#include "db_engine.h"

using namespace std;

db_engine::db_engine(){
	//
}

//create a new table in memory
//creates a vector 
void db_engine::createCmd(string tableName, vector<string> attributes, vector<string> pkeys){
	string output = "";
	output += "CREATE TABLE " + tableName + " (";
	
	vector<string>::iterator it = attributes.begin();
	while (it != attributes.end()){
		if (it == attributes.begin())
			if ((it + 1) != attributes.end())
				output += *it + ",";
			else
				output += *it;
		else
			output+= " " + *it;
		
		++it;
	}
	
	output += ") PRIMARY KEY (";
	
	vector<string>::iterator it2 = pkeys.begin();
	while (it2 != pkeys.end()){
		if (it2 == pkeys.begin())
			if ((it2 + 1) != pkeys.end())
				output += *it2 + ",";
			else
				output += *it2;
		else
			output+= " " + *it2;
		
		++it2;
	}
	
	output += ");";
	
	cout << output;
	//cmdList.push_back(output);
}
	
//open a txt file, parse SQL script, load data in table
//void db_engine::openCmd(){
	//
//}

//should write cmdList to a .txt file
void db_engine::saveCmd(){
	ofstream dbCmdFile;
	dbCmdFile.open("dbCmds.txt", ios_base::app);
	
	vector<string>::iterator it = cmdList.begin();
	while (it != cmdList.end()){
		dbCmdFile << *it << "\n";
		++it;
	}
	
	cmdList.clear();
}

//display the database
void db_engine::showCmd(string tableName){
	cmdList.push_back("SHOW " + tableName + "");
}

//add a tuple to a table in the memory
void db_engine::insertQuery(){
	//table.push_back();
}

//remove a tuple from a table in the memory
void db_engine::deleteQuery(){
	//
}

//search and return one more tuples from a table in the memory
void db_engine::selectQuery(){
	//
}

//return a subset of attributes (columns)
void db_engine::projectQuery(){
	//
}

//each row in the first table is paired with all the rows in the second table
void db_engine::productQuery(){
	//
}

//true if relations have the same # of attributes and each attribute must be from the same domain
bool db_engine::unionComp(){
	return false;
}