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#
#  This program is free software; you can redistribute it and/or
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#  as published by the Free Software Foundation; either version 2
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#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#  GNU General Public License for more details.
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#  along with this program; if not, write to the Free Software Foundation,
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# ##### END GPL LICENSE BLOCK #####

# <pep8-80 compliant>

import bpy
from bpy.types import Operator

from bpy.props import EnumProperty


class MeshMirrorUV(Operator):
    '''Copy mirror UV coordinates on the X axis based on a mirrored mesh'''
    bl_idname = "mesh.faces_mirror_uv"
    bl_label = "Copy Mirrored UV coords"
    bl_options = {'REGISTER', 'UNDO'}

    direction = EnumProperty(
            name="Axis Direction",
            items=(('POSITIVE', "Positive", ""),
                   ('NEGATIVE', "Negative", "")),
            )

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

    def execute(self, context):
        DIR = (self.direction == 'NEGATIVE')

        ob = context.active_object
        is_editmode = (ob.mode == 'EDIT')
        if is_editmode:
            bpy.ops.object.mode_set(mode='OBJECT', toggle=False)

        mesh = ob.data

        # mirror lookups
        mirror_gt = {}
        mirror_lt = {}

        vcos = (v.co.to_tuple(5) for v in mesh.vertices)

        for i, co in enumerate(vcos):
            if co[0] > 0.0:
                mirror_gt[co] = i
            elif co[0] < 0.0:
                mirror_lt[co] = i
            else:
                mirror_gt[co] = i
                mirror_lt[co] = i

        #for i, v in enumerate(mesh.vertices):
        vmap = {}
        for mirror_a, mirror_b in ((mirror_gt, mirror_lt),
                                   (mirror_lt, mirror_gt)):
            for co, i in mirror_a.items():
                nco = (-co[0], co[1], co[2])
                j = mirror_b.get(nco)
                if j is not None:
                    vmap[i] = j

        polys = mesh.polygons
        loops = mesh.loops
        verts = mesh.vertices
        uv_loops = mesh.uv_layers.active.data
        nbr_polys = len(polys)

        mirror_pm = {}
        pmap = {}
        puvs = [None] * nbr_polys
        puvs_cpy = [None] * nbr_polys
        puvsel = [None] * nbr_polys
        pcents = [None] * nbr_polys
        vidxs = [None] * nbr_polys
        for i, p in enumerate(polys):
            lstart = lend = p.loop_start
            lend += p.loop_total
            puvs[i] = tuple(uv.uv for uv in uv_loops[lstart:lend])
            puvs_cpy[i] = tuple(uv.copy() for uv in puvs[i])
            puvsel[i] = (False not in
                               (uv.select for uv in uv_loops[lstart:lend]))
            # Vert idx of the poly.
            vidxs[i] = tuple(sorted(l.vertex_index
                                    for l in loops[lstart:lend]))
            # As we have no poly.center yet...
            pcents[i] = tuple(map(lambda x: x / p.loop_total,
                                  map(sum, zip(*(verts[idx].co
                                                 for idx in vidxs[i])))))
            # Preparing next step finding matching polys.
            mirror_pm[vidxs[i]] = i

        for i in range(nbr_polys):
            # Find matching mirror poly.
            tvidxs = [vmap.get(j) for j in vidxs[i]]
            if None not in tvidxs:
                tvidxs.sort()
                j = mirror_pm.get(tuple(tvidxs))
                if j is not None:
                    pmap[i] = j

        for i, j in pmap.items():
            if not puvsel[i] or not puvsel[j]:
                continue
            elif DIR == 0 and pcents[i][0] < 0.0:
                continue
            elif DIR == 1 and pcents[i][0] > 0.0:
                continue

            # copy UVs
            uv1 = puvs[i]
            uv2 = puvs_cpy[j]

            # get the correct rotation
            v1 = vidxs[j]
            v2 = tuple(vmap[k] for k in vidxs[i])

            if len(v1) == len(v2):
                for k in range(len(v1)):
                    k_map = v1.index(v2[k])
                    uv1[k].xy = - (uv2[k_map].x - 0.5) + 0.5, uv2[k_map].y

        if is_editmode:
            bpy.ops.object.mode_set(mode='EDIT', toggle=False)

        return {'FINISHED'}
