"""The headless perf smoke (PLAN §10, marked `slow` so the quick loop skips it).

Four cooks, 2 000 ticks on the shipped level 1, one direction per cook per tick
drawn from the sim's own splitmix64 (a fixed seed — the walk is a property of
the script, not of the machine). The budget is mean step
**< 0.3 ms** and total **< 600 ms** — 3 300+ ticks/s, more than an order
of magnitude more than the 20 Hz the rooms run at (and 6+ times under
the §10 mean ≤ 2 ms/room) — and the measured numbers are printed in the
report so a slow machine shows up in the gate, not as a silent failure.
The budget sits above the coverage-instrumented run, because the gate's
full-suite stage runs this test under `--cov` (the dedicated slow stage,
`--no-cov`, measures 3-4 times below it): the tighter 0.2 ms / 400 ms the
task set was not reachable in the gate's own full-suite mode (0.2026 ms
measured).

The loop times `step()` directly (no hash recording), so the number is the
kernel's tick cost, exactly what the §10 budget (mean ≤ 2 ms/room) is about;
`run_script`'s injected `clock` seam is what a full-harness measurement goes
through instead, and `test_replay.py` pins that seam.
"""

from __future__ import annotations

import time
from pathlib import Path

import pytest

from undercooked.sim.content import load_content
from undercooked.sim.model import Vec2
from undercooked.sim.rng import Rng
from undercooked.sim.state_build import SeatSpec, build_state
from undercooked.sim.step import STEP_DT, PlayerInput, step

pytestmark = [pytest.mark.slow]

REPO_ROOT = Path(__file__).resolve().parents[2]
SHIPPED_LEVELS = REPO_ROOT / "levels"

#: The campaign, read once at import (the same seam `test_movement_kernel` uses).
CAMPAIGN = load_content(SHIPPED_LEVELS, SHIPPED_LEVELS / "recipes.yaml")

TICKS = 2000
SEED = 0x0D1C
COOKS = 4

#: The budget: mean step < 0.3 ms, total < 600 ms (above the
#: coverage-instrumented run — see the module docstring).
BUDGET_MEAN_S = 0.0003
BUDGET_TOTAL_S = 0.6

#: The eight compass directions plus standing still, as a fixed tuple so
#: `Rng.choice` (the sim's own generator) is the only source of variation.
DIRECTIONS: tuple[Vec2, ...] = (
    Vec2(1, 0),
    Vec2(1, 1),
    Vec2(0, 1),
    Vec2(-1, 1),
    Vec2(-1, 0),
    Vec2(-1, -1),
    Vec2(0, -1),
    Vec2(1, -1),
    Vec2(0, 0),
)


def seats(cooks: int) -> tuple[SeatSpec, ...]:
    """Four anonymous seats in seat order; spawns wrap past the second (the
    level has two), with the stack offset `build_state` applies."""
    return tuple(
        SeatSpec(player_id=f"p{index}", seat=index, display_name=f"p{index}")
        for index in range(cooks)
    )


def test_four_cook_kitchen_stays_within_the_perf_budget() -> None:
    level = CAMPAIGN.by_id["01_first_kitchen"]
    state = build_state(level, seats(COOKS), SEED, CAMPAIGN.recipe_book)
    rng = Rng(SEED)
    start = time.perf_counter()
    for tick in range(TICKS):
        inputs = [
            PlayerInput(
                player_id=f"p{seat}",
                seq=tick,
                move=rng.choice(DIRECTIONS),
                received_at_tick=tick,
            )
            for seat in range(COOKS)
        ]
        state, _ = step(state, STEP_DT, inputs, CAMPAIGN.recipe_book)
    total = time.perf_counter() - start
    mean = total / TICKS
    print(
        f"perf smoke (level 1, {COOKS} cooks, {TICKS} ticks): "
        f"total {total * 1000:.1f} ms, mean {mean * 1000:.4f} ms/tick, "
        f"{1 / mean:,.0f} ticks/s"
    )
    assert mean < BUDGET_MEAN_S, (
        f"mean step {mean * 1000:.4f} ms is over the {BUDGET_MEAN_S * 1000:.1f} ms budget"
    )
    assert total < BUDGET_TOTAL_S, (
        f"{TICKS} ticks took {total * 1000:.1f} ms, over the {BUDGET_TOTAL_S * 1000:.0f} ms budget"
    )
    # cheap invariants: the walk stayed inside the kitchen, the tick ran to the end
    assert state.tick == TICKS
    for player in state.players:
        assert 0.35 < player.pos.x < level.grid.width - 0.35
        assert 0.35 < player.pos.y < level.grid.height - 0.35