */

     protected String getSystemId() {

         if (antCompatibilityMode) {

             return "data.dtd";

         } else {

             return getArtifactId() + ".dtd";

         }

     }

     /**

      * Return the XML Document object that we will serialize to disk

      */

     protected DocumentImpl getDocument(final TableHelper helper, final String tableName) throws SQLException {

         // Generate the document type

         DocumentTypeImpl docType = new DocumentTypeImpl(null, "dataset", null, getSystemId());

         // Generate an empty document

         DocumentImpl doc = new DocumentImpl(docType);

         // Append a comment

         doc.appendChild(doc.createComment(" " + getComment() + " "));

         // Extract the data from the table

         Element datasetNode = getDatasetNode(helper, doc, tableName);

         if (datasetNode == null) {

             // There was no data (zero rows), we are done

             return null;

         }

         // Add the dataset to the document

         doc.appendChild(datasetNode);

         // Return what we found

         return doc;

     }

     /**

      * <code>

      * Convert a List<Table> into a List<String> of table names

      * </code>

      */

     protected List<String> getTableNamesFromTableObjects(final List<?> list) {

         List<String> names = new ArrayList<String>();

         for (Object object : list) {

             Table table = (Table) object;

             names.add(table.getName());

         }

         return names;

     }

     /**

      * Convert a List to a Set

      *

      * @param list

      * @return

      */

     protected Set<String> getSet(final List<String> list) {

         Set<String> set = new TreeSet<String>();

         set.addAll(list);

         return set;

     }

     /**

      * Generate XML from the data in the tables in the database

      */

     protected void generateXML(final Platform platform) throws Exception {

         Connection connection = null;

         try {

             connection = getConnection();

             // Get metadata about the database

             DatabaseMetaData dbMetaData = connection.getMetaData();

             // Get the correct platform (oracle, mysql etc)

             // Get ALL the table names

             Set<String> tableNames = getSet(getJDBCTableNames(dbMetaData));

             log("Table Count: " + tableNames.size());

             int completeSize = tableNames.size();

             StringFilter filterer = new StringFilter(includePatterns, excludePatterns);

             filterer.filter(tableNames.iterator());

             int filteredSize = tableNames.size();

             if (filteredSize != completeSize) {

                 log("Filtered table count: " + tableNames.size());

             } else {

                 log("No tables were filtered out.  Exporting all tables.");

             }

             TableHelper helper = new TableHelper();

             helper.setConnection(connection);

             helper.setPlatform(platform);

             helper.setDbMetaData(dbMetaData);

             helper.setTableNames(tableNames);

             processTables(helper);

         } catch (Exception e) {

             closeQuietly(connection);

         }

     }

     /**

      * Process the tables, keeping track of which tables had at least one row of data

      */

     protected void processTables(final TableHelper helper) throws IOException, SQLException {

         long start = System.currentTimeMillis();

         int exportCount = 0;

         int skipCount = 0;

         for (String tableName : helper.getTableNames()) {

             boolean exported = processTable(helper, tableName);

             if (exported) {

                 exportCount++;

             } else {

                 skipCount++;

             }

         }

         long elapsed = System.currentTimeMillis() - start;

         log(utils.pad("Processed " + helper.getTableNames().size() + " tables", elapsed));

         log("Exported data from " + exportCount + " tables to XML");

         log("Skipped " + skipCount + " tables that had zero rows");

     }

     /**

      * Process one table. Only create an XML file if there is at least one row of data

      */

     protected boolean processTable(final TableHelper helper, final String tableName) throws SQLException, IOException {

         log("Processing: " + tableName, Project.MSG_DEBUG);

         long ts1 = System.currentTimeMillis();

         DocumentImpl doc = getDocument(helper, tableName);

         long ts2 = System.currentTimeMillis();

         log(utils.pad("Extracting: " + tableName + " ", ts2 - ts1), Project.MSG_DEBUG);

         boolean exported = false;

         if (doc != null) {

             serialize(tableName, doc);

             exported = true;

         }

         long ts3 = System.currentTimeMillis();

         log(utils.pad("Serializing: " + tableName + " ", ts3 - ts2), Project.MSG_DEBUG);

         if (!exported) {

             log(utils.pad("Rows: " + StringUtils.leftPad(helper.getRowCount() + "", 5) + " " + tableName, (ts3 - ts1)),

                     Project.MSG_DEBUG);

         } else {

             log(utils.pad("Rows: " + StringUtils.leftPad(helper.getRowCount() + "", 5) + " " + tableName, (ts3 - ts1)));

         }

         return exported;

     }

     /**

      * This is where the XML will be written to

      */

     protected Writer getWriter(final String tableName) throws FileNotFoundException {

         String filename = getDataXMLDir() + FS + tableName + ".xml";

         log("filename:" + filename, Project.MSG_DEBUG);

         return new PrintWriter(new FileOutputStream(filename));

     }

     /**

      * This is the XMLSerializer responsible for outputting the XML document

      */

     protected XMLSerializer getSerializer(final Writer out) {

         return new XMLSerializer(out, new OutputFormat(Method.XML, getEncoding(), true));

     }

     /**

      * Serialize the document

      */

     protected void serialize(final String tableName, final DocumentImpl doc) throws IOException {

         Writer out = null;

         try {

             out = getWriter(tableName);

             XMLSerializer serializer = getSerializer(out);

             serializer.serialize(doc);

             out.flush();

         } catch (IOException e) {

             throw e;

         } finally {

             IOUtils.closeQuietly(out);

         }

     }

     /**

      * Escape characters that would cause issues for XML parsers

      */

     protected String xmlEscape(final String st) {

         StringBuffer buff = new StringBuffer();

         char[] block = st.toCharArray();

         String stEntity = null;

         int i, last;

         for (i = 0, last = 0; i < block.length; i++) {

             if (XMLChar.isInvalid(block[i])) {

                 stEntity = " ";

             }

             if (stEntity != null) {

                 buff.append(block, last, i - last);

                 buff.append(stEntity);

                 stEntity = null;

                 last = i + 1;

             }

         }

         if (last < block.length) {

             buff.append(block, last, i - last);

         }

         return buff.toString();

     }

     /**

      * Get the names of all the tables in our schema

      */

     public List<String> getJDBCTableNames(final DatabaseMetaData dbMeta) throws SQLException {

         // these are the entity types we want from the database

         String[] types = { "TABLE" }; // JHK: removed views from list

         List<String> tables = new ArrayList<String>();

         ResultSet tableNames = null;

         try {

             // JHK: upper-cased schema name (required by Oracle)

             tableNames = dbMeta.getTables(null, getSchema().toUpperCase(), null, types);

             while (tableNames.next()) {

                 String name = tableNames.getString(3);

                 tables.add(name);

             }

         } finally {

             closeQuietly(tableNames);

         }

         return tables;

     }

     public File getDataXMLDir() {

         return dataXMLDir;

     }

     public void setDataXMLDir(final File outputDirectory) {

         this.dataXMLDir = outputDirectory;

     }

     public String getDateFormat() {

         return dateFormat;

     }

     public void setDateFormat(final String dateFormat) {

         this.dateFormat = dateFormat;

     }

 }