/* SPDX-License-Identifier: MIT */
/*
 * konparticles.h
 *
 * Copyright (c) 2026 KonAki
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

#ifndef KONPARTICLES_H
#define KONPARTICLES_H

#include "konsofren.h"

#ifdef __cplusplus
extern "C" {
#endif

/*** definition ***/

typedef struct kon_particle {
	float x, y, vx, vy;
	float age, life; /* life is 0 for a free slot */
	float size0, size1;
	uint32_t color0, color1;
} kon_particle_t;

/* a stream of small things, sparks, dust, rain, snow, smoke. one of these is one kind of thing, use several for several kinds.
   the particles live in a pool you give it, so nothing is allocated and a full pool just means no new ones are made.
   kon_particlesInit gives plain white specks, fill in the public fields to change them. everything is in pixels and seconds, a particle at a whole x and y sits on the middle of that pixel */
typedef struct kon_particles {
	kon_particle_t *pool;
	int capacity;

	/* where they are born: a random point in this rectangle */
	float x, y, width, height;
	float rate; /* born every second, 0 for only bursts */

	/* how they leave: the direction in radians with 0 to the right and a quarter turn down, a random speed and lifetime */
	float angle, spread; /* spread is how far either side of the angle */
	float speedMin, speedMax;
	float lifeMin, lifeMax;
	float ax, ay; /* acceleration, gravity and wind */
	kon_rect_t area; /* if it has a size, particles die when they leave it */

	/* how they look over their life, blended from the first to the last. size is in pixels and never goes under 1, fade with alpha */
	float size0, size1;
	uint32_t color0, color1;
	float stretch; /* 0 for squares, otherwise they are long in the way they move, this many seconds of movement long */
	kon_blend_t blend;
	const kon_image *image; /* NULL for squares, otherwise each is this picture (or the part of it in src) drawn size pixels wide */
	kon_rect_t src;

	/* private */
	float carry;
	uint32_t seed;
} kon_particles_t;

/* capacity is how many can be alive at once. seed any number, the same seed makes the same effect */
void kon_particlesInit(kon_particles_t *ps, kon_particle_t *pool, int capacity, uint32_t seed);

/* makes count at once, as many as there is room for. returns how many */
int kon_particlesBurst(kon_particles_t *ps, int count);

void kon_particlesUpdate(kon_particles_t *ps, float dt);

/* how many are alive */
int kon_particlesCount(const kon_particles_t *ps);

/* removes them all */
void kon_particlesClear(kon_particles_t *ps);

/* offset is added to every position, for a camera that scrolls */
void kon_particlesDraw(const kon_particles_t *ps, kon_framebuffer_t *fb, int offsetX, int offsetY);

/*** weather ***/

/* set the emitter up as rain, snow or a storm for a view of that size. power from 1 to 9 is how heavy, like RPG Maker's.
   they only change the public fields, so adjust them afterwards. call kon_particlesUpdate and kon_particlesDraw as usual,
   with a pool of a few hundred (power 9 on a large view wants more, particles that do not fit are skipped) */
void kon_weatherRain(kon_particles_t *ps, int viewWidth, int viewHeight, int power);
void kon_weatherSnow(kon_particles_t *ps, int viewWidth, int viewHeight, int power);
void kon_weatherStorm(kon_particles_t *ps, int viewWidth, int viewHeight, int power);


#ifdef __cplusplus
}
#endif
#endif