"""Tests for the paper-trading service."""

from __future__ import annotations

from datetime import date, datetime, timedelta, timezone

import pytest

from app.exceptions import ValidationError
from app.models.benchmark_price import BenchmarkPrice
from app.models.ohlcv import OHLCVRecord
from app.models.paper_trade import PaperTrade
from app.models.ticker import Ticker
from app.models.user import User
from app.services import paper_trade_service as svc
from tests.conftest import _test_session_factory  # type: ignore


@pytest.fixture
async def session():
    async with _test_session_factory() as s:
        yield s


async def _seed(session, symbol: str, close: float) -> int:
    user = await session.get(User, 1)
    if user is None:
        session.add(User(id=1, username="u", password_hash="x", role="user", has_access=True))
        await session.flush()
    t = Ticker(symbol=symbol)
    session.add(t)
    await session.flush()
    session.add(OHLCVRecord(ticker_id=t.id, date=date.today(),
                            open=close, high=close, low=close, close=close, volume=1))
    await session.commit()
    return t.id


async def test_create_and_list_open(session):
    await _seed(session, "AAA", close=110.0)
    await svc.create_trade(session, 1, symbol="AAA", direction="long",
                           entry_price=100.0, shares=10, stop_loss=95.0, target=120.0)
    rows = await svc.list_trades(session, 1)
    assert len(rows) == 1
    row = rows[0]
    assert row["symbol"] == "AAA"
    assert row["status"] == "open"
    assert row["current_price"] == 110.0  # marked to the latest close


async def test_close_uses_current_price(session):
    await _seed(session, "AAA", close=112.0)
    trade = await svc.create_trade(session, 1, symbol="AAA", direction="long",
                                   entry_price=100.0, shares=5, stop_loss=95.0, target=120.0)
    closed = await svc.close_trade(session, 1, trade.id)
    assert closed.status == "closed"
    assert closed.close_price == 112.0
    assert closed.closed_at is not None

    rows = await svc.list_trades(session, 1, status="closed")
    assert rows[0]["current_price"] == 112.0  # closed → realized exit


async def test_close_with_explicit_price(session):
    await _seed(session, "AAA", close=112.0)
    trade = await svc.create_trade(session, 1, symbol="AAA", direction="short",
                                   entry_price=100.0, shares=5, stop_loss=105.0, target=90.0)
    closed = await svc.close_trade(session, 1, trade.id, close_price=93.0)
    assert closed.close_price == 93.0


async def test_invalid_direction_rejected(session):
    await _seed(session, "AAA", close=100.0)
    with pytest.raises(ValidationError):
        await svc.create_trade(session, 1, symbol="AAA", direction="sideways",
                               entry_price=100.0, shares=1, stop_loss=95.0, target=110.0)


async def test_double_close_rejected(session):
    await _seed(session, "AAA", close=100.0)
    trade = await svc.create_trade(session, 1, symbol="AAA", direction="long",
                                   entry_price=100.0, shares=1, stop_loss=95.0, target=110.0)
    await svc.close_trade(session, 1, trade.id)
    with pytest.raises(ValidationError):
        await svc.close_trade(session, 1, trade.id)


async def _add_bars(session, ticker_id: int, highs_lows: list[tuple[float, float]], start: date) -> None:
    for i, (hi, lo) in enumerate(highs_lows):
        mid = (hi + lo) / 2
        session.add(OHLCVRecord(ticker_id=ticker_id, date=start + timedelta(days=i + 1),
                                open=mid, high=hi, low=lo, close=mid, volume=1))
    await session.commit()


async def test_resolve_closes_on_target(session):
    await svc.set_exit_policy(session, mode="target")
    tid = await _seed(session, "AAA", close=100.0)
    trade = await svc.create_trade(session, 1, symbol="AAA", direction="long",
                                   entry_price=100.0, shares=10, stop_loss=95.0, target=110.0)
    # later bars: a day that trades up through 110
    await _add_bars(session, tid, [(103, 101), (111, 108)], start=date.today())
    closed = await svc.resolve_open_trades(session)
    assert closed == 1
    await session.refresh(trade)
    assert trade.status == "closed"
    assert trade.close_price == 110.0  # closed at target


async def test_resolve_closes_on_stop(session):
    await svc.set_exit_policy(session, mode="target")
    tid = await _seed(session, "AAA", close=100.0)
    trade = await svc.create_trade(session, 1, symbol="AAA", direction="long",
                                   entry_price=100.0, shares=10, stop_loss=95.0, target=110.0)
    await _add_bars(session, tid, [(101, 94)], start=date.today())  # low pierces stop
    closed = await svc.resolve_open_trades(session)
    assert closed == 1
    await session.refresh(trade)
    assert trade.close_price == 95.0  # closed at stop


async def test_resolve_leaves_open_when_neither_hit(session):
    await svc.set_exit_policy(session, mode="target")
    tid = await _seed(session, "AAA", close=100.0)
    await svc.create_trade(session, 1, symbol="AAA", direction="long",
                           entry_price=100.0, shares=10, stop_loss=95.0, target=110.0)
    await _add_bars(session, tid, [(103, 98), (104, 99)], start=date.today())  # range-bound
    closed = await svc.resolve_open_trades(session)
    assert closed == 0
    rows = await svc.list_trades(session, 1, status="open")
    assert len(rows) == 1


async def _seed_benchmark(session, points: dict) -> None:
    for d, close in points.items():
        session.add(BenchmarkPrice(symbol="SPY", date=d, close=close))
    await session.commit()


async def _add_open_trade(session, ticker_id: int, direction: str, *, entry: float,
                          shares: float, days_ago: int) -> None:
    session.add(PaperTrade(
        user_id=1, ticker_id=ticker_id, direction=direction, entry_price=entry,
        shares=shares, stop_loss=entry * 0.95, target=entry * 1.2, status="open",
        opened_at=datetime.now(timezone.utc) - timedelta(days=days_ago),
    ))
    await session.commit()


async def test_alpha_long_open(session):
    tid = await _seed(session, "AAA", close=110.0)  # current price 110 → +10% on a 100 entry
    today = date.today()
    await _seed_benchmark(session, {today - timedelta(days=10): 400.0, today: 420.0})  # SPY +5%
    await _add_open_trade(session, tid, "long", entry=100.0, shares=10, days_ago=10)

    row = (await svc.list_trades(session, 1, status="open"))[0]
    assert row["benchmark_return_pct"] == pytest.approx(5.0)
    assert row["alpha_pct"] == pytest.approx(5.0)            # +10% trade − 5% bench
    assert row["alpha_usd"] == pytest.approx(50.0)           # 5% of 100*10


async def test_alpha_short_and_missing_benchmark(session):
    tid = await _seed(session, "BBB", close=90.0)  # price fell to 90 → short +10%
    today = date.today()
    await _add_open_trade(session, tid, "short", entry=100.0, shares=4, days_ago=10)

    # No benchmark data yet → alpha unset, not an error.
    row = (await svc.list_trades(session, 1, status="open"))[0]
    assert row["alpha_pct"] is None
    assert row["benchmark_return_pct"] is None

    # Flat benchmark → alpha equals the (direction-signed) trade return.
    await _seed_benchmark(session, {today - timedelta(days=10): 400.0, today: 400.0})
    row = (await svc.list_trades(session, 1, status="open"))[0]
    assert row["benchmark_return_pct"] == pytest.approx(0.0)
    assert row["alpha_pct"] == pytest.approx(10.0)


def _b(d: date, hi: float, lo: float):
    return svc.Bar(date=d, high=hi, low=lo)


class TestTrailingClose:
    def test_long_locks_gain(self):
        # Runs to 120; the 12%-from-peak stop (120 → 105.6) is pierced on the drop.
        bars = [_b(date(2026, 1, 2), 120, 110), _b(date(2026, 1, 3), 130, 100)]
        hit = svc._trailing_close("long", 100.0, 95.0, 0.12, bars)
        assert hit is not None
        price, when, reason = hit
        assert price == pytest.approx(105.6)
        assert reason == "trailing"
        assert when == date(2026, 1, 3)

    def test_initial_stop_caps_loss(self):
        bars = [_b(date(2026, 1, 2), 101, 94)]  # through the initial stop before running
        hit = svc._trailing_close("long", 100.0, 95.0, 0.12, bars)
        assert hit is not None
        price, _, reason = hit
        assert price == pytest.approx(95.0)
        assert reason == "stop"

    def test_none_when_neither_hit(self):
        bars = [_b(date(2026, 1, 2), 105, 99), _b(date(2026, 1, 3), 106, 100)]
        assert svc._trailing_close("long", 100.0, 95.0, 0.12, bars) is None


async def test_exit_policy_defaults_and_round_trip(session):
    # Default: the backtest-validated hold-to-horizon exit.
    assert await svc.get_exit_policy(session) == {
        "mode": "time", "trailing_pct": 12.0, "hold_days": 30,
    }
    updated = await svc.set_exit_policy(session, mode="target", trailing_pct=15.0, hold_days=21)
    assert updated == {"mode": "target", "trailing_pct": 15.0, "hold_days": 21}
    assert (await svc.get_exit_policy(session))["mode"] == "target"


async def test_exit_policy_rejects_bad_input(session):
    with pytest.raises(ValidationError):
        await svc.set_exit_policy(session, mode="bogus")
    with pytest.raises(ValidationError):
        await svc.set_exit_policy(session, trailing_pct=200.0)
    with pytest.raises(ValidationError):
        await svc.set_exit_policy(session, hold_days=1)


def _r(d: date, open_: float, hi: float, lo: float, close: float) -> tuple:
    return (d, open_, hi, lo, close)


class TestTimeClose:
    def test_closes_at_hold_days_close(self):
        rows = [
            _r(date(2026, 1, 2), 101, 103, 100, 102),
            _r(date(2026, 1, 3), 102, 104, 101, 103),
            _r(date(2026, 1, 4), 103, 106, 102, 105),
        ]
        assert svc._time_close("long", 95.0, 3, rows) == (105.0, date(2026, 1, 4), "time")

    def test_stop_before_horizon(self):
        rows = [_r(date(2026, 1, 2), 100, 101, 94, 96)]
        assert svc._time_close("long", 95.0, 30, rows) == (95.0, date(2026, 1, 2), "stop")

    def test_gap_through_stop_fills_at_open(self):
        rows = [_r(date(2026, 1, 2), 92, 93, 90, 91)]
        assert svc._time_close("long", 95.0, 30, rows) == (92.0, date(2026, 1, 2), "stop")

    def test_none_before_horizon(self):
        rows = [_r(date(2026, 1, 2), 101, 103, 100, 102)]
        assert svc._time_close("long", 95.0, 5, rows) is None


async def test_resolve_time_mode_closes_at_horizon(session):
    await svc.set_exit_policy(session, mode="time", hold_days=2)
    tid = await _seed(session, "AAA", close=100.0)
    trade = await svc.create_trade(session, 1, symbol="AAA", direction="long",
                                   entry_price=100.0, shares=10, stop_loss=95.0, target=200.0)
    await _add_bars(session, tid, [(103, 101), (105, 102)], start=date.today())
    assert await svc.resolve_open_trades(session) == 1
    await session.refresh(trade)
    assert trade.status == "closed"
    assert trade.close_reason == "time"
    assert trade.close_price == pytest.approx((105 + 102) / 2)  # day-2 close (= bar mid)


async def test_resolve_time_mode_stop_still_governs(session):
    await svc.set_exit_policy(session, mode="time", hold_days=30)
    tid = await _seed(session, "AAA", close=100.0)
    trade = await svc.create_trade(session, 1, symbol="AAA", direction="long",
                                   entry_price=100.0, shares=10, stop_loss=95.0, target=200.0)
    await _add_bars(session, tid, [(101, 94)], start=date.today())  # low pierces the stop
    assert await svc.resolve_open_trades(session) == 1
    await session.refresh(trade)
    assert trade.close_reason == "stop"
    assert trade.close_price == pytest.approx(95.0)


async def test_resolve_trailing_closes_with_reason(session):
    await svc.set_exit_policy(session, mode="trailing", trailing_pct=12.0)
    tid = await _seed(session, "AAA", close=100.0)
    await _add_open_trade(session, tid, "long", entry=100.0, shares=10, days_ago=10)
    await _add_bars(session, tid, [(120, 110), (130, 100)], start=date.today())  # run up, pull back
    assert await svc.resolve_open_trades(session) == 1
    closed = await svc.list_trades(session, 1, status="closed")
    assert closed[0]["close_reason"] == "trailing"


async def test_manual_close_sets_reason(session):
    await _seed(session, "AAA", close=112.0)
    trade = await svc.create_trade(session, 1, symbol="AAA", direction="long",
                                   entry_price=100.0, shares=5, stop_loss=95.0, target=120.0)
    await svc.close_trade(session, 1, trade.id)
    assert (await svc.list_trades(session, 1, status="closed"))[0]["close_reason"] == "manual"


async def test_list_open_exposes_trailing_stop(session):
    await svc.set_exit_policy(session, mode="trailing", trailing_pct=12.0)
    tid = await _seed(session, "AAA", close=120.0)
    await _add_open_trade(session, tid, "long", entry=100.0, shares=10, days_ago=10)
    await _add_bars(session, tid, [(125, 118)], start=date.today())  # peak 125
    row = (await svc.list_trades(session, 1, status="open"))[0]
    assert row["trailing_stop"] == pytest.approx(110.0)  # 125 * (1 - 0.12)
    assert row["trailing_distance_pct"] is not None