#!/usr/bin/env python3
"""Dataset analysis utility for the Unitree G1 AMASS trajectories.

Run:
    python analyze_dataset.py --root /home/ubuntu/MoCapDataset/AMASSDataset/UnitreeG1

The script outputs two files in the same folder:
    ├─ episode_stats.json   – per-trajectory statistics
    └─ aggregate_stats.json – averages / extrema over the whole dataset

Useful for diagnosing AMP training issues (range mismatch, outliers, etc.).
"""

from __future__ import annotations

import argparse
import json
import os
from pathlib import Path
from collections import defaultdict
from typing import Any, Dict, List

import torch
import numpy as np

import isaaclab.utils.math as math_utils

_ALLOWED_EXT = {".pt", ".pth", ".pkl", ".npz"}

# ----------------------------------------------------------------------------------
# helpers
# ----------------------------------------------------------------------------------

def _load_file(path: Path) -> Dict[str, torch.Tensor]:
    """Load torch / numpy trajectory file into a dict of torch tensors."""
    if path.suffix in {".npz", ".pkl"}:
        data = dict(np.load(path, allow_pickle=True))
        for k, v in data.items():
            if isinstance(v, np.ndarray) and v.dtype.kind in {"f", "c", "i", "u", "b"}:
                data[k] = torch.from_numpy(v)
            else:
                data[k] = v  # keep python objects (e.g. list[str]) as-is
        return data  # type: ignore[return-value]
    # torch files
    return torch.load(path, map_location="cpu")  # type: ignore[return-value]


def _tensor_range(t: torch.Tensor):
    return t.min().item(), t.max().item()


def _analyze_field(value: Any) -> Dict[str, Any]:
    """Analyze a field value and return metadata about it."""
    if isinstance(value, torch.Tensor):
        return {
            "type": "tensor",
            "dtype": str(value.dtype),
            "shape": list(value.shape),
            "ndim": value.ndim,
            "size": value.numel(),
        }
    elif isinstance(value, np.ndarray):
        return {
            "type": "numpy_array", 
            "dtype": str(value.dtype),
            "shape": list(value.shape),
            "ndim": value.ndim,
            "size": value.size,
        }
    elif isinstance(value, list):
        return {
            "type": "list",
            "length": len(value),
            "element_type": type(value[0]).__name__ if value else "unknown",
        }
    elif isinstance(value, (str, int, float, bool)):
        return {
            "type": type(value).__name__,
            "value": value if isinstance(value, (int, float, bool)) else f"<string of length {len(value)}>",
        }
    else:
        return {
            "type": type(value).__name__,
            "repr": str(value)[:100] + ("..." if len(str(value)) > 100 else ""),
        }

def _determine_angular_unit(max_vel: float) -> str:
    """Determine if angular velocity is in deg/s or rad/s based on magnitude."""
    return "deg/s" if max_vel > 20.0 else "rad/s"

def _analyze_angular_velocity(velocities: torch.Tensor, name: str = "") -> Dict[str, Any]:
    """Analyze angular velocity data to determine if it's in deg/s or rad/s.
    
    Uses multiple heuristics:
    1. Physical limits - robots rarely exceed 1000 deg/s or ~17 rad/s
    2. Distribution of values - deg/s values tend to be larger
    3. Common ranges for motion capture data
    
    Args:
        velocities: Tensor of angular velocities
        name: Name of the joint/axis for reporting
    
    Returns:
        Dict with analysis results
    """
    abs_max = float(torch.abs(velocities).max())
    abs_mean = float(torch.abs(velocities).mean())
    
    # Convert to both units for analysis
    if abs_max > 20.0:  # Assuming it might be deg/s
        rad_max = abs_max * np.pi / 180
        rad_mean = abs_mean * np.pi / 180
        deg_max = abs_max
        deg_mean = abs_mean
        original_unit = "deg/s"
    else:  # Assuming it might be rad/s
        rad_max = abs_max
        rad_mean = abs_mean
        deg_max = abs_max * 180 / np.pi
        deg_mean = abs_mean * 180 / np.pi
        original_unit = "rad/s"
    
    # Scoring system for unit determination
    deg_score = 0
    rad_score = 0
    
    # Physical limits check
    if deg_max > 1000:  # Unusually high for deg/s
        rad_score += 2
    if rad_max > 17:  # Unusually high for rad/s (~1000 deg/s)
        deg_score += 2
        
    # Common ranges check
    if 20 <= deg_max <= 720:  # Common range for deg/s in motion capture
        deg_score += 1
    if 0.3 <= rad_max <= 12:  # Common range for rad/s in motion capture
        rad_score += 1
        
    # Mean value check
    if 5 <= deg_mean <= 180:  # Common mean range for deg/s
        deg_score += 1
    if 0.1 <= rad_mean <= 3:  # Common mean range for rad/s
        rad_score += 1
    
    # Determine most likely unit
    likely_unit = "deg/s" if deg_score > rad_score else "rad/s"
    confidence = abs(deg_score - rad_score) / (deg_score + rad_score) if (deg_score + rad_score) > 0 else 0
    
    return {
        "likely_unit": likely_unit,
        "confidence": confidence,
        "max_value": abs_max,
        "mean_value": abs_mean,
        "deg_score": deg_score,
        "rad_score": rad_score,
        "analysis": {
            "deg/s": {"max": deg_max, "mean": deg_mean},
            "rad/s": {"max": rad_max, "mean": rad_mean}
        },
        "original_unit": original_unit
    }

# ----------------------------------------------------------------------------------
# main analysis
# ----------------------------------------------------------------------------------

def analyse_dataset(root: Path) -> None:
    # discover files
    files: List[Path] = []
    for p, _, names in os.walk(root):
        for n in names:
            if n == "shape_optimized.pkl":
                continue
            if Path(n).suffix in _ALLOWED_EXT:
                files.append(Path(p) / n)
    files.sort()

    if not files:
        raise RuntimeError(f"No trajectory files found under {root}")

    print(f"Found {len(files)} trajectory files.  Analysing…")

    # aggregate accumulators
    agg = {
        "num_episodes": len(files),
        "total_frames": 0,
        "lengths": [],
        "base_lin_vel_b": {"min": torch.full((3,), torch.inf), "max": torch.full((3,), -torch.inf)},
        "base_ang_vel_b": {"min": torch.full((3,), torch.inf), "max": torch.full((3,), -torch.inf)},
        "base_height": {"min": torch.tensor(torch.inf), "max": torch.tensor(-torch.inf)},
        "base_quat": {"min": torch.full((4,), torch.inf), "max": torch.full((4,), -torch.inf)},
        "joint_pos": {},  # type: ignore[dict[str, Any]]
        "joint_vel": {},  # type: ignore[dict[str, Any]]
        "base_pos": {"min": torch.full((3,), torch.inf), "max": torch.full((3,), -torch.inf)},
        "start_pos_list": [],
    }

    # field analysis accumulator
    field_analysis = defaultdict(lambda: {
        "count": 0,
        "files_with_field": [],
        "metadata": None,
        "consistent_shape": True,
        "shapes_seen": set(),
    })

    episode_stats: List[Dict[str, Any]] = []

    for f_idx, path in enumerate(files):
        data = _load_file(path)
        
        # Analyze all fields in this file
        for field_name, field_value in data.items():
            field_info = field_analysis[field_name]
            field_info["count"] += 1
            field_info["files_with_field"].append(str(path.relative_to(root)))
            
            # Analyze field metadata
            metadata = _analyze_field(field_value)
            if field_info["metadata"] is None:
                field_info["metadata"] = metadata
            
            # Track shape consistency for tensors/arrays
            if metadata["type"] in ["tensor", "numpy_array"]:
                shape_tuple = tuple(metadata["shape"])
                field_info["shapes_seen"].add(shape_tuple)
                if len(field_info["shapes_seen"]) > 1:
                    field_info["consistent_shape"] = False

        # Continue with existing analysis for specific fields
        if "qpos" not in data or "qvel" not in data:
            print(f"[WARN] {path.name}: Missing qpos or qvel, skipping detailed analysis")
            continue

        qpos, qvel = data["qpos"].float(), data["qvel"].float()
        n = qpos.shape[0]
        agg["total_frames"] += n
        agg["lengths"].append(n)

        # root quantities
        base_pos = qpos[:, :3]
        base_quat = math_utils.quat_unique(qpos[:, 3:7])  # shape [n,4]
        base_lin_vel = qvel[:, :3]
        base_ang_vel = qvel[:, 3:6]
        base_lin_vel_b = math_utils.quat_rotate_inverse(base_quat, base_lin_vel)
        base_ang_vel_b = math_utils.quat_rotate_inverse(base_quat, base_ang_vel)

        height = base_pos[:, 2]

        # update global min/max
        agg["base_height"]["min"] = torch.minimum(agg["base_height"]["min"], height.min())
        agg["base_height"]["max"] = torch.maximum(agg["base_height"]["max"], height.max())
        for k, tensor in zip(["base_lin_vel_b", "base_ang_vel_b"], [base_lin_vel_b, base_ang_vel_b]):
            agg[k]["min"] = torch.minimum(agg[k]["min"], tensor.min(dim=0).values)
            agg[k]["max"] = torch.maximum(agg[k]["max"], tensor.max(dim=0).values)
        agg["base_quat"]["min"] = torch.minimum(agg["base_quat"]["min"], base_quat.min(dim=0).values)
        agg["base_quat"]["max"] = torch.maximum(agg["base_quat"]["max"], base_quat.max(dim=0).values)

        # update base_pos ranges
        agg["base_pos"]["min"] = torch.minimum(agg["base_pos"]["min"], base_pos.min(dim=0).values)
        agg["base_pos"]["max"] = torch.maximum(agg["base_pos"]["max"], base_pos.max(dim=0).values)

        # save starting position
        agg["start_pos_list"].append(base_pos[0].tolist())

        # joint ranges per episode
        joint_pos = qpos[:, 7:]
        joint_vel = qvel[:, 6:]  # skip floating base velocities (first 6)
        num_joints = joint_pos.shape[1]
        joint_names = data.get("joint_names", None)
        if joint_names is not None and len(joint_names) == num_joints + 1:
            # Likely the first entry is the floating base/root joint which is not in joint_pos
            joint_names = joint_names[1:]

        if joint_names is None or len(joint_names) != num_joints:
            # Generate fallback names if missing or mismatched
            if joint_names is not None and len(joint_names) != num_joints:
                print(f"[WARN] {path.name}: joint_names length {len(joint_names)} != joint dim {num_joints}. Using generic names.")
            joint_names = [f"joint_{i}" for i in range(num_joints)]

        ep_joint_range = {}
        ep_joint_vel_range = {}
        for j in range(num_joints):
            name = joint_names[j]
            # Position ranges
            j_min, j_max = _tensor_range(joint_pos[:, j])
            ep_joint_range[name] = {"min": j_min, "max": j_max}

            # Velocity ranges
            v_min, v_max = _tensor_range(joint_vel[:, j])
            ep_joint_vel_range[name] = {"min": v_min, "max": v_max}

            # accumulate global position ranges
            if name not in agg["joint_pos"]:
                agg["joint_pos"][name] = {"min": j_min, "max": j_max}
            else:
                agg["joint_pos"][name]["min"] = min(agg["joint_pos"][name]["min"], j_min)
                agg["joint_pos"][name]["max"] = max(agg["joint_pos"][name]["max"], j_max)

            # accumulate global velocity ranges
            if name not in agg["joint_vel"]:
                agg["joint_vel"][name] = {"min": v_min, "max": v_max}
            else:
                agg["joint_vel"][name]["min"] = min(agg["joint_vel"][name]["min"], v_min)
                agg["joint_vel"][name]["max"] = max(agg["joint_vel"][name]["max"], v_max)

        # Analyze base angular velocities
        base_ang_vel_analysis = {}
        for i, axis in enumerate(['x', 'y', 'z']):
            base_ang_vel_axis = base_ang_vel_b[:, i]
            base_ang_vel_analysis[axis] = _analyze_angular_velocity(base_ang_vel_axis, f"base_ang_vel_{axis}")

        # Analyze joint velocities
        joint_vel_analysis = {}
        for j in range(num_joints):
            name = joint_names[j]
            joint_vel_analysis[name] = _analyze_angular_velocity(joint_vel[:, j], name)

        # store per-episode stats
        episode_stats.append({
            "file": str(path.relative_to(root)),
            "length": n,
            "base_height": _tensor_range(height),
            "base_pos_start": base_pos[0].tolist(),
            "base_pos_range": {
                "min": base_pos.min(dim=0).values.tolist(),
                "max": base_pos.max(dim=0).values.tolist(),
            },
            "base_lin_vel_b": {
                "min": base_lin_vel_b.min(dim=0).values.tolist(),
                "max": base_lin_vel_b.max(dim=0).values.tolist(),
            },
            "base_ang_vel_b": {
                "min": base_ang_vel_b.min(dim=0).values.tolist(),
                "max": base_ang_vel_b.max(dim=0).values.tolist(),
            },
            "base_quat": {k: v.tolist() for k, v in agg["base_quat"].items()},
            "joint_pos_range": ep_joint_range,
            "joint_vel_range": ep_joint_vel_range,
            "base_ang_vel_analysis": base_ang_vel_analysis,
            "joint_vel_analysis": joint_vel_analysis,
        })

        if (f_idx + 1) % 50 == 0:
            print(f"Processed {f_idx+1}/{len(files)} files…")

    # Process field analysis results
    # print("\n" + "="*60)
    # print("DATASET FIELD ANALYSIS")
    # print("="*60)
    
    # all_fields = sorted(field_analysis.keys())
    # for field_name in all_fields:
    #     info = field_analysis[field_name]
    #     print(f"\nField: '{field_name}'")
    #     print(f"  Present in: {info['count']}/{len(files)} files ({info['count']/len(files)*100:.1f}%)")
        
    #     if info['metadata']:
    #         meta = info['metadata']
    #         if meta['type'] in ['tensor', 'numpy_array']:
    #             if info['consistent_shape']:
    #                 print(f"  Type: {meta['type']} ({meta['dtype']})")
    #                 print(f"  Shape: {meta['shape']}")
    #             else:
    #                 print(f"  Type: {meta['type']} ({meta['dtype']}) - INCONSISTENT SHAPES")
    #                 print(f"  Shapes seen: {sorted(info['shapes_seen'])}")
    #         elif meta['type'] == 'list':
    #             print(f"  Type: {meta['type']} (length: {meta['length']}, elements: {meta['element_type']})")
    #         else:
    #             print(f"  Type: {meta['type']}")
    #             if 'value' in meta:
    #                 print(f"  Value: {meta['value']}")

    # Create field summary for JSON output
    field_summary = {}
    for field_name, info in field_analysis.items():
        field_summary[field_name] = {
            "present_in_files": info["count"],
            "present_in_percentage": round(info["count"] / len(files) * 100, 1),
            "metadata": info["metadata"],
            "consistent_shape": info["consistent_shape"],
        }
        if not info["consistent_shape"]:
            field_summary[field_name]["shapes_seen"] = sorted([list(s) for s in info["shapes_seen"]])

    # final aggregate statistics
    agg_stats = {
        "num_episodes": agg["num_episodes"],
        "average_length": float(np.mean(agg["lengths"])),
        "min_length": int(min(agg["lengths"])),
        "max_length": int(max(agg["lengths"])),
        "base_height": {k: v.item() if torch.is_tensor(v) else v.tolist() for k, v in agg["base_height"].items()},
        "base_lin_vel_b": {k: v.tolist() for k, v in agg["base_lin_vel_b"].items()},
        "base_ang_vel_b": {k: v.tolist() for k, v in agg["base_ang_vel_b"].items()},
        "base_quat": {k: v.tolist() for k, v in agg["base_quat"].items()},
        "joint_pos_global_range": agg["joint_pos"],
        "joint_vel_global_range": agg["joint_vel"],  # Added joint velocity global ranges
        "base_pos": {k: v.tolist() for k, v in agg["base_pos"].items()},
        "avg_start_pos": np.mean(agg["start_pos_list"], axis=0).tolist(),
        "field_analysis": field_summary,
        "angular_velocity_analysis": {
            "base": base_ang_vel_analysis,
            "joints": joint_vel_analysis,
        }
    }

    # Determine angular-velocity unit (deg/s vs rad/s)
    max_ang_vel = max(abs(x) for x in agg_stats["base_ang_vel_b"]["max"])
    base_ang_unit = _determine_angular_unit(max_ang_vel)
    agg_stats["base_ang_vel_unit"] = base_ang_unit

    # Analyze joint velocity units
    joint_vel_units = {}
    max_joint_vels = {}
    for joint_name, vel_range in agg["joint_vel"].items():
        max_vel = max(abs(vel_range["min"]), abs(vel_range["max"]))
        max_joint_vels[joint_name] = max_vel
        joint_vel_units[joint_name] = _determine_angular_unit(max_vel)
    
    # Check if all joints use the same unit
    unique_units = set(joint_vel_units.values())
    if len(unique_units) == 1:
        joint_vel_unit = next(iter(unique_units))
        print(f"\nAll joint velocities appear to be in {joint_vel_unit}")
    else:
        print("\nWARNING: Inconsistent joint velocity units detected:")
        for unit in unique_units:
            joints = [name for name, u in joint_vel_units.items() if u == unit]
            print(f"  {unit}: {', '.join(joints)}")

    # Add joint velocity analysis to aggregate stats
    agg_stats["joint_vel_units"] = joint_vel_units
    agg_stats["joint_vel_max_magnitude"] = max_joint_vels

    print(f"\nEstimated base angular velocity unit: {base_ang_unit} (max ω ≈ {max_ang_vel:.2f})")
    print("Joint velocity analysis added to aggregate_stats.json")

    # Print detailed analysis
    print("\nAngular Velocity Analysis:")
    print("\nBase Angular Velocity:")
    for axis, analysis in base_ang_vel_analysis.items():
        print(f"  {axis}-axis: Likely {analysis['likely_unit']} (confidence: {analysis['confidence']:.2f})")
        print(f"    Max: {analysis['max_value']:.2f} {analysis['original_unit']}")
        print(f"    Mean: {analysis['mean_value']:.2f} {analysis['original_unit']}")

    print("\nJoint Velocities:")
    for joint, analysis in joint_vel_analysis.items():
        print(f"  {joint}: Likely {analysis['likely_unit']} (confidence: {analysis['confidence']:.2f})")
        print(f"    Max: {analysis['max_value']:.2f} {analysis['original_unit']}")
        print(f"    Mean: {analysis['mean_value']:.2f} {analysis['original_unit']}")

    # write files
    (root / "episode_stats.json").write_text(json.dumps(episode_stats, indent=2))
    (root / "aggregate_stats.json").write_text(json.dumps(agg_stats, indent=2))

    print(f"\nAnalysis complete. Results saved to episode_stats.json and aggregate_stats.json")
    # print(f"Field analysis included for {len(all_fields)} unique fields found across all files.")

# ----------------------------------------------------------------------------------

if __name__ == "__main__":
    parser = argparse.ArgumentParser(description="Analyse Unitree G1 AMASS dataset")
    parser.add_argument("--root", type=str, required=True, help="Root folder of trajectories")
    args = parser.parse_args()

    analyse_dataset(Path(args.root).expanduser())