// Copyright(C) 2019 Lars Pontoppidan. All rights reserved.
// Use of this source code is governed by an MIT license file distributed with this software package

module particle
import vec2
import rand
import sokol.sgl

pub struct SystemConfig {
	pool	int
}

pub struct System {
	width			int
	height			int
mut:
	pool			[]&Particle
	bin				[]&Particle
}

pub fn (mut s System) init(sc SystemConfig) {
	for i := 0; i < sc.pool; i++ {
		p := particle.new( vec2.Vec2{f32(s.width)*0.5, f32(s.height)*0.5} )
		s.pool << p
	}
}

pub fn (mut s System) update(dt f64) {

	mut p := &Particle(0)
	for i := 0; i < s.pool.len; i++ {
		p = s.pool[i]

		p.update(dt)

		if p.is_dead() {
			s.bin << p
			s.pool.delete(i)
		}
	}
}

pub fn (s System) draw() {
	sgl.begin_quads()
	for p in s.pool {
		p.draw()
	}
	sgl.end()
}

pub fn (mut s System) reset() {
	for p in s.pool {
		p.reset()
		p.life_time = 0
	}
	for p_ in s.bin {
		p_.reset()
		p_.life_time = 0
	}
}

pub fn (mut s System) explode(x f32, y f32) {

	mut reserve := 500

	center := vec2.Vec2{x,y}

	mut p := &Particle(0)
	for i := 0; i < s.bin.len && reserve > 0; i++ {
		p = s.bin[i]

		p.reset()

		p.location.from(center)
		p.acceleration = vec2.Vec2{rand.f32_in_range(-0.5,0.5),rand.f32_in_range(-0.5,0.5)}
		p.velocity = vec2.Vec2{rand.f32_in_range(-0.5,0.5),rand.f32_in_range(-0.5,0.5)}
		p.life_time = rand.f64_in_range(500,2000)

		s.pool << p
		s.bin.delete(i)

		reserve--
	}
}

pub fn (mut s System) free() {
	for p in s.pool {
		if p == 0 {
			print(ptr_str(p)+' ouch')
			continue
		}
		unsafe{
			free(p)
		}
	}
	s.pool.clear()
	for p in s.bin {
		if p == 0 {
			print(ptr_str(p)+' ouch')
			continue
		}

		unsafe{
			//println('Freeing from bin')
			free(p)
		}
	}
	s.bin.clear()
}