#include "aoc.h"
#include <string.h>
#include <vector>

namespace aoc2015 {

static spell bosskill = {"bosskill", 0, 1, 8, 0, 0, 0, 0};
static spell spells[5] = {
  {"Magic Missile", 53, 1, 4, 0, 0, 0, 0},
  {"Drain", 73, 1, 2, 2, 0, 0, 0},
  {"Shield", 113, 6, 0, 0, 0, 7, 0},
  {"Poison", 173, 6, 3, 0, 0, 0, 0},
  {"Recharge", 229, 5, 0, 0, 101, 0, 0},
};

// spells wizard w can pick
std::vector<spell*> can_spell(const wizard& w) {
  std::vector<spell*> is;
  for (int i = 0; i < 5; i++) {
    spell* s = w.wp->spells[i];
    if (s != nullptr && s->tick == 0 && w.mana >= s->costs) {
      is.push_back(s);
    }
  }
  return is;
}

char * indent(int t) {
  static char idn[60] = {0};
  memset(idn, 0, 60);
  for (int i = 0; i < ((t+1) / 2) * 2; i++) {
    idn[i] = ' ';
  }
  return idn;
}

void start_of_each_turn (int t, wizard& me,  wizard& boss) {
  // printf("%sT[%d] boss[%d] player[%d] armor[%d] mana[%d]\n", indent(t), t, boss.points, me.points, me.armor, me.mana);
  for (int i = 0; i < 5; i++) {
    spell* s = boss.spells[i];
    if (s->tick > 0) {
      // printf("%sT[%d] %s has tick %d\n", indent(t), t, s->name, s->tick);
      if (strcmp(s->name, "Magic Missile") == 0 && t % 2 == 0) {
        boss.points -= s->damage;
      }
      if (strcmp(s->name, "Drain") == 0 && t % 2 == 0) {
        boss.points -= s->damage;
        me.points += s->heals;
      }
      if (strcmp(s->name, "Shield") == 0) {
        me.armor = 7;
      }
      if (strcmp(s->name, "Poison") == 0) {
        boss.points -= s->damage;
      }
      if (strcmp(s->name, "Recharge") == 0) {
        me.mana += s->payback;
      }
      s->tick -= 1;
    }
    else {
      if (strcmp(s->name, "Shield") == 0) {
        me.armor = 0;
      }
    }
  }
}

void save_ticks(int ticks[], spell* spells[]) {
  for(int i = 0; i < 5; i++) {
    ticks[i] = spells[i]->tick;
  }
}

void undo_ticks(int ticks[], spell* spells[]) {
  for(int i = 0; i < 5; i++) {
    spells[i]->tick = ticks[i];
  }
}

void fight(int turn, wizard me, wizard boss, int cost, std::vector<int>& costs) {
  start_of_each_turn(turn, me, boss);
  if (turn > 18) return; // !!! THIS IS IMPORTANT !!!
  if (turn % 2 == 1) { // my turn
    // me.points -= 1; // part 2
    if (me.points > 0) {
      auto ss = can_spell(me);
      for(auto& s : ss) {
        // printf("%sT[%d] choose %s =============\n", indent(turn), turn, s->name);
        s->tick = s->turns;
        me.mana -= s->costs;
        int ticks[5] = {0};
        save_ticks(ticks, boss.spells);

        fight(turn+1, me, boss, cost + s->costs, costs);

        undo_ticks(ticks, boss.spells);
        me.mana += s->costs;
        s->tick = 0;
      }
    }
  } else { // boss turn
    if (boss.points <= 0) { // boss lose
      // printf("%sT[%d] player win %d\n", indent(turn), turn, cost);
      costs.push_back(cost); 
    }
    else {
      me.points -= bosskill.damage - me.armor;
      fight(turn+1, me, boss, cost, costs);
    }
  }
}

std::pair<int, int> day22(wizard me, wizard boss) {
  me.wp = &boss;
  boss.wp = &me;
  me.spells[0] = &bosskill;
  for (int i = 0; i < 5; i++) {
    boss.spells[i] = spells + i;
  }
  std::vector<int> costs;
  fight(1, me, boss, 0, costs);

  int min{INT32_MAX};
  for(auto& c : costs) {
    if (c < min) {
      min = c;
    }
  }

  return {min, 0};
}

}