import bpy
import bmesh
import math

# This will remove all the objects.  Did we really need to?
# It's handy if we're going to run this a bunch of times
bpy.ops.object.mode_set(mode="OBJECT")

bpy.ops.object.select_all(action='SELECT') # Default action is TOGGLE
bpy.ops.object.delete()

bpy.ops.mesh.primitive_torus_add(major_segments=480)
torus = bpy.context.active_object
for i in range(len(torus.data.vertices)):
    theta = math.atan2(torus.data.vertices[i].co.y, torus.data.vertices[i].co.x)
    r = math.sqrt(math.pow(torus.data.vertices[i].co.y, 2) + math.pow(torus.data.vertices[i].co.x, 2))
    c_factor = math.sin(theta * 30) / 20
    torus.data.vertices[i].co.z += c_factor
    if r > 1.2:
        r += c_factor
    elif r < 0.8:
        r -= c_factor
    torus.data.vertices[i].co.x = r * math.cos(theta)
    torus.data.vertices[i].co.y = r * math.sin(theta)

bpy.ops.object.mode_set(mode="EDIT")

torus_mesh = bmesh.from_edit_mesh(bpy.context.object.data)    
color_layer = torus_mesh.loops.layers.color.new("Giraffe")
for face in torus_mesh.faces:
    for loop in face.loops:
        gval = abs(math.sin(loop.vert.co.x))
        bval = abs(math.sin(loop.vert.co.y))
        rval = 1 - gval
        loop[color_layer] = (rval, gval, bval, 1.0)
    
mat = bpy.data.materials.new("color_material")
mat.use_nodes = True
torus.data.materials.append(mat)


bsdf = mat.node_tree.nodes.get("Principled BSDF")
color_node = mat.node_tree.nodes.new(type="ShaderNodeVertexColor")
color_node.layer_name = "Giraffe"
mat.node_tree.links.new(color_node.outputs["Color"], bsdf.inputs["Base Color"])
        
bpy.ops.object.mode_set(mode="OBJECT")

for area in bpy.context.screen.areas:
    if area.type == "VIEW_3D":
        for space in area.spaces:
            if space.type == "VIEW_3D":
                space.shading.type = "MATERIAL"