# Copyright (c) 2019 Ultimaker B.V.
# Cura is released under the terms of the LGPLv3 or higher.
import numpy

from typing import Optional, cast

from UM.Qt.Bindings.Theme import Theme
from UM.Qt.QtApplication import QtApplication
from UM.Logger import Logger


class LayerPolygon:
    NoneType = 0
    Inset0Type = 1
    InsetXType = 2
    SkinType = 3
    SupportType = 4
    SkirtType = 5
    InfillType = 6
    SupportInfillType = 7
    MoveCombingType = 8
    MoveRetractionType = 9
    SupportInterfaceType = 10
    PrimeTowerType = 11
    __number_of_types = 12

    __jump_map = numpy.logical_or(numpy.logical_or(numpy.arange(__number_of_types) == NoneType, numpy.arange(__number_of_types) == MoveCombingType), numpy.arange(__number_of_types) == MoveRetractionType)

    def __init__(self, extruder: int, line_types: numpy.ndarray, data: numpy.ndarray, line_widths: numpy.ndarray, line_thicknesses: numpy.ndarray, line_feedrates: numpy.ndarray) -> None:
        """LayerPolygon, used in ProcessSlicedLayersJob

        :param extruder: The position of the extruder
        :param line_types: array with line_types
        :param data: new_points
        :param line_widths: array with line widths
        :param line_thicknesses: array with type as index and thickness as value
        :param line_feedrates: array with line feedrates
        """

        self._extruder = extruder
        self._types = line_types
        for i in range(len(self._types)):
            if self._types[i] >= self.__number_of_types: # Got faulty line data from the engine.
                Logger.log("w", "Found an unknown line type: %s", i)
                self._types[i] = self.NoneType
        self._data = data
        self._line_widths = line_widths
        self._line_thicknesses = line_thicknesses
        self._line_feedrates = line_feedrates

        self._vertex_begin = 0
        self._vertex_end = 0
        self._index_begin = 0
        self._index_end = 0

        self._jump_mask = self.__jump_map[self._types]
        self._jump_count = numpy.sum(self._jump_mask)
        self._cumulative_type_change_counts = numpy.zeros(len(self._types))  # See the comment on the 'cumulativeTypeChangeCounts' property below.
        last_type = self.types[0]
        current_type_count = 0
        for i in range(0, len(self._cumulative_type_change_counts)):
            if last_type != self.types[i]:
                current_type_count += 1
                last_type = self.types[i]
            self._cumulative_type_change_counts[i] = current_type_count
        self._mesh_line_count = len(self._types) - self._jump_count
        self._vertex_count = self._mesh_line_count + numpy.sum(self._types[1:] == self._types[:-1])

        # Buffering the colors shouldn't be necessary as it is not 
        # re-used and can save a lot of memory usage.
        self._color_map = LayerPolygon.getColorMap()
        self._colors = self._color_map[self._types]  # type: numpy.ndarray

        # When type is used as index returns true if type == LayerPolygon.InfillType or type == LayerPolygon.SkinType or type == LayerPolygon.SupportInfillType
        # Should be generated in better way, not hardcoded.
        self._is_infill_or_skin_type_map = numpy.array([0, 0, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0], dtype = bool)

        self._build_cache_line_mesh_mask = None  # type: Optional[numpy.ndarray]
        self._build_cache_needed_points = None  # type: Optional[numpy.ndarray]

    def buildCache(self) -> None:
        # For the line mesh we do not draw Infill or Jumps. Therefore those lines are filtered out.
        self._build_cache_line_mesh_mask = numpy.ones(self._jump_mask.shape, dtype = bool)
        self._index_begin = 0
        self._index_end = cast(int, numpy.sum(self._build_cache_line_mesh_mask))

        self._build_cache_needed_points = numpy.ones((len(self._types), 2), dtype = bool)
        # Only if the type of line segment changes do we need to add an extra vertex to change colors
        self._build_cache_needed_points[1:, 0][:, numpy.newaxis] = self._types[1:] != self._types[:-1]
        # Mark points as unneeded if they are of types we don't want in the line mesh according to the calculated mask
        numpy.logical_and(self._build_cache_needed_points, self._build_cache_line_mesh_mask, self._build_cache_needed_points )

        self._vertex_begin = 0
        self._vertex_end = cast(int, numpy.sum(self._build_cache_needed_points))

    def build(self, vertex_offset: int, index_offset: int, vertices: numpy.ndarray, colors: numpy.ndarray, line_dimensions: numpy.ndarray, feedrates: numpy.ndarray, extruders: numpy.ndarray, line_types: numpy.ndarray, indices: numpy.ndarray) -> None:
        """Set all the arrays provided by the function caller, representing the LayerPolygon

        The arrays are either by vertex or by indices.

        :param vertex_offset: determines where to start and end filling the arrays
        :param index_offset: determines where to start and end filling the arrays
        :param vertices: vertex numpy array to be filled
        :param colors: vertex numpy array to be filled
        :param line_dimensions: vertex numpy array to be filled
        :param feedrates: vertex numpy array to be filled
        :param extruders: vertex numpy array to be filled
        :param line_types: vertex numpy array to be filled
        :param indices: index numpy array to be filled
        """

        if self._build_cache_line_mesh_mask is None or self._build_cache_needed_points is None:
            self.buildCache()

        if self._build_cache_line_mesh_mask is None or self._build_cache_needed_points is None:
            Logger.log("w", "Failed to build cache for layer polygon")
            return

        line_mesh_mask = self._build_cache_line_mesh_mask
        needed_points_list = self._build_cache_needed_points

        # Index to the points we need to represent the line mesh. This is constructed by generating simple
        # start and end points for each line. For line segment n these are points n and n+1. Row n reads [n n+1] 
        # Then then the indices for the points we don't need are thrown away based on the pre-calculated list. 
        index_list = ( numpy.arange(len(self._types)).reshape((-1, 1)) + numpy.array([[0, 1]]) ).reshape((-1, 1))[needed_points_list.reshape((-1, 1))]

        # The relative values of begin and end indices have already been set in buildCache, so we only need to offset them to the parents offset.
        self._vertex_begin += vertex_offset
        self._vertex_end += vertex_offset

        # Points are picked based on the index list to get the vertices needed. 
        vertices[self._vertex_begin:self._vertex_end, :] = self._data[index_list, :]

        # Create an array with colors for each vertex and remove the color data for the points that has been thrown away. 
        colors[self._vertex_begin:self._vertex_end, :] = numpy.tile(self._colors, (1, 2)).reshape((-1, 4))[needed_points_list.ravel()]

        # Create an array with line widths and thicknesses for each vertex.
        line_dimensions[self._vertex_begin:self._vertex_end, 0] = numpy.tile(self._line_widths, (1, 2)).reshape((-1, 1))[needed_points_list.ravel()][:, 0]
        line_dimensions[self._vertex_begin:self._vertex_end, 1] = numpy.tile(self._line_thicknesses, (1, 2)).reshape((-1, 1))[needed_points_list.ravel()][:, 0]

        # Create an array with feedrates for each line
        feedrates[self._vertex_begin:self._vertex_end] = numpy.tile(self._line_feedrates, (1, 2)).reshape((-1, 1))[needed_points_list.ravel()][:, 0]

        extruders[self._vertex_begin:self._vertex_end] = self._extruder

        # Convert type per vertex to type per line
        line_types[self._vertex_begin:self._vertex_end] = numpy.tile(self._types, (1, 2)).reshape((-1, 1))[needed_points_list.ravel()][:, 0]

        # The relative values of begin and end indices have already been set in buildCache, so we only need to offset them to the parents offset.
        self._index_begin += index_offset
        self._index_end += index_offset

        indices[self._index_begin:self._index_end, :] = numpy.arange(self._index_end-self._index_begin, dtype = numpy.int32).reshape((-1, 1))
        # When the line type changes the index needs to be increased by 2.
        indices[self._index_begin:self._index_end, :] += numpy.cumsum(needed_points_list[line_mesh_mask.ravel(), 0], dtype = numpy.int32).reshape((-1, 1))
        # Each line segment goes from it's starting point p to p+1, offset by the vertex index. 
        # The -1 is to compensate for the necessarily True value of needed_points_list[0,0] which causes an unwanted +1 in cumsum above.
        indices[self._index_begin:self._index_end, :] += numpy.array([self._vertex_begin - 1, self._vertex_begin])

        self._build_cache_line_mesh_mask = None
        self._build_cache_needed_points = None

    def getColors(self):
        return self._colors

    def mapLineTypeToColor(self, line_types: numpy.ndarray) -> numpy.ndarray:
        return self._color_map[line_types]

    def isInfillOrSkinType(self, line_types: numpy.ndarray) -> numpy.ndarray:
        return self._is_infill_or_skin_type_map[line_types]

    def lineMeshVertexCount(self) -> int:
        return self._vertex_end - self._vertex_begin

    def lineMeshElementCount(self) -> int:
        return self._index_end - self._index_begin

    @property
    def extruder(self):
        return self._extruder

    @property
    def types(self):
        return self._types

    @property
    def data(self):
        return self._data

    @property
    def vertexCount(self):
        return self._vertex_end - self._vertex_begin

    @property
    def elementCount(self):
        return (self._index_end - self._index_begin) * 2  # The range of vertices multiplied by 2 since each vertex is used twice

    @property
    def lineWidths(self):
        return self._line_widths

    @property
    def lineThicknesses(self):
        return self._line_thicknesses

    @property
    def lineFeedrates(self):
        return self._line_feedrates

    @property
    def jumpMask(self):
        return self._jump_mask

    @property
    def meshLineCount(self):
        return self._mesh_line_count

    @property
    def jumpCount(self):
        return self._jump_count

    @property
    def cumulativeTypeChangeCounts(self):
        """ This polygon class stores with a vertex the type of the line to the next vertex. However, in other contexts,
        other ways of representing this might be more suited to the task (for example, when a vertex can possibly only
        have _one_ type, it's unavoidable to duplicate vertices when the type is changed). In such situations it's might
        be useful to know how many times the type has changed, in order to keep the various vertex-indices aligned.

        :return: The total times the line-type changes from one type to another within this LayerPolygon.
        """
        return self._cumulative_type_change_counts

    def getNormals(self) -> numpy.ndarray:
        """Calculate normals for the entire polygon using numpy.

        :return: normals for the entire polygon
        """

        normals = numpy.copy(self._data)
        normals[:, 1] = 0.0 # We are only interested in 2D normals

        # Calculate the edges between points.
        # The call to numpy.roll shifts the entire array by one so that
        # we end up subtracting each next point from the current, wrapping
        # around. This gives us the edges from the next point to the current
        # point.
        normals = numpy.diff(normals, 1, 0)

        # Calculate the length of each edge using standard Pythagoras
        lengths = numpy.sqrt(normals[:, 0] ** 2 + normals[:, 2] ** 2)
        # The normal of a 2D vector is equal to its x and y coordinates swapped
        # and then x inverted. This code does that.
        normals[:, [0, 2]] = normals[:, [2, 0]]
        normals[:, 0] *= -1

        # Normalize the normals.
        normals[:, 0] /= lengths
        normals[:, 2] /= lengths

        return normals

    __color_map = None  # type: numpy.ndarray

    @classmethod
    def getColorMap(cls) -> numpy.ndarray:
        """Gets the instance of the VersionUpgradeManager, or creates one."""

        if cls.__color_map is None:
            theme = cast(Theme, QtApplication.getInstance().getTheme())
            cls.__color_map = numpy.array([
                theme.getColor("layerview_none").getRgbF(), # NoneType
                theme.getColor("layerview_inset_0").getRgbF(), # Inset0Type
                theme.getColor("layerview_inset_x").getRgbF(), # InsetXType
                theme.getColor("layerview_skin").getRgbF(), # SkinType
                theme.getColor("layerview_support").getRgbF(), # SupportType
                theme.getColor("layerview_skirt").getRgbF(), # SkirtType
                theme.getColor("layerview_infill").getRgbF(), # InfillType
                theme.getColor("layerview_support_infill").getRgbF(), # SupportInfillType
                theme.getColor("layerview_move_combing").getRgbF(), # MoveCombingType
                theme.getColor("layerview_move_retraction").getRgbF(), # MoveRetractionType
                theme.getColor("layerview_support_interface").getRgbF(),  # SupportInterfaceType
                theme.getColor("layerview_prime_tower").getRgbF()   # PrimeTowerType
            ])

        return cls.__color_map