"""Atividade — iluminação incremental do octaedro da Aula 07.

Aula 08 — Modelos de Iluminação.

Execute com:

    python octaedro_iluminado_base.py
"""

from __future__ import annotations

import math
import sys

from PySide6.QtCore import Qt
from PySide6.QtGui import QSurfaceFormat
from PySide6.QtOpenGLWidgets import QOpenGLWidget
from PySide6.QtWidgets import QApplication
from OpenGL.GL import *
from OpenGL.GLU import gluLookAt, gluPerspective

VERTICES = [(0, 1.4, 0), (0, -1.4, 0), (-1, 0, 0), (0, 0, -1), (1, 0, 0), (0, 0, 1)]

FACES = [
    (0, 3, 2), (0, 4, 3), (0, 5, 4), (0, 2, 5),
    (1, 2, 3), (1, 3, 4), (1, 4, 5), (1, 5, 2),
]


def normal_face(face):
    a, b, c = (VERTICES[i] for i in face)
    u = tuple(b[i] - a[i] for i in range(3))
    v = tuple(c[i] - a[i] for i in range(3))
    normal = (u[1] * v[2] - u[2] * v[1], u[2] * v[0] - u[0] * v[2], u[0] * v[1] - u[1] * v[0])
    tamanho = math.sqrt(sum(componente * componente for componente in normal))
    return tuple(componente / tamanho for componente in normal)


class Octaedro(QOpenGLWidget):
    def __init__(self, parent=None):
        super().__init__(parent)
        self.setWindowTitle("Octaedro iluminado | setas: rotação | Esc: sair")
        self.angulo = 25.0
        self.setFocusPolicy(Qt.FocusPolicy.StrongFocus)

    def initializeGL(self):
        # Passo 1: a malha, a câmera e a visibilidade já estão prontas.
        glClearColor(0.08, 0.09, 0.12, 1.0)
        glEnable(GL_DEPTH_TEST)
        glEnable(GL_CULL_FACE)
        glFrontFace(GL_CCW)
        glCullFace(GL_BACK)
        glShadeModel(GL_FLAT)
        # TODO 2: habilite GL_LIGHTING, GL_LIGHT0 e GL_NORMALIZE.
        # Passo 2: elimine ambiente global e use o observador local.
        glLightModelfv(GL_LIGHT_MODEL_AMBIENT, (0.0, 0.0, 0.0, 1.0))
        glLightModeli(GL_LIGHT_MODEL_LOCAL_VIEWER, GL_TRUE)
        glLightfv(GL_LIGHT0, GL_AMBIENT, (0.12, 0.12, 0.12, 1.0))
        glLightfv(GL_LIGHT0, GL_DIFFUSE, (0.9, 0.9, 0.9, 1.0))
        glLightfv(GL_LIGHT0, GL_SPECULAR, (1.0, 1.0, 1.0, 1.0))
        # TODO 4: configure GL_AMBIENT_AND_DIFFUSE, GL_SPECULAR e
        # GL_SHININESS do material com glMaterialfv/glMaterialf.

    def resizeGL(self, w, h):
        dpr = self.devicePixelRatioF()
        w, h = max(1, round(w * dpr)), max(1, round(h * dpr))
        glViewport(0, 0, w, h)
        glMatrixMode(GL_PROJECTION); glLoadIdentity()
        gluPerspective(50.0, w / float(h), 0.1, 100.0)
        glMatrixMode(GL_MODELVIEW)

    def paintGL(self):
        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT)
        glLoadIdentity(); gluLookAt(0, 1.8, 5, 0, 0, 0, 0, 1, 0)
        # TODO 3a: envie GL_POSITION = (3.0, 4.0, 5.0, 1.0) aqui.
        glRotatef(self.angulo, 0, 1, 0)
        glColor3f(0.85, 0.45, 0.20)  # visível apenas enquanto LIGHTING está desligado
        glBegin(GL_TRIANGLES)
        for face in FACES:
            # TODO 3b: envie normal_face(face) com glNormal3f antes dos vértices.
            for indice in face:
                glVertex3f(*VERTICES[indice])
        glEnd()

    def keyPressEvent(self, event):
        if event.key() == Qt.Key.Key_Escape: self.close(); return
        if event.key() == Qt.Key.Key_Left: self.angulo -= 5
        elif event.key() == Qt.Key.Key_Right: self.angulo += 5
        else: return
        self.update()


def main():
    fmt = QSurfaceFormat(); fmt.setVersion(2, 1)
    fmt.setProfile(QSurfaceFormat.OpenGLContextProfile.NoProfile); fmt.setDepthBufferSize(24)
    QSurfaceFormat.setDefaultFormat(fmt)
    app = QApplication(sys.argv); janela = Octaedro(); janela.resize(800, 600); janela.show()
    return app.exec()


if __name__ == "__main__": raise SystemExit(main())