#!/usr/bin/env python3
import pathlib
import sys
import wave

import bpy


def write_silence(path):
    path.parent.mkdir(parents=True, exist_ok=True)
    with wave.open(str(path), "wb") as stream:
        stream.setnchannels(1)
        stream.setsampwidth(2)
        stream.setframerate(8000)
        stream.writeframes(b"\0\0" * 8000)


def main(output_path):
    output = pathlib.Path(output_path).resolve()
    media = output.parent / "media"
    audio_path = media / "WBV2P5002-silence.wav"
    image_path = media / "WBV2P5002-frame.png"
    write_silence(audio_path)

    bpy.ops.wm.read_factory_settings(use_empty=True)
    image = bpy.data.images.new("WBV2P5002Frame", width=8, height=8, alpha=True)
    image.generated_color = (0.12, 0.35, 0.8, 1.0)
    image.filepath_raw = str(image_path)
    image.file_format = "PNG"
    image.save()
    bpy.data.images.remove(image)

    scene = bpy.context.scene
    scene.name = "WBV2P5002MediaScene"
    scene.frame_start = 1
    scene.frame_end = 48
    scene.frame_set(1)
    scene.render.fps = 24
    scene.render.fps_base = 1.0

    tree = bpy.data.node_groups.new("WBV2P5002CompositorTree", "CompositorNodeTree")
    scene.compositing_node_group = tree
    tree.interface.new_socket(name="Image", in_out="OUTPUT", socket_type="NodeSocketColor")
    color = tree.nodes.new("CompositorNodeRGB")
    color.name = "WBV2P5002Constant"
    color.outputs["Color"].default_value = (0.1, 0.2, 0.4, 1.0)
    exposure = tree.nodes.new("CompositorNodeExposure")
    exposure.name = "WBV2P5002Exposure"
    exposure.inputs["Exposure"].default_value = 0.5
    invert = tree.nodes.new("CompositorNodeInvert")
    invert.name = "WBV2P5002Invert"
    composite = tree.nodes.new("NodeGroupOutput")
    composite.name = "WBV2P5002Composite"
    tree.links.new(color.outputs["Color"], exposure.inputs["Image"])
    tree.links.new(exposure.outputs["Image"], invert.inputs["Color"])
    tree.links.new(invert.outputs["Color"], composite.inputs["Image"])

    editor = scene.sequence_editor_create()
    sound = editor.strips.new_sound("WBV2P5002Sound", str(audio_path), channel=1, frame_start=1)
    sound.sound.filepath = "//media/WBV2P5002-silence.wav"
    sound.mute = True
    image_strip = editor.strips.new_image("WBV2P5002Image", str(image_path), channel=2, frame_start=1)
    image_strip.directory = "//media/"
    image_strip.elements[0].filename = "WBV2P5002-frame.png"
    image_strip.frame_final_duration = 24
    second = editor.strips.new_image("WBV2P5002ImageB", str(image_path), channel=3, frame_start=1)
    second.directory = "//media/"
    second.elements[0].filename = "WBV2P5002-frame.png"
    second.frame_final_duration = 24
    cross = editor.strips.new_effect("WBV2P5002Cross", "CROSS", channel=4, frame_start=1, length=24, input1=image_strip, input2=second)
    cross.mute = True

    output.parent.mkdir(parents=True, exist_ok=True)
    bpy.ops.wm.save_as_mainfile(filepath=str(output), check_existing=False, compress=True)


if __name__ == "__main__":
    arguments = sys.argv[sys.argv.index("--") + 1 :]
    if len(arguments) != 1:
        raise SystemExit("usage: blender -b --factory-startup --python WBV2-P5-002.py -- OUTPUT")
    main(arguments[0])