#pragma once

#include "coordinates.hpp"

struct actor_t
{
  enum direction {
    up,
    down,
    left,
    right,
  };

  enum collision {
    impassable,
    jump,
    passable,
  };

  world_t world;
  enum direction facing;
  bool moving;
  enum collision collision;
  uint8_t frame;
  uint8_t cycle;

  constexpr inline int32_t frame_pixels()
  {
    switch (collision) {
    case jump: return frame;
    default:   return frame;
    }
  }

  constexpr inline offset_t offset()
  {
    const int32_t pixels = frame_pixels();

    switch (collision) {
    default:
      return {0, 0};
    case jump: [[fallthrough]];
    case passable:
      switch (facing) {
      case left:
	return {-pixels, 0};
      case right:
	return {pixels, 0};
      case up:
	return {0, -pixels};
      case down:
	return {0, pixels};
      default:
	return {0, 0};
      }
    }
  }

  // engine/overworld/player_animations.asm
  // $38, $36, $34, $32, $31, $30, $30, $30, $31, $32, $33, $34, $36, $38, $3C, $3C
  // ^ these are in absolute position, subtract 60 from each to get the offset:
  // an offset of -4 is the same as not jumping
  static constexpr int8_t jump_screen_offset[16] = {-4, -8, -10, -12, -14, -15, -16, -16, -16, -15, -14, -13, -12, -10, -8, -4};

  // in pixels
  constexpr inline int32_t y_offset()
  {
    if (collision == jump)
      return jump_screen_offset[frame >> 1 & 15];
    else
      return -4;
  }

  constexpr inline int32_t world_increment()
  {
    switch (collision) {
    case jump: return 2;
    default:   return 1;
    }
  }

  // call tick() before move()
  constexpr inline void tick()
  {
    if (!moving) return;

    frame = frame + 1;
    if (frame == (16 * world_increment())) {
      cycle += 1;
      frame = 0;
      int32_t inc = world_increment();
      switch (collision) {
      default: break;
      case jump: [[fallthrough]];
      case passable:
	switch (facing) {
	case left:  world.x -= inc; break;
	case right: world.x += inc; break;
	case up:    world.y -= inc; break;
	case down:  world.y += inc; break;
	}
      }
      moving = false;
    }
  }

  constexpr inline void move(enum collision collision,
			     enum direction dir)
  {
    /*
      m 1 . 2 . 3 . 4 .
      | - | - | - | - |

     */

    // don't change directions in the middle of a movement animation
    if (this->collision != impassable && moving) return;

    // reset animation frame if there is no collision
    // if there is a collision, keep animating
    if (collision != impassable) frame = 0;

    facing = dir;
    moving = true;
    this->collision = collision;
  }
};