"""
Initial Author: Siddharth Kothiyal (sidkothiyal, https://github.com/sidkothiyal)
Other Authors:
Owner: AerospaceResearch.net
About: This module aims to create a 3D graph with X, Y and Z axis, using OpenGL and then plot the equation of line or plane on it.
    In the next stage of development, it can be provided with a rotation, translation and scaling feature.
    This module is just a rough implementation for now, and can be (and most probably will be) completely changed according to need.
Note: Please try to maintain proper documentation
Logic Description:
from OpenGL.GL import *
from OpenGL.GLU import *
from OpenGL.GLUT import *


# -----------
# VARIABLES
# -----------

g_fViewDistance = 9.
g_Width = 600
g_Height = 600

g_nearPlane = 1.
g_farPlane = 1000.

action = ""
xStart = yStart = 0.
zoom = 65.

xRotate = 0.
yRotate = 0.
zRotate = 0.

xTrans = 0.
yTrans = 0.


# -------------------
# SCENE CONSTRUCTOR
# -------------------
verticies = [
    (0, 0, 0),
    (1000, 0, 0),
    (-1000, 0, 0),
    (0, 1000, 0),
    (0, -1000, 0),
    (0, 0, 1000),
    (0, 0, -1000)
]

edges = [
    (0, 1),
    (0, 2),
    (0, 3),
    (0, 4),
    (0, 5),
    (0, 6)
]


def scenemodel():
    glRotate(90, 0., 0., 1.)

    glBegin(GL_LINES)
    val = 0
    col = 0
    for edge in edges:
        for vertex in edge:
            if col == 0:
                glColor(1.0, 0, 0)
            elif col == 1:
                glColor(0, 1.0, 0)
            else:
                glColor(0, 0, 1.0)

            glVertex3fv(verticies[vertex])
        val += 1
        if val % 2 == 0:
            col += 1
    glEnd()


# --------
# VIEWER
# --------

def printHelp():
    print('''\n\n
         -------------------------------------------------------------------\n
         Left Mousebutton       - move eye position (+ Shift for third axis)\n
         Middle Mousebutton     - translate the scene\n
         Right Mousebutton      - move up / down to zoom in / out\n
         R Key                - reset viewpoint\n
         Q Key                - exit the program\n
         -------------------------------------------------------------------\n
         \n''')


def init():
    glEnable(GL_NORMALIZE)
    # glLightfv(GL_LIGHT0,GL_POSITION,[ .0, 10.0, 10., 0. ] )
    # glLightfv(GL_LIGHT0,GL_AMBIENT,[ .0, .0, .0, 1.0 ]);
    # glLightfv(GL_LIGHT0,GL_DIFFUSE,[ 1.0, 1.0, 1.0, 1.0 ]);
    # glLightfv(GL_LIGHT0,GL_SPECULAR,[ 1.0, 1.0, 1.0, 1.0 ]);
    # glEnable(GL_LIGHT0)
    # glEnable(GL_LIGHTING)
    glEnable(GL_DEPTH_TEST)
    glDepthFunc(GL_LESS)
    glShadeModel(GL_SMOOTH)
    resetView()


def resetView():
    global zoom, xRotate, yRotate, zRotate, xTrans, yTrans
    zoom = 65.
    xRotate = 0.
    yRotate = 0.
    zRotate = 0.
    xTrans = 0.
    yTrans = 0.
    glutPostRedisplay()


def display():
    # Clear frame buffer and depth buffer
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT)
    # Set up viewing transformation, looking down -Z axis
    glLoadIdentity()
    gluLookAt(0, 0, -g_fViewDistance, 0, 0, 0, -.1, 0, 0)  # -.1,0,0
    # Set perspective (also zoom)
    glMatrixMode(GL_PROJECTION)
    glLoadIdentity()
    gluPerspective(zoom, float(g_Width) / float(g_Height),
                   g_nearPlane, g_farPlane)
    glMatrixMode(GL_MODELVIEW)
    # Render the scene
    polarView()
    scenemodel()
    # Make sure changes appear onscreen
    glutSwapBuffers()


def reshape(width, height):
    global g_Width, g_Height
    g_Width = width
    g_Height = height
    glViewport(0, 0, g_Width, g_Height)


def polarView():
    glTranslatef(yTrans / 100., 0.0, 0.0)
    glTranslatef(0.0, -xTrans / 100., 0.0)
    glRotatef(-zRotate, 0.0, 0.0, 1.0)
    glRotatef(-xRotate, 1.0, 0.0, 0.0)
    glRotatef(-yRotate, .0, 1.0, 0.0)


def keyboard(key, x, y):
    global xTr, yTr, zTr
    if(key == 'r'):
        resetView()
    if(key == 'q'):
        exit(0)
    glutPostRedisplay()


def mouse(button, state, x, y):
    global action, xStart, yStart
    if (button == GLUT_LEFT_BUTTON):
        if (glutGetModifiers() == GLUT_ACTIVE_SHIFT):
            action = "MOVE_EYE_2"
        else:
            action = "MOVE_EYE"
    elif (button == GLUT_MIDDLE_BUTTON):
        action = "TRANS"
    elif (button == GLUT_RIGHT_BUTTON):
        action = "ZOOM"
    xStart = x
    yStart = y


def motion(x, y):
    global zoom, xStart, yStart, xRotate, yRotate, zRotate, xTrans, yTrans
    if (action == "MOVE_EYE"):
        xRotate += x - xStart
        yRotate -= y - yStart
    elif (action == "MOVE_EYE_2"):
        zRotate += y - yStart
    elif (action == "TRANS"):
        xTrans += x - xStart
        yTrans += y - yStart
    elif (action == "ZOOM"):
        zoom -= y - yStart
        if zoom > 150.:
            zoom = 150.
        elif zoom < 1.1:
            zoom = 1.1
    else:
        print("unknown action\n", action)
    xStart = x
    yStart = y
    glutPostRedisplay()


# ------
# MAIN
# ------
if __name__ == "__main__":
    # GLUT Window Initialization
    glutInit()
    glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH)      # zBuffer
    glutInitWindowSize(g_Width, g_Height)
    glutInitWindowPosition(0 + 4, g_Height // 4)
    glutCreateWindow("VisMa")
    glClearColor(1.0, 1.0, 1.0, 0.0)
    # Initialize OpenGL graphics state
    init()
    # Register callbacks
    glutReshapeFunc(reshape)
    glutDisplayFunc(display)
    glutMouseFunc(mouse)
    glutMotionFunc(motion)
    glutKeyboardFunc(keyboard)
    printHelp()
    # Turn the flow of control over to GLUT
    glutMainLoop()
"""