# Copyright (c) 2019-2020 Manfred Moitzi
# License: MIT License
from typing import TYPE_CHECKING, Iterable
from ezdxf.math import Vec3, Matrix44, linspace, ConstructionArc, Vertex
from ezdxf.math.transformtools import OCSTransform

from ezdxf.lldxf.attributes import (
    DXFAttr, DXFAttributes, DefSubclass, group_code_mapping
)
from ezdxf.lldxf.const import DXF12, SUBCLASS_MARKER
from .dxfentity import base_class, SubclassProcessor
from .dxfgfx import acdb_entity
from .circle import acdb_circle, Circle
from .factory import register_entity

if TYPE_CHECKING:
    from ezdxf.eztypes import TagWriter, DXFNamespace, Vec3

__all__ = ['Arc']

acdb_arc = DefSubclass('AcDbArc', {
    'start_angle': DXFAttr(50, default=0),
    'end_angle': DXFAttr(51, default=360),
})

acdb_arc_group_codes = group_code_mapping(acdb_arc)


@register_entity
class Arc(Circle):
    """ DXF ARC entity """
    DXFTYPE = 'ARC'
    DXFATTRIBS = DXFAttributes(base_class, acdb_entity, acdb_circle, acdb_arc)

    def load_dxf_attribs(
            self, processor: SubclassProcessor = None) -> 'DXFNamespace':
        dxf = super().load_dxf_attribs(processor)
        if processor:
            processor.fast_load_dxfattribs(
                dxf, acdb_arc_group_codes, subclass=3, recover=True)
        return dxf

    def export_entity(self, tagwriter: 'TagWriter') -> None:
        """ Export entity specific data as DXF tags. """
        super().export_entity(tagwriter)
        # AcDbEntity export is done by parent class
        # AcDbCircle export is done by parent class
        if tagwriter.dxfversion > DXF12:
            tagwriter.write_tag2(SUBCLASS_MARKER, acdb_arc.name)
        self.dxf.export_dxf_attribs(tagwriter, ['start_angle', 'end_angle'])

    @property
    def start_point(self) -> 'Vec3':
        """  Returns the start point of the arc in WCS, takes OCS into account.
        """
        v = list(self.vertices([self.dxf.start_angle]))
        return v[0]

    @property
    def end_point(self) -> 'Vec3':
        """ Returns the end point of the arc in WCS, takes OCS into account.
        """
        v = list(self.vertices([self.dxf.end_angle]))
        return v[0]

    def angles(self, num: int) -> Iterable[float]:
        """ Returns `num` angles from start- to end angle in degrees in counter
        clockwise order.

        All angles are normalized in the range from [0, 360).

        """
        if num < 2:
            raise ValueError('num >= 2')
        start = self.dxf.start_angle % 360
        stop = self.dxf.end_angle % 360
        if stop <= start:
            stop += 360
        for angle in linspace(start, stop, num=num, endpoint=True):
            yield angle % 360

    def flattening(self, sagitta: float) -> Iterable[Vertex]:
        """ Approximate the arc by vertices in WCS, argument `segment` is the
        max. distance from the center of an arc segment to the center of its
        chord. Yields :class:`~ezdxf.math.Vec2` objects for 2D arcs and
        :class:`~ezdxf.math.Vec3` objects for 3D arcs.

        .. versionadded:: 0.15

        """
        arc = self.construction_tool()
        to_wcs = self.ocs().points_to_wcs
        yield from to_wcs(arc.flattening(sagitta))

    def transform(self, m: Matrix44) -> 'Arc':
        """ Transform ARC entity by transformation matrix `m` inplace.

        Raises ``NonUniformScalingError()`` for non uniform scaling.

        .. versionadded:: 0.13

        """
        ocs = OCSTransform(self.dxf.extrusion, m)
        super().transform(m)
        self.dxf.start_angle = ocs.transform_deg_angle(self.dxf.start_angle)
        self.dxf.end_angle = ocs.transform_deg_angle(self.dxf.end_angle)
        return self

    def construction_tool(self) -> ConstructionArc:
        """
        Returns 2D construction tool :class:`ezdxf.math.ConstructionArc`,
        ignoring the extrusion vector.

        .. versionadded:: 0.14

        """
        dxf = self.dxf
        return ConstructionArc(
            dxf.center,
            dxf.radius,
            dxf.start_angle,
            dxf.end_angle,
        )

    def apply_construction_tool(self, arc: ConstructionArc) -> 'Arc':
        """
        Set ARC data from construction tool :class:`ezdxf.math.ConstructionArc`,
        will not change the extrusion vector.

        .. versionadded:: 0.14

        """
        dxf = self.dxf
        dxf.center = Vec3(arc.center)
        dxf.radius = arc.radius
        dxf.start_angle = arc.start_angle
        dxf.end_angle = arc.end_angle
        return self  # floating interface
