# <pep8-80 compliant>

# ##### BEGIN GPL LICENSE BLOCK #####
#
#  This program is free software; you can redistribute it and/or
#  modify it under the terms of the GNU General Public License
#  as published by the Free Software Foundation; either version 2
#  of the License, or (at your option) any later version.
#
#  This program is distributed in the hope that it will be useful,
#  but WITHOUT ANY WARRANTY; without even the implied warranty of
#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#  GNU General Public License for more details.
#
#  You should have received a copy of the GNU General Public License
#  along with this program; if not, write to the Free Software Foundation,
#  Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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# ##### END GPL LICENSE BLOCK #####

__author__ = "Keith (Wahooney) Boshoff, Nutti <nutti.metro@gmail.com>"
__status__ = "production"
__version__ = "4.4"
__date__ = "2 Aug 2017"

import bpy
from bpy.props import (
        EnumProperty,
        FloatProperty,
        )
import bmesh
from mathutils import Vector
from . import muv_common


class MUV_MirrorUV(bpy.types.Operator):
    """
    Operation class: Mirror UV
    """

    bl_idname = "uv.muv_mirror_uv"
    bl_label = "Mirror UV"
    bl_options = {'REGISTER', 'UNDO'}

    axis = EnumProperty(
        items=(
            ('X', "X", "Mirror Along X axis"),
            ('Y', "Y", "Mirror Along Y axis"),
            ('Z', "Z", "Mirror Along Z axis")
        ),
        name="Axis",
        description="Mirror Axis",
        default='X'
    )
    error = FloatProperty(
        name="Error",
        description="Error threshold",
        default=0.001,
        min=0.0,
        max=100.0,
        soft_min=0.0,
        soft_max=1.0
    )

    def __is_vector_similar(self, v1, v2, error):
        """
        Check if two vectors are similar, within an error threshold
        """
        within_err_x = abs(v2.x - v1.x) < error
        within_err_y = abs(v2.y - v1.y) < error
        within_err_z = abs(v2.z - v1.z) < error

        return within_err_x and within_err_y and within_err_z

    def __mirror_uvs(self, uv_layer, src, dst, axis, error):
        """
        Copy UV coordinates from one UV face to another
        """
        for sl in src.loops:
            suv = sl[uv_layer].uv.copy()
            svco = sl.vert.co.copy()
            for dl in dst.loops:
                dvco = dl.vert.co.copy()
                if axis == 'X':
                    dvco.x = -dvco.x
                elif axis == 'Y':
                    dvco.y = -dvco.y
                elif axis == 'Z':
                    dvco.z = -dvco.z

                if self.__is_vector_similar(svco, dvco, error):
                    dl[uv_layer].uv = suv.copy()

    def __get_face_center(self, face):
        """
        Get center coordinate of the face
        """
        center = Vector((0.0, 0.0, 0.0))
        for v in face.verts:
            center = center + v.co

        return center / len(face.verts)

    @classmethod
    def poll(cls, context):
        obj = context.active_object
        return obj and obj.type == 'MESH'

    def execute(self, context):
        obj = context.active_object
        bm = bmesh.from_edit_mesh(obj.data)

        error = self.error
        axis = self.axis

        if muv_common.check_version(2, 73, 0) >= 0:
            bm.faces.ensure_lookup_table()
        if not bm.loops.layers.uv:
            self.report({'WARNING'}, "Object must have more than one UV map")
            return {'CANCELLED'}
        uv_layer = bm.loops.layers.uv.verify()

        faces = [f for f in bm.faces if f.select]
        for f_dst in faces:
            count = len(f_dst.verts)
            for f_src in bm.faces:
                # check if this is a candidate to do mirror UV
                if f_src.index == f_dst.index:
                    continue
                if count != len(f_src.verts):
                    continue

                # test if the vertices x values are the same sign
                dst = self.__get_face_center(f_dst)
                src = self.__get_face_center(f_src)
                if (dst.x > 0 and src.x > 0) or (dst.x < 0 and src.x < 0):
                    continue

                # invert source axis
                if axis == 'X':
                    src.x = -src.x
                elif axis == 'Y':
                    src.y = -src.z
                elif axis == 'Z':
                    src.z = -src.z

                # do mirror UV
                if self.__is_vector_similar(dst, src, error):
                    self.__mirror_uvs(
                        uv_layer, f_src, f_dst, self.axis, self.error)

        bmesh.update_edit_mesh(obj.data)

        return {'FINISHED'}