#include <fstream>
#include <iostream>
#include <vector>
#include "Condition.h"
#include "DBEngine.h"

DBEngine::DBEngine(){
	size = 0;
}

void DBEngine::createTable(string n){
	Relation r(n);
	tables.push_back(r);
	size++;
}

void DBEngine::createTable(string n, vector<Attribute> a){
	Relation r(n, a);
	tables.push_back(r);
	size++;
}
	
void DBEngine::createTable(Relation r){ 
	tables.push_back(r); 
	size++;
}
	
vector<Relation> DBEngine::getRelations(){ 
	return tables; 
}

	
Relation& DBEngine::getTableFromName(string n){
	for(int i = 0; i < tables.size(); i++){
		if (tables[i].getTableName() == n){
			return tables[i];
		}
	}
}

//currently writes nothing meaningful
void DBEngine::saveToFile(vector<string> cmds){ 
	ofstream file;
	file.open("savefile.db");
	
	for(int i = 0; i < cmds.size(); ++i){
		file << cmds[i] << endl;
	}
	
	file.close();
}


Relation DBEngine::selection(string attName, string s, Relation r){
	equality(attName, s, r);
}

//assumes that all attribute titles are unique
Relation DBEngine::projection(vector<string> input, Relation r){
	
	vector<Attribute> v;
	string new_name = r.getTableName() + " Projection";
	
	for(int i = 0; i < input.size(); ++i) {
		
		for(int j = 0; j < r.getSize(); ++j) {
			if((r.getAttributes())[j].getName() == input[i])
				v.push_back((r.getAttributes())[j]);
		}
	}
	
	Relation temp(new_name, v);
	return temp;
}

Relation DBEngine::product(string new_name, Relation r1, Relation r2){
	
	Relation temp(new_name);
	vector<Attribute> a1;
	
	
	for(int i = 0; i < r1.getAttributes().size(); ++i){
		a1.push_back(r1.getAttributes()[i]);
	}
	
	for(int i = 0; i < r2.getAttributes().size(); ++i){
		a1.push_back(r2.getAttributes()[i]);
	}
	
	temp.insertAttributes(a1);
	
	vector<string> tuple1;
	vector<string> tuple2;
	vector<string> result_tuple;
	
	
	//Don't we need to find the bigger one to start first?
	if(r1.getSize() >= r2.getSize())
	{
		//Combine tuples from relations into one, push back that tuple into the resultant relation via insertTuple
		//Yeah have fun
	}
	
	else if(r2.getSize() > r1.getSize())
	{
		//
	}
	
	
	return temp;
}

//test error matching
void DBEngine::rename(Relation& r, vector<string> oldnames, vector<string> newnames){
	if (oldnames.size() != newnames.size()) {
		cout << "FAILURE TO RENAME: number of attributes do not match.\n";
		return;
	}
	
	else if (oldnames != r.getAttributeNames()) {
		cout << "FAILURE TO RENAME: the attributes to be renamed do not exist in the relation.\n";
		return;
	}
	
	else {
		for(int i = 0; i < oldnames.size(); ++i){
			r.renameAttribute(oldnames[i], newnames[i]);
		}
	}
}

/*Relation DBEngine::setUnion(Relation r1, Relation r2){
	if (r1.getAttributeNames() != r2.getAttributeNames()){
		cout << "Failure to union: the relations are not union-compatible";
		return;
	}

	else {
		vector<Attribute> r1_atts = r1.getAttributes();
		vector<Attribute> r2_atts = r2.getAttributes();
		vector<Attribute> new_atts = r1_atts;
		
		for (int i = 0; i < r2_atts.size(); ++i) {
			for (int j = 0; j < r2_atts[i].getSize(); ++j){
				new_atts[i].addCell(r2_atts[i][j]);
			}
		}

		for (int i = 0; i < new_atts.size(); ++i) {
			for (int j = 0; j < new_atts.size(); ++j){
				if (new_atts[i] == new_atts[j]){
					new_atts.erase(new_atts.begin() + i);
					continue;
				}
			}
		}

		//currently all returned relations are called TEMP
		Relation new_r("TEMP", new_atts);
		return new_r;
	}
}*/