"""R622：合成运行分层快照，定位首次差异，保留后续影响。"""
from copy import deepcopy
from hashlib import sha256
import json
from math import isclose
from random import Random

LAYERS = ["data", "config", "runtime", "signals", "fills", "equity"]


def fingerprint(value):
    return sha256(json.dumps(value, sort_keys=True, separators=(",", ":")).encode()).hexdigest()


def simulate(prices, hidden_fee=0):
    config = {"threshold": 0, "seed": 7, "initial_cash": 1000}
    rng = Random(config["seed"])
    signals = [int(prices[t] / prices[t-1] - 1 > config["threshold"])
               for t in range(1, len(prices)-1)]
    cash, shares, fills, equity = float(config["initial_cash"]), 0, [], []
    for t, signal in enumerate(signals, 1):
        if signal:
            price = round(prices[t+1] + rng.random() / 100, 6)
            fills.append({"signal_t": t, "fill_t": t+1, "qty": 1,
                          "price": price, "fee": hidden_fee})
            cash -= price + hidden_fee
            shares += 1
        equity.append(round(cash + shares * prices[t+1], 6))
    return {"data": list(prices), "config": config,
            "runtime": {"engine": "synthetic-v1", "code": "frozen-example"},
            "signals": signals, "fills": fills, "equity": equity}


def first_difference(left, right):
    return next((layer for layer in LAYERS if left[layer] != right[layer]), None)


def run():
    base = simulate([100, 102, 101, 104])
    repeat = simulate([100, 102, 101, 104])
    assert first_difference(base, repeat) is None
    assert fingerprint(base) == fingerprint(repeat)
    revised = simulate([100, 102, 103, 104])
    assert first_difference(base, revised) == "data"
    assert base["signals"] == [1, 0] and revised["signals"] == [1, 1]
    hidden = simulate([100, 102, 101, 104], hidden_fee=0.25)
    assert first_difference(base, hidden) == "fills"
    assert isclose(base["equity"][-1] - hidden["equity"][-1], 0.25, abs_tol=1e-9)
    # 不同文件外观也可能来自对象键次序，规范化摘要应相同。
    reordered = {key: deepcopy(base[key]) for key in reversed(LAYERS)}
    assert fingerprint(base) == fingerprint(reordered)
    print("repeat_first_difference=None normalized_digest_equal=True")
    print("revised_first_difference=data signals=[1, 0]->[1, 1]")
    print("hidden_fee_first_difference=fills final_equity_delta=0.250000")
    print("reordered_keys_normalized_equal=True")


if __name__ == "__main__":
    run()