from __future__ import annotations

import pytest

from arbitrade.detection.engine import IncrementalCycleDetector
from arbitrade.detection.graph import CurrencyGraph
from arbitrade.exchange.models import BookLevel
from arbitrade.market_data.order_book import OrderBook


def _make_book(*, bid: float, ask: float) -> OrderBook:
    book = OrderBook()
    book.apply_bids([BookLevel(price=bid, volume=2_000.0)])
    book.apply_asks([BookLevel(price=ask, volume=2_000.0)])
    return book


def _make_book_levels(
    *, bids: list[tuple[float, float]], asks: list[tuple[float, float]]
) -> OrderBook:
    book = OrderBook()
    book.apply_bids([BookLevel(price=price, volume=volume) for price, volume in bids])
    book.apply_asks([BookLevel(price=price, volume=volume) for price, volume in asks])
    return book


def test_synthetic_single_cycle_known_exact_rates() -> None:
    asset_pairs = {
        "XXBTZUSD": {"wsname": "BTC/USD"},
        "XETHXXBT": {"wsname": "ETH/BTC"},
        "XETHZUSD": {"wsname": "ETH/USD"},
    }
    graph = CurrencyGraph.from_kraken_asset_pairs(asset_pairs)
    detector = IncrementalCycleDetector(
        graph.index_cycles_by_pair(graph.triangular_cycles()),
        fee_rate=0.001,
        max_depth_levels=1,
    )

    books = {
        "BTC/USD": _make_book(bid=99.9, ask=100.0),
        "ETH/BTC": _make_book(bid=0.049, ask=0.05),
        "ETH/USD": _make_book(bid=5.20, ask=5.21),
    }

    scores = detector.score_updated_pair("ETH/BTC", books)

    assert len(scores) == 1
    score = scores[0]
    # Known path result: 1 USD -> 0.01 BTC -> 0.2 ETH -> 1.04 USD gross.
    assert score.gross_rate == pytest.approx(1.04)
    assert score.net_rate == pytest.approx(1.04 * (1 - 0.001) ** 3)


def test_synthetic_two_cycles_known_filtering_and_pair_index() -> None:
    asset_pairs = {
        "XXBTZUSD": {"wsname": "BTC/USD"},
        "XETHXXBT": {"wsname": "ETH/BTC"},
        "XETHZUSD": {"wsname": "ETH/USD"},
        "XLTCXXBT": {"wsname": "LTC/BTC"},
        "XLTCZUSD": {"wsname": "LTC/USD"},
    }
    graph = CurrencyGraph.from_kraken_asset_pairs(asset_pairs)
    detector = IncrementalCycleDetector(
        graph.index_cycles_by_pair(graph.triangular_cycles()),
        min_profit_threshold=0.02,
        max_depth_levels=3,
    )

    books = {
        # ETH cycle expected to pass threshold (~4% gross)
        "BTC/USD": _make_book(bid=99.9, ask=100.0),
        "ETH/BTC": _make_book(bid=0.049, ask=0.05),
        "ETH/USD": _make_book(bid=5.20, ask=5.21),
        # LTC cycle expected to fail threshold (<2% gross)
        "LTC/BTC": _make_book(bid=0.01005, ask=0.0101),
        "LTC/USD": _make_book(bid=1.01, ask=1.011),
    }

    scores = detector.score_updated_pair("BTC/USD", books)

    assert len(scores) == 1
    assert scores[0].cycle.currencies == ("BTC", "ETH", "USD")
    assert (scores[0].net_rate - 1.0) >= 0.02


def test_synthetic_depth_scenario_known_no_result_when_not_fillable() -> None:
    asset_pairs = {
        "XXBTZUSD": {"wsname": "BTC/USD"},
        "XETHXXBT": {"wsname": "ETH/BTC"},
        "XETHZUSD": {"wsname": "ETH/USD"},
    }
    graph = CurrencyGraph.from_kraken_asset_pairs(asset_pairs)
    detector = IncrementalCycleDetector(
        graph.index_cycles_by_pair(graph.triangular_cycles()),
        max_depth_levels=2,
    )

    books = {
        # Not enough ask-side BTC/USD capacity inside top-2 levels for initial USD->BTC conversion.
        "BTC/USD": _make_book_levels(
            bids=[(99.9, 10.0)],
            asks=[(100.0, 0.003), (101.0, 0.003)],
        ),
        "ETH/BTC": _make_book_levels(
            bids=[(0.049, 10.0)],
            asks=[(0.05, 10.0)],
        ),
        "ETH/USD": _make_book_levels(
            bids=[(5.20, 10.0)],
            asks=[(5.21, 10.0)],
        ),
    }

    scores = detector.score_updated_pair("BTC/USD", books)

    assert scores == []