# -*- coding: utf-8 -*-
"""build_moves / apply_move 的正确性自测（无需 pytest）: python tests/test_moves.py"""
import os
import random
import sys

sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
sys.stdout.reconfigure(encoding="utf-8")

from favsort import apply_move, build_moves, lcs_keep  # noqa: E402


def run_case(cur, tgt, label):
    moves = build_moves(cur, tgt)
    work = list(cur)
    for m in moves:
        assert m["pred"] is not None, f"{label}: pred 为空"
        work = apply_move(work, m)
    assert work == tgt, f"{label}: 结果不符\n  cur={cur}\n  tgt={tgt}\n  got={work}"
    lower = len(lcs_keep(cur, tgt))
    # 不追求严格最优（多轮 LCS 会略多于下界），但不能出现病态膨胀
    assert len(moves) <= len(cur) + 8, (
        f"{label}: 步数异常 {len(moves)} (n={len(cur)}, 下界={len(cur) - lower})"
    )
    return len(moves)


def main():
    random.seed(20261031)
    total = 0
    for n in range(1, 13):
        ids = [1000 + i for i in range(n)]
        for _ in range(200):
            cur = ids[:]
            tgt = ids[:]
            random.shuffle(cur)
            random.shuffle(tgt)
            run_case(cur, tgt, f"n={n}")
            total += 1

    # 头部必须换人的用例
    cases = [
        ([3, 2, 1], [1, 2, 3]),
        ([5, 4, 3, 2, 1], [1, 2, 3, 4, 5]),
        ([2, 3, 1], [1, 2, 3]),
        ([4, 1, 2, 3], [1, 2, 3, 4]),
    ]
    for cur, tgt in cases:
        run_case(cur, tgt, f"head {cur}->{tgt}")

    # 已排序不应产生移动
    assert build_moves([1, 2, 3], [1, 2, 3]) == []
    print(f"OK: {total} 个随机用例 + {len(cases)} 个头部用例全部通过")


if __name__ == "__main__":
    main()