"""Tests for strategies handling zero-volume candles gracefully."""

import sys
from datetime import datetime, timezone
from decimal import Decimal
from pathlib import Path

sys.path.insert(0, str(Path(__file__).resolve().parents[2] / "services" / "strategy-engine"))
sys.path.insert(0, str(Path(__file__).resolve().parents[2] / "services" / "backtester" / "src"))

from shared.models import Candle
from strategies.vwap_strategy import VwapStrategy
from strategies.volume_profile_strategy import VolumeProfileStrategy
from strategies.rsi_strategy import RsiStrategy


def _candle(close: str, volume: str = "0", idx: int = 0) -> Candle:
    base = datetime(2025, 1, 1, tzinfo=timezone.utc)
    from datetime import timedelta

    return Candle(
        symbol="BTCUSDT",
        timeframe="1h",
        open_time=base + timedelta(hours=idx),
        open=Decimal(close),
        high=Decimal(close),
        low=Decimal(close),
        close=Decimal(close),
        volume=Decimal(volume),
    )


class TestVwapZeroVolume:
    """VWAP strategy must not divide by zero when all volume is 0."""

    def test_all_zero_volume_no_crash(self):
        strategy = VwapStrategy()
        for i in range(50):
            result = strategy.on_candle(_candle("100", "0", i))
        # Should return None (no signal) rather than raising ZeroDivisionError
        assert result is None

    def test_mixed_zero_and_nonzero_volume(self):
        strategy = VwapStrategy()
        # First 30 candles with volume to pass warmup, then zero volume
        for i in range(30):
            strategy.on_candle(_candle("100", "10", i))
        # Now feed zero-volume candles; cumulative_vol > 0 so VWAP still defined
        result = strategy.on_candle(_candle("100", "0", 30))
        # Should not crash
        assert result is None or result is not None  # just checking no exception


class TestVolumeProfileZeroVolume:
    """Volume Profile strategy with all-zero volumes should return None."""

    def test_all_zero_volume_returns_none(self):
        strategy = VolumeProfileStrategy()
        for i in range(150):
            result = strategy.on_candle(_candle(str(100 + i % 10), "0", i))
        # With zero total volume, should return None (no meaningful signal)
        assert result is None


class TestRsiZeroVolume:
    """RSI strategy should process price correctly regardless of volume."""

    def test_rsi_with_zero_volume_processes_price(self):
        strategy = RsiStrategy()
        # Feed descending prices to trigger oversold RSI
        signals = []
        for i in range(30):
            price = str(100 - i)
            result = strategy.on_candle(_candle(price, "0", i))
            if result is not None:
                signals.append(result)
        # RSI uses only close prices, volume is irrelevant; should work fine
        # With steadily dropping prices, RSI should go below oversold threshold
        assert len(signals) >= 1
        assert signals[0].side.value == "BUY"  # oversold signal