/*
 * This file is a part of CMSLU -- Content Management System like Unix
 * and is not publicly distributed
 * 
 * Copyright (c) 2008, Tomasz Sowa
 * All rights reserved.
 * 
 */
 
#include "db.h"


Db::Db()
{
	pg_conn = 0;	
}


Db::~Db()
{
	Close();	
}



void Db::Init(const std::string & d, const std::string & u, const std::string & p)
{
	db_database = d;
	db_user     = u;
	db_pass     = p;

	Connect();
}


void Db::Connect()
{
	std::ostringstream buf;
	buf << "dbname=" << db_database << " user=" << db_user << " password=" << db_pass;
	
	pg_conn = PQconnectdb(buf.str().c_str());

	if( !pg_conn )
		log << log1 <<  "Db: Fatal error during connecting" << logend;

	if( PQsetClientEncoding(pg_conn, "LATIN2") == -1 )
		log << log1 << "Db: Can't set the proper client encoding" << logend;
}



void Db::Close()
{
	if( pg_conn )
	{
		PQfinish(pg_conn);
		pg_conn = 0;
	}
}


void Db::AssertConnection()
{
	if( !pg_conn )
	{
		log << log1 << "Db: Trying to connect into the database...";
		Connect();
		
		if( !pg_conn )
			// logend from Connect()
			throw Error(Error::db_fatal_error_during_connecting);
			
		log << log1 << "ok" << logend;
	}
		
		
	if( PQstatus(pg_conn) != CONNECTION_OK )
	{
		log << log2 << "Db: connection into the database is lost, trying to recover..." << logend;
		PQreset(pg_conn);
		
		if( PQstatus(pg_conn) != CONNECTION_OK )
		{
			log << log2 << "no" << logend;
			throw Error(Error::db_fatal_error_during_connecting);
		}
		else
		{
			log << log2 << "ok" << logend;
		}
	}
}



std::string Db::Escape(const std::string & s)
{
std::string result;	
	
	result.resize(s.length() * 2 + 1);
	
	size_t len = PQescapeStringConn(pg_conn, const_cast<char*>( result.c_str() ), s.c_str(), s.length(), 0);
	result.resize(len);
	
return result;
}


std::string Db::Escape(const char * s)
{
std::string result;	
int len;

	for(len=0 ; s[len] != 0 ; ++len);
	
	result.resize(len * 2 + 1);
	
	size_t len_new = PQescapeStringConn(pg_conn, const_cast<char*>( result.c_str() ), s, len, 0);
	result.resize(len_new);
	
return result;
}



// ------------------



PGresult * Db::AssertQuery(const std::string & q)
{
	PGresult * r = PQexec(pg_conn, q.c_str());
	
	if( !r )
	{
		log << log1 << "Db: Problem with query: " << PQerrorMessage(pg_conn) << logend;
		throw Error(Error::db_incorrect_query);
	}
	
return r;
}



void Db::AssertResultStatus(PGresult * r, ExecStatusType t)
{
	if( PQresultStatus(r) != t )
	{
		log << "Db: Incorrect result status: " << PQerrorMessage(pg_conn) << logend;
		
		throw Error(Error::db_incorrent_result_status);
	}	
}



int Db::AssertColumn(PGresult * r, const char * column_name)
{
	int c = PQfnumber(r, column_name);
	
	if( c == -1 )
	{
		log << log1 << "Db: there is no column: " << column_name << logend;
		
		throw Error(Error::db_no_column);
	}
		
return c;
}


const char * Db::AssertValue(PGresult * r, int row, int col)
{
	const char * res = PQgetvalue(r, row, col);
	
	if( !res )
	{
		log << log1 << "Db: there is no such an item in the result, row:" << row << ", col:" << col << logend;
		
		throw Error(Error::db_no_item);
	}
	
return res;
}


void Db::ClearResult(PGresult * r)
{
	if( r )
		PQclear(r);
}


bool Db::CheckUser(std::string & login, std::string & password, long & user_id)
{
	PGresult * r = 0;
	bool user_ok = false;

	try
	{
		AssertConnection();
		
		std::ostringstream query;
		query << "select id from core.user where login='" << Escape(login) << "' and password='" << Escape(password) << "';";
		
		r = AssertQuery( query.str() );

		AssertResultStatus(r, PGRES_TUPLES_OK);

		int rows = PQntuples(r);
		
		if( rows == 0 )
			throw Error(Error::db_incorrect_login);
		
		if( rows > 1 )
		{
			log << log1 << "Db: there is more than one user: " << login << " (with the same password)" << logend;
			throw Error(Error::db_more_than_one_login);
		}

		int cuser_id = AssertColumn(r, "id");		
		const char * fuser_id = AssertValue(r, 0, cuser_id);
		user_id = atol( fuser_id );
		
		user_ok = true;
	}
	catch(const Error &)
	{
	}

	ClearResult(r);
	
	
return user_ok;
}











bool Db::AddItemCreateUrlSubject(Item & item)
{
bool is_that_url;
PGresult * r = 0;
int index = 1;
const int max_index = 100;
char appendix[20];
appendix[0] = 0;

			
	try
	{
		do
		{
			std::ostringstream query;
			
			// this Escape can be put at the beginning (performance)
			query << "select id from core.item where url_subject='" << Escape(item.url_subject) << appendix << "' and parent_id='" << item.parent_id << "';";
			r = AssertQuery(query.str());
			AssertResultStatus(r, PGRES_TUPLES_OK);
	
			if( PQntuples(r) != 0 )
			{
				sprintf(appendix, "_(%d)", ++index);
				is_that_url = true;
			}
			else
			{
				item.url_subject += appendix;
				is_that_url = false;
			}
		
			ClearResult(r);
			r = 0;
		}
		while( is_that_url && index <= max_index );
	}
	catch(const Error &)
	{
		is_that_url = true; // for return false
	}
	
	
	ClearResult(r);

	
return !is_that_url;	
}


// for testing consistency
void Db::CheckAllUrlSubjectModifyItem(Item & item)
{
	PGresult * r = 0;
	
	try
	{
		std::ostringstream query;
		query << "update core.item set url_subject=";
		
		// url_subject
		if( AddItemCreateUrlSubject(item) )  
			query << '\'' << Escape(item.url_subject) << '\'';
		else
		{
			query << '\'' << item.id << '\'';
			item.url_subject.clear();
		}
		
		query << " where id='" << item.id << "';";
		
		r = AssertQuery(query.str());
		AssertResultStatus(r, PGRES_COMMAND_OK);
	}
	catch(const Error &)
	{
	}
	
	ClearResult(r);
}



// for checking consistency
void Db::CheckAllUrlSubject()
{
	PGresult * r = 0;
	Item item;
		
	try
	{
		AssertConnection();
		std::ostringstream query, query2;
		query << "select id, subject from core.item where url_subject is null or url_subject=''";
		
		r = AssertQuery(query.str());
		AssertResultStatus(r, PGRES_TUPLES_OK);
		
		int rows = PQntuples(r);
		int cid  = AssertColumn(r, "id");
		int csubject = AssertColumn(r, "subject");
		
		for(int i = 0 ; i<rows ; ++i)
		{
			item.id = atol( AssertValue(r, i, cid) );
			item.subject = AssertValue(r, i, csubject);
			
			CheckAllUrlSubjectModifyItem(item);
		}
	}
	catch(const Error &)
	{
	}
	
	ClearResult(r);
}



long Db::AssertCurrval(const char * table)
{
	PGresult * r;
	std::ostringstream query;
	
	query << "select currval('" << table << "');";
	
	r = AssertQuery(query.str());
	AssertResultStatus(r, PGRES_TUPLES_OK);

	if( PQntuples(r) != 1 )
	{
		log << log1 << "Db: error (currval) for table: " << table << ", " << PQerrorMessage(pg_conn) << logend;
		throw Error(Error::db_err_currval);
	}
	
	long res = strtol( AssertValue(r, 0, 0), 0, 10 );

return res;	
}



Error Db::AddItem(Item & item)
{
	PGresult * r = 0;
	Error result = Error::ok;
	bool url_without_id = false;
		
	try
	{
		AssertConnection();
		std::ostringstream query;
		query << "insert into core.item (subject, content, url_subject, type, parent_id) values (";
		query << '\'' << Escape(item.subject) << "', ";
		query << '\'' << Escape(item.content) << "', ";
		
		// url_subject
		url_without_id = AddItemCreateUrlSubject(item);
		
		if( url_without_id )
		{
			query << '\'' << Escape(item.url_subject) << "', ";
		}
		else
		{
			query << "currval('core.item_id_seq')" << ", ";
		}
		
		
		query << '\'' << static_cast<int>(item.type) << "', ";
		query << '\'' << item.parent_id << "' ";
		query << ");";
		
		r = AssertQuery(query.str());
		AssertResultStatus(r, PGRES_COMMAND_OK);

		item.id = AssertCurrval("core.item_id_seq");

		if( !url_without_id )
			ToString(item.url_subject, item.id);

	}
	catch(const Error & e)
	{
		result = e;
	}
	
	ClearResult(r);

return result;
}


Error Db::EditItem(Item & item, bool with_subject)
{
	PGresult * r = 0;
	Error result = Error::ok;
	bool url_without_id = false;
		
	try
	{
		AssertConnection();
		std::ostringstream query;
		query << "update core.item set (";
		
		if( with_subject )
			query << "subject, url_subject, ";
		
		query << "content, type, parent_id) = (";
		
		if( with_subject )
		{
			query << '\'' << Escape(item.subject) << "', ";
	
			// url_subject
			url_without_id = AddItemCreateUrlSubject(item);
			
			if( url_without_id )
			{
				query << '\'' << Escape(item.url_subject) << "', ";
			}
			else
			{
				query << '\'' << item.id << "', ";
			}
		}
	
		query << '\'' << Escape(item.content) << "', ";
		
		query << '\'' << static_cast<int>(item.type) << "', ";
		query << '\'' << item.parent_id << "' ";
		query << ") where id='" << item.id << "';";
		
		r = AssertQuery(query.str());
		AssertResultStatus(r, PGRES_COMMAND_OK);

		if( with_subject && !url_without_id )
			ToString(item.url_subject, item.id);
	}
	catch(const Error & e)
	{
		result = e;
	}
	
	ClearResult(r);

return result;
}



PGresult * Db::GetItemsQuery(Item & item_ref)
{
	std::ostringstream query;
	query << "select * from core.item where type!='0' and parent_id='" << item_ref.parent_id << "'";
	
	if( item_ref.id != -1 )
		query << " and id='" << item_ref.id << "'";	
	
	if( !item_ref.url_subject.empty() )
		query << " and url_subject='" << Escape(item_ref.url_subject) << "'";	

	query << ';';	
	
return AssertQuery(query.str());
}



void Db::GetItems(std::vector<Item> & item_table, Item & item_ref)
{
	item_table.clear();
	PGresult * r = 0;
	
	try
	{
		AssertConnection();
		
		r = GetItemsQuery(item_ref);
		AssertResultStatus(r, PGRES_TUPLES_OK);

		Item item;
		int rows = PQntuples(r);

		ItemColumns col;
		col.SetColumns(r);
			
		for(int i = 0 ; i<rows ; ++i)
		{
			col.SetItem(r, i, item);
			item_table.push_back(item);
		}
	}
	catch(const Error &)
	{
	}
	
	ClearResult(r);
}



void Db::GetItem(std::vector<Item> & item_table, long id)
{
	PGresult * r = 0;
	
	try
	{
		AssertConnection();

		std::ostringstream query;
		query << "select * from core.item where type='1' and id='" << id << "';";
		
		r = AssertQuery( query.str() );
		AssertResultStatus(r, PGRES_TUPLES_OK);

		Item item;
		int rows = PQntuples(r);
	
		if( rows > 1 )
			log << log1 << "Db: we have more than one item with id: " << id << logend;

		ItemColumns col;
		col.SetColumns(r);
			
		for(int i = 0 ; i<rows ; ++i)
		{
			col.SetItem(r, i, item);
			item_table.push_back(item);
		}
	}
	catch(const Error &)
	{
	}
	
	ClearResult(r);
}


bool Db::DelItem(long id)
{
	long rows = 0;
	PGresult * r = 0;
	
	try
	{
		AssertConnection();

		std::ostringstream query;
		query << "delete from core.item where type='1' and id='" << id << "';";
		
		r = AssertQuery( query.str() );
		AssertResultStatus(r, PGRES_COMMAND_OK);
		
		const char * crows = PQcmdTuples(r);
		if( crows )
		{
			rows = atol(crows);
		
			if( rows > 1 )
				log << log1 << "Db: more than one item were deleted" << logend;	
		}
	}
	catch(const Error &)
	{
	}
	
	ClearResult(r);
	
return rows != 0;
}


void Db::GetDirs(DirContainer & dir_table)
{
	PGresult * r = 0;
	
	try
	{
		AssertConnection();

		std::ostringstream query;
		query << "select * from core.item where type='0';";
		
		r = AssertQuery( query.str() );
		AssertResultStatus(r, PGRES_TUPLES_OK);

		Item item;
		int rows = PQntuples(r);

		ItemColumns col;
		col.SetColumns(r);

		for(int i = 0 ; i<rows ; ++i)
		{
			col.SetItem(r, i, item);
			dir_table.PushBack( item );
		}
	}
	catch(const Error &)
	{
	}
	
	ClearResult(r);
	
}