"""Export the site meshes from the assembled site .blend, one FBX per object.

    blender -b --factory-startup Art/blender/site/site-2026-11-06.blend \
        --python Art/blender/site/export_site_fbx.py -- --out /tmp/gigline/site

Why one file per object: terrain, road, sidewalks and kerbs want different
collision settings in Unreal, and a single combined mesh cannot carry that.

Uses the same named export preset `ue_metric_v1` as the scale test, so the metre
to centimetre mapping is identical to the one already verified.
"""

import argparse
import os
import sys

import bpy
sys.path.insert(0, os.path.join(os.path.join(os.path.dirname(__file__), "..", "..", ".."), "Tools"))
import fbx_export_preset as fbx_preset  # noqa: E402


MESHES = ("Terrain_DEM", "Road_Hollywood", "Sidewalk_South", "Sidewalk_North",
          "Kerb_South", "Kerb_North", "Crossing_Markings")


def main():
    argv = sys.argv[sys.argv.index("--") + 1:] if "--" in sys.argv else []
    ap = argparse.ArgumentParser()
    ap.add_argument("--out", default="/tmp/gigline/site")
    args = ap.parse_args(argv)
    os.makedirs(args.out, exist_ok=True)

    print(f"[site] scene objects: {len(bpy.data.objects)}")
    found = []
    for name in MESHES:
        obj = bpy.data.objects.get(name)
        if obj is None or obj.type != "MESH":
            print(f"[site] MISSING {name}")
            continue
        found.append(name)

    for name in found:
        # export only the object under test: select it, export, deselect
        bpy.ops.object.select_all(action="DESELECT")
        obj = bpy.data.objects[name]
        obj.select_set(True)
        # Sidewalks were generated with their north/south offsets inverted relative
        # to the road and kerbs: in Unreal the north sidewalk landed at the south
        # kerb. Mirror this one object across Y so the export matches the source
        # frame instead of rotating the actor in the map.
        mirrored = False  # the south sidewalk is correct in the .blend; see street_mesh
        if mirrored:
            obj.scale.y *= -1.0
            bpy.context.view_layer.objects.active = obj
            bpy.ops.object.transform_apply(location=False, rotation=False, scale=True)
            # Object mode has no mesh context; flip winding through the mesh data.
            me = obj.data
            for poly in me.polygons:
                verts = list(poly.vertices)
                verts.reverse()
                poly.vertices = verts
            me.update()
            _ = bpy.context.view_layer
        bpy.context.view_layer.objects.active = obj
        path = os.path.join(args.out, name + ".fbx")
        fbx_preset.export_static(path, selection=True)
        if mirrored:
            # The flip is an export correction, not a change to the source: undo it.
            obj.scale.y *= -1.0
            bpy.ops.object.transform_apply(location=False, rotation=False, scale=True)
            for poly in obj.data.polygons:
                verts = list(poly.vertices)
                verts.reverse()
                poly.vertices = verts
            obj.data.update()
        zs = [(obj.matrix_world @ v.co).z for v in obj.data.vertices]
        print(f"[site] {name:18} verts {len(obj.data.vertices):6}  z {min(zs):+.2f}..{max(zs):+.2f} m "
              f"-> {path}")

    print(f"[site] exported {len(found)} of {len(MESHES)} meshes")


main()