from vispy.visuals import CompoundVisual, LineVisual, MeshVisual
from vispy.scene.visuals import create_visual_node
from vispy.gloo import set_state
from vispy.color import Color
from shapely.geometry import Polygon, LineString, LinearRing
from multiprocessing import Pool
import threading
import numpy as np
from VisPyTesselators import GLUTess


def _update_shape_buffers(data, triangulation='glu'):
    """
    Translates Shapely geometry to internal buffers for speedup redraws
    :param data: dict
        Input shape data
    :param triangulation: str
        Triangulation engine
    """
    mesh_vertices = []                                              # Vertices for mesh
    mesh_tris = []                                                  # Faces for mesh
    mesh_colors = []                                                # Face colors
    line_pts = []                                                   # Vertices for line
    line_colors = []                                                # Line color

    geo, color, face_color, tolerance = data['geometry'], data['color'], data['face_color'], data['tolerance']

    if geo is not None and not geo.is_empty:
        simple = geo.simplify(tolerance) if tolerance else geo      # Simplified shape
        pts = []                                                    # Shape line points
        tri_pts = []                                                # Mesh vertices
        tri_tris = []                                               # Mesh faces

        if type(geo) == LineString:
            # Prepare lines
            pts = _linestring_to_segments(list(simple.coords))

        elif type(geo) == LinearRing:
            # Prepare lines
            pts = _linearring_to_segments(list(simple.coords))

        elif type(geo) == Polygon:
            # Prepare polygon faces
            if face_color is not None:
                if triangulation == 'glu':
                    gt = GLUTess()
                    tri_tris, tri_pts = gt.triangulate(simple)
                else:
                    print "Triangulation type '%s' isn't implemented. Drawing only edges." % triangulation

            # Prepare polygon edges
            if color is not None:
                pts = _linearring_to_segments(list(simple.exterior.coords))
                for ints in simple.interiors:
                    pts += _linearring_to_segments(list(ints.coords))

        # Appending data for mesh
        if len(tri_pts) > 0 and len(tri_tris) > 0:
            mesh_tris += tri_tris
            mesh_vertices += tri_pts
            mesh_colors += [Color(face_color).rgba] * (len(tri_tris) / 3)

        # Appending data for line
        if len(pts) > 0:
            line_pts += pts
            line_colors += [Color(color).rgba] * len(pts)

    # Store buffers
    data['line_pts'] = line_pts
    data['line_colors'] = line_colors
    data['mesh_vertices'] = mesh_vertices
    data['mesh_tris'] = mesh_tris
    data['mesh_colors'] = mesh_colors

    # Clear shapely geometry
    del data['geometry']

    return data


def _linearring_to_segments(arr):
    # Close linear ring
    """
    Translates linear ring to line segments
    :param arr: numpy.array
        Array of linear ring vertices
    :return: numpy.array
        Line segments
    """
    if arr[0] != arr[-1]:
        arr.append(arr[0])

    return _linestring_to_segments(arr)


def _linestring_to_segments(arr):
    """
    Translates line strip to segments
    :param arr: numpy.array
        Array of line strip vertices
    :return: numpy.array
        Line segments
    """
    return [arr[i / 2] for i in range(0, len(arr) * 2)][1:-1]


class ShapeGroup(object):
    def __init__(self, collection):
        """
        Represents group of shapes in collection
        :param collection: ShapeCollection
            Collection to work with
        """
        self._collection = collection
        self._indexes = []
        self._results = {}
        self._visible = True

    def add(self, **kwargs):
        """
        Adds shape to collection and store index in group
        :param kwargs: keyword arguments
            Arguments for ShapeCollection.add function
        """
        self._indexes.append(self._collection.add(**kwargs))

    def clear(self, update=False):
        """
        Removes group shapes from collection, clear indexes
        :param update: bool
            Set True to redraw collection
        """
        for i in self._indexes:
            self._collection.remove(i, False)

        del self._indexes[:]

        if update:
            self._collection.redraw([])             # Skip waiting results

    def redraw(self):
        """
        Redraws shape collection
        """
        self._collection.redraw(self._indexes)

    @property
    def visible(self):
        """
        Visibility of group
        :return: bool
        """
        return self._visible

    @visible.setter
    def visible(self, value):
        """
        Visibility of group
        :param value: bool
        """
        self._visible = value
        for i in self._indexes:
            self._collection.data[i]['visible'] = value

        self._collection.redraw([])


class ShapeCollectionVisual(CompoundVisual):

    # Shared multiprocessing pool
    pool = None

    def __init__(self, line_width=1, triangulation='gpc', layers=3, **kwargs):
        """
        Represents collection of shapes to draw on VisPy scene
        :param line_width: float
            Width of lines/edges
        :param triangulation: str
            Triangulation method used for polygons translation
            'vispy' - VisPy lib triangulation
            'gpc' - Polygon2 lib
        :param layers: int
            Layers count
            Each layer adds 2 visuals on VisPy scene. Be careful: more layers cause less fps
        :param kwargs:
        """
        self.data = {}
        self.last_key = -1
        self.lock = threading.Lock()
        if not ShapeCollection.pool:
            ShapeCollection.pool = Pool()
        self.results = {}

        self._meshes = [MeshVisual() for _ in range(0, layers)]
        self._lines = [LineVisual(antialias=True) for _ in range(0, layers)]

        self._line_width = line_width
        self._triangulation = triangulation

        visuals = [self._lines[i / 2] if i % 2 else self._meshes[i / 2] for i in range(0, layers * 2)]

        CompoundVisual.__init__(self, visuals, **kwargs)

        for m in self._meshes:
            pass
            m.set_gl_state(polygon_offset_fill=True, polygon_offset=(1, 1), cull_face=False)

        for l in self._lines:
            pass
            l.set_gl_state(blend=True)

        self.freeze()

    def add(self, shape=None, color=None, face_color=None, visible=True, update=False, layer=1, tolerance=0.01):
        """
        Adds shape to collection
        :return:
        :param shape: shapely.geometry
            Shapely geometry object
        :param color: str, tuple
            Line/edge color
        :param face_color: str, tuple
            Polygon face color
        :param visible: bool
            Shape visibility
        :param update: bool
            Set True to redraw collection
        :param layer: int
            Layer number. 0 - lowest.
        :param tolerance: float
            Geometry simplifying tolerance
        :return: int
            Index of shape
        """
        # Get new key
        self.lock.acquire(True)
        self.last_key += 1
        key = self.last_key
        self.lock.release()

        # Prepare data for translation
        self.data[key] = {'geometry': shape, 'color': color, 'face_color': face_color,
                          'visible': visible, 'layer': layer, 'tolerance': tolerance}

        # Add data to process pool
        self.results[key] = self.pool.apply_async(_update_shape_buffers, [self.data[key]])

        if update:
            self.redraw()                       # redraw() waits for pool process end

        return key

    def remove(self, key, update=False):
        """
        Removes shape from collection
        :param key: int
            Shape index to remove
        :param update:
            Set True to redraw collection
        """
        del self.results[key]
        del self.data[key]

        if update:
            self.__update()

    def clear(self, update=False):
        """
        Removes all shapes from colleciton
        :param update: bool
            Set True to redraw collection
        """
        self.data.clear()
        if update:
            self.__update()

    def __update(self):
        """
        Merges internal buffers, sets data to visuals, redraws collection on scene
        """
        mesh_vertices = [[] for _ in range(0, len(self._meshes))]       # Vertices for mesh
        mesh_tris = [[] for _ in range(0, len(self._meshes))]           # Faces for mesh
        mesh_colors = [[] for _ in range(0, len(self._meshes))]         # Face colors
        line_pts = [[] for _ in range(0, len(self._lines))]             # Vertices for line
        line_colors = [[] for _ in range(0, len(self._lines))]          # Line color

        # Merge shapes buffers
        for data in self.data.values():
            if data['visible'] and 'line_pts' in data:
                try:
                    line_pts[data['layer']] += data['line_pts']
                    line_colors[data['layer']] += data['line_colors']
                    mesh_tris[data['layer']] += [x + len(mesh_vertices[data['layer']])
                                                 for x in data['mesh_tris']]

                    mesh_vertices[data['layer']] += data['mesh_vertices']
                    mesh_colors[data['layer']] += data['mesh_colors']
                except Exception as e:
                    print "Data error", e

        # Updating meshes
        for i, mesh in enumerate(self._meshes):
            if len(mesh_vertices[i]) > 0:
                set_state(polygon_offset_fill=False)
                mesh.set_data(np.asarray(mesh_vertices[i]), np.asarray(mesh_tris[i], dtype=np.uint32)
                              .reshape((-1, 3)), face_colors=np.asarray(mesh_colors[i]))
            else:
                mesh.set_data()

            mesh._bounds_changed()

        # Updating lines
        for i, line in enumerate(self._lines):
            if len(line_pts[i]) > 0:
                line.set_data(np.asarray(line_pts[i]), np.asarray(line_colors[i]), self._line_width, 'segments')
            else:
                line.clear_data()

            line._bounds_changed()

        self._bounds_changed()

    def redraw(self, indexes=None):
        """
        Redraws collection
        :param indexes: list
            Shape indexes to get from process pool
        """
        for i in self.data.keys() if not indexes else indexes:
            try:
                self.results[i].wait()                              # Wait for process results
                if i in self.data:
                    self.data[i] = self.results[i].get()            # Store translated data
            except Exception as e:
                print e

        self.__update()


ShapeCollection = create_visual_node(ShapeCollectionVisual)