"""
YouTubeASL Dataset Preprocessing for SMKD
Generates {mode}_info.npy and gloss_dict.npy in the same format as Phoenix/CSL-Daily.
"""

import argparse
import csv
import os
import random
import re
from collections import Counter

import numpy as np


BASE_COLUMNS = {"VIDEO_NAME", "CLIP_INDEX", "CLIP_PATH"}


def _str2bool(value):
    if isinstance(value, bool):
        return value
    if value is None:
        return False
    value = str(value).strip().lower()
    if value in {"1", "true", "yes", "y", "t"}:
        return True
    if value in {"0", "false", "no", "n", "f"}:
        return False
    raise ValueError(f"Invalid boolean value: {value}")


def _normalize_label(raw_text, label_column):
    text = (raw_text or "").strip()
    if not text:
        return ""
    if label_column.upper() == "TEXT":
        normalized = text.lower()
        normalized = re.sub(r"[^\w']+", " ", normalized)
        normalized = " ".join(normalized.split())
        return normalized
    return " ".join(text.split())


def _read_manifest(manifest_path, label_column, video_root=None):
    samples = []
    skipped = {"missing": 0, "empty": 0, "no_text": 0}

    with open(manifest_path, "r", encoding="utf-8") as f:
        reader = csv.DictReader(f, delimiter="\t")
        fieldnames = reader.fieldnames or []
        field_map = {name.upper(): name for name in fieldnames}
        required = {c.upper() for c in BASE_COLUMNS}
        required.add(label_column.upper())
        missing = sorted([c for c in required if c not in field_map])
        if missing:
            raise ValueError(
                f"Manifest missing required columns: {missing}. "
                f"Available: {fieldnames}"
            )

        video_key = field_map["VIDEO_NAME"]
        clip_index_key = field_map["CLIP_INDEX"]
        clip_path_key = field_map["CLIP_PATH"]
        label_key = field_map[label_column.upper()]
        start_key = field_map.get("START")
        end_key = field_map.get("END")

        for row in reader:
            clip_path = (row.get(clip_path_key) or "").strip()
            raw_label = (row.get(label_key) or "").strip()
            label = _normalize_label(raw_label, label_column)
            if not label:
                skipped["no_text"] += 1
                continue

            if video_root and clip_path and not os.path.isabs(clip_path):
                clip_path = os.path.join(video_root, clip_path)

            if not clip_path or not os.path.exists(clip_path):
                skipped["missing"] += 1
                continue
            if os.path.getsize(clip_path) == 0:
                skipped["empty"] += 1
                continue

            video_name = (row.get(video_key) or "").strip()
            clip_index_raw = (row.get(clip_index_key) or "").strip()
            try:
                clip_index = int(clip_index_raw)
                file_id = f"{video_name}_{clip_index:04d}"
            except ValueError:
                file_id = f"{video_name}_{clip_index_raw}"

            sample = {
                "id": file_id,
                "video_name": video_name,
                "clip_index": clip_index_raw,
                "label": label,
                "clip_path": clip_path,
                "start": (row.get(start_key) or "").strip() if start_key else "",
                "end": (row.get(end_key) or "").strip() if end_key else "",
            }
            samples.append(sample)

    return samples, skipped


def _split_by_video(samples, seed, val_size, test_size):
    groups = {}
    for sample in samples:
        groups.setdefault(sample["video_name"], []).append(sample)

    rng = random.Random(seed)
    video_names = list(groups.keys())
    rng.shuffle(video_names)

    train, val, test = [], [], []
    for video_name in video_names:
        group = groups[video_name]
        if len(test) < test_size:
            test.extend(group)
            continue
        if len(val) < val_size:
            val.extend(group)
            continue
        train.extend(group)

    return train, val, test


def _move_one_video_group(src, dst):
    if not src:
        return False
    video_name = src[0]["video_name"]
    group = [s for s in src if s["video_name"] == video_name]
    if not group:
        return False
    src[:] = [s for s in src if s["video_name"] != video_name]
    dst.extend(group)
    return True


def preprocess_youtubeasl(
    manifest_path,
    label_column,
    output_dir,
    prefix_for_smkd=None,
    seed=1234,
    val_size=300,
    test_size=100,
    sample_ratio=1.0,
    val_ratio=None,
    test_ratio=None,
    dev_from_train_count=0,
    dev_from_train_keep=False,
    video_root=None,
    frames_root=None,
    min_frames=0,
    max_frames=0,
    evaluation_prefix="youtubeasl-groundtruth",
):
    print(f"Loading manifest: {manifest_path}")
    samples, skipped = _read_manifest(
        manifest_path, label_column=label_column, video_root=video_root
    )

    print(f"Total samples: {len(samples)}")
    if not (0 < sample_ratio <= 1.0):
        raise ValueError(f"sample_ratio must be in (0, 1], got {sample_ratio}")
    if sample_ratio < 1.0:
        rng = random.Random(seed)
        rng.shuffle(samples)
        keep = max(1, int(len(samples) * sample_ratio))
        samples = samples[:keep]
        print(f"Sampled {len(samples)} samples ({sample_ratio:.2%} of manifest)")
    if any(skipped.values()):
        print(
            "Skipped samples: "
            + ", ".join(f"{k}={v}" for k, v in skipped.items() if v)
        )

    if val_ratio is not None or test_ratio is not None:
        if val_ratio is None or test_ratio is None:
            raise ValueError("Both val_ratio and test_ratio must be set when using ratios")
        if not (0 <= val_ratio < 1.0 and 0 <= test_ratio < 1.0):
            raise ValueError("val_ratio and test_ratio must be in [0, 1)")
        if val_ratio + test_ratio >= 1.0:
            raise ValueError("val_ratio + test_ratio must be < 1.0")
        val_size = max(1, int(len(samples) * val_ratio)) if val_ratio > 0 else 0
        test_size = max(1, int(len(samples) * test_ratio)) if test_ratio > 0 else 0
        print(
            f"Using ratio-based split: val={val_ratio:.2%} ({val_size}), "
            f"test={test_ratio:.2%} ({test_size})"
        )

    train_samples, val_samples, test_samples = _split_by_video(
        samples, seed=seed, val_size=val_size, test_size=test_size
    )

    # Ensure non-empty dev/test splits when possible by moving one video group.
    if len(val_samples) == 0:
        moved = _move_one_video_group(train_samples, val_samples)
        if not moved:
            _move_one_video_group(test_samples, val_samples)
        if len(val_samples) > 0:
            print(f"Adjusted split to ensure non-empty dev; dev={len(val_samples)}")
    if len(test_samples) == 0:
        moved = _move_one_video_group(train_samples, test_samples)
        if not moved:
            _move_one_video_group(val_samples, test_samples)
        if len(test_samples) > 0:
            print(f"Adjusted split to ensure non-empty test; test={len(test_samples)}")

    if dev_from_train_count and train_samples:
        rng = random.Random(seed)
        rng.shuffle(train_samples)
        count = min(int(dev_from_train_count), len(train_samples))
        val_samples = train_samples[:count]
        if not dev_from_train_keep:
            train_samples = train_samples[count:]
            print(f"Dev set overridden by {count} sample(s) from train (removed from train).")
        else:
            print(f"Dev set overridden by {count} sample(s) from train (kept in train).")
    elif dev_from_train_count and not train_samples:
        print("Warning: dev_from_train_count set but train split is empty; dev unchanged.")

    if len(val_samples) < val_size or len(test_samples) < test_size:
        print(
            "Warning: requested split sizes not reached. "
            f"val={len(val_samples)} (target {val_size}), "
            f"test={len(test_samples)} (target {test_size})."
        )

    if len(val_samples) > val_size or len(test_samples) > test_size:
        print(
            "Note: split sizes exceeded targets due to grouping by VIDEO_NAME. "
            f"val={len(val_samples)} (target {val_size}), "
            f"test={len(test_samples)} (target {test_size})."
        )

    splits = {
        "train": train_samples,
        "dev": val_samples,
        "test": test_samples,
    }

    print(
        f"Split - Train: {len(train_samples)}, Dev: {len(val_samples)}, Test: {len(test_samples)}"
    )

    os.makedirs(output_dir, exist_ok=True)

    if frames_root:
        frames_root = os.path.abspath(frames_root)
        prefix_for_smkd = frames_root

    kept_by_split = {}
    for mode, samples_list in splits.items():
        info_dict = {"prefix": prefix_for_smkd}
        kept = 0
        kept_samples = []

        for sample in samples_list:
            frame_count = -1
            if frames_root:
                clip_name = os.path.splitext(os.path.basename(sample["clip_path"]))[0]
                folder_path = os.path.join(sample["video_name"], clip_name, "crop_frame", "*.jpg")
                abs_dir = os.path.join(frames_root, sample["video_name"], clip_name, "crop_frame")
                if not os.path.isdir(abs_dir):
                    continue
                frame_count = len([p for p in os.listdir(abs_dir) if p.lower().endswith(".jpg")])
                if min_frames and frame_count < min_frames:
                    continue
                if max_frames and frame_count > max_frames:
                    continue
            else:
                folder_path = sample["clip_path"]

            info_dict[kept] = {
                "fileid": sample["id"],
                "folder": folder_path,
                "signer": "Unknown",
                "label": sample["label"],
                "num_frames": frame_count,
                "original_info": (sample, kept, sample["id"]),
            }
            kept += 1
            kept_samples.append(sample)

        info_path = os.path.join(output_dir, f"{mode}_info.npy")
        np.save(info_path, info_dict)
        print(f"Saved {mode}_info.npy with {kept} samples")

        kept_by_split[mode] = kept_samples

    gloss_counter = Counter()
    for kept_samples in kept_by_split.values():
        for sample in kept_samples:
            gloss_counter.update(sample["label"].split())

    gloss_dict = {}
    for idx, (gloss, count) in enumerate(sorted(gloss_counter.items()), start=1):
        gloss_dict[gloss] = [idx, count]

    gloss_dict_path = os.path.join(output_dir, "gloss_dict.npy")
    np.save(gloss_dict_path, gloss_dict)
    print(f"Saved gloss_dict.npy with {len(gloss_dict)} glosses")

    for mode, kept_samples in kept_by_split.items():
        stm_path = os.path.join(output_dir, f"{evaluation_prefix}-{mode}.stm")
        with open(stm_path, "w", encoding="utf-8") as f:
            for sample in kept_samples:
                utt_id = sample["id"]
                gloss = sample["label"]
                signer = "Unknown"
                f.write(f"{utt_id} 1 {signer} 0.0 1.79769e+308 {gloss}\n")
        print(f"Saved {stm_path}")

    print("\nPreprocessing complete!")
    print(f"Output directory: {output_dir}")
    print("Files generated:")
    print("  - gloss_dict.npy")
    print("  - train_info.npy, dev_info.npy, test_info.npy")
    print(
        f"  - {evaluation_prefix}-train.stm, {evaluation_prefix}-dev.stm, {evaluation_prefix}-test.stm"
    )


if __name__ == "__main__":
    parser = argparse.ArgumentParser(
        description="Preprocess YouTubeASL dataset for SMKD (video inputs)."
    )
    parser.add_argument(
        "--manifest-path",
        type=str,
        default="../../../YouTubeASL/video1000size/manifest_top1000.tsv",
        help="Path to manifest_top1000.tsv (relative to scripts/)",
    )
    parser.add_argument(
        "--label-column",
        type=str,
        default="TEXT",
        help="Column to use as label (e.g., TEXT or GLOSS).",
    )
    parser.add_argument(
        "--video-root",
        type=str,
        default="../../../YouTubeASL",
        help="Root for relative CLIP_PATH entries (relative to scripts/)",
    )
    parser.add_argument(
        "--prefix-for-smkd",
        type=str,
        default="",
        help="Prefix stored in info.npy; leave empty to use absolute clip paths",
    )
    parser.add_argument(
        "--output-dir",
        type=str,
        default="../../smkd/youtubeasl",
        help="Output directory for preprocessed files",
    )
    parser.add_argument("--seed", type=int, default=1234, help="Random seed")
    parser.add_argument(
        "--val-size",
        type=int,
        default=300,
        help="Validation split size (by clips)",
    )
    parser.add_argument(
        "--test-size",
        type=int,
        default=100,
        help="Test split size (by clips)",
    )
    parser.add_argument(
        "--val-ratio",
        type=float,
        default=None,
        help="Validation split ratio over the sampled manifest (e.g., 0.06)",
    )
    parser.add_argument(
        "--test-ratio",
        type=float,
        default=None,
        help="Test split ratio over the sampled manifest (e.g., 0.04)",
    )
    parser.add_argument(
        "--dev-from-train-count",
        type=int,
        default=0,
        help="Override dev split with N samples drawn from train.",
    )
    parser.add_argument(
        "--dev-from-train-keep",
        type=_str2bool,
        default=False,
        help="Keep dev samples in train when overriding dev split.",
    )
    parser.add_argument(
        "--sample-ratio",
        type=float,
        default=1.0,
        help="Randomly sample this fraction of the manifest before splitting",
    )
    parser.add_argument(
        "--frames-root",
        type=str,
        default="../../../YouTubeASL/video1000size_frames",
        help="Root directory containing extracted frames (relative to scripts/).",
    )
    parser.add_argument(
        "--min-frames",
        type=int,
        default=5,
        help="Minimum number of frames required when using extracted frames.",
    )
    parser.add_argument(
        "--evaluation-prefix",
        type=str,
        default="youtubeasl-groundtruth",
        help="Prefix for generated STM files",
    )

    args = parser.parse_args()

    prefix_for_smkd = args.prefix_for_smkd if args.prefix_for_smkd else None
    video_root = args.video_root if args.video_root else None
    frames_root = args.frames_root if args.frames_root else None
    min_frames = args.min_frames if args.min_frames else 0
    if frames_root and not prefix_for_smkd:
        prefix_for_smkd = frames_root

    preprocess_youtubeasl(
        manifest_path=args.manifest_path,
        label_column=args.label_column,
        output_dir=args.output_dir,
        prefix_for_smkd=prefix_for_smkd,
        seed=args.seed,
        val_size=args.val_size,
        test_size=args.test_size,
        sample_ratio=args.sample_ratio,
        val_ratio=args.val_ratio,
        test_ratio=args.test_ratio,
        dev_from_train_count=args.dev_from_train_count,
        dev_from_train_keep=args.dev_from_train_keep,
        video_root=video_root,
        frames_root=frames_root,
        min_frames=min_frames,
        evaluation_prefix=args.evaluation_prefix,
    )