from OpenGL.GL import *
from OpenGL.GLUT import *
from OpenGL.GLU import *
from time import time
from queue import Queue

from renderer import ImageRenderer, TransitionMix
from manager import PixMan

class PixDisplay:
    def __init__(self, textures):
        self.last_time = 0
        self.start_time = 0
        self.image_time = 0
        self.paused = False
        self.textures = textures
        self.current_texture_index = 0
        self.renderer = None
        self.win_w = 0
        self.win_h = 0

        self.transition_reverse = False
        self.text_prev = None
        self.tex = None

        self._force_redraw = False
        self.queue = Queue()

        self.update_config()

    def update_config(self):
        config = PixMan().config
        self.max_framerate = config.max_framerate
        self.image_duration = config.image_duration
        self.transition_duration = config.transition_duration
        self.auto_transition = config.auto_transition

    @property
    def max_framerate(self):
        #return int(1000/int(1000/self.frame_time))
        return self.frame_time

    @max_framerate.setter
    def max_framerate(self, max_fps):
        self._max_fps = max_fps  # This is just for the getter since otherwise e.g. int(1000/int(1000/60)) would round to 62
        self.frame_time = int(1000 / max_fps)  # In ms

    def increment_texture_index(self, increment):
        self.transition_reverse = increment < 0

        self.tex_prev = self.textures[self.current_texture_index]
        self.current_texture_index = (self.current_texture_index + increment) % len(self.textures)
        self.tex      = self.textures[self.current_texture_index]

        if not self.tex.initialized or not self.tex_prev.initialized:
            return

        # Ensure textures are initialized for opengl
        self.tex_prev.gl_init()
        self.tex.gl_init()

    # Main display function
    def display(self):
        # Calculate timings
        current_time = time()
        alive_time = current_time - self.start_time
        delta_time = current_time - self.last_time
        self.last_time = current_time

        if not self.tex or not self.tex.initialized or not self.tex.id:
            self.increment_texture_index(0)
            # Draw black window if no textures are available
            if not self.tex.id:
                glClearColor(0.0, 0.0, 0.0, 1.0)
                glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT)
                glutSwapBuffers()
                return

        # Run queue events
        while not self.queue.empty():
            f = self.queue.get()  # Get the task and its data
            f()

        # Progress image time
        if not self.paused:
            self.image_time += delta_time

        # Get window size
        old_win_w, old_win_h = self.win_w, self.win_h
        self.win_w, self.win_h = glutGet(GLUT_WINDOW_WIDTH), glutGet(GLUT_WINDOW_HEIGHT)

        # Draw static image except during a transition
        if self.image_time < self.image_duration:
            # Avoid unforced-redraw unless window size has changed
            if self._force_redraw or self.win_w != old_win_w or self.win_h != old_win_h:
                self.renderer.draw_static(self.tex, self.win_w, self.win_h, 1.0)
                self._force_redraw = False
            return

        # Start drawing transition once image_time >= image_duration
        if self.auto_transition:
            self.increment_texture_index(1)
            self.auto_transition = False

        transition_time = self.image_time - self.image_duration

        self.renderer.draw_transition(self.tex_prev, self.tex, self.win_w, self.win_h, delta_time, transition_time, self.transition_duration, self.transition_reverse)

        if transition_time >= self.transition_duration:
            self.image_time = 0
            self.auto_transition = True

    # Limit framerate
    def timer(self, value):
        glutPostRedisplay()
        glutTimerFunc(self.frame_time, self.timer, 0)  # Schedule next frame

    def seek(self, increment):
        self.auto_transition = False
        self.increment_texture_index(increment)
        self.image_time = self.image_duration

    def handle_special_key(self, key, x, y):
        if   key == GLUT_KEY_LEFT:
            self.seek(-1)
        elif key == GLUT_KEY_RIGHT:
            self.seek(1)

    def handle_visibility_change(self, state):
        if state == GLUT_VISIBLE:
            self._force_redraw = True
            glutPostRedisplay()

    # Initialization and main loop
    def main(self, glut_args):
        # Initialize the window
        glutInit(glut_args)
        glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB)
        glutCreateWindow("Image Viewer with Fade Transition")
        glEnable(GL_TEXTURE_2D)

        self.renderer = ImageRenderer()
        self.renderer.set_transition(TransitionMix)
        self.image_time = 0
        self.start_time = time()
        self.last_time  = time()

        # Set up the OpenGL viewport and projection
        glMatrixMode(GL_PROJECTION)
        glLoadIdentity()
        glOrtho(-1, 1, -1, 1, -1, 1)
        glMatrixMode(GL_MODELVIEW)

        # Enable alpha blending
        glEnable(GL_BLEND)
        glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA)

        # Run display
        glutDisplayFunc(self.display)
        glutTimerFunc(self.frame_time, self.timer, 0)
        glutVisibilityFunc(self.handle_visibility_change)  # Redraw in case framebuffer gets destroyed when window is obscured
        glutSpecialFunc(self.handle_special_key)
        glutMainLoop()