from OpenGL.GL import *
import itertools
import numpy as np
import pygame

FLOAT = np.float32
VOXEL_TYPE = np.uint8
VERTEX_ATTRS = ["vec3 position", "vec4 col", "vec3 normal", "vec4 refls"]
UNIFORMS = {
    "MVP": ["vert", "mat4", None],
    "lightPos": ["frag", "vec4", None],
    "camPos": ["frag", "vec3", None]
}

LIGHT_POS = [5, 30, 10]
REGION_SIZE = 8
GRAVITY = 1
VIEW_DIST = 30
FPS = 60
ARROWS = [
    ["RIGHT", "e", "d"], ["LEFT", "a"],
    ["SPACE"], ["LSHIFT"],
    ["UP", "COMMA", "w"], ["DOWN", "o", "s"],
]
ARROWS = [[getattr(pygame, f"K_{n}") for n in opts] for opts in ARROWS]

def vec(l):
    return np.array(l, dtype=FLOAT)

RED = vec([1.0, 0.0, 0.0, 1.0])
YELLOW = vec([1.0, 1.0, 0.0, 1.0])
GREEN = vec([0.0, 1.0, 0.0, 1.0])

def normalise(v):
    norm = np.linalg.norm(v)
    return v / norm if norm > 0 else v

def roll_vec3(l, k):
    match k:
        case 1:
            l[:] = [l[2], l[0], l[1]]
        case 2:
            l[:] = [l[1], l[2], l[0]]

def axis2offset(a, mag=1):
    o = [0, 0, mag * np.sign(a)]
    roll_vec3(o, abs(a))
    return o

def smerp(corners, weights):
    for w in weights:
        t = w ** 2 * (3 - 2 * w)
        pairs = zip(corners[::2], corners[1::2])
        corners = [a + t * (b - a) for (a, b) in pairs]
    return corners[0]

def norm_tri(verts):
    assert verts.shape[0] == 3
    return normalise(np.cross(verts[2] - verts[0], verts[1] - verts[0]))

def update_attr(ent, n, l=None):
    if isinstance(n, int):
        i, name = n, VERTEX_ATTRS[n].split()[1]
    elif isinstance(n, str):
        # https://stackoverflow.com/a/30197797
        i, name = next((i for (i, s) in enumerate(VERTEX_ATTRS) if n in s)), n
    if l is None:
        match name:
            case "position":
                l = ent.verts
            case "col":
                l = ent.mat_list()[0]
            case "normal":
                l = ent.norm_list()
            case "refls":
                l = ent.mat_list()[1]
    if ent.vao:
        glBindBuffer(GL_ARRAY_BUFFER, ent.vbos[i][0])
        if l.shape[0] != ent.vbos[i][1]:
            glBufferData(GL_ARRAY_BUFFER, l.nbytes, l, GL_DYNAMIC_DRAW)
            ent.vbos[i][1] = l.shape[0]
        else:
            glBufferSubData(GL_ARRAY_BUFFER, 0, l.nbytes, l)
        return l