/*
 * This file is a part of morm
 * and is distributed under the 2-Clause BSD licence.
 * Author: Tomasz Sowa <t.sowa@ttmath.org>
 */

/*
 * Copyright (c) 2018-2021, Tomasz Sowa
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 * this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 * notice, this list of conditions and the following disclaimer in the
 * documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 */

#include <cstdlib>
#include <memory>
#include "space/spaceparser.h"
#include "dbconnector.h"
#include "dbexpression.h"
#include "model.h"
#include "utf8/utf8.h"
#include "convert/convert.h"


namespace morm
{

DbConnector::DbConnector()
{
	db_expression = nullptr;
	expression_allocated = false;
	log = nullptr;
	log_queries = false;
}

DbConnector::DbConnector(const DbConnector &)
{
	db_expression = nullptr;
	expression_allocated = false;
	log = nullptr;
}


DbConnector::~DbConnector()
{
	deallocate_expression();
}


void DbConnector::set_logger(pt::Log * log)
{
	this->log = log;
}


void DbConnector::set_logger(pt::Log & log)
{
	this->log = &log;
}


void DbConnector::set_log_queries(bool log_queries)
{
	this->log_queries = log_queries;
}


bool DbConnector::query(const pt::TextStream & stream)
{
	std::unique_ptr<QueryResult> query_result_ptr(create_query_result());
	return query(stream, *query_result_ptr);
}


bool DbConnector::query(const std::string & query_str)
{
	std::unique_ptr<QueryResult> query_result_ptr(create_query_result());
	return query(query_str, *query_result_ptr);
}


bool DbConnector::query(const char * query_str)
{
	std::unique_ptr<QueryResult> query_result_ptr(create_query_result());
	return query(query_str, *query_result_ptr);
}



bool DbConnector::query(const pt::TextStream & stream, QueryResult & query_result)
{
	std::string query_str;
	stream.to_string(query_str);

	return query(query_str, query_result);
}


bool DbConnector::query(const std::string & query_str, QueryResult & query_result)
{
	return query(query_str.c_str(), query_result);
}


bool DbConnector::query(const char * query_str, QueryResult & query_result)
{
	// do query
	return false;
}



bool DbConnector::query_select(const char * query_str, QueryResult & query_result)
{
	return query(query_str, query_result);
}

bool DbConnector::query_update(const char * query_str, QueryResult & query_result)
{
	return query(query_str, query_result);
}

bool DbConnector::query_insert(const char * query_str, QueryResult & query_result)
{
	return query(query_str, query_result);
}

bool DbConnector::query_remove(const char * query_str, QueryResult & query_result)
{
	return query(query_str, query_result);
}



bool DbConnector::query_select(const pt::TextStream & stream, QueryResult & query_result)
{
	return query(stream, query_result);
}

bool DbConnector::query_update(const pt::TextStream & stream, QueryResult & query_result)
{
	return query(stream, query_result);
}

bool DbConnector::query_insert(const pt::TextStream & stream, QueryResult & query_result)
{
	return query(stream, query_result);
}

bool DbConnector::query_remove(const pt::TextStream & stream, QueryResult & query_result)
{
	return query(stream, query_result);
}



DbExpression * DbConnector::get_expression()
{
	allocate_default_expression_if_needed();
	return db_expression;
}


void DbConnector::generate_select_columns(pt::TextStream & stream, Model & model)
{
	allocate_default_expression_if_needed();

	if( db_expression )
	{
		db_expression->clear();
		db_expression->set_work_mode(MORM_WORK_MODE_MODEL_FIELDS);
		db_expression->set_output_type(MORM_OUTPUT_TYPE_SELECT_COLUMNS);
		db_expression->allow_to_use_prefix(true);
		db_expression->generate_from_model(stream, model);
	}
}


void DbConnector::generate_insert_query(pt::TextStream & stream, Model & model)
{
	allocate_default_expression_if_needed();

	if( db_expression )
	{
		db_expression->clear();
		db_expression->allow_to_use_prefix(false);

		stream << "insert into ";
		db_expression->schema_table_to_stream(stream, model.model_env->schema_name, model.model_env->table_name);

		stream << " (";
		db_expression->set_work_mode(MORM_WORK_MODE_MODEL_FIELDS);
		db_expression->set_output_type(MORM_OUTPUT_TYPE_DB_INSERT);
		db_expression->generate_from_model(stream, model);

		stream << ") values (";
		db_expression->set_work_mode(MORM_WORK_MODE_MODEL_VALUES);
		db_expression->generate_from_model(stream, model);
		stream << ")";
	}
}


void DbConnector::generate_update_query(pt::TextStream & stream, Model & model)
{
	allocate_default_expression_if_needed();

	if( db_expression )
	{
		db_expression->clear();
		db_expression->allow_to_use_prefix(false);

		stream << "update ";
		db_expression->schema_table_to_stream(stream, model.model_env->schema_name, model.model_env->table_name);

		stream << " set ";
		db_expression->set_work_mode(MORM_WORK_MODE_MODEL_FIELDS_VALUES);
		db_expression->set_output_type(MORM_OUTPUT_TYPE_DB_UPDATE);
		db_expression->generate_from_model(stream, model);

		stream << " where ";
		db_expression->set_work_mode(MORM_WORK_MODE_MODEL_FIELDS_VALUES);
		db_expression->set_output_type(MORM_OUTPUT_TYPE_DB_PRIMARY_KEY);
		db_expression->generate_from_model(stream, model);
	}
}


void DbConnector::generate_remove_query(pt::TextStream & stream, Model & model)
{
	allocate_default_expression_if_needed();

	if( db_expression )
	{
		db_expression->clear();
		db_expression->allow_to_use_prefix(false);

		stream << "delete from ";
		db_expression->schema_table_to_stream(stream, model.model_env->schema_name, model.model_env->table_name);

		stream << " where ";
		db_expression->set_work_mode(MORM_WORK_MODE_MODEL_FIELDS_VALUES);
		db_expression->set_output_type(MORM_OUTPUT_TYPE_DB_PRIMARY_KEY);
		db_expression->generate_from_model(stream, model);
	}
}

bool DbConnector::insert(pt::TextStream & stream, Model & model)
{
	std::unique_ptr<QueryResult> query_result_ptr(create_query_result());

	generate_insert_query(stream, model);
	return query_insert(stream, *query_result_ptr);
}


bool DbConnector::update(pt::TextStream & stream, Model & model)
{
	std::unique_ptr<QueryResult> query_result_ptr(create_query_result());

	generate_update_query(stream, model);
	return query_update(stream, *query_result_ptr);
}


bool DbConnector::remove(pt::TextStream & stream, Model & model)
{
	std::unique_ptr<QueryResult> query_result_ptr(create_query_result());

	generate_remove_query(stream, model);
	return query_remove(stream, *query_result_ptr);
}


void DbConnector::deallocate_expression()
{
	if( expression_allocated )
	{
		delete db_expression;
		db_expression = nullptr;
		expression_allocated = false;
	}
}



void DbConnector::allocate_default_expression_if_needed()
{
	if( !db_expression )
	{
		allocate_default_expression();
	}
}


char DbConnector::unescape_hex_char_part(char hex)
{
	if( hex>='0' && hex<='9' )
	{
		return hex - '0';
	}
	else
	if( hex>='a' && hex<='f' )
	{
		return hex - 'a' + 10;
	}
	else
	if( hex>='A' && hex<='F' )
	{
		return hex - 'A' + 10;
	}
	else
	{
		if( log )
		{
			(*log) << pt::Log::log2 << "Morm: incorrect character when reading a hex string, char code: " << (int)(unsigned char)hex;

			if( hex >= 32 )
			{
				(*log) << " '" << hex << "'";
			}

			(*log) << pt::Log::logend;
		}
	}

	return 0;
}


char DbConnector::unescape_hex_char(char char1, char char2)
{
	int c1 = unescape_hex_char_part(char1);
	int c2 = unescape_hex_char_part(char2);

	return static_cast<char>(((c1 << 4) | c2));
}


void DbConnector::unescape_hex_string(const char * str, std::string & out)
{
	for(size_t i=0 ; str[i] != 0 ; i+=2 )
	{
		out += unescape_hex_char(str[i], str[i+1]);
	}
}


void DbConnector::unescape_hex_string(const char * str, std::wstring & out, const FT & field_type)
{
	if( field_type.use_utf8() )
	{
		size_t len;
		wchar_t c;

		while( *str != 0 && (len = unescape_hex_char(str, c, field_type)) > 0 )
		{
			out += c;
			str += len;
		}
	}
	else
	{
		for(size_t i=0 ; str[i] != 0 ; i+=2 )
		{
			out += static_cast<wchar_t>(static_cast<unsigned char>(unescape_hex_char(str[i], str[i+1])));
		}
	}
}


void DbConnector::unescape_bin_string(const char * str, std::string & out)
{
	unescape_hex_string(str, out);
}


void DbConnector::unescape_bin_string(const char * str, std::wstring & out, const FT & field_type)
{
	unescape_hex_string(str, out, field_type);
}


// returns how many characters have been provided to utf8_str buffer
// min size of utf8_str should be 5 bytes (max 4 bytes for utf8 sequence + terminating null)
size_t DbConnector::unescape_hex_char(const char * value_str, char * utf8_str, size_t utf8_str_max_len)
{
	size_t value_str_index = 0;
	size_t utf8_str_index = 0;

	utf8_str[0] = 0;

	while( utf8_str_index + 1 < utf8_str_max_len )
	{
		if( value_str[value_str_index] != 0 && value_str[value_str_index+1] != 0 )
		{
			utf8_str[utf8_str_index] = unescape_hex_char(value_str[value_str_index], value_str[value_str_index+1]);
			utf8_str[utf8_str_index+1] = 0;
		}
		else
		{
			break;
		}

		value_str_index += 2;
		utf8_str_index += 1;
	}

	return utf8_str_index;
}


// CHECKME need to be tested
// returns how many characters were used from value_str
size_t DbConnector::unescape_hex_char(const char * value_str, wchar_t & field_value, const FT & field_type)
{
	size_t len = 0;

	if( field_type.use_utf8() )
	{
		char utf8_str[4 + 1]; // max utf8 sequence length + terminating zero
		size_t utf8_str_len = unescape_hex_char(value_str, utf8_str, sizeof(utf8_str) / sizeof(char));

		int value_int;
		bool is_correct;
		len = pt::UTF8ToInt(utf8_str, utf8_str_len, value_int, is_correct);
		len = len * 2;

		if( is_correct )
		{
			field_value = static_cast<wchar_t>(value_int);
		}
		else
		{
			if( log )
			{
				(*log) << pt::Log::log2 << "Morm: incorrect utf-8 sequence (ignoring)" << pt::Log::logend;
			}
		}
	}
	else
	{
		if( value_str[0] != 0 && value_str[1] != 0 )
		{
			field_value = static_cast<wchar_t>(static_cast<unsigned char>(unescape_hex_char(value_str[0], value_str[1])));
			len = 2;
		}
		else
		{
			if( log )
			{
				(*log) << pt::Log::log2 << "Morm: unexpected end of string (ignoring)" << pt::Log::logend;
			}
		}
	}

	return len;
}


size_t DbConnector::unescape_bin_char(const char * value_str, wchar_t & field_value, const FT & field_type)
{
	return unescape_hex_char(value_str, field_value, field_type);
}



// CHECKME need to be tested
void DbConnector::get_value(const char * value_str, char & field_value, const FT & field_type)
{
	wchar_t c;

	field_value = 0;
	get_value(value_str, c, field_type);

	if( field_type.use_utf8() )
	{
		if( c <= 127 )
		{
			field_value = static_cast<char>(c);
		}
		else
		{
			if( log )
			{
				(*log) << pt::Log::log2 << "Morm: a character greater than 127 cannot be stored in char type, code point: "
					   << (int)c << " '" << c << "'" << pt::Log::logend;
			}
		}
	}
	else
	{
		field_value = static_cast<char>(c);
	}
}



// CHECKME need to be tested
void DbConnector::get_value(const char * value_str, unsigned char & field_value, const FT & field_type)
{
	char tmp_char;
	get_value(value_str, tmp_char, field_type);

	field_value = static_cast<unsigned char>(tmp_char);
}



// CHECKME need to be tested
void DbConnector::get_value(const char * value_str, wchar_t & field_value, const FT & field_type)
{
	field_value = 0;

	if( field_type.is_binary() )
	{
		unescape_bin_char(value_str, field_value, field_type);
	}
	else
	if( field_type.is_hexadecimal() )
	{
		unescape_hex_char(value_str, field_value, field_type);
	}
	else
	{
		if( field_type.use_utf8() )
		{
			int value_int;
			bool is_correct;

			pt::UTF8ToInt(value_str, value_int, is_correct);

			if( is_correct )
			{
				field_value = static_cast<wchar_t>(value_int);
			}
			else
			{
				// report an error?
			}
		}
		else
		{
			field_value = static_cast<wchar_t>((unsigned char)*value_str);
		}
	}
}



// CHECKME need to be tested
void DbConnector::get_value(const char * value_str, std::wstring & field_value, const FT & field_type)
{
	if( field_type.is_binary() )
	{
		unescape_bin_string(value_str, field_value, field_type);
	}
	else
	if( field_type.is_hexadecimal() )
	{
		unescape_hex_string(value_str, field_value, field_type);
	}
	else
	{
		if( field_type.use_utf8() )
		{
			pt::UTF8ToWide(value_str, field_value);
		}
		else
		{
			for(size_t i=0 ; value_str[i] != 0 ; ++i)
			{
				field_value += static_cast<wchar_t>(value_str[i]);
			}
		}
	}
}


// CHECKME need to be tested
void DbConnector::get_value(const char * value_str, std::string & field_value, const FT & field_type)
{
	if( field_type.is_binary() )
	{
		unescape_bin_string(value_str, field_value);
	}
	else
	if( field_type.is_hexadecimal() )
	{
		unescape_hex_string(value_str, field_value);
	}
	else
	{
		field_value = value_str;
	}
}


void DbConnector::get_value(const char * value_str, bool & field_value, const FT & field_type)
{
	// IMPROVE ME
	// this 't' is locale dependent
	field_value = (value_str[0]=='t' || value_str[0]=='y' || value_str[0]=='1');
}


void DbConnector::get_value(const char * value_str, short & field_value, const FT & field_type)
{
	// IMPROVE ME give some overflow checking
	field_value = (short)pt::Toi(value_str, 10);
}


void DbConnector::get_value(const char * value_str, unsigned short & field_value, const FT & field_type)
{
	// IMPROVE ME give some overflow checking
	field_value = (unsigned short)pt::Toui(value_str, 10);
}


void DbConnector::get_value(const char * value_str, int & field_value, const FT & field_type)
{
	// IMPROVE ME give some overflow checking
	field_value = pt::Toi(value_str, 10);
}


void DbConnector::get_value(const char * value_str, unsigned int & field_value, const FT & field_type)
{
	// IMPROVE ME give some overflow checking
	field_value = pt::Toui(value_str, 10);
}


void DbConnector::get_value(const char * value_str, long & field_value, const FT & field_type)
{
	// IMPROVE ME give some overflow checking
	field_value = pt::Tol(value_str, 10);
}


void DbConnector::get_value(const char * value_str, unsigned long & field_value, const FT & field_type)
{
	// IMPROVE ME give some overflow checking
	field_value = pt::Toul(value_str, 10);
}


void DbConnector::get_value(const char * value_str, long long & field_value, const FT & field_type)
{
	// IMPROVE ME give some overflow checking
	field_value = pt::Toll(value_str, 10);
}


void DbConnector::get_value(const char * value_str, unsigned long long & field_value, const FT & field_type)
{
	// IMPROVE ME give some overflow checking
	field_value = pt::Toull(value_str, 10);
}


void DbConnector::get_value(const char * value_str, float & field_value, const FT & field_type)
{
	// IMPROVE ME give some overflow checking
	field_value = strtof(value_str, 0);
}


void DbConnector::get_value(const char * value_str, double & field_value, const FT & field_type)
{
	// IMPROVE ME give some overflow checking
	field_value = strtod(value_str, 0);
}


void DbConnector::get_value(const char * value_str, long double & field_value, const FT & field_type)
{
	// IMPROVE ME give some overflow checking
	field_value = strtold(value_str, 0);
}


void DbConnector::get_value(const char * value_str, pt::Date & field_value, const FT & field_type)
{
	// IMPROVE ME give some log if parsing failed
	field_value.Parse(value_str);
}


void DbConnector::get_value(const char * value_str, pt::Space & field_value, const FT & field_type)
{
	field_value.clear();

	if( *value_str != '\0' )
	{
		pt::SpaceParser space_parser;
		space_parser.SetSpace(field_value);

		if( space_parser.ParseSpace(value_str) != pt::SpaceParser::ok )
		{
			field_value.clear();

			if( log )
			{
				(*log) << pt::Log::log2 << "Morm: I cannot correctly parse the Space struct from the datebase"
					   << ", the raw string is: " << value_str << pt::Log::logend;
			}
		}
	}
}


const char * DbConnector::query_last_sequence(const wchar_t * sequence_table_name)
{
	return nullptr;
}

}