import bpy

import bmesh
import math

# this assumes you have the vertexAccumulator.py source in a text buffer named "vertexAccumulator.py"
bufferName = 'vertexAccumulator.py'
lib1 = bpy.data.texts[bufferName].as_string()
exec(lib1)


class Voxels:
    def __init__(self):
        self.dict = {}

    def set(self, x, y, z, val):
        key = self.key_for(x, y, z)
        self.dict[key] = val

    @staticmethod
    def key_for(x, y, z):
        return "%d,%d,%d" % (x, y, z)

    def get(self, x, y, z):
        key = self.key_for(x, y, z)
        return self.dict.get(key)

#
#


def image_for_stuff(name, c1, c2):
    """

    :param c1: an rgba tuple
    :param c2: the other rgba tuple
    :return: a blender image
    """

    if (len(c1)!=4):
        raise "c1 is not RGBA tuple"

    if (len(c2)!=4):
        raise "c2 is not RGBA tuple"

    i1 = bpy.data.images.get(name)
    if i1 is not None:
        return i1
    else:
        i1 = bpy.data.images.new(name, 64, 64)

    for u in range(64):
        for v in range(64):
            x = abs(((u/63)-0.5)*2)
            y = abs(((v/63)-0.5)*2)
            q = x*x*x + y*y*y
            #print(q)
            offset = 4*(u+v*64)
            if 0.8 > q > 0.4:
                i1.pixels[offset:offset+4] = c1
            else:
                i1.pixels[offset:offset+4] = c2

    #print(pixels)

    # if we don't pack the image, it will be missing the next time you load the .blend file.
    i1.pack(True)

    return i1


def material_for_something(name, c1=(1, 0, 0, 1), c2=(1, 0.5, 0.5, 1)):
    mat = bpy.data.materials.get(name)
    if mat is not None:
        return mat
    else:
        mat = bpy.data.materials.new(name)
        mat.texture_slots.add()

    # create a texture for the image
    t1 = bpy.data.textures.new("stripe", 'IMAGE')
    t1.image = image_for_stuff(name, c1, c2)
    # give it sharp uninterpolated edges.
    t1.use_interpolation = False
    t1.filter_type = 'BOX'

    mat.texture_slots[0].texture = t1
    mat.texture_slots[0].texture_coords = 'UV'
    mat.texture_slots[0].uv_layer = 'uv'
    #mat.texture_slots[0].use_map_alpha = True

    mat.emit = 0.2
    mat.diffuse_intensity = 0.9-mat.emit
    mat.preview_render_type='CUBE'

    return mat


def material_for_alpha():
    return material_for_something("layer alpha")


def material_for_beta():
    return material_for_something("layer beta", (0, 0.7, 0, 1), (0.5, 1, 0.5, 1))


def material_for_gamma():
    rval = material_for_something("layer gamma", (0, 0, 0.7, 1), (0.5, 0.5, 1, 1))
    rval.use_transparency = False
    rval.alpha = 0.2
    return rval


def material_for_delta():
    rval = material_for_something("layer delta", (0.5, 0.5, 0, 1), (1, 1, 0.5, 1))
    return rval

#
#


def add_for_cell(x, y, z, va, grid, faces):
    code = grid.get(x, y, z)
    if code is None:
        return

    if code==1:
        if math.ceil(z/2) % 2 == 0:
            material_index = 0
        else:
            material_index = 1
    else:
        material_index = code

    z2 = (z + 0.5)/2
    z1 = (z - 0.5)/2
    if grid.get(x-1, y, z) is None:
        i1 = va.idxFor((x-0.5, y-0.5, z2))
        i2 = va.idxFor((x-0.5, y+0.5, z2))
        i3 = va.idxFor((x-0.5, y+0.5, z1))
        i4 = va.idxFor((x-0.5, y-0.5, z1))
        faces.append( { "vi": [i1,i2,i3,i4], "mi":material_index })
    if grid.get(x+1, y, z) is None:
        i1 = va.idxFor((x+0.5, y+0.5, z1))
        i2 = va.idxFor((x+0.5, y+0.5, z2))
        i3 = va.idxFor((x+0.5, y-0.5, z2))
        i4 = va.idxFor((x+0.5, y-0.5, z1))
        faces.append( { "vi": [i1,i2,i3,i4], "mi":material_index} )

    if grid.get(x,y-1,z) is None:
        i1 = va.idxFor((x+0.5, y-0.5, z1))
        i2 = va.idxFor((x+0.5, y-0.5, z2))
        i3 = va.idxFor((x-0.5, y-0.5, z2))
        i4 = va.idxFor((x-0.5, y-0.5, z1))
        faces.append( { "vi": [i4,i3,i2,i1], "mi":material_index} )

    if grid.get(x,y+1,z) is None:
        i1 = va.idxFor((x+0.5, y+0.5, z1))
        i2 = va.idxFor((x+0.5, y+0.5, z2))
        i3 = va.idxFor((x-0.5, y+0.5, z2))
        i4 = va.idxFor((x-0.5, y+0.5, z1))
        faces.append( { "vi": [i1,i2,i3,i4], "mi":material_index} )

    if grid.get(x, y, z+1) is None:
        i1 = va.idxFor((x+0.5, y-0.5, z2) )
        i2 = va.idxFor((x+0.5, y+0.5, z2) )
        i3 = va.idxFor((x-0.5, y+0.5, z2) )
        i4 = va.idxFor((x-0.5, y-0.5, z2) )
        faces.append( { "vi": [i1,i2,i3,i4], "mi":material_index} )

    if (grid.get(x, y, z-1) is None):
        i1 = va.idxFor((x+0.5, y-0.5, z1) )
        i2 = va.idxFor((x+0.5, y+0.5, z1) )
        i3 = va.idxFor((x-0.5, y+0.5, z1) )
        i4 = va.idxFor((x-0.5, y-0.5, z1) )
        faces.append( { "vi": [i4,i3,i2,i1], "mi":material_index} )


def guess_uvs_z(face, uvl, axis1, axis2):
    x0 = face.verts[0].co[axis1]
    y0 = face.verts[0].co[axis2]
    for v in face.verts:
        x0 = min(x0, v.co[axis1])
        y0 = min(y0, v.co[axis2])
    x0 = math.floor(x0-0.5)+0.5
    if (axis2==2):
        y0 = math.floor(y0-0.25)+0.25
    else:
        y0 = math.floor(y0-0.5)+0.5

    for i in range(len(face.verts)):
        face.loops[i][uvl].uv = ( face.verts[i].co[axis1] - x0 ,
                                  face.verts[i].co[axis2] - y0)


def guess_uvs(face, uvl):
    va = face.verts[0].co - face.verts[1].co
    vb = face.verts[2].co - face.verts[1].co
    cross = va.cross(vb)
    if (abs(cross[2]) > abs(cross[1])):
        if (abs(cross[2]) > abs(cross[0])):
            guess_uvs_z(face, uvl, 0, 1)
        else:
            guess_uvs_z(face, uvl, 1, 2)
    elif (abs(cross[1]) > abs(cross[0])):
        guess_uvs_z(face, uvl, 0, 2)
    else:
        guess_uvs_z(face, uvl, 1, 2)

def adjacent_z2(radius, x2, y2):

    zsq = radius*radius - x2*x2 - y2*y2
    if (zsq<0):
        return 0

    return math.sqrt(zsq)

def adjacent_z(radius, x,y):
    if (x<0):
        z1 = adjacent_z2(radius, x-1, y)
    else:
        z1 = adjacent_z2(radius, x+1, y)

    if (y<0):
        z2 = adjacent_z2(radius, x, y-1)
    else:
        z2 = adjacent_z2(radius, x, y+1)
    return min(z1, z2)

def sphere_minecraft_mesh(name, radius):
    verts =[]
    faces = []

    va = VertexAccumulator()

    over = math.ceil(radius)

    grid = Voxels()

    for x in range (-over, over+1):
        for y in range(x, over+1):
            zsq = radius * radius - x * x - y * y
            if (zsq<0):
                continue

            z = math.sqrt(zsq)
            z2 = math.ceil(z*2)

            mi2 = 1
            if (x%5==0 and y%5==0):
                mi2 = 3
            grid.set(x,y,-z2, 1)
            grid.set(x,y,-z2+1, mi2)

            z3 = math.ceil( 2* adjacent_z(radius, x,y))
            for i in range(-z2+2, -z3):
                grid.set(x,y,i, 2)


    for x in range(-over, over+1):
        for y in range(-over, over+1):
            for z in range(-2*over, 1):
                add_for_cell(x,y,z, va, grid, faces)

    verts = va.verts()

    mesh = bpy.data.meshes.new(name)
    mesh.from_pydata(verts, [], [ f["vi"] for f in faces])

    #

    for i in range(len(faces)):
        mesh.polygons[i].material_index = faces[i]["mi"]

    mesh.materials.append(material_for_alpha())
    mesh.materials.append(material_for_beta())
    mesh.materials.append(material_for_gamma())
    mesh.materials.append(material_for_delta())

    #

    mesh.uv_textures.new("uv")

    bm = bmesh.new()
    bm.from_mesh(mesh)
    bm.faces.ensure_lookup_table()

    uvl = bm.loops.layers.uv[0]

    for fi in range(len(bm.faces)):

        for i in range(len(bm.faces[fi].loops)):
            guess_uvs(bm.faces[fi], uvl)

    bm.to_mesh(mesh)


    #

    return mesh


def cliche(scn, name):
    mesh = sphere_minecraft_mesh(name, 20.5)
    obj = bpy.data.objects.new(name, mesh)
    scn.objects.link(obj)


scn = bpy.context.scene

name = "sphere"



cliche(scn, name)