/*******************************************************************************
    * Copyhacked (H) 2012-2025.
    * This program and the accompanying materials
    * are made available under no term at all, use it like
    * you want, but share and discuss it
    * every time possible with every body.
    * 
    * Contributors:
    *      ron190 at ymail dot com - initial implementation
   ******************************************************************************/
  package com.jsql.model.accessible;
  
  import com.jsql.model.InjectionModel;
  import com.jsql.model.bean.database.*;
  import com.jsql.model.suspendable.Input;
  import com.jsql.view.subscriber.Seal;
  import com.jsql.model.exception.AbstractSlidingException;
  import com.jsql.model.exception.InjectionFailureException;
  import com.jsql.model.exception.JSqlException;
  import com.jsql.model.suspendable.SuspendableGetRows;
  import com.jsql.util.I18nUtil;
  import com.jsql.util.LogLevelUtil;
  import org.apache.commons.lang3.StringUtils;
  import org.apache.logging.log4j.LogManager;
  import org.apache.logging.log4j.Logger;
  
  import java.util.ArrayList;
  import java.util.List;
  import java.util.regex.Pattern;
  
  /**
   * Database resource object to read name of databases, tables, columns and values
   * using most suited injection strategy.
   */
  public class DataAccess {
      
      private static final Logger LOGGER = LogManager.getRootLogger();
      
      /**
       * Regex characters marking the end of the result of an injection.
       * Process stops when this schema is encountered:
       * <pre>SQLix01x03x03x07
       */
      public static final String TRAIL_RGX = "\\x01\\x03\\x03\\x07";
      
      /**
       * Regex character used between each table cells.
       * Expected schema of multiple table cells :
       * <pre>
       * x04[table cell]x05[number of occurrences]x04x06x04[table cell]x05[number of occurrences]x04
       */
      public static final String SEPARATOR_CELL_RGX = "\\x06";
      
      /**
       * Regex character used between the table cell and the number of occurrence of the cell text.
       * Expected schema of a table cell data is
       * <pre>x04[table cell]x05[number of occurrences]x04
       */
      public static final String SEPARATOR_QTE_RGX = "\\x05";
  
      /**
       * Regex character enclosing a table cell returned by injection.
       * It allows to detect the correct end of a table cell data during parsing.
       * Expected schema of a table cell data is
       * <pre>x04[table cell]x05[number of occurrences]x04
       */
      public static final String ENCLOSE_VALUE_RGX = "\\x04";
      
      public static final String LEAD = "SqLi";
      public static final String SHELL_LEAD = "${shell.lead}";
      public static final String TRAIL = "iLQS";
      public static final String SHELL_TRAIL = "${shell.trail}";
      
      /**
       * Regex keywords corresponding to multiline and case-insensitive match.
       */
      public static final String MODE = "(?si)";
      
      /**
       * Regex schema describing a table cell with firstly the cell content and secondly the number of occurrences
       * of the cell text, separated by the reserved character x05 in hexadecimal.
       * The range of characters from x01 to x1F are not printable ASCII characters used to parse the data and exclude
       * printable characters during parsing.
       * Expected schema of a table cell data is
       * <pre>x04[table cell]x05[number of occurrences]x04
       */
      public static final String CELL_TABLE = "([^\\x01-\\x09\\x0B-\\x0C\\x0E-\\x1F]*)"+ DataAccess.SEPARATOR_QTE_RGX +"([^\\x01-\\x09\\x0B-\\x0C\\x0E-\\x1F]*)(\\x08)?";
  
      private final InjectionModel injectionModel;
      
      public DataAccess(InjectionModel injectionModel) {
          this.injectionModel = injectionModel;
      }
      
      /**
       * Get general database information.<br>
       * => version{%}database{%}user{%}CURRENT_USER
       */
      public void getDatabaseInfos() {
         LOGGER.log(LogLevelUtil.CONSOLE_DEFAULT, () -> I18nUtil.valueByKey("LOG_FETCHING_INFORMATIONS"));
         
         var sourcePage = new String[]{ StringUtils.EMPTY };
 
         var resultToParse = StringUtils.EMPTY;
         try {
             resultToParse = new SuspendableGetRows(this.injectionModel).run(new Input(
                 this.injectionModel.getMediatorEngine().getEngine().instance().sqlInfos(),
                 sourcePage,
                 false,
                 0,
                 MockElement.MOCK,
                 "metadata"
             ));
         } catch (AbstractSlidingException e) {
             resultToParse = DataAccess.getPartialResultAndLog(e, resultToParse);
         } catch (Exception e) {  // Catch all exceptions but prevent detecting bug
             LOGGER.log(LogLevelUtil.CONSOLE_ERROR, e.getMessage(), e);
         }
 
         if (StringUtils.isEmpty(resultToParse)) {
             this.injectionModel.sendResponseFromSite("Incorrect metadata", sourcePage[0].trim());
         }
         
         try {
             String versionDatabase = resultToParse.split(DataAccess.ENCLOSE_VALUE_RGX)[0].replaceAll("\\s+", StringUtils.SPACE);
             String nameDatabase = resultToParse.split(DataAccess.ENCLOSE_VALUE_RGX)[1];
             String username = resultToParse.split(DataAccess.ENCLOSE_VALUE_RGX)[2];
 
             LOGGER.log(
                 LogLevelUtil.CONSOLE_SUCCESS,
                 "Database [{}] on {} [{}] for user [{}]",
                 nameDatabase,
                 this.injectionModel.getMediatorEngine().getEngine(),
                 versionDatabase,
                 username
             );
         } catch (ArrayIndexOutOfBoundsException e) {
             LOGGER.log(LogLevelUtil.CONSOLE_ERROR,"{}: {}", I18nUtil.valueByKey("LOG_DB_METADATA_INCORRECT"), resultToParse);
             LOGGER.log(LogLevelUtil.CONSOLE_INFORM, I18nUtil.valueByKey("LOG_DB_METADATA_WARN"));
         }
     }
 
     /**
      * Get database names and table counts and send them to the view.<br>
      * Use readable text (not hexa) and parse this pattern:<br>
      * => hh[database name 1]jj[table count]hhgghh[database name 2]jj[table count]hhggh...hi<br>
      * Data window can be cut before the end of the request but the process helps to obtain
      * the rest of the unreachable data. The process can be interrupted by the user (stop/pause).
      * @return list of databases found
      * @throws JSqlException when injection failure or stopped by user
      */
     public List<Database> listDatabases() throws JSqlException {
         LOGGER.log(LogLevelUtil.CONSOLE_DEFAULT, () -> I18nUtil.valueByKey("LOG_FETCHING_DATABASES"));
         List<Database> databases = new ArrayList<>();
         String resultToParse = StringUtils.EMPTY;
         
         try {
             var sourcePage = new String[]{ StringUtils.EMPTY };
             resultToParse = new SuspendableGetRows(this.injectionModel).run(new Input(
                 this.injectionModel.getMediatorEngine().getEngine().instance().sqlDatabases(),
                 sourcePage,
                 true,
                 0,
                 MockElement.MOCK,
                 "databases"
             ));
         } catch (AbstractSlidingException e) {
             resultToParse = DataAccess.getPartialResultAndLog(e, resultToParse);
         } catch (Exception e) {  // Catch all exceptions but prevent detecting bug
             LOGGER.log(LogLevelUtil.CONSOLE_ERROR, e.getMessage(), e);
         }
 
         // Parse all data we have retrieved
         var regexSearch = Pattern.compile(
                 DataAccess.MODE
                 + DataAccess.ENCLOSE_VALUE_RGX
                 + DataAccess.CELL_TABLE
                 + DataAccess.ENCLOSE_VALUE_RGX
             )
             .matcher(resultToParse);
         if (!regexSearch.find()) {
             throw new InjectionFailureException("No match while injecting databases");
         }
         
         regexSearch.reset();
         // Build an array of Database objects from the data we have parsed
         while (regexSearch.find()) {
             String databaseName = regexSearch.group(1);
             String tableCount = regexSearch.group(2);
 
             var newDatabase = new Database(databaseName, tableCount);
             databases.add(newDatabase);
         }
 
         this.injectionModel.sendToViews(new Seal.AddDatabases(databases));
         return databases;
     }
 
     /**
      * Get tables name and row count and send them to the view.<br>
      * Use readable text (not hexa) and parse this pattern:<br>
      * => hh[table name 1]jj[rows count]hhgghh[table name 2]jj[rows count]hhggh...hi<br>
      * Data window can be cut before the end of the request but the process helps to obtain
      * the rest of the unreachable data. The process can be interrupted by the user (stop/pause).
      * @param database which contains tables to find
      * @return list of tables found
      * @throws JSqlException when injection failure or stopped by user
      */
     public List<Table> listTables(Database database) throws JSqlException {
         // Reset stoppedByUser if list of Databases is partial
         // and some Tables are still reachable
         this.injectionModel.setIsStoppedByUser(false);
         
         // Inform the view that database has just been used
         this.injectionModel.sendToViews(new Seal.StartProgress(database));
 
         var tableCount = Integer.toString(database.getChildCount());
         
         String resultToParse = StringUtils.EMPTY;
         try {
             var pageSource = new String[]{ StringUtils.EMPTY };
             resultToParse = new SuspendableGetRows(this.injectionModel).run(new Input(
                 this.injectionModel.getMediatorEngine().getEngine().instance().sqlTables(database),
                 pageSource,
                 true,
                 Integer.parseInt(tableCount),
                 database,
                 "tables"
             ));
         } catch (AbstractSlidingException e) {
             resultToParse = DataAccess.getPartialResultAndLog(e, resultToParse);
         } catch (Exception e) {  // Catch all exceptions but prevent detecting bug
             LOGGER.log(LogLevelUtil.CONSOLE_ERROR, e.getMessage(), e);
         }
 
         // Parse all the data we have retrieved
         var regexSearch = Pattern.compile(
                 DataAccess.MODE
                 + DataAccess.ENCLOSE_VALUE_RGX
                 + DataAccess.CELL_TABLE
                 + DataAccess.ENCLOSE_VALUE_RGX
             )
             .matcher(resultToParse);
         
         this.injectionModel.sendToViews(new Seal.EndProgress(database));
 
         if (!regexSearch.find()) {
             throw new InjectionFailureException("No match while injecting tables");
         }
         regexSearch.reset();
         
         List<Table> tables = new ArrayList<>();
         
         // Build an array of Table objects from the data we have parsed
         while (regexSearch.find()) {
             String tableName = regexSearch.group(1);
             String rowCount = regexSearch.group(2);
             
             var newTable = new Table(tableName, rowCount, database);
             tables.add(newTable);
         }
 
         this.injectionModel.sendToViews(new Seal.AddTables(tables));
         return tables;
     }
 
     /**
      * Get column names and send them to the view.<br>
      * Use readable text (not hexa) and parse this pattern with 2nd member forced to 31 (1 in ascii):<br>
      * => hh[column name 1]jj[31]hhgghh[column name 2]jj[31]hhggh...hi<br>
      * Data window can be cut before the end of the request but the process helps to obtain
      * the rest of the unreachable data. The process can be interrupted by the user (stop/pause).
      * @param table which contains columns to find
      * @return list of columns found
      * @throws JSqlException when injection failure or stopped by user
      */
     public List<Column> listColumns(Table table) throws JSqlException {
         List<Column> columns = new ArrayList<>();
         
         // Inform the view that table has just been used
         this.injectionModel.sendToViews(new Seal.StartIndeterminateProgress(table));
 
         String resultToParse = StringUtils.EMPTY;
         
         try {
             var pageSource = new String[]{ StringUtils.EMPTY };
             resultToParse = new SuspendableGetRows(this.injectionModel).run(new Input(
                 this.injectionModel.getMediatorEngine().getEngine().instance().sqlColumns(table),
                 pageSource,
                 true,
                 0,
                 table,
                 "columns"
             ));
         } catch (AbstractSlidingException e) {
             resultToParse = DataAccess.getPartialResultAndLog(e, resultToParse);
         } catch (Exception e) {  // Catch all exceptions but prevent detecting bug
             LOGGER.log(LogLevelUtil.CONSOLE_ERROR, e.getMessage(), e);
         }
 
         resultToParse = this.injectionModel.getMediatorEngine().getEngine().transform(resultToParse);  // build columns (e.g sqlite)
 
         // Parse all the data we have retrieved
         var regexSearch = Pattern.compile(
                 DataAccess.MODE
                 + DataAccess.ENCLOSE_VALUE_RGX
                 + DataAccess.CELL_TABLE
                 + DataAccess.ENCLOSE_VALUE_RGX
             )
             .matcher(resultToParse);
 
         this.injectionModel.sendToViews(new Seal.EndIndeterminateProgress(table));
 
         if (!regexSearch.find()) {
             throw new InjectionFailureException("No match while injecting columns");
         }
 
         regexSearch.reset();
 
         // Build an array of Column objects from the data we have parsed
         while (regexSearch.find()) {
             String nameColumn = regexSearch.group(1);
             var column = new Column(nameColumn, table);
             columns.add(column);
         }
 
         this.injectionModel.sendToViews(new Seal.AddColumns(columns));
         return columns;
     }
 
     /**
      * Get table values and count each occurrence and send it to the view.<br>
      * Values are on clear text (not hexa) and follows this window pattern<br>
      * => hh[value 1]jj[count]hhgghh[value 2]jj[count]hhggh...hi<br>
      * Data window can be cut before the end of the request but the process helps to obtain
      * the rest of the unreachable data. The process can be interrupted by the user (stop/pause).
      * @param columnsBean choice by the user
      * @return a 2x2 table containing values by columns
      * @throws JSqlException when injection failure or stopped by user
      */
     public String[][] listValues(List<Column> columnsBean) throws JSqlException {
         var databaseBean = (Database) columnsBean.getFirst().getParent().getParent();
         var tableBean = (Table) columnsBean.getFirst().getParent();
         int rowCount = columnsBean.getFirst().getParent().getChildCount();
 
         // Inform the view that table has just been used
         this.injectionModel.sendToViews(new Seal.StartProgress(tableBean));
 
         // Build an array of column names
         List<String> columnsName = new ArrayList<>();
         for (AbstractElementDatabase columnBean: columnsBean) {
             columnsName.add(columnBean.toString());
         }
 
         // From that array, build the SQL fields nicely
         // => col1{%}col2...
         // ==> trim(ifnull(`col1`,0x00)),0x7f,trim(ifnull(`Col2`,0x00))...
         String[] columns = columnsName.toArray(new String[0]);
 
         List<List<String>> listValues = this.getRows(databaseBean, tableBean, rowCount, columns);
 
         // Add the default title to the columns: row number, occurrence
         columnsName.addFirst(StringUtils.EMPTY);
         columnsName.addFirst(StringUtils.EMPTY);
 
         String[][] table = this.getTable(columnsName, listValues);
 
         columns = columnsName.toArray(new String[0]);
         
         this.injectionModel.sendToViews(new Seal.CreateValuesTab(columns, table, tableBean));
         this.injectionModel.sendToViews(new Seal.EndProgress(tableBean));
         return table;
     }
 
     private List<List<String>> getRows(Database database, Table table, int rowCount, String[] columns) throws InjectionFailureException {
         String resultToParse = StringUtils.EMPTY;
         
         try {
             var pageSource = new String[]{ StringUtils.EMPTY };
             resultToParse = new SuspendableGetRows(this.injectionModel).run(new Input(
                 this.injectionModel.getMediatorEngine().getEngine().instance().sqlRows(columns, database, table),
                 pageSource,
                 true,
                 rowCount,
                 table,
                 "rows"
             ));
         } catch (AbstractSlidingException e) {  // Catch all exceptions but prevent detecting bug
             resultToParse = DataAccess.getPartialResultAndLog(e, resultToParse);
         } catch (Exception e) {
             LOGGER.log(LogLevelUtil.CONSOLE_ERROR, e.getMessage(), e);
         }
         return SuspendableGetRows.parse(resultToParse);
     }
 
     private static String getPartialResultAndLog(AbstractSlidingException e, String resultToParse) {
         LOGGER.log(LogLevelUtil.CONSOLE_ERROR, e.getMessage());
 
         // Get pieces of data already retrieved instead of losing them
         String resultFromWindow = resultToParse;
         if (StringUtils.isNotEmpty(e.getSlidingWindowAllRows())) {
             resultFromWindow = e.getSlidingWindowAllRows();
         } else if (StringUtils.isNotEmpty(e.getSlidingWindowCurrentRows())) {
             resultFromWindow = e.getSlidingWindowCurrentRows();
         }
         return resultFromWindow;
     }
 
     private String[][] getTable(List<String> columnsName, List<List<String>> values) {
         // Build a proper 2D array from the data
         var table = new String[values.size()][columnsName.size()];
         
         for (var indexRow = 0 ; indexRow < values.size() ; indexRow++) {
             var isIncomplete = false;
             
             for (var indexColumn = 0 ; indexColumn < columnsName.size() ; indexColumn++) {
                 try {
                     table[indexRow][indexColumn] = values.get(indexRow).get(indexColumn);
                 } catch (IndexOutOfBoundsException e) {
                     isIncomplete = true;
                     LOGGER.log(LogLevelUtil.CONSOLE_DEFAULT, I18nUtil.valueByKey("LOG_LIST_VALUES_INCOMPLETE"));
                     LOGGER.log(LogLevelUtil.IGNORE, e);
                 }
             }
             
             if (isIncomplete) {
                 int logIndexRow = indexRow;
                 LOGGER.log(
                     LogLevelUtil.CONSOLE_ERROR,
                     "{}{}: ",
                     () -> I18nUtil.valueByKey("LOG_LIST_VALUES_TOO_LONG"),
                     () -> logIndexRow + 1
                 );
 
                 LOGGER.log(
                     LogLevelUtil.CONSOLE_ERROR,
                     () -> String.join(
                         ", ",
                         values.get(logIndexRow).toArray(new String[0])
                     )
                 );
             }
         }
         return table;
     }
 }