/*
 * Driver.h -- generic SQL driver access
 *
 * Copyright (c) 2013, David Demelier <markand@malikania.fr>
 *
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#ifndef _DRIVER_H_
#define _DRIVER_H_

#include <iostream>
#include <map>
#include <memory>
#include <string>

class Query;

class Date
{
private:
	time_t m_timestamp;

public:
	Date()
	{
	}

	Date(time_t)
	{
	}

	~Date()
	{
	}
};

/**
 * @enum ColumnType
 * @brief The column type request
 *
 * Used for the drivers.
 */
enum class ColumnType {
	Boolean,			//! bool or 0 / 1
	Date,				//! date see Common/Date.h
	Double,				//! double
	Integer,			//! 32 or 64 bit int
	String,				//! varchar to std::string
};

/**
 * @enum QueryCheck
 * @brief Result enumeration for check* functions
 *
 * This is used for the Query drivers check functions so we can now which
 * kind of error happened.
 */
enum class QueryCheck {
	NoError = 0,			//! success
	InvalidColumn,			//! non existent column
	InvalidRow,			//! out of range row
	InvalidType,			//! bad column type requested
};

/**
 * @class QueryError
 * @brief Query exception on driver error
 *
 * Exception thrown usually when an error appeared in driver.
 */
class QueryError : public std::exception
{
private:
	std::string m_error;
public:
	QueryError();

	QueryError(const std::string &error);

	~QueryError();

	virtual const char *what() const throw();
};

/**
 * @class Query
 * @brief Class for querying the database
 */
class Query {
private:
	/**
	 * Check if the request is valid and throws an exception
	 * on error.
	 *
	 * @param row the row number
	 * @param column the column name
	 * @param check the result
	 * @throw Query::ErrorException on erro
	 */
	void checkValidRequest(int row, const std::string &column, QueryCheck check);

protected:
	/**
	 * Check if the request is correct, if the row is not out of range
	 * if the column exist and if the type is correct.
	 *
	 * @param row the row number
	 * @param column the column name
	 * @param type the type requested
	 * @return true if request is correct
	 */
	virtual QueryCheck checkRequest(int row, const std::string &column, ColumnType type) = 0;

	/**
	 * Get a bool.
	 *
	 * @param row the row number
	 * @param column the column
	 * @return the value
	 */
	virtual bool checkBool(int row, const std::string &column) = 0;

	/**
	 * Get a Date.
	 *
	 * @param row the row number
	 * @param column the column
	 * @return the value
	 */
	virtual Date checkDate(int row, const std::string &column) = 0;

	/**
	 * Get a double.
	 *
	 * @param row the row number
	 * @param column the column
	 * @return the value
	 */
	virtual double checkDouble(int row, const std::string &column) = 0;

	/**
	 * Get a integer.
	 *
	 * @param row the row number
	 * @param column the column
	 * @return the value
	 */
	virtual int checkInt(int row, const std::string &column) = 0;

	/**
	 * Get a string.
	 *
	 * @param row the row number
	 * @param column the column
	 * @return the value
	 */
	virtual std::string checkString(int row, const std::string &column) = 0;

public:
	Query(void);
	virtual ~Query(void);

	/**
	 * Get bool at a specified row / column.
	 *
	 * @param row the row number
	 * @param column the column
	 * @return a boolean
	 * @throw Query::ErrorException on error
	 */
	bool getBool(int row, const std::string &column);

	/**
	 * Get a Date at a specified row / column.
	 *
	 * @param row the row number
	 * @param column the column
	 * @return a Date
	 * @throw Query::ErrorException on error
	 */
	Date getDate(int row, const std::string &column);

	/**
	 * Get a double at a specified row / column.
	 *
	 * @param row the row number
	 * @param column the column
	 * @return a double
	 * @throw Query::ErrorException on error
	 */
	double getDouble(int row, const std::string &column);

	/**
	 * Get an integer at a specified row / column.
	 *
	 * @param row the row number
	 * @param column the column
	 * @return an integer
	 * @throw Query::ErrorException on error
	 */
	int getInt(int row, const std::string &column);

	/**
	 * Get a string at a specified row / column.
	 *
	 * @param row the row number
	 * @param column the column
	 * @return a string
	 * @throw Query::ErrorException on error
	 */
	std::string getString(int row, const std::string &column);

	/**
	 * Tells how many rows has been fetched.
	 *
	 * @return the number of rows
	 */
	virtual int countRows(void) = 0;

	/**
	 * Tells how many number of columns are present for each
	 * row.
	 *
	 * @return the number of columns
	 */
	virtual int countColumns(void) = 0;

	/**
	 * Tells if the column is null or not.
	 *
	 * @param row the row number
	 * @param column the column
	 * @return an true if null
	 */
	virtual bool isNull(int row, const std::string &column) = 0;

	/**
	 * Dump all rows and columns.
	 */
	virtual void dump(void) = 0;
};

class Driver {
protected:
	std::string m_error;

public:
	typedef std::map<std::string, std::string> Params;

	Driver();
	virtual ~Driver();

	/**
	 * Get the error.
	 *
	 * @return the error
	 */
	const std::string & getError() const;

	/**
	 * Create a synchronous connection, it waits and block until
	 * the connection is made up to a specified timeout max.
	 *
	 * @param params a list of parameters.
	 */
	virtual bool connect(const Params &params) = 0;

	/**
	 * Execute a query.
	 *
	 * @param query the SQL command
	 * @return a result
	 * @throw Query::Exception on failure
	 */
	virtual std::unique_ptr<Query> query(const std::string &command) = 0;

	/**
	 * Get the driver connection description.
	 *
	 * @return the description
	 */
	virtual std::string description() const = 0;
};

#endif // !_DRIVER_H_