"""账本两阶段计费测试（T-P1）：预扣-结算-回补一致 / 幂等 / 跨日重置 / 并发不超扣。"""
import threading

import pytest

from gateway.proxy.ledger import Ledger


@pytest.fixture()
def led(tmp_path):
    return Ledger.init_db(tmp_path / "proxy.sqlite3")


def _mk_student_key(led, balance_yuan=1.0, cap_yuan=5.0):
    sid = led.upsert_student("测试生", balance_yuan=balance_yuan, daily_cap_yuan=cap_yuan)
    kid = led.create_key(sid, f"hash-{sid}", f"prefix-{sid}")
    return sid, kid


def test_hold_settle_refund_consistency(led):
    """预扣-结算-回补全链条：余额/日消费/流水三处一致。"""
    sid, kid = _mk_student_key(led, balance_yuan=1.0)            # 1000 毫元
    ts = 1788300000.0
    assert led.try_hold("r1", kid, sid, "m", "b", 400, ts) is True
    assert led.get_student(sid)["balance_milli"] == 600
    assert led.get_student(sid)["spent_today_milli"] == 400
    # 结算实际 300 -> 回补 100
    assert led.settle("r1", 300, in_miss_tok=100, out_tok=50,
                      upstream_cost_milli=200) is True
    stu = led.get_student(sid)
    assert stu["balance_milli"] == 700
    assert stu["spent_today_milli"] == 300
    u = led.get_usage("r1")
    assert u["charged_milli"] == 300
    assert u["margin_milli"] == 100                     # charged - upstream_cost
    assert u["status"] == "ok"


def test_settle_underpay_and_overpay(led):
    """结算高于预扣（多扣余额）/低于预扣（回补）两个方向。"""
    sid, kid = _mk_student_key(led, balance_yuan=1.0)
    ts = 1788300000.0
    led.try_hold("r1", kid, sid, "m", "b", 100, ts)
    led.settle("r1", 250)                                # 实际更贵 -> 余额再多扣 150
    assert led.get_student(sid)["balance_milli"] == 1000 - 250
    led.try_hold("r2", kid, sid, "m", "b", 100, ts)
    led.settle("r2", 40)                                 # 实际更便宜 -> 回补 60
    assert led.get_student(sid)["balance_milli"] == 1000 - 250 - 40


def test_hold_insufficient_balance_402(led):
    sid, kid = _mk_student_key(led, balance_yuan=0.01)   # 10 毫元
    assert led.try_hold("r1", kid, sid, "m", "b", 11, ts=1788300000.0) is False
    u = led.get_usage("r1")
    assert u["status"] == "insufficient" and u["charged_milli"] == 0
    assert led.get_student(sid)["balance_milli"] == 10   # 未扣


def test_daily_cap_blocks(led):
    """日消费上限：累计超限拒（402 语义）。"""
    sid, kid = _mk_student_key(led, balance_yuan=10.0, cap_yuan=0.5)   # 日上限 500
    ts = 1788300000.0
    assert led.try_hold("r1", kid, sid, "m", "b", 300, ts) is True
    assert led.try_hold("r2", kid, sid, "m", "b", 300, ts) is False    # 600 > 500
    assert led.try_hold("r3", kid, sid, "m", "b", 200, ts) is True     # 500 == 500 可
    # 结算回补后额度释放：spent = 500 - 200(回补) = 300
    led.settle("r1", 100)
    assert led.try_hold("r4", kid, sid, "m", "b", 300, ts) is False   # 300+300=600 超限
    assert led.try_hold("r5", kid, sid, "m", "b", 200, ts) is True    # 300+200=500 恰好


def test_hold_idempotent_on_request_id(led):
    """request_id 幂等：重复 hold 不重复扣。"""
    sid, kid = _mk_student_key(led, balance_yuan=1.0)
    ts = 1788300000.0
    assert led.try_hold("dup", kid, sid, "m", "b", 100, ts) is True
    assert led.try_hold("dup", kid, sid, "m", "b", 100, ts) is True
    assert led.get_student(sid)["balance_milli"] == 900


def test_daily_reset_across_days(led):
    """跨日重置：注入更晚时间戳，req_today/spent_today 归零。"""
    sid, kid = _mk_student_key(led, balance_yuan=1.0, cap_yuan=0.1)    # 日上限 100
    t1 = 1788300000.0                                   # 某日
    led.check_and_count(kid, sid, t1)
    led.try_hold("r1", kid, sid, "m", "b", 100, t1)
    assert led.get_student(sid)["spent_today_milli"] == 100
    t2 = t1 + 86400 + 60                                # 次日
    assert led.check_and_count(kid, sid, t2) is True    # 新一天计数重置
    assert led.try_hold("r2", kid, sid, "m", "b", 100, t2) is True
    assert led.get_student(sid)["spent_today_milli"] == 100   # 新一天重新累计


def test_void_full_refund(led):
    """上游失败全额退款；重复 void 不二次退。"""
    sid, kid = _mk_student_key(led, balance_yuan=1.0)
    ts = 1788300000.0
    led.try_hold("r1", kid, sid, "m", "b", 400, ts)
    assert led.void("r1", status="aborted") is True
    assert led.get_student(sid)["balance_milli"] == 1000
    assert led.get_usage("r1")["charged_milli"] == 0
    assert led.get_usage("r1")["status"] == "aborted"
    assert led.void("r1") is False                      # 已不是 holding


def test_concurrent_hold_never_overdraft(led):
    """并发 N 路同时预扣：余额不足者精确拒绝、不超扣（D-P11 核心验收）。"""
    sid, kid = _mk_student_key(led, balance_yuan=0.01)   # 10 毫元
    results = []
    lock = threading.Lock()

    def worker(i):
        ok = led.try_hold(f"c{i}", kid, sid, "m", "b", 5, ts=1788300000.0)
        with lock:
            results.append(ok)

    threads = [threading.Thread(target=worker, args=(i,)) for i in range(10)]
    for t in threads:
        t.start()
    for t in threads:
        t.join()
    assert sorted(results) == [False] * 8 + [True] * 2  # 恰好 2 路成功
    assert led.get_student(sid)["balance_milli"] == 0   # 精确扣完，不为负


def test_record_idempotent_via_primary_key(led):
    """流水主键幂等：同 request_id 只保留一条。"""
    sid, kid = _mk_student_key(led)
    led.try_hold("px", kid, sid, "m", "b", 10, ts=1788300000.0)
    led.try_hold("px", kid, sid, "m", "b", 10, ts=1788300000.0)
    led.settle("px", 5)
    assert led.get_usage("px")["charged_milli"] == 5
    assert len(led.list_usage()) == 1