from __future__ import annotations

from pathlib import Path
from typing import Any

import numpy as np
import pandas as pd

from fall.data.features import add_keypoint_noise, apply_frame_drop, pose_to_feature_vector, resize_or_pad_sequence
from fall.data.video import read_sampled_frames


class PoseDataset:
    def __init__(
        self,
        manifest: str | Path,
        split: str = "train",
        frames: int = 32,
        use_confidence: bool = True,
        use_velocity: bool = True,
        min_confidence: float = 0.05,
        frame_drop: float = 0.0,
        keypoint_noise: float = 0.0,
        seed: int = 42,
    ) -> None:
        import torch
        from torch.utils.data import Dataset

        self._base = Dataset
        self.torch = torch
        df = pd.read_csv(manifest)
        if split != "all" and "split" in df.columns:
            df = df[df["split"] == split]
        if df.empty:
            raise RuntimeError(f"No rows for split '{split}' in {manifest}")
        self.df = df.reset_index(drop=True)
        self.frames = frames
        self.use_confidence = use_confidence
        self.use_velocity = use_velocity
        self.min_confidence = min_confidence
        self.frame_drop = frame_drop
        self.keypoint_noise = keypoint_noise
        self.rng = np.random.default_rng(seed)

    def __len__(self) -> int:
        return len(self.df)

    def __getitem__(self, idx: int) -> dict[str, Any]:
        row = self.df.iloc[idx]
        pose_path = row.get("pose_path")
        if not isinstance(pose_path, str):
            raise KeyError("PoseDataset requires a 'pose_path' column.")
        pose = np.load(pose_path).astype(np.float32)
        pose = resize_or_pad_sequence(pose, self.frames)
        pose = apply_frame_drop(pose, self.frame_drop, self.rng)
        pose = add_keypoint_noise(pose, self.keypoint_noise, self.rng)
        x = pose_to_feature_vector(
            pose,
            use_confidence=self.use_confidence,
            use_velocity=self.use_velocity,
            min_conf=self.min_confidence,
        )
        return {
            "x": self.torch.from_numpy(x),
            "y": self.torch.tensor(float(row["label"]), dtype=self.torch.float32),
            "video_id": str(row.get("video_id", idx)),
        }

    @property
    def input_dim(self) -> int:
        item = self[0]["x"]
        return int(item.shape[-1])


class RGBVideoDataset:
    def __init__(
        self,
        manifest: str | Path,
        split: str = "train",
        frames: int = 32,
        image_size: int = 112,
    ) -> None:
        import torch

        self.torch = torch
        df = pd.read_csv(manifest)
        if split != "all" and "split" in df.columns:
            df = df[df["split"] == split]
        if df.empty:
            raise RuntimeError(f"No rows for split '{split}' in {manifest}")
        self.df = df.reset_index(drop=True)
        self.frames = frames
        self.image_size = image_size

    def __len__(self) -> int:
        return len(self.df)

    def __getitem__(self, idx: int) -> dict[str, Any]:
        row = self.df.iloc[idx]
        rgb_path = row.get("rgb_path", None)
        if isinstance(rgb_path, str) and rgb_path:
            frames = np.load(rgb_path).astype(np.float32) / 255.0
            frames = frames[: self.frames]
            while len(frames) < self.frames:
                frames = np.concatenate([frames, frames[-1:]], axis=0)
        else:
            start = row.get("start", None)
            end = row.get("end", None)
            fps = row.get("fps", None)
            start = None if pd.isna(start) else float(start)
            end = None if pd.isna(end) else float(end)
            fps = None if pd.isna(fps) else float(fps)
            frames = read_sampled_frames(row["video_path"], self.frames, resize=self.image_size, start=start, end=end, fps=fps).astype(np.float32) / 255.0
        frames = np.transpose(frames, (0, 3, 1, 2))
        return {
            "x": self.torch.from_numpy(frames),
            "y": self.torch.tensor(float(row["label"]), dtype=self.torch.float32),
            "video_id": str(row.get("video_id", idx)),
        }