#include "backpack.h"
#include <algorithm>
#include <cmath>

/*  Optimized insertion sort algorithm utilizing the Item's getRatio() function
 */
void Backpack::sortAvailableItems() {
  int i = 0;
  while (i < (int)this->availableItems.size()) {
    Item x = this->availableItems[i];
    int j = i - 1;
    while (j >= 0 && this->availableItems[j].getRatio() < x.getRatio()) {
      this->availableItems[j + 1] = this->availableItems[j];
      j--;
    }
    this->availableItems[j + 1] = x;
    i++;
  }
}

/*  Iterates through all packed items and returns the total value   */
int Backpack::getValuePacked() {
  int total = 0;
  for (int i = 0; i < (int)this->packedItems.size(); i++) {
    total += this->packedItems[i].value;
  }
  return total;
}

/*  the algorithm to pack the backpack  */
void Backpack::greedyPack(bool continuous) {
  this->packedItems
      .clear(); /*  resets the packedItems -> removes all elements! */
  this->currentWeight = 0; /*  ...and also sets the current weight to 0.0  */

  this->sortAvailableItems(); //  sort the available items first!
  const char *text = "";
  float partialValue = 0.0f;
  float partialWeight = 0.0f;
  if (!continuous) {
    text = "non-";
  }
  std::cout << "Backpack has been packed " << text
            << "continuously:\n";                                 //  output
  std::cout << "\t\tWeight\tValue\n";                             //  output
  std::cout << "---------------------------------------------\n"; //  output

  for (int i = 0; i < (int)this->availableItems.size();
       i++) { //  iterate through all available items
    if (this->currentWeight + (float)this->availableItems[i].weight <=
        this->maxWeight) { //  check if the item still fits in the backpack
      this->packedItems.push_back(
          this->availableItems[i]); //  and if so, put it in there (by adding it
                                    //  to this->packedItems)
      currentWeight +=
          this->availableItems[i].weight; //  adjust currentWeight accordingly
      std::cout << "\t" << this->availableItems[i].name << ":\t"
                << this->availableItems[i].weight << "\t"
                << this->availableItems[i].value
                << "\t Factor: 1.00\n"; //  output
    } else if (continuous) {
      float factor = (float)(this->maxWeight - this->currentWeight) /
                     this->availableItems[i].weight;
      factor = std::round(factor * 100) / 100;
      std::cout << "\t" << this->availableItems[i].name << ":\t"
                << this->availableItems[i].weight << "\t"
                << this->availableItems[i].value << "\t Factor: " << factor
                << std::endl;
      partialWeight = this->availableItems[i].weight * factor;
      partialValue = this->availableItems[i].value * factor;
      break;
    }
    if ((this->currentWeight - this->maxWeight) ==
        0) { //  if the backpack is completely full, the loop can be exited -
             //  small optimization
      break;
    }
  }
  std::cout << "---------------------------------------------\n"; //  output
  std::cout << "\tTotal:\t" << this->currentWeight + partialWeight << "\t"
            << this->getValuePacked() + partialValue << "\n"; //  output
}

void Backpack::printItems() {
  for (int i = 0; i < (int)this->availableItems.size(); i++) {
    std::cout << this->availableItems[i].name << "\t"
              << this->availableItems[i].weight << "\t"
              << this->availableItems[i].value << "\t"
              << this->availableItems[i].getRatio() << "\n";
  }
}