#!/usr/bin/env python3
"""Merge multiple JSON list files into one training JSON."""

import argparse
import json
import os
import sys
from typing import List, Tuple


"""
python sample_data/merge_json.py \
    --inputs /share/zhaohu_workspace/VideoDataProcessing/syncnet_claude/sample_data/sampled_data_1.json /share/zhaohu_workspace/VideoDataProcessing/syncnet_claude/sample_data/sampled_data_2.json /share/zhaohu_workspace/VideoDataProcessing/syncnet_claude/sample_data/sampled_data_3.json \
    --output sample_data/train_merged.json \
    --shuffle --seed 123 \
    --bins "0,2;2,5;5,8;8,10"
"""
def parse_args() -> argparse.Namespace:
    parser = argparse.ArgumentParser(
        description="Merge multiple JSON list files into a single JSON file.",
    )
    parser.add_argument(
        "--inputs",
        nargs="+",
        required=True,
        help="Input JSON paths (each must be a list)",
    )
    parser.add_argument(
        "--output",
        required=True,
        help="Output JSON path",
    )
    parser.add_argument(
        "--shuffle",
        action="store_true",
        help="Shuffle merged items before saving",
    )
    parser.add_argument(
        "--seed",
        type=int,
        default=42,
        help="Random seed used when --shuffle is set (default: 42)",
    )
    parser.add_argument(
        "--bins",
        default="0,2;2,5",
        help=(
            "Score bins as 'start,end;start,end;...'. "
            "Example: 0,2;2,5;5,10 (default: 0,2;2,5)"
        ),
    )
    return parser.parse_args()


def main() -> int:
    args = parse_args()

    merged = []
    null_dropped = 0
    score_null_dropped = 0
    total_scored = 0
    for path in args.inputs:
        with open(path, "r", encoding="utf-8") as f:
            data = json.load(f)
        if not isinstance(data, list):
            print(f"Input JSON must be a list: {path}", file=sys.stderr)
            return 2
        for item in data:
            if item is None:
                null_dropped += 1
                continue
            if isinstance(item, dict) and item.get("syncnet_confidence_score") is None:
                score_null_dropped += 1
                continue
            merged.append(item)

    if args.shuffle:
        import random

        random.seed(args.seed)
        random.shuffle(merged)

    bins = _parse_bins(args.bins)
    bin_counts = [0 for _ in bins]
    for item in merged:
        if not isinstance(item, dict):
            continue
        score = item.get("syncnet_confidence_score")
        if score is None:
            continue
        total_scored += 1
        for i, (start, end) in enumerate(bins):
            if start <= score < end:
                bin_counts[i] += 1
                break

    os.makedirs(os.path.dirname(args.output) or ".", exist_ok=True)
    with open(args.output, "w", encoding="utf-8") as f:
        json.dump(merged, f, ensure_ascii=False, indent=2)

    print(
        f"Merged {len(args.inputs)} files, total {len(merged)} items "
        f"(dropped {null_dropped} nulls, "
        f"{score_null_dropped} missing syncnet_confidence_score) -> {args.output}"
    )
    _print_bin_stats(bins, bin_counts, total_scored)
    return 0


def _parse_bins(text: str) -> List[Tuple[float, float]]:
    bins: List[Tuple[float, float]] = []
    for part in text.split(";"):
        part = part.strip()
        if not part:
            continue
        try:
            start_str, end_str = part.split(",")
            start = float(start_str)
            end = float(end_str)
        except ValueError as exc:
            raise SystemExit(f"Invalid --bins value: {part}") from exc
        if end <= start:
            raise SystemExit(f"Invalid --bins range (end<=start): {part}")
        bins.append((start, end))
    if not bins:
        raise SystemExit("No valid bins parsed from --bins")
    return bins


def _print_bin_stats(
    bins: List[Tuple[float, float]],
    bin_counts: List[int],
    total_scored: int,
) -> None:
    if total_scored == 0:
        print("Score bin stats: no valid scores to analyze")
        return
    print("Score bin stats:")
    for (start, end), count in zip(bins, bin_counts):
        ratio = count / total_scored
        print(f"  [{start}, {end}): {count} ({ratio:.2%})")


if __name__ == "__main__":
    raise SystemExit(main())