#!/usr/bin/env python3
"""Convert one BONES-SEED Unitree G1 CSV file to Isaac-style NPZ format."""

from __future__ import annotations

import argparse
from pathlib import Path

import mujoco
import numpy as np

from converter_common import (
    ISAAC_BODY_NAMES,
    ISAAC_JOINT_NAMES,
    MT_JOINT_NAMES,
    body_angular_velocity_wxyz,
    ensure_output_parent,
    finite_difference,
    interpolate_linear,
    interpolate_quaternions,
    load_csv_motion,
    load_g1_model,
    output_frame_count,
    require_body_id,
    validate_fps,
)


def convert_csv_to_isaac(
    csv_path: str | Path,
    output_path: str | Path,
    g1_xml: str | Path,
    source_fps: int = 120,
    target_fps: int = 50,
    verbose: bool = True,
) -> Path:
    """Convert a single CSV motion to Isaac format and return the output path."""
    validate_fps(source_fps, target_fps)
    root_pos, root_rot_xyzw, dof_pos_mt = load_csv_motion(csv_path)

    model = load_g1_model(str(Path(g1_xml).expanduser().resolve()))
    model_data = mujoco.MjData(model)

    body_ids = {}
    for body_name in ISAAC_BODY_NAMES:
        source_name = "pelvis" if body_name == "pelvis_contour_link" else body_name
        body_ids[body_name] = require_body_id(model, source_name)

    mt_indices = np.asarray(
        [MT_JOINT_NAMES.index(name) for name in ISAAC_JOINT_NAMES],
        dtype=np.int64,
    )
    joint_pos = dof_pos_mt[:, mt_indices]

    body_pos_w = np.zeros(
        (len(root_pos), len(ISAAC_BODY_NAMES), 3), dtype=np.float32
    )
    body_quat_w = np.zeros(
        (len(root_pos), len(ISAAC_BODY_NAMES), 4), dtype=np.float32
    )

    for frame in range(len(root_pos)):
        model_data.qpos[:3] = root_pos[frame]
        model_data.qpos[3:7] = root_rot_xyzw[frame, [3, 0, 1, 2]]
        model_data.qpos[7:] = dof_pos_mt[frame]
        mujoco.mj_forward(model, model_data)

        for output_index, body_name in enumerate(ISAAC_BODY_NAMES):
            body_id = body_ids[body_name]
            body_pos_w[frame, output_index] = model_data.xpos[body_id]
            body_quat_w[frame, output_index] = model_data.xquat[body_id]

    target_frames = output_frame_count(
        len(root_pos), source_fps, target_fps
    )
    joint_pos = interpolate_linear(joint_pos, target_frames)
    body_pos_w = interpolate_linear(body_pos_w, target_frames)
    body_quat_w = interpolate_quaternions(body_quat_w, target_frames)

    joint_vel = finite_difference(joint_pos, target_fps)
    body_lin_vel_w = finite_difference(body_pos_w, target_fps)
    body_ang_vel_w = body_angular_velocity_wxyz(
        body_quat_w, target_fps
    )

    output_path = ensure_output_parent(output_path)
    np.savez(
        output_path,
        fps=np.asarray([target_fps], dtype=np.int64),
        joint_pos=joint_pos.astype(np.float32),
        joint_vel=joint_vel.astype(np.float32),
        body_pos_w=body_pos_w.astype(np.float32),
        body_quat_w=body_quat_w.astype(np.float32),
        body_lin_vel_w=body_lin_vel_w.astype(np.float32),
        body_ang_vel_w=body_ang_vel_w.astype(np.float32),
    )

    if verbose:
        print(
            f"Saved Isaac: {output_path} "
            f"({len(joint_pos)} frames @ {target_fps} fps)"
        )
    return output_path


def parse_args() -> argparse.Namespace:
    parser = argparse.ArgumentParser(
        description="Convert one BONES-SEED G1 CSV motion to Isaac NPZ"
    )
    parser.add_argument("--input", required=True, help="Input G1 CSV file")
    parser.add_argument(
        "--output", required=True, help="Output Isaac NPZ file"
    )
    parser.add_argument(
        "--g1-xml", required=True, help="Compatible Unitree G1 MJCF XML"
    )
    parser.add_argument("--source-fps", type=int, default=120)
    parser.add_argument("--target-fps", type=int, default=50)
    return parser.parse_args()


def main() -> None:
    args = parse_args()
    convert_csv_to_isaac(
        csv_path=args.input,
        output_path=args.output,
        g1_xml=args.g1_xml,
        source_fps=args.source_fps,
        target_fps=args.target_fps,
    )


if __name__ == "__main__":
    main()