#include <iostream>
#include <memory>
#include <exception>

#include "ArrayT.h"

using namespace std;

ArrayT::ArrayT(){
    data = nullptr; // probably not required.
    size = 0;
}

void CopyData(const unique_ptr<int[]> & src, unique_ptr<int[]> & dest, 
                                                              size_t size) {
    for(size_t i = 0; i < size; i++) {
       dest[i] = src[i];
    }
    return;
}

ArrayT::ArrayT(const ArrayT & other){
   
    size = other.size;
    // data = new int[size]
    data = make_unique<int []>(size);
    CopyData(other.data, data, size);

    return;
}

ArrayT & ArrayT::operator =(const ArrayT & other){
    if (this != &other) {
       size = other.size;

       // delete [] data
       // data = new int[size];
       //data.reset();

       // data = new int[size]
       data = make_unique<int[]>(size);
       // a_single_data = make_unique<int> 
       CopyData(other.data, data, size);
    }

    return *this;
}

size_t ArrayT::Size() const {
    return size;
}

void ArrayT::PushBack(int i){
    auto tmp = make_unique<int[]>(size+1);
    CopyData(data, tmp, size);

    //data.reset();
    data = move(tmp);

    data[size] = i;
    size++;

    return;
}

void ArrayT::PopBack(){

    if (size > 0) {
        size--;

        auto tmp = make_unique<int[]>(size);
        CopyData(data,tmp,size);
        data.swap(tmp);
        // tmp will go out of scope deleteing the old memory when it does.

    } else {
        throw length_error("Invalid length in pop back");
    }

    return;
}

int ArrayT::Back()const{
    if (size > 0) {
        return data[size-1];
    } else {
        throw length_error("Invalid length in back");
    }
}

int & ArrayT::operator[](size_t i) {
    return data[i];
}

const int & ArrayT::operator[](size_t i) const {
    return data[i];
}

int & ArrayT::At(size_t i){
    if (i < size ) {
        return data[i];
    } else {
        throw length_error("Invalid index in at");
    }
}

const int & ArrayT::At(size_t i) const {
    if (i < size ) {
        return data[i];
    } else {
        throw length_error("Invalid index in at");
    }
}