#ifndef SPACEINVADERS_H
#define SPACEINVADERS_H

#define ROCKET_MAX 20

#include "mode/Mode.h"

struct Rocket {
    volatile bool alive;
    uint8_t x;
    uint8_t y;
};

struct Invader {
    bool alive;
    uint8_t x;
    uint8_t y;
};

class SpaceInvaders : public Mode {

private:

    millis_t heroRuntime = 0;
    uint8_t heroX = 0;
    bool heroLeft = false;
    uint8_t heroShoot = 0;

    uint8_t invadersCountX;
    uint8_t invadersCountY;
    uint8_t invadersAlive = 0;

    millis_t swarmRuntime = 0;
    uint8_t swarmY = 0;
    bool swarmLeft = false;
    bool swarmDown = false;
    uint8_t swarmX = 0;
    Invader *swarmBegin;
    Invader *swarmEnd;

    millis_t rocketRuntime = 0;
    Rocket *rocketsBegin;
    Rocket *rocketsEnd;

public:

    explicit SpaceInvaders(Display *display) :
      Mode(display),
      invadersCountX(display->width / 3),
      invadersCountY(display->height / 4) {

      swarmBegin = (Invader *) malloc(sizeof(Invader) * invadersCountX * invadersCountY);
      swarmEnd = swarmBegin + invadersCountX * invadersCountY;

      rocketsBegin = (Rocket *) malloc(sizeof(Rocket) * ROCKET_MAX);
      rocketsEnd = rocketsBegin + ROCKET_MAX;

      reset();
    }

    ~SpaceInvaders() override {
      free(swarmBegin);
      free(rocketsBegin);
    };

    const char *getName() override {
      return "Space Invaders";
    }

    void step(millis_t dt) override {
      stepRockets(dt);
      stepInvaders(dt);
      stepHero(dt);

      draw();

      collide();
      if (invadersAlive == 0) {
        Serial.println("WINNER!");
        reset();
      }
      if (swarmY + (invadersCountY - 1) * 2 >= display->height - 1) {
        Serial.println("GAME OVER");
        reset();
      }
    }

    void stepRockets(millis_t dt) {
      rocketRuntime += dt;
      if (rocketRuntime > 200) {
        rocketRuntime -= 200;
        for (Rocket *rocket = rocketsBegin; rocket < rocketsEnd; rocket++) {
          if (rocket->alive) {
            if (rocket->y == 0) {
              rocket->alive = false;
            } else {
              rocket->y -= 1;
            }
          }
        }
      }
    }

    void stepInvaders(millis_t dt) {
      swarmRuntime += dt;

      if (swarmDown && swarmRuntime > 500) {
        swarmDown = false;
        swarmY++;
      }

      if (swarmRuntime >= 1000) {
        swarmRuntime -= 1000;
        if (swarmLeft) {
          swarmX--;
          if (swarmX == 0) {
            swarmLeft = false;
          }
        } else {
          swarmX++;
          if (swarmX == 3) {
            swarmLeft = true;
          }
        }
        if (swarmX == 0) {
          swarmDown = true;
        }
      }
    }

    void stepHero(millis_t dt) {
      heroRuntime += dt;
      if (heroRuntime >= 50) {
        heroRuntime -= 50;
        if (heroLeft) {
          heroX--;
          if (heroX <= 1) {
            heroLeft = false;
          }
        } else {
          heroX++;
          if (heroX >= display->width - 2) {
            heroLeft = true;
          }
        }

        heroShoot++;
        if (heroShoot >= 10) {
          heroShoot = 0;
          shoot();
        }
      }
    }

    void shoot() {
      for (Rocket *rocket = rocketsBegin; rocket < rocketsEnd; rocket++) {
        if (!rocket->alive) {
          rocket->alive = true;
          rocket->x = heroX;
          rocket->y = display->height - 2;
        }
      }
    }

    void collide() {
      for (Rocket *rocket = rocketsBegin; rocket < rocketsEnd; rocket++) {
        for (Invader *invader = swarmBegin; invader < swarmEnd; invader++) {
          if (invader->alive && rocket->alive && collide(rocket, invader)) {
            rocket->alive = false;
            invader->alive = false;
            invadersAlive--;
//            Serial.printf("Killed invader at (%2u/%2u): %2u/%2u alive.\n", invader->x, invader->y, invadersAlive, invadersCountX * invadersCountY);
          }
        }
      }
    }

    bool collide(const Rocket *rocket, const Invader *invader) const {
      return swarmY + invader->y * 2 == rocket->y && swarmX + invader->x * 3 <= rocket->x && rocket->x <= swarmX + invader->x * 3 + 1;
    }

    void draw() {
      display->clear();
      drawInvaders();
      drawRockets();
      drawHero();
    }

    void drawInvaders() {
      for (Invader *invader = swarmBegin; invader < swarmEnd; invader++) {
        if (invader->alive) {
          display->set(swarmX + invader->x * 3 + 0, swarmY + invader->y * 2, 255, 0, 0);
          display->set(swarmX + invader->x * 3 + 1, swarmY + invader->y * 2, 255, 0, 0);
        }
      }
    }

    void drawRockets() {
      for (Rocket *rocket = rocketsBegin; rocket < rocketsEnd; rocket++) {
        if (!rocket->alive) {
          continue;
        }
        display->set(rocket->x, rocket->y, 255, 255, 0);
      }
    }

    void drawHero() {
      display->set(heroX - 1, display->height - 1, 0, 0, 255);
      display->set(heroX + 0, display->height - 1, 0, 0, 255);
      display->set(heroX + 1, display->height - 1, 0, 0, 255);
    }

    void reset() {
      heroRuntime = 0;
      heroLeft = false;
      heroShoot = 0;
      heroX = display->width / 2;

      rocketRuntime = 0;
      for (Rocket *rocket = rocketsBegin; rocket < rocketsEnd; rocket++) {
        rocket->alive = false;
        rocket->x = 0;
        rocket->y = 0;
      }

      swarmRuntime = 0;
      invadersAlive = invadersCountX * invadersCountY;
      swarmX = 0;
      swarmY = 0;
      swarmLeft = false;
      swarmDown = false;
      uint8_t n = 0;
      for (Invader *invader = swarmBegin; invader < swarmEnd; invader++) {
        invader->alive = true;
        invader->x = n % invadersCountX;
        invader->y = n / invadersCountX;
        n++;
      }
    }

};

#endif