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bl_info = {
    "name": "Add Chain",
    "author": "Brian Hinton (Nichod)",
    "version": (0, 1, 2),
    "blender": (2, 71, 0),
    "location": "Toolshelf > Create Tab",
    "description": "Adds Chain with curve guide for easy creation",
    "warning": "",
    "wiki_url": "https://wiki.blender.org/index.php/Extensions:2.6/Py/"
                "Scripts/Object/Add_Chain",
    "category": "Object",
}

import bpy
from bpy.types import Operator


def Add_Chain():
    # Adds Empty to scene
    bpy.ops.object.add(
            type='EMPTY',
            view_align=False,
            enter_editmode=False,
            location=(0, 0, 0),
            rotation=(0, 0, 0),
            )

    # Changes name of Empty to rot_link adds variable emp
    emp = bpy.context.object
    emp.name = "rot_link"

    # Rotate emp ~ 90 degrees
    emp.rotation_euler = [1.570796, 0, 0]

    # Adds Curve Path to scene
    bpy.ops.curve.primitive_nurbs_path_add(
            view_align=False,
            enter_editmode=False,
            location=(0, 0, 0),
            rotation=(0, 0, 0),
            )

    # Change Curve name to deform adds variable curv
    curv = bpy.context.object
    curv.name = "deform"

    # Inserts Torus primitive
    bpy.ops.mesh.primitive_torus_add(
            major_radius=1,
            minor_radius=0.25,
            major_segments=12,
            minor_segments=4,
            abso_major_rad=1,
            abso_minor_rad=0.5,
            )

    # Positions Torus primitive to center of scene
    bpy.context.active_object.location = 0.0, 0.0, 0.0

    # Reseting Torus rotation in case of 'Align to view' option enabled
    bpy.context.active_object.rotation_euler = 0.0, 0.0, 0.0

    # Changes Torus name to chain adds variable tor
    tor = bpy.context.object
    tor.name = "chain"

    # Adds Array Modifier to tor
    bpy.ops.object.modifier_add(type='ARRAY')

    # Adds subsurf modifier tor
    bpy.ops.object.modifier_add(type='SUBSURF')

    # Smooths tor
    bpy.ops.object.shade_smooth()

    # Select curv
    sce = bpy.context.scene
    sce.objects.active = curv

    # Toggle into editmode
    bpy.ops.object.editmode_toggle()

    # TODO, may be better to move objects directly
    # Translate curve object
    bpy.ops.transform.translate(
            value=(2, 0, 0),
            constraint_axis=(True, False, False),
            constraint_orientation='GLOBAL',
            mirror=False,
            proportional='DISABLED',
            proportional_edit_falloff='SMOOTH',
            proportional_size=1,
            snap=False,
            snap_target='CLOSEST',
            snap_point=(0, 0, 0),
            snap_align=False,
            snap_normal=(0, 0, 0),
            release_confirm=False,
            )

    # Toggle into objectmode
    bpy.ops.object.editmode_toggle()

    # Select tor or chain
    sce.objects.active = tor

    # Selects Array Modifier for editing
    array = tor.modifiers['Array']

    # Change Array Modifier Parameters
    array.fit_type = 'FIT_CURVE'
    array.curve = curv
    array.offset_object = emp
    array.use_object_offset = True
    array.relative_offset_displace = 0.549, 0.0, 0.0

    # Add curve modifier
    bpy.ops.object.modifier_add(type='CURVE')

    # Selects Curve Modifier for editing
    cur = tor.modifiers['Curve']

    # Change Curve Modifier Parameters
    cur.object = curv


class AddChain(Operator):
    bl_idname = "mesh.primitive_chain_add"
    bl_label = "Add Chain"
    bl_description = ("Create a Chain segment with helper objects controlling modifiers:\n"
                      "1) A Curve Modifier Object (deform) for the length and shape,\n"
                      "Edit the Path to extend Chain Length\n"
                      "2) An Empty (rot_link) as an Array Offset for rotation")
    bl_options = {'REGISTER', 'UNDO'}

    def execute(self, context):
        try:
            Add_Chain()

        except Exception as e:
            self.report({'WARNING'},
                        "Some operations could not be performed (See Console for more info)")

            print("\n[Add Advanced  Objects]\nOperator: "
                  "mesh.primitive_chain_add\nError: {}".format(e))

            return {'CANCELLED'}

        return {'FINISHED'}


def register():
    bpy.utils.register_class(AddChain)


def unregister():
    bpy.utils.unregister_class(AddChain)


if __name__ == "__main__":
    register()