"""Restore recorded non-robot scene while retaining target embodiment and actuators."""
import copy,xml.etree.ElementTree as ET
import numpy as np

PREFIXES=('robot0_','gripper0_','mount0_')
def robot_element(element):
    return any(e.get('name','').startswith(PREFIXES) for e in element.iter())

def merge_scene(target_xml,source_xml):
    target=ET.fromstring(target_xml);source=ET.fromstring(source_xml)
    tw=target.find('worldbody');sw=source.find('worldbody')
    assert tw is not None and sw is not None
    for el in list(tw):
        if not robot_element(el):tw.remove(el)
    for el in sw:
        if not robot_element(el):tw.append(copy.deepcopy(el))
    ta=target.find('asset');sa=source.find('asset')
    if ta is not None and sa is not None:
        for el in sa:
            if el.get('name','').startswith(PREFIXES):continue
            for old in list(ta):
                if old.tag==el.tag and old.get('name')==el.get('name'):ta.remove(old)
            ta.append(copy.deepcopy(el))
    for tag in ['contact','equality']:
        ts=target.find(tag);ss=source.find(tag)
        if ss is None:continue
        if ts is None:ts=ET.SubElement(target,tag)
        def has_robot_ref(el):return any(v.startswith(PREFIXES) for v in el.attrib.values())
        for el in list(ts):
            if not has_robot_ref(el):ts.remove(el)
        for el in ss:
            if not has_robot_ref(el):ts.append(copy.deepcopy(el))
    return ET.tostring(target,encoding='unicode')

def nonrobot_joint_state(env):
    return {env.sim.model.joint_id2name(i):np.array(env.sim.data.get_joint_qpos(env.sim.model.joint_id2name(i))).copy()
            for i in range(env.sim.model.njnt) if not env.sim.model.joint_id2name(i).startswith(PREFIXES)}

def bind_scene(env,demo):
    env.reset()
    if getattr(demo,'scene_xml',None):
        xml=merge_scene(env.sim.model.get_xml(),demo.scene_xml)
        env.reset_from_xml_string(xml);env.sim.reset()
    for name,value in demo.object_init.items():
        env.sim.data.set_joint_qpos(name,value)
        velocity=np.asarray(env.sim.data.get_joint_qvel(name))
        env.sim.data.set_joint_qvel(name,np.zeros_like(velocity))
    env.sim.forward();env._get_observations(force_update=True)