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#
#  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 #####

# <pep8 compliant>

import bpy
from mathutils import Vector


def align_objects(align_x, align_y, align_z, align_mode, relative_to):

    cursor = bpy.context.scene.cursor_location

    Left_Up_Front_SEL = [[], [], []]
    Right_Down_Back_SEL = [[], [], []]

    flag_first = True

    for obj in bpy.context.selected_objects:
        if obj.type == 'MESH':

            bb_world = [obj.matrix_world * Vector(v[:]) for v in obj.bound_box]

            Left_Up_Front = bb_world[1]
            Right_Down_Back = bb_world[7]

            # Active Center

            if obj == bpy.context.active_object:

                center_active_x = (Left_Up_Front[0] + Right_Down_Back[0]) / 2
                center_active_y = (Left_Up_Front[1] + Right_Down_Back[1]) / 2
                center_active_z = (Left_Up_Front[2] + Right_Down_Back[2]) / 2

                size_active_x = (Right_Down_Back[0] - Left_Up_Front[0]) / 2
                size_active_y = (Right_Down_Back[1] - Left_Up_Front[1]) / 2
                size_active_z = (Left_Up_Front[2] - Right_Down_Back[2]) / 2

            # Selection Center

            if flag_first:
                flag_first = False

                Left_Up_Front_SEL[0] = Left_Up_Front[0]
                Left_Up_Front_SEL[1] = Left_Up_Front[1]
                Left_Up_Front_SEL[2] = Left_Up_Front[2]

                Right_Down_Back_SEL[0] = Right_Down_Back[0]
                Right_Down_Back_SEL[1] = Right_Down_Back[1]
                Right_Down_Back_SEL[2] = Right_Down_Back[2]

            else:
                # X axis
                if Left_Up_Front[0] < Left_Up_Front_SEL[0]:
                    Left_Up_Front_SEL[0] = Left_Up_Front[0]
                # Y axis
                if Left_Up_Front[1] < Left_Up_Front_SEL[1]:
                    Left_Up_Front_SEL[1] = Left_Up_Front[1]
                # Z axis
                if Left_Up_Front[2] > Left_Up_Front_SEL[2]:
                    Left_Up_Front_SEL[2] = Left_Up_Front[2]

                # X axis
                if Right_Down_Back[0] > Right_Down_Back_SEL[0]:
                    Right_Down_Back_SEL[0] = Right_Down_Back[0]
                # Y axis
                if Right_Down_Back[1] > Right_Down_Back_SEL[1]:
                    Right_Down_Back_SEL[1] = Right_Down_Back[1]
                # Z axis
                if Right_Down_Back[2] < Right_Down_Back_SEL[2]:
                    Right_Down_Back_SEL[2] = Right_Down_Back[2]

    center_sel_x = (Left_Up_Front_SEL[0] + Right_Down_Back_SEL[0]) / 2
    center_sel_y = (Left_Up_Front_SEL[1] + Right_Down_Back_SEL[1]) / 2
    center_sel_z = (Left_Up_Front_SEL[2] + Right_Down_Back_SEL[2]) / 2

    # Main Loop

    for obj in bpy.context.selected_objects:
        if obj.type == 'MESH':

            loc_world = obj.location
            bb_world = [obj.matrix_world * Vector(v[:]) for v in obj.bound_box]

            Left_Up_Front = bb_world[1]
            Right_Down_Back = bb_world[7]

            center_x = (Left_Up_Front[0] + Right_Down_Back[0]) / 2
            center_y = (Left_Up_Front[1] + Right_Down_Back[1]) / 2
            center_z = (Left_Up_Front[2] + Right_Down_Back[2]) / 2

            positive_x = Right_Down_Back[0]
            positive_y = Right_Down_Back[1]
            positive_z = Left_Up_Front[2]

            negative_x = Left_Up_Front[0]
            negative_y = Left_Up_Front[1]
            negative_z = Right_Down_Back[2]

            obj_loc = obj.location

            if align_x:

                # Align Mode

                if relative_to == 'OPT_4': # Active relative
                    if align_mode == 'OPT_1':
                        obj_x = obj_loc[0] - negative_x - size_active_x

                    elif align_mode == 'OPT_3':
                        obj_x = obj_loc[0] - positive_x + size_active_x

                else: # Everything else relative
                    if align_mode == 'OPT_1':
                        obj_x = obj_loc[0] - negative_x

                    elif align_mode == 'OPT_3':
                        obj_x = obj_loc[0] - positive_x

                if align_mode == 'OPT_2': # All relative
                    obj_x = obj_loc[0] - center_x

                # Relative To

                if relative_to == 'OPT_1':
                    loc_x = obj_x

                elif relative_to == 'OPT_2':
                    loc_x = obj_x + cursor[0]

                elif relative_to == 'OPT_3':
                    loc_x = obj_x + center_sel_x

                elif relative_to == 'OPT_4':
                    loc_x = obj_x + center_active_x

                obj.location[0] = loc_x


            if align_y:

                # Align Mode

                if relative_to == 'OPT_4': # Active relative
                    if align_mode == 'OPT_1':
                        obj_y = obj_loc[1] - negative_y - size_active_y

                    elif align_mode == 'OPT_3':
                        obj_y = obj_loc[1] - positive_y + size_active_y

                else: # Everything else relative
                    if align_mode == 'OPT_1':
                        obj_y = obj_loc[1] - negative_y

                    elif align_mode == 'OPT_3':
                        obj_y = obj_loc[1] - positive_y

                if align_mode == 'OPT_2': # All relative
                    obj_y = obj_loc[1] - center_y

                # Relative To

                if relative_to == 'OPT_1':
                    loc_y = obj_y

                elif relative_to == 'OPT_2':
                    loc_y = obj_y + cursor[1]

                elif relative_to == 'OPT_3':
                    loc_y = obj_y + center_sel_y

                elif relative_to == 'OPT_4':
                    loc_y = obj_y + center_active_y

                obj.location[1] = loc_y


            if align_z:

                # Align Mode

                if relative_to == 'OPT_4': # Active relative
                    if align_mode == 'OPT_1':
                        obj_z = obj_loc[2] - negative_z - size_active_z

                    elif align_mode == 'OPT_3':
                        obj_z = obj_loc[2] - positive_z + size_active_z

                else: # Everything else relative
                    if align_mode == 'OPT_1':
                        obj_z = obj_loc[2] - negative_z

                    elif align_mode == 'OPT_3':
                        obj_z = obj_loc[2] - positive_z

                if align_mode == 'OPT_2': # All relative
                    obj_z = obj_loc[2] - center_z

                # Relative To

                if relative_to == 'OPT_1':
                    loc_z = obj_z

                elif relative_to == 'OPT_2':
                    loc_z = obj_z + cursor[2]

                elif relative_to == 'OPT_3':
                    loc_z = obj_z + center_sel_z

                elif relative_to == 'OPT_4':
                    loc_z = obj_z + center_active_z

                obj.location[2] = loc_z


from bpy.props import *


class AlignObjects(bpy.types.Operator):
    '''Align Objects'''
    bl_idname = "object.align"
    bl_label = "Align Objects"
    bl_options = {'REGISTER', 'UNDO'}

    align_mode = bpy.props.EnumProperty(items=(
            ('OPT_1', "Negative Sides", ""),
            ('OPT_2', "Centers", ""),
            ('OPT_3', "Positive Sides", "")),
        name="Align Mode:",
        description="",
        default='OPT_2')

    relative_to = bpy.props.EnumProperty(items=(
            ('OPT_1', "Scene Origin", ""),
            ('OPT_2', "3D Cursor", ""),
            ('OPT_3', "Selection", ""),
            ('OPT_4', "Active", "")),
        name="Relative To:",
        description="",
        default='OPT_4')

    align_x = BoolProperty(name="Align X",
        description="Align in the X axis", default=False)

    align_y = BoolProperty(name="Align Y",
        description="Align in the Y axis", default=False)

    align_z = BoolProperty(name="Align Z",
        description="Align in the Z axis", default=False)

    @staticmethod
    def poll(context):
        return context.mode == 'OBJECT'

    def execute(self, context):

        align_mode = self.properties.align_mode
        relative_to = self.properties.relative_to
        align_x = self.properties.align_x
        align_y = self.properties.align_y
        align_z = self.properties.align_z

        align_objects(align_x, align_y, align_z, align_mode, relative_to)

        return {'FINISHED'}


def menu_func(self, context):
    if context.mode == 'OBJECT':
        self.layout.operator(AlignObjects.bl_idname,
        text="Align Objects")


def register():
    bpy.types.VIEW3D_MT_transform.append(menu_func)


def unregister():
    bpy.types.VIEW3D_MT_transform.remove(menu_func)

if __name__ == "__main__":
    register()