// SqlResultTable.h

#ifndef dset__SqlResultTable_H
#define dset__SqlResultTable_H

// Chitra Kannan
// April 2004
// Modified by David Adams
// November 2004
//
// This is a concrete subclass of the Abstract class SqlTable
// which is used primarily for testing the classes that use the 
// abstract class SqlTable.
//
// This table may be written to disk by calling the method write(fname).
//
// It may be accessed from SqlTable::Create("SQLRESULT", params)
// where params holds name of such a file.

#include "dataset_util/FileStatus.h"
#include "dataset_sql/SqlQuery.h"
#include "dataset_sql/InsertQuery.h"
#include "dataset_sql/DeleteQuery.h"
#include "dataset_sql/SqlResult.h"
#include "dataset_sql/SqlTable.h"

namespace dset {

class SqlResultTable : public SqlTable {

private: // Data.
  mutable SqlResult m_res; 
  mutable int m_error;
  mutable std::string m_filename;
  std::string m_mcol;
  std::string m_ccol;
 	
private:  // private functions

  // Write the table to its file.
  // Returns 0 for success.
  int write() const ;

  // Read the table from its file.
  // Returns 0 for success.
  int read() const ;

public:  // inherited methods

  // Constructor from a result.
  // mcol = modify time column
  // mcol = create time column
  explicit SqlResultTable(SqlResult& res);
  
  
  // Constructor from a file name.
  // Result is read from this file for each operation and
  // written back after each change.
  // Use with caution: file loking is *not* implemented.
  explicit SqlResultTable(std::string fname);
  
  // Destructor.
  ~SqlResultTable();

  // Is this a valid ResultTable?
  bool is_valid() const;

  // Return the error code.
  int error() const;

  // Return a string describing an error.
  std::string error_string(int ecode) const;

  // Fetch the ResultTable schema.
  SqlResult get_schema() const;
  
  // Fetch the description of the column holding the modification time.
  // The returned time must be in unix format (seconds since 1970).
  // E.g. "modtime" or "unix_timestamp(modtime)".
  // Blank if there is no such column.
  std::string modify_time_column() const { return m_mcol; }
  
  // Fetch the description of the column holding the creation time.
  // The returned time must be in unix format (seconds since 1970).
  // E.g. "createtime" or "unix_timestamp(createtime)".
  // Blank if there is no such column.
  std::string create_time_column() const { return m_ccol; }
  
  // Fetch the total number of rows in the ResultTable.
  int get_row_count(SelectQuery query =SelectQuery()) const;

  // Fetch the total number of columns/fields in the ResultTable.
  int get_col_count(SelectQuery query =SelectQuery()) const;

  // Get result of executing Select sql query.
  // Argument carries the select clause (column names ) as well
  // as the constraint; not from clause.
  SqlResult execute_select_query(SelectQuery query =SelectQuery()) const;

  // Set the modify time column.
  void set_modify_time_column(std::string col) { m_mcol = col; }

  // Set the create time column.
  void set_create_time_column(std::string col) { m_ccol = col; }

  // Get result of executing Insert sql query.
  // Argument carries the column names as well as the values.
  int execute_insert_query(InsertQuery query);

  // Get result of executing Update sql query.
  // Argument carries the column names as well as the values.
  int execute_update_query(InsertQuery insquery, SelectQuery selquery);

  // Get result of executing Delete sql query.
  // Argument carries the constraint; not from clause.
  int execute_delete_query(DeleteQuery query =DeleteQuery());

  // Write the table to a file.
  // File may not exist.
  // Returns 0 for success.
  int write(std::string fname) const ;

};

}  // end dset namespace

#endif