"""Account-aware position sizing: risk-based, capped by buying power + liquidity.

Critical for a small REAL account ($300) — sizing must come off real equity and
no single position can exceed buying power.
"""

from strategy.risk.position_sizing import (
    PositionSizingConfig,
    calculate_position_size,
    rank_risk_factor,
)

CFG = PositionSizingConfig(risk_per_trade_pct=0.01)


def test_sizes_off_small_equity():
    # $300 equity, 1% = $3 risk; entry 4.00 stop 3.80 (risk 0.20) -> 14 shares
    # (3/0.20 = 14.999.. truncates down — conservative, never over-risk)
    r = calculate_position_size(4.0, 3.80, equity=300, config=CFG)
    assert r.position_size == 14
    assert r.dollar_amount <= 300 * CFG.risk_per_trade_pct / 0.20 * 4.0 + 1e-6


def test_value_cap_binds_on_tight_stop():
    # tight stop -> risk-based wants 150 sh ($600); cap at $120 -> 30 shares
    r = calculate_position_size(4.0, 3.98, equity=300, config=CFG, max_position_value=120)
    assert r.position_size == 30
    assert r.dollar_amount <= 120 + 1e-6


def test_liquidity_cap_binds():
    r = calculate_position_size(4.0, 3.80, equity=300, config=CFG, max_shares=5)
    assert r.position_size == 5


def test_default_equity_when_unset():
    # no equity passed -> falls back to config default (not zero)
    r = calculate_position_size(4.0, 3.80, config=PositionSizingConfig(default_equity=100000))
    assert r.position_size > 0


def test_max_risk_dollars_caps_wide_stop():
    # $90k, 1% = $900 budget; entry 2.00 stop 1.69 (0.31/sh wide stop)
    uncapped = calculate_position_size(2.00, 1.69, equity=90000, config=CFG)
    assert abs(uncapped.risk_amount - 900) < 2            # risks the full % budget
    capped = calculate_position_size(2.00, 1.69, equity=90000, config=CFG, max_risk_dollars=500)
    assert capped.position_size < uncapped.position_size  # sized down
    assert 490 < capped.risk_amount <= 500.5              # hard $ cap honored (~$500)


def test_max_risk_dollars_noop_when_budget_smaller():
    # small account: 1% of $300 = $3 budget << the $500 cap -> cap doesn't bind
    r = calculate_position_size(4.0, 3.80, equity=300, config=CFG, max_risk_dollars=500)
    assert r.position_size == 14                          # unchanged from the % budget


def test_risk_amount_reports_actual_not_budget():
    # after a binding value cap, risk_amount = the SIZED position's risk, not the budget
    r = calculate_position_size(4.0, 3.98, equity=300, config=CFG, max_position_value=120)
    assert r.position_size == 30
    assert abs(r.risk_amount - 30 * 0.02) < 1e-6          # ~$0.60 actual, not the $3 budget


def test_rank_risk_factor_concentrates():
    assert rank_risk_factor(1, 0) == 1.0     # concentration OFF -> full
    assert rank_risk_factor(5, 0) == 1.0
    assert rank_risk_factor(1, 2) == 1.0     # rank-1 full budget
    assert rank_risk_factor(2, 2) == 0.5     # rank-2 half
    assert rank_risk_factor(3, 2) == 0.0     # outside top-2 -> skip
    assert rank_risk_factor(0, 2) == 1.0     # unranked -> not concentrated


# --- zero-equity guards (2026-09-13) -----------------------------------------
# Tradier returned total_equity 0.0 sixteen times in fourteen days, all inside
# its ~01:06 maintenance window. `equity or default` read that real zero as
# "not supplied" and sized off default_equity (100k) — on a $241 account that
# is a position risking 5% of 100k. Two independent holes made it reachable:
# the falsy-zero fallback, and a `max_position_value > 0` test that SKIPPED the
# cap exactly when the cap was zero.

def test_zero_equity_refuses_to_size():
    """A real 0.0 reading must size nothing — never fall back to default_equity."""
    r = calculate_position_size(
        4.0, 3.80, equity=0.0,
        config=PositionSizingConfig(risk_per_trade_pct=0.05, default_equity=100000),
    )
    assert r.position_size == 0
    assert r.dollar_amount == 0.0


def test_negative_equity_refuses_to_size():
    r = calculate_position_size(4.0, 3.80, equity=-5.0, config=CFG)
    assert r.position_size == 0


def test_none_equity_still_uses_the_default():
    """The documented fallback must survive: not-passed is not the same as zero."""
    r = calculate_position_size(
        4.0, 3.80, equity=None,
        config=PositionSizingConfig(risk_per_trade_pct=0.01, default_equity=100000),
    )
    assert r.position_size > 0


def test_zero_position_cap_blocks_the_trade():
    """A cap of 0 means no room (no settled cash / gross budget spent), not 'no cap'."""
    r = calculate_position_size(4.0, 3.80, equity=300, config=CFG, max_position_value=0.0)
    assert r.position_size == 0


def test_positive_cap_still_caps():
    r = calculate_position_size(4.0, 3.80, equity=300, config=CFG, max_position_value=40.0)
    assert r.position_size == 10   # 40 / 4.00