#!/usr/bin/env python3
"""Машинная карта сдвигов, заказанная §2.5: set-diff по id и номеру, same/moved/gone/new."""
import json, sys

def load(p):
    m = json.load(open(p, encoding="utf-8"))
    return {c["id"]: c["number"] for c in m["chapters"]}, m

def diff(before_path, after_path, source):
    a, ma = load(before_path)
    b, mb = load(after_path)
    same  = sorted(i for i in a if i in b and a[i] == b[i])
    moved = sorted(i for i in a if i in b and a[i] != b[i])
    gone  = sorted(i for i in a if i not in b)
    new   = sorted(i for i in b if i not in a)
    return {
        "source": source,
        "before": {"chapters": len(a), "structure": ma.get("structure"), "key": ma.get("key")},
        "after":  {"chapters": len(b), "structure": mb.get("structure"), "key": mb.get("key")},
        "same": len(same), "moved": len(moved), "gone": len(gone), "new": len(new),
        "moved_detail": [{"id": i, "from": a[i], "to": b[i]} for i in moved][:200],
        "gone_ids": gone[:200], "new_ids": new[:200],
        "cut_unchanged": not moved and not gone and not new,
    }

if __name__ == "__main__":
    out = [diff(*t) for t in (sys.argv[1:][i:i+3] for i in range(0, len(sys.argv)-1, 3))]
    json.dump(out, sys.stdout, ensure_ascii=False, indent=1)
    print()