import math
import array, itertools
import sys

from OpenGL.GL import *
from OpenGL.GLU import *

def use_pango_font(font, start, count, will_call_prepost=False):
    import gi
    gi.require_version('Pango','1.0')
    gi.require_version('PangoCairo','1.0')
    from gi.repository import Pango
    from gi.repository import PangoCairo
    #from gi.repository import Cairo as cairo
    import cairo

    fontDesc = Pango.FontDescription(font)
    a = array.array('b', itertools.repeat(0, 256*256))
    surface = cairo.ImageSurface.create_for_data(a, cairo.FORMAT_A8, 256, 256)
    context  = cairo.Context(surface)
    pango_context = PangoCairo.create_context(context)
    layout = PangoCairo.create_layout(context)
    fontmap = PangoCairo.font_map_get_default()
    font = fontmap.load_font(fontmap.create_context(), fontDesc)
    layout.set_font_description(fontDesc)
    metrics = font.get_metrics()
    descent = metrics.get_descent()
    d = descent / Pango.SCALE
    linespace = metrics.get_ascent() + metrics.get_descent()
    width = metrics.get_approximate_char_width()

    glPushClientAttrib(GL_CLIENT_PIXEL_STORE_BIT)
    glPixelStorei(GL_UNPACK_SWAP_BYTES, 0)
    glPixelStorei(GL_UNPACK_LSB_FIRST, 1)
    glPixelStorei(GL_UNPACK_ROW_LENGTH, 256)
    glPixelStorei(GL_UNPACK_IMAGE_HEIGHT, 256)
    glPixelStorei(GL_UNPACK_SKIP_PIXELS, 0)
    glPixelStorei(GL_UNPACK_SKIP_ROWS, 0)
    glPixelStorei(GL_UNPACK_SKIP_IMAGES, 0)
    glPixelStorei(GL_UNPACK_ALIGNMENT, 1)
    glPixelZoom(1, -1)

    base = glGenLists(count)
    for i in range(count):
        ch = chr(start+i)
        layout.set_text(ch, -1)
        w, h = layout.get_size()
        context.save()
        context.new_path()
        context.rectangle(0, 0, 256, 256)
        context.set_source_rgba(0., 0., 0., 0.)
        context.set_operator (cairo.OPERATOR_SOURCE)
        context.paint()
        context.restore()

        context.save()
        context.set_source_rgba(1., 1., 1., 1.)
        context.set_operator (cairo.OPERATOR_SOURCE)
        context.move_to(0, 0)
        PangoCairo.update_context(context,pango_context)
        PangoCairo.show_layout(context,layout)
        context.restore()
        w, h = int(w / Pango.SCALE), int(h / Pango.SCALE)
        glNewList(base+i, GL_COMPILE)
        glBitmap(0, 0, 0, 0, 0, h-d, None)
        #glDrawPixels(0, 0, 0, 0, 0, h-d, '');
        if not will_call_prepost:
            pango_font_pre()
        if w and h: 
            try:
                pass
                glDrawPixels(w, h, GL_LUMINANCE, GL_UNSIGNED_BYTE, a.tobytes())
            except Exception as e:
                print("glnav Exception ",e)

        glBitmap(0, 0, 0, 0, w, -h+d, None)
        if not will_call_prepost:
            pango_font_post()
        glEndList()

    glPopClientAttrib()
    return base, int(width / Pango.SCALE), int(linespace / Pango.SCALE)


def pango_font_pre(rgba=(1., 1., 0., 1.)):
    glPushAttrib(GL_COLOR_BUFFER_BIT)
    glEnable(GL_BLEND)
    glBlendFunc(GL_ONE, GL_ONE)

def pango_font_post():
    glPopAttrib()

def glTranslateScene(w, s, x, y, mousex, mousey):
    glMatrixMode(GL_MODELVIEW)
    mat = glGetDoublev(GL_MODELVIEW_MATRIX)
    glLoadIdentity()
    glTranslatef(s * (x - mousex), s * (mousey - y), 0.0)
    glMultMatrixd(mat)

def glRotateScene(w, s, xcenter, ycenter, zcenter, x, y, mousex, mousey):
    def snap(a):
        m = a%90
        if m < 3:
            return a-m
        elif m > 87:
            return a-m+90
        else:
            return a

    lat = min(w.maxlat, max(w.minlat, w.lat + (y - mousey) * .5))
    lon = (w.lon + (x - mousex) * .5) % 360

    glMatrixMode(GL_MODELVIEW)

    glTranslatef(xcenter, ycenter, zcenter)
    mat = glGetDoublev(GL_MODELVIEW_MATRIX)

    glLoadIdentity()
    tx, ty, tz = mat[3][:3]
    glTranslatef(tx, ty, tz)
    glRotatef(snap(lat), *w.rotation_vectors[0])
    glRotatef(snap(lon), *w.rotation_vectors[1])
    glTranslatef(-xcenter, -ycenter, -zcenter)
    w.lat = lat
    w.lon = lon

def sub(x, y):
    return list(map(lambda a, b: a-b, x, y))

def dot(x, y):
    t = 0
    for i in range(len(x)):
        t = t + x[i]*y[i]
    return t

def glDistFromLine(x, p1, p2):
    f = list(map(lambda x, y: x-y, p2, p1))
    g = list(map(lambda x, y: x-y, x, p1))
    return dot(g, g) - dot(f, g)**2/dot(f, f)

def v3distsq(a,b):
    d = ( a[0] - b[0], a[1] - b[1], a[2] - b[2] )
    return d[0]*d[0] + d[1]*d[1] + d[2]*d[2]

class GlNavBase:
    rotation_vectors = [(1.,0.,0.), (0., 0., 1.)]

    def __init__(self):
        # Current coordinates of the mouse.
        self.xmouse = 0
        self.ymouse = 0

        # Where we are centering.
        self.xcenter = 0.0
        self.ycenter = 0.0
        self.zcenter = 0.0

        # The _back color
        self.r_back = 1.
        self.g_back = 0.
        self.b_back = 1.

        # Where the eye is
        self.distance = 10.0

        # Field of view in y direction
        self.fovy = 30.0

        # Position of clipping planes.
        self.near = 0.1
        self.far = 1000.0

        # View settings
        self.perspective = 0
        self.lat = 0
        self.lon = 0
        self.minlat = -90
        self.maxlat = 90

        # keep track of total translations
        # since last view reset
        self._totalx = 0.0
        self._totaly = 0.0

    # This should almost certainly be part of some derived class.
    # But I have put it here for convenience.
    def basic_lighting(self):
        """\
        Set up some basic lighting (single infinite light source).

        Also switch on the depth buffer."""

        self.activate()
        glLightfv(GL_LIGHT0, GL_POSITION, (1, -1, 1, 0))
        glLightfv(GL_LIGHT0, GL_AMBIENT, (.4, .4, .4, 1))
        glLightfv(GL_LIGHT0, GL_DIFFUSE, (.6, .6, .6, 1))
        glEnable(GL_LIGHTING)
        glEnable(GL_LIGHT0)
        glDepthFunc(GL_LESS)
        glEnable(GL_DEPTH_TEST)
        glMatrixMode(GL_MODELVIEW)
        glLoadIdentity()


    def set_background(self, r, g, b):
        """Change the background colour of the widget."""

        self.r_back = r
        self.g_back = g
        self.b_back = b

        self._redraw()


    def set_centerpoint(self, x, y, z):
        """Set the new center point for the model.
        This is where we are looking."""

        self.xcenter = x
        self.ycenter = y
        self.zcenter = z

        self._redraw()


    def set_latitudelimits(self, minlat, maxlat):
        """Set the new "latitude" limits for rotations."""

        if maxlat > 180:
            return
        if minlat < -180:
            return
        if maxlat <= minlat:
            return
        self.maxlat = maxlat
        self.minlat = minlat

        self._redraw()


    def set_eyepoint(self, distance):
        """Set how far the eye is from the position we are looking."""

        self.distance = distance
        self._redraw()

    def set_eyepoint_from_extents(self, e1, e2):
        """Set how far the eye is from the position we are looking
        based on the screen width and height of a subject."""
        w = self.winfo_width()
        h = self.winfo_height()

        ztran = max(2.0, e1, e2 * w/h) ** 2
        self.set_eyepoint(ztran - self.zcenter)

    def reset(self):
        """Reset rotation matrix for this widget."""

        glMatrixMode(GL_MODELVIEW)
        glLoadIdentity()
        self._redraw()
        # zero the translations - we will be recentering
        self._totalx = 0.0
        self._totaly = 0.0

    def recordMouse(self, x, y):
        self.xmouse = x
        self.ymouse = y

    def startRotate(self, x, y):
        self.recordMouse(x, y)

    def scale(self, x, y):
        """Scale the scene.  Achieved by moving the eye position.

        Dragging up zooms in, while dragging down zooms out
        """
        scale = 1 - 0.01 * (event.y - self.ymouse)
        # do some sanity checks, scale no more than
        # 1:1000 on any given click+drag
        if scale < 0.001:
            scale = 0.001
        elif scale > 1000:
            scale = 1000
        newdistance = self.distance * scale
        if newdistance < 1e-30 or newdistance > 1e30:
            return
        self.distance = newdistance
        self._redraw()
        self.recordMouse(x, y)

    def rotate(self, x, y):
        """Perform rotation of scene."""

        self.activate()
        self.perspective = True
        glRotateScene(self, 0.5, self.xcenter, self.ycenter, self.zcenter, x, y, self.xmouse, self.ymouse)
        self._redraw()
        self.recordMouse(x, y)

    def translate(self, x, y):
        """Perform translation of scene."""

        self.activate()

        # Scale mouse translations to object viewplane so object tracks with mouse
        win_height = max( 1,self.winfo_height() )
        obj_c     = ( self.xcenter, self.ycenter, self.zcenter )
        win     = gluProject( obj_c[0], obj_c[1], obj_c[2])
        obj     = gluUnProject( win[0], win[1] + 0.5 * win_height, win[2])
        dist       = math.sqrt( v3distsq( obj, obj_c ) )
        scale     = abs( dist / ( 0.5 * win_height ) )

        glTranslateScene(self, scale, x, y, self.xmouse, self.ymouse)
        # keep track of all translations since view reset
        self._totalx = self._totalx + (x - self.xmouse)
        self._totaly = self._totaly - (self.ymouse - y)

        self._redraw()
        self.recordMouse(x, y)


    def set_viewangle(self, lat, lon, forcerotate=0):
        self.lat = lat
        self.lon = lon
        if forcerotate or self.perspective:
            glRotateScene(self, 0.5, self.xcenter, self.ycenter, self.zcenter, 0, 0, 0, 0)
        self._redraw()

    def get_viewangle(self):
        return self.lat, self.lon

    def get_zoom_distance(self):
        data = self.distance
        return data

    def set_zoom_distance(self,data):
        self.distance = data
        self._redraw()

    def zoomin(self):
        self.distance = self.distance / 1.1
        self._redraw()

    def zoomout(self):
        self.distance = self.distance * 1.1
        self._redraw()

    def startZoom(self, y):
        self.y0 = y
        self.original_zoom = self.distance

    def continueZoom(self, y):
        dy = y - self.y0
        self.distance = self.original_zoom * pow(1.25, dy / 16.)
        self._redraw()

    def getRotateMode(self): return False

    def translateOrRotate(self, x, y):
        if self.getRotateMode():
            self.rotate(x, y)
        else:
            self.translate(x, y)

    def rotateOrTranslate(self, x, y):
        if not self.getRotateMode():
            self.rotate(x, y)
        else:
            self.translate(x, y)

    # can be used to get current view position
    def get_total_translation(self):
        return self._totalx, self._totaly

    def set_view_x(self):
        self.reset()
        glRotatef(-90, 0, 1, 0)
        glRotatef(-90, 1, 0, 0)
        mid, size = self.extents_info()
        glTranslatef(-mid[0], -mid[1], -mid[2])
        self.set_eyepoint_from_extents(size[1], size[2])
        self.perspective = False
        self.lat = -90
        self.lon = 270
        self._redraw()

    def set_view_y(self):
        self.reset()
        glRotatef(-90, 1, 0, 0)
        if self.is_lathe():
            glRotatef(90, 0, 1, 0)
        mid, size = self.extents_info()
        glTranslatef(-mid[0], -mid[1], -mid[2])
        self.set_eyepoint_from_extents(size[0], size[2])
        self.perspective = False
        self.lat = -90
        self.lon = 0
        self._redraw()

        # lathe backtool display
    def set_view_y2(self):
        self.reset()
        glRotatef(90, 1, 0, 0)
        glRotatef(90, 0, 1, 0)
        mid, size = self.extents_info()
        glTranslatef(-mid[0], -mid[1], -mid[2])
        self.set_eyepoint_from_extents(size[0], size[2])
        self.perspective = False
        self.lat = -90
        self.lon = 0
        self._redraw()

    def set_view_z(self):
        self.reset()
        mid, size = self.extents_info()
        glTranslatef(-mid[0], -mid[1], -mid[2])
        self.set_eyepoint_from_extents(size[0], size[1])
        self.perspective = False
        self.lat = self.lon = 0
        self._redraw()

    def set_view_z2(self):
        self.reset()
        glRotatef(-90, 0, 0, 1)
        mid, size = self.extents_info()
        glTranslatef(-mid[0], -mid[1], -mid[2])
        self.set_eyepoint_from_extents(size[1], size[0])
        self.perspective = False
        self.lat = 0
        self.lon = 270
        self._redraw()

    def set_view_p(self):
        self.reset()
        self.perspective = True
        mid, size = self.extents_info()
        glTranslatef(-mid[0], -mid[1], -mid[2])
        size = (size[0] ** 2 + size[1] ** 2 + size[2] ** 2) ** .5
        if size > 1e99: size = 5. # in case there are no moves in the preview
        w = self.winfo_width()
        h = self.winfo_height()
        fovx = self.fovy if h == 0 else self.fovy * w / h
        fov = min(fovx, self.fovy)
        self.set_eyepoint((size * 1.1 + 1.0) / 2 / math.sin ( fov * math.pi / 180 / 2))
        self.lat = -60
        self.lon = 335
        glRotateScene(self, 1.0, mid[0], mid[1], mid[2], 0, 0, 0, 0)
        self._redraw()

# vim:ts=8:sts=4:sw=4:et: