#include <gint/display.h>

#include "camera.h"
#include "conf.h"
#include "vec.h"
#include "player.h"
#include "level.h"

void camera_step(Camera *camera) {
	/* lerp towards target */
	vec_lerp(&camera->pos, *camera->target, camera->speed);
	/* put the camera in the right place */
	vec_clamp(&camera->pos, camera->min, camera->max);
	/* calculate pixel offset */
	Vec * const offset = &camera->offset; /* DRY */
	vec_cpy(offset, camera->pos);
	vec_div(offset, VEC_PRECISION);
	vec_sub(offset, VEC_SCALED_DCENTER);
}

void camera_init(Camera *camera, Player *player, const Level *level) {
	/* initialize struct */
	camera->pos = (Vec){ DWIDTH * VEC_PRECISION, DHEIGHT * VEC_PRECISION };
	camera->target = &player->pos;
	camera->speed = 0.04;
	/* NOTE: This system doesn't totally works, but it's good enough
	 * for now.  TODO: Add informations about what isn't working
	 * correctly and/or fix the issues.
	 */
	/* check level size */
	const Vec level_dim = {level->width * (TILE_SIZE / VEC_PRECISION * SCALE),
		level->height * (TILE_SIZE / VEC_PRECISION * SCALE)};
	if (level_dim.x > DWIDTH || level_dim.y > DHEIGHT) {
		/* level cannot be displayed on a single screen */
		/* calculate min and max */
		vec_cpy(&camera->min, VEC_SCALED_DCENTER);
		vec_mul(&camera->min, VEC_PRECISION);
		vec_cpy(&camera->max, (Vec){ 0, 0 });
		vec_sub(&camera->max, VEC_SCALED_DCENTER);
		vec_mul(&camera->max, VEC_PRECISION);
		vec_add(&camera->max, (Vec){ TILE_SIZE * level->width, TILE_SIZE * level->height });
		vec_cpy(&camera->pos, player->pos);
	}
	else {
		/* level is single screen */
		/* We calculate the offset and setup the camera to center everything. */
		const Vec screen_center_precise = {level->width * TILE_SIZE / 2,
			level->height * TILE_SIZE / 2};
		vec_cpy(&camera->min, screen_center_precise);
		vec_cpy(&camera->max, screen_center_precise);
	}
	vec_clamp(&camera->pos, camera->min, camera->max);
}

void camera_draw_debug(Camera *camera) {
	dprint(0, 0, C_BLACK, "-x: %d, -y: %d", camera->min.x, camera->min.y);
	dprint(0, 10, C_BLACK, "+x: %d, +y: %d", camera->max.x, camera->max.y);
	dprint(0, 20, C_BLACK, "cx: %d, cy: %d", camera->pos.x, camera->pos.y);
	dprint(0, 30, C_BLACK, "px: %d, py: %d", camera->offset.x, camera->offset.y);
}