"""Builds the phone LOD of the grand tourer. Headless only:

    blender -b --python scripts/blender/make-lite-car.py -- \
        src/assets/nightdrive-grand-tourer-chromatic.glb \
        src/assets/nightdrive-grand-tourer-lite.glb

On a phone the car is about 200 px wide and seen from behind, so the wheel
machining, the tyre treads and the dense trim carry detail nobody can see.
They are collapsed; the silhouette parts (body, haunches, glass) are kept
as authored so the car reads the same. Node names and the hierarchy are
preserved: car.ts finds the wheels, the light bar and the underglow by name.
"""

import sys

import bpy

source, target = sys.argv[sys.argv.index("--") + 1 :][:2]

# Fraction of faces kept, by node name prefix (after the "evolution-" prefix).
RATIOS = {
    "wheel-machining": 0.22,
    "tires": 0.25,
    "body-trim": 0.35,
    "rear-light-bar": 0.4,
    "car-underglow-source": 0.35,
}

bpy.ops.wm.read_factory_settings(use_empty=True)
bpy.ops.import_scene.gltf(filepath=source)

before = after = 0
for obj in bpy.data.objects:
    if obj.type != "MESH":
        continue
    name = obj.name.removeprefix("evolution-")
    faces = len(obj.data.polygons)
    before += faces
    ratio = next((r for prefix, r in RATIOS.items() if name.startswith(prefix)), None)
    if ratio is not None and faces > 200:
        # Meshes can be shared between wheels; give each object its own data.
        obj.data = obj.data.copy()
        modifier = obj.modifiers.new("lod", "DECIMATE")
        modifier.decimate_type = "COLLAPSE"
        modifier.ratio = ratio
        modifier.use_collapse_triangulate = True
        bpy.context.view_layer.objects.active = obj
        for other in bpy.context.view_layer.objects:
            other.select_set(other is obj)
        bpy.ops.object.modifier_apply(modifier=modifier.name)
    after += len(obj.data.polygons)

bpy.ops.export_scene.gltf(
    filepath=target,
    export_format="GLB",
    export_apply=True,
    export_yup=True,
    export_texcoords=False,
    export_normals=True,
    export_materials="EXPORT",
    export_animations=False,
)
print(f"LITE faces {before} -> {after}")