/*********************************************************************
  C201 Computer Programming II
  Fall 2006
  Dana Vrajitoru &

  A class to represent the inventory of a shop.

**********************************************************************/

#include "inventory.h"
#include <cstdlib>
#include <iostream>
using namespace std;

// *********************** Constructors - Destructor ******************

// Constructor with specified size and default value so that we can
// use it as default constructor too.
Inventory::Inventory(int nr_items)
  : size(0), capacity(0), items(NULL)
{
  if (nr_items < SIZE_DEF)
    Init(SIZE_DEF);
  else
    Init(nr_items);
}

// Destructor: must delete the array items if it's not NULL.
Inventory::~Inventory()
{
  Clear();
}

// **************** Initialize, reset, resize functions ***************

// Initialize the array items with a given capacity. If the array is
// not empty it must delete it. It does not copy the previous objects
// in the array.
void Inventory::Init(int nr_items)
{
  if (capacity)
    Clear();
  capacity = nr_items;
  items = new Product[capacity];
  size = nr_items;
}

// Delete the array items and reset all values to 0. We're creating a
// separate function for this because we may need it in more than one
// place.
void Inventory::Clear()
{
  if (capacity) {
    delete [] items;
    items = NULL;
    size = 0;
    capacity = 0;
  }
}

// Double the size of the array items and copy all the items from the
// previous one to the new one. No need to change the size: the number
// of product objects in use is the same.
void Inventory::Resize()
{
  // Allocate a new array and copy the elements from the old one.
  Product *temp = new Product[capacity*2];
  for (int i=0; i<capacity; i++)
    temp[i] = items[i];
  // Delete the old array and then make the pointer reference the new
  // one.
  delete [] items;
  items = temp;
  capacity *= 2;
}

// ******************** Stock manipulation ****************************

// Adds a new product to the inventory by inputing it from the user.
void Inventory::Add_new()
{
  if (size == capacity)
    Resize();
  items[size].Input();
  size++;
}

// Increases the quantity of an existing item identified by its
// name. If the name is not yet used it gives an error message.
bool Inventory::Add_by_name()
{
  char input_name[20];
  int amount;
  cout << "Enter a name to add the quantity to" << endl;
  cin >> input_name;
  for (int i=0; i<size; i++)
    if (strcmp(items[i].name, input_name) == 0) {
      // Only ask for the quantity if we find the item.
      cout << "Enter the quantity" << endl;
      cin >> amount;
      items[i].Add(amount);
      return true;
    }
  // If the loop ends without a return it means we didn't find the
  // name.
  cout << "Item doesn't exist. Add a new item instead." << endl;
  return false;
}

// Sells a quantity of an existing item identified by name. If there
// is no item with that name or if the quantity of the item is less
// than the required amount to sell then the function should print an
// error message and return false. If the operation is successful the
// function should output the total price for those items (quantity
// sold times the price).
bool Inventory::Sell_by_name()
{
  // To be copied from homework 7.
}

// ****************** General purpose functions ***********************

// Print a list of the entire inventory.
void Inventory::Output_all()
{
  cout << "There are " << size << " items in the inventory." << endl;
  for (int i=0; i<size; i++)
    items[i].Output();
}

// Reads the items from a file for which we specify the name.
// This function erases the previous contents of the inventory.
bool Inventory::Input_file(char *filename)
{
  ifstream fin(filename);
  if (fin.fail()) {
    cout << "Failed to open the file: " << filename << endl;
    return false;
  }
  else {
    int nr_items, ty;
    cout << "Reading the inventory from the file " << filename << endl;
    // Input the number of items first.
    fin >> nr_items;
    // Prepare the memory for these items.
    Init(nr_items);
    for(int i=0; i<nr_items && fin.good(); i++) {
      fin >> items[i].name >> items[i].barcode >> ty
          >> items[i].quantity >> items[i].price;
      items[i].type = Category(ty);
      if (!fin.good()) {
        cout << "Could read only " << i << " items from the file" << endl;
        // reset the size to the number of items 
        // we were actually able to read from the file
        size = i;
      }
    }
    fin .close();
    return true;
  }
}