#include <iostream>
#include <fstream>
using namespace std;


struct cell
{
	char symbol;
	size_t amount;

	cell* next;

	cell(char symbol) : symbol(symbol), next(nullptr)
	{
		amount = 1;
	}
	cell(char symbol, size_t amount) : symbol(symbol), amount(amount),next(nullptr)
	{
	}
};

class queue
{
private:

	cell* first;
	cell* last;
	size_t size;
public:
	queue() : first(nullptr), last(nullptr), size(0) {};
	bool isEmpty() { return size == 0; }

	void push(char symbol);
	cell pop();
	void sortByAmount();
	cell getById(size_t id);

	friend void print(const queue my);
};
void print(queue my)
{
	if(my.isEmpty())
	{
		cout << "Queue is empty" << endl;
		return;
	}


	size_t counter = 1;
	cell* it = my.first;
	while(it!= nullptr)
	{
		cout << counter++ << ") Symbol = " << it->symbol << " | Amount = " << it->amount << endl;
		it = it->next;
	}
};

void fillFromFile(queue& my, const char* fileName)
{
	ifstream input(fileName);
	if (!input.is_open())
	{
		cout << "File is not open" << endl;
		return;
	}

	char temp;
	while (!input.eof())
	{
		input >> temp;
		my.push(temp);
	}

	input.close();
}


int main()
{
	queue a;
	cout << "Before adding" << endl;
	print(a);
	fillFromFile(a, "file.txt");
	cout << "After adding" << endl;
	print(a);

	cout << endl;
	cell save = a.getById(4);
	cout << "I got = " << save.symbol << endl << " amount = " << save.amount << endl;
	cout << "After adding" << endl;
	print(a);
	return 0;
}

void
queue::push(char symbol)
{

	if(isEmpty())
	{
		cell* newCell = new cell(symbol);
		first = last = newCell;
		size++;
		return;
	}

	cell* it = first;
	while (it != nullptr)
	{
		if (it->symbol == symbol)
		{
			it->amount++;
			return;
		}
		it = it->next;
	}
	cell* newCell = new cell(symbol);
	last->next = newCell;
	last = newCell;
	size++;

}

cell
queue::pop()
{
	if(isEmpty())
	{
		cout << "Error: Queue is empty " << endl;
		return '-';
	}

	if(first != last)
	{
		cell toReturn(first->symbol,first->amount);
		cell* toDelete = first;

		first = first->next;
		delete toDelete;
		size--;
		return toReturn;
	}
	else
	{
		cell toReturn(first->symbol, first->amount);
		delete first;
		first = last = nullptr;
		size--;
		return toReturn;
	}
}



cell
queue::getById(size_t id)
{
	if(isEmpty() | id > size)
	{
		cout << "Out of range" << endl;
		return cell('-');
	}

	cell* it = first;
	for(size_t i = 0 ;i < id; i++)
	{
		it = it-> next;
	}

	return cell(it->symbol, it->amount);
}