#include <gint/display.h>
#include <gint/defs/util.h>
#include "animation.h"
#include "engine.h"

//---
//  Generation of animation frames from sheets
//---

/* struct sheet: Structure of an image with animation frames */
struct sheet
{
	/* Source image */
	bopti_image_t *img;
	/* Width and height of single entry */
	int frame_w;
	int frame_h;
};

extern bopti_image_t img_spritesheet;
struct sheet const anim_player = {
	.img = &img_spritesheet,
	.frame_w = 12,
	.frame_h = 16,
};

/* anim_frame(): Get a frame from a sheet */
static struct anim_frame anim_frame(struct sheet const *sheet, int col,int row)
{
	struct anim_frame f = {
		.source = sheet->img,
		.left   = sheet->frame_w * col,
		.top    = sheet->frame_h * row,
		.w      = sheet->frame_w,
		.h      = sheet->frame_h,
	};
	return f;
}

void dframe(int x, int y, struct anim_frame const frame)
{
	dsubimage(x, y, frame.source, frame.left, frame.top, frame.w, frame.h,
		DIMAGE_NONE);
}

//---
//  Animation functions
//---

int anim_player_idle(struct anim_data *data, int init)
{
	/* Animation initialization; takes [data->dir] as input */
	if(init)
	{
		data->function = anim_player_idle;
		data->frame = 0;
		data->duration = 500;
	}
	else
	{
		data->frame = (data->frame + 1) % 2;
		data->duration += 500;
	}

	data->img = anim_frame(&anim_player, data->dir, data->frame);
	data->dx = 0;
	data->dy = 0;
	return 0;
}

int anim_player_walking(struct anim_data *data, int init)
{
	/* Animation initialization; takes [data->dir] as input */
	if(init)
	{
		data->function = anim_player_walking;
		data->frame = 0;
		data->duration = 50;

		int dx = (data->dir == DIR_LEFT) - (data->dir == DIR_RIGHT);
		int dy = (data->dir == DIR_UP)   - (data->dir == DIR_DOWN);

		data->dx = 10 * dx;
		data->dy = 10 * dy;
	}
	else
	{
		data->dx -= sgn(data->dx);
		data->dy -= sgn(data->dy);

		/* Animation finishes if both displacements are zero */
		if(!data->dx && !data->dy)
		{
			return anim_player_idle(data, 1);
		}

		data->frame = (data->frame + 1) % 8;
		data->duration += 50;
	}

	data->img = anim_frame(&anim_player, data->dir + 4, data->frame / 2);
	return 1;
}