# simulation_core.pyx

cimport cython
from libc.math cimport sqrt

cdef class CParticle:
    cdef float x, y, vx, vy, mass, gravity

    def __init__(self, float x, float y, float vx, float vy, float mass, float gravity):
        self.x = x
        self.y = y
        self.vx = vx
        self.vy = vy
        self.mass = mass
        self.gravity = gravity

    cpdef void apply_gravity(self, float dt):
        self.vy += self.gravity * dt
        self.y += self.vy * dt
        self.x += self.vx * dt


cdef class SimulationCore:
    cdef list particles

    def __init__(self):
        self.particles = []

    cpdef void add_particle(self, CParticle particle):
        self.particles.append(particle)

    cpdef void update(self, float dt):
        cdef CParticle particle
        for particle in self.particles:
            particle.apply_gravity(dt)