#!/usr/bin/env python3
"""
Transform:
{
    "<property>": [
        {"ts": 123, "value": 10},
        {"ts": 456, "value": 20},
        ...
    ],
    ...
}

into:
[
    {"ts": 123, "values": {"<property>": 10}},
    {"ts": 456, "values": {"<property>": 20}},
    ...
]
"""

import json
import sys
from collections import defaultdict

def transform(data: dict) -> list:
    """
    Accepts a dict where each key is a property name and the value is a
    list of {ts, value} objects.  Returns a list of objects sorted by
    timestamp, each with a 'values' dict that maps the property name to
    its value for that timestamp.
    """
    # Group values by timestamp first (so if you have several properties
    # they’ll be merged on the same ts).
    grouped = defaultdict(dict)

    for prop, items in data.items():
        for item in items:
            ts = item["ts"]
            grouped[ts][prop] = item["value"]

    # Build the final list, sorted by ts for deterministic order
    result = [{"ts": ts, "values": grouped[ts]} for ts in sorted(grouped)]
    return result


def main():
    # Load JSON from stdin or a file
    if len(sys.argv) > 1:          # optional filename argument
        with open(sys.argv[1], "r", encoding="utf-8") as f:
            raw = json.load(f)
    else:
        raw = json.load(sys.stdin)

    out = transform(raw)

    # Pretty‑print to stdout
    json.dump(out, sys.stdout, indent=2, ensure_ascii=False)
    print()  # add final newline


if __name__ == "__main__":
    main()