"""峰谷定价（DeepSeek 自 2026-08-17 起高峰单价翻倍）。

保护的是：同一次调用在高峰与空闲时段必须记出不同的成本。若只配一套单价，
``ob_ai_call`` 会与真实账单差出接近 2 倍，而这张表是 V2 定价的唯一依据。
"""

from __future__ import annotations

from datetime import UTC, datetime, timedelta, timezone
from decimal import Decimal

import pytest

from packages.llm.cost import (
    TIER_FLAT,
    TIER_OFF_PEAK,
    TIER_PEAK,
    ModelRate,
    PeakAwareRateTable,
    RateTable,
    compute_cost_cents,
    is_peak,
)
from packages.llm.types import Usage

BEIJING = timezone(timedelta(hours=8))

OFF_PEAK = ModelRate(Decimal("150"), Decimal("5"), Decimal("450"))
PEAK = ModelRate(Decimal("300"), Decimal("10"), Decimal("900"))
MODEL = "deepseek-v4-flash"


def _table(*, enabled: bool = True) -> PeakAwareRateTable:
    return PeakAwareRateTable(
        RateTable({MODEL: OFF_PEAK}, default=OFF_PEAK),
        RateTable({MODEL: PEAK}, default=PEAK),
        enabled=enabled,
    )


@pytest.mark.parametrize(
    ("hour", "expected"),
    [
        (0, False),
        (8, False),
        (9, True),  # 高峰左闭
        (11, True),
        (12, False),  # 高峰右开
        (13, False),
        (14, True),
        (17, True),
        (18, False),
        (23, False),
    ],
)
def test_peak_windows_follow_the_published_schedule(hour: int, expected: bool) -> None:
    assert is_peak(datetime(2026, 8, 20, hour, 30, tzinfo=BEIJING)) is expected


def test_utc_input_is_converted_to_beijing_before_judging() -> None:
    # 02:00 UTC = 10:00 北京时间，属高峰。按 UTC 判定会把高峰算成空闲、成本少记一半
    assert is_peak(datetime(2026, 8, 20, 2, 0, tzinfo=UTC)) is True


def test_peak_rate_is_double_the_off_peak_rate() -> None:
    table = _table()
    usage = Usage(tokens_in=10_000, tokens_out=2_000, tokens_cached=0)

    off_peak_cost = compute_cost_cents(
        usage, table.for_model(MODEL, datetime(2026, 8, 20, 13, 0, tzinfo=BEIJING))
    )
    peak_cost = compute_cost_cents(
        usage, table.for_model(MODEL, datetime(2026, 8, 20, 10, 0, tzinfo=BEIJING))
    )

    assert peak_cost == off_peak_cost * 2


def test_disabling_peak_pricing_keeps_one_rate() -> None:
    # 供应商若取消峰谷定价，改一个开关即可，不必回滚代码
    table = _table(enabled=False)
    assert table.for_model(MODEL, datetime(2026, 8, 20, 10, 0, tzinfo=BEIJING)) is OFF_PEAK


def test_unknown_model_still_costs_money_in_both_tiers() -> None:
    table = _table()
    for hour in (10, 13):
        rate = table.for_model("some-new-model", datetime(2026, 8, 20, hour, tzinfo=BEIJING))
        assert rate.input_cents_per_mtok > 0


def test_tier_is_reported_so_cost_can_be_rechecked_later() -> None:
    # 没有档位，事后就无法判断某行 cost_cents 是按哪套单价算的
    table = _table()
    assert table.current_tier(datetime(2026, 8, 20, 10, 0, tzinfo=BEIJING)) == TIER_PEAK
    assert table.current_tier(datetime(2026, 8, 20, 13, 0, tzinfo=BEIJING)) == TIER_OFF_PEAK


def test_single_rate_tables_report_a_flat_tier() -> None:
    assert RateTable({MODEL: OFF_PEAK}, default=OFF_PEAK).current_tier() == TIER_FLAT
    assert _table(enabled=False).current_tier() == TIER_FLAT