"""Door robot arm: the LODs side by side (LOD0, LOD1, LOD2 of each version, imported back from fbx/), Workbench, a side
view, to check that the silhouette holds -> previews/lods_<A|B>.png.

    blender -b --factory-startup --python build/dra_lod_preview.py
"""
import os
import math
import bpy
from mathutils import Vector

HERE = os.path.dirname(os.path.abspath(__file__))
ROOT = os.path.dirname(HERE)
FBX = os.path.join(ROOT, "fbx")

for ver in ("A", "B"):
    bpy.ops.wm.read_factory_settings(use_empty=True)
    sc = bpy.context.scene
    tris = []
    groups = []
    for i, suf in enumerate(("", "_LOD1", "_LOD2")):
        before = set(bpy.data.objects)
        bpy.ops.import_scene.fbx(filepath=os.path.join(FBX, "SK_DoorRobotArm_%s%s.fbx" % (ver, suf)))
        new = [o for o in bpy.data.objects if o not in before]
        groups.append(new)
        for o in new:
            if o.type == 'MESH':
                o.data.calc_loop_triangles()
                tris.append(len(o.data.loop_triangles))
    bpy.context.view_layer.update()
    # the arm's forward axis lies along the longer horizontal side of its bounds: spread the copies along it and look
    # across it (a side view, as ref1)
    me0 = next(o for o in groups[0] if o.type == 'MESH')
    pts = [me0.matrix_world @ v.co for v in me0.data.vertices]
    ex = max(p.x for p in pts) - min(p.x for p in pts)
    ey = max(p.y for p in pts) - min(p.y for p in pts)
    along = Vector((1, 0, 0)) if ex >= ey else Vector((0, 1, 0))
    print("[dra] extents", round(ex, 3), round(ey, 3), tuple(along), flush=True)
    across = Vector((0, 1, 0)) if ex >= ey else Vector((1, 0, 0))
    for i, grp in enumerate(groups):
        for o in grp:
            if o.parent is None:
                o.location += along * (i * 3.6)
    sc.render.engine = 'BLENDER_WORKBENCH'
    sh = sc.display.shading
    sh.light = 'STUDIO'
    sh.color_type = 'MATERIAL'
    sh.show_cavity = True
    sh.show_object_outline = True
    sc.render.resolution_x, sc.render.resolution_y = 2400, 900
    cd = bpy.data.cameras.new("cam")
    cd.type = 'ORTHO'
    cd.ortho_scale = 13.0
    cam = bpy.data.objects.new("cam", cd)
    sc.collection.objects.link(cam)
    tgt = along * 3.6 + Vector((0, 0, 1.2))
    cam.location = tgt + across * 14.0
    d = (tgt - cam.location).normalized()
    cam.rotation_euler = d.to_track_quat('-Z', 'Y').to_euler()
    sc.camera = cam
    print("[dra] camera", tuple(round(c, 2) for c in cam.location), tuple(round(c, 3) for c in d), flush=True)
    w = bpy.data.worlds.new("w")
    w.color = (0.6, 0.6, 0.6)
    sc.world = w
    sc.render.filepath = os.path.join(ROOT, "previews", "lods_%s.png" % ver)
    bpy.ops.render.render(write_still=True)
    print("[dra] lods", ver, tris, sc.render.filepath, flush=True)