Hanging blocks

displayName = "Hanging blocks"

inputs = (
    ("Replace", "blocktype"),
    ("With", "blocktype"),
    ("Frequency %", (50, 0, 100)),
    ("Length %", (50, 0, 100)),
    ("Check above", False),
)

def perform(level, box, options):
    mat1 = options["Replace"]
    mat2 = options["With"]
    frequency = options["Frequency %"]
    length = options["Length %"]
    mode = options["Check above"]
    blockAbove = False
    if mode:
        first = True
        for x in xrange(box.minx, box.maxx):
            for z in xrange(box.minz, box.maxz):
                for y in reversed(xrange(box.miny, box.maxy)):
                    if level.blockAt(x, y, z) == mat1.ID:
                        if first:
                            if randomGen() <= frequency and blockAbove:
                                level.setBlockAt(x, y, z, mat2.ID)
                                first = False
                            else:
                                blockAbove = False
                        else:
                            if randomGen() <= length and blockAbove:
                                level.setBlockAt(x, y, z, mat2.ID)
                            else:
                                blockAbove = False
                    else:
                        blockAbove = True
                blockAbove = False
                first = True
        level.markDirtyBox(box)
    else:
        first = True
        for x in xrange(box.minx, box.maxx):
            for z in xrange(box.minz, box.maxz):
                for y in reversed(xrange(box.miny, box.maxy)):
                    if level.blockAt(x, y, z) == mat1.ID:
                        if first:
                            if randomGen() <= frequency:
                                level.setBlockAt(x, y, z, mat2.ID)
                                first = False
                            else:
                                break
                        else:
                            if randomGen() <= length:
                                level.setBlockAt(x, y, z, mat2.ID)
                            else:
                                break
                first = True
        level.markDirtyBox(box)
def randomGen():
    return int(random.random() * 100)