"""`sim/interact.py` targeting — what the reach zone contains (phase 03 task 03).

The reach zone is discrete first and continuous second: `candidate_cells()` names
the tiles the hand walks (front, the two diagonal-front, underfoot) and
`REACH + FORGIVE` decides whether the cook is actually standing close enough to
the tile it found. This file pins both halves with hand-computed geometry:

* **candidate cells** — the per-facing order, and the fact that the four
  facings are 90° rotations of one row rather than four ad-hoc tie-breaks;
* **reach** — the forgiveness boundary (0.99 ok, 1.6 itself inclusive, 1.61
  rejected), including the case the diagonal tier exists for: the same diagonal
  station is out of reach from the far corner of the cook's tile and in reach
  from the near corner;
* **priority** — item outranks the fixture it sits on, a full hand skips the
  item, a non-ready fixture holds its contents, the serve window is its own
  target kind, nothing at all is `None`;
* **the wall** — a fixture two tiles ahead (wall in between) is never a
  candidate: the discrete walk has no "through the wall" mode, and the
  out-of-reach skip keeps the walk going so a nearer tile still gets its turn.

The press-edge behaviour — one press, one named refusal, however long the button
stays held — is at the bottom, through the full `step()`.
"""

from __future__ import annotations

import pytest

from undercooked.sim.grid import Grid
from undercooked.sim.interact import (
    FORGIVE,
    REACH,
    DeniedReason,
    ItemTarget,
    ServeTarget,
    StationTarget,
    Verb,
    candidate_cells,
    faces_target,
    select_target,
    select_verb,
    station_cells,
    target_center,
    within_reach,
)
from undercooked.sim.model import (
    EventKind,
    Facing,
    Item,
    ItemForm,
    ItemKind,
    KitchenState,
    Player,
    PlayerState,
    Station,
    StationKind,
    StationState,
    TileKind,
    Vec2,
)
from undercooked.sim.step import MAX_DT, STEP_DT, PlayerInput, step

pytestmark = pytest.mark.unit

WIDTH, HEIGHT = 13, 9
DEFAULT_POS = Vec2(5.5, 5.5)  # module-level so a default argument may use it (B008)


# --- fixtures ---------------------------------------------------------------------------


def make_state(
    stations: tuple[Station, ...] = (),
    players: tuple[Player, ...] = (),
    tile_overrides: dict[tuple[int, int], TileKind] | None = None,
) -> KitchenState:
    tiles = [TileKind.FLOOR] * (WIDTH * HEIGHT)
    for (x, y), kind in (tile_overrides or {}).items():
        tiles[y * WIDTH + x] = kind
    return KitchenState(
        level_id="03_targeting",
        seed=1,
        grid=Grid(width=WIDTH, height=HEIGHT, tiles=tuple(tiles)),
        stations=stations,
        players=players,
        target_score=40,
        time_left=90.0,
    )


def cook(
    player_id: str = "p0",
    *,
    pos: Vec2 = DEFAULT_POS,
    facing: Facing = Facing.UP,
    carrying: Item | None = None,
    stun: float = 0.0,
    state: PlayerState = PlayerState.IDLE,
    seat: int = 0,
    held_ticks: int = 0,
    pressed_tick: int = 0,
) -> Player:
    return Player(
        id=player_id,
        pos=pos,
        facing=facing,
        carrying=carrying,
        state=state,
        stun=stun,
        seat=seat,
        action_held_ticks=held_ticks,
        action_pressed_tick=pressed_tick,
    )


def fixture(
    kind: StationKind = StationKind.STOVE,
    *,
    x: int = 5,
    y: int = 4,
    state: StationState = StationState.IDLE,
    contents: tuple[Item, ...] = (),
    worker_id: str | None = None,
    dirty: bool = False,
    cooldown: float = 0.0,
) -> Station:
    return Station(
        id=f"{kind.value}-{x}-{y}",
        kind=kind,
        x=x,
        y=y,
        state=state,
        contents=contents,
        worker_id=worker_id,
        dirty=dirty,
        cooldown=cooldown,
    )


def tomato(form: ItemForm = ItemForm.RAW) -> Item:
    return Item(kind=ItemKind.TOMATO, form=form)


# --- candidate cells --------------------------------------------------------------------


@pytest.mark.parametrize(
    ("facing", "expected"),
    [
        (Facing.UP, ((2, 2), (1, 2), (3, 2), (2, 3))),
        (Facing.RIGHT, ((3, 3), (3, 2), (3, 4), (2, 3))),
        (Facing.DOWN, ((2, 4), (3, 4), (1, 4), (2, 3))),
        (Facing.LEFT, ((1, 3), (1, 4), (1, 2), (2, 3))),
    ],
)
def test_candidate_cells_walk_front_then_both_diagonals_then_underfoot(
    facing: Facing, expected: tuple[tuple[int, int], ...]
) -> None:
    # The cook stands at the centre of cell (2, 3); every facing reports the front
    # tile first, its two diagonal neighbours second (left, then right, in the
    # rotated row), and the tile underfoot last.
    player = cook("p0", pos=Vec2(2.5, 3.5), facing=facing)
    assert player.pos == Vec2(2.5, 3.5)
    assert candidate_cells(player) == expected


def test_candidate_cells_do_not_depend_on_where_in_the_tile_the_cook_stands() -> None:
    positions = [Vec2(2.51, 3.99), Vec2(2.02, 3.01), Vec2(2.99, 3.51)]
    for facing in Facing:
        baseline = candidate_cells(cook("p0", pos=positions[0], facing=facing))
        for position in positions[1:]:
            assert candidate_cells(cook("p0", pos=position, facing=facing)) == baseline


def test_candidate_cells_use_the_floor_of_the_position() -> None:
    # (3.0, 3.0) is in cell (3, 3), not (2, 2): the body centre decides.
    assert candidate_cells(cook("p0", pos=Vec2(3.0, 3.0), facing=Facing.UP)) == (
        (3, 2),
        (2, 2),
        (4, 2),
        (3, 3),
    )


def test_candidate_cells_are_ordered_and_deduplicated() -> None:
    cells = candidate_cells(cook("p0", pos=Vec2(2.5, 3.5), facing=Facing.RIGHT))
    assert len(cells) == 4
    assert len(set(cells)) == 4
    assert cells[3] == (2, 3)  # underfoot is always last, whatever the facing


# --- the forgiveness boundary -----------------------------------------------------------


def test_reach_plus_forgive_is_the_number_the_boundary_tests_use() -> None:
    assert abs((REACH + FORGIVE) - 1.6) < 1e-12


@pytest.mark.parametrize(
    ("distance", "in_reach"),
    [
        (0.99, True),  # the task boundary: 0.99 is ok
        (REACH, True),  # the front tile itself
        (1.6, True),  # the boundary is inclusive (with REACH_EPS of slack)
        (1.61, False),  # the task boundary: 1.61 is rejected
    ],
)
def test_within_reach_forgives_up_to_the_boundary(
    distance: float, in_reach: bool
) -> None:
    state = make_state(stations=(fixture(),))
    # The player sits on the vertical line through the station centre (5.5, 4.5),
    # so the distance is exactly `distance` and no corner math gets in.
    player = cook("p0", pos=Vec2(5.5, 4.5 - distance), facing=Facing.UP)
    assert within_reach(state, player, StationTarget(state.stations[0])) is in_reach


def test_target_center_is_the_cell_centre_for_a_fixture() -> None:
    state = make_state(stations=(fixture(kind=StationKind.SINK, x=3, y=2),))
    assert target_center(state, StationTarget(state.stations[0])) == Vec2(3.5, 2.5)


def test_target_center_falls_back_to_the_stamped_position_when_the_station_is_gone() -> None:
    state = make_state()
    stale = ItemTarget(item=tomato(), on_station_id="gone", at=Vec2(5.5, 4.5))
    assert target_center(state, stale) == Vec2(5.5, 4.5)


def test_an_item_already_in_the_hand_needs_no_reach() -> None:
    state = make_state()
    player = cook("p0")
    in_hand = ItemTarget(item=tomato())  # no station, no world position
    assert target_center(state, in_hand) is None
    assert within_reach(state, player, in_hand) is True
    assert faces_target(state, player, in_hand) is True


# --- select_target: reach through the cell walk ------------------------------------------


def test_a_station_at_0p99_in_front_is_targeted() -> None:
    state = make_state(
        stations=(fixture(),),
        players=(cook("p0", pos=Vec2(5.5, 4.51), facing=Facing.DOWN),),  # 0.99 below the centre
    )
    target = select_target(state, state.players[0])
    assert isinstance(target, StationTarget)
    assert target.station.id == "stove-5-4"


def test_a_diagonal_station_at_1p61_is_skipped_not_refused() -> None:
    # From the far corner of the cook's own tile the diagonal centre is
    # 1.15 * sqrt(2) = 1.618 away, outside REACH + FORGIVE, so the tile is
    # skipped rather than becoming the answer.
    state = make_state(
        stations=(fixture(kind=StationKind.STOVE, x=6, y=6),),
        players=(cook("p0", pos=Vec2(5.35, 5.35), facing=Facing.RIGHT),),
    )
    assert select_target(state, state.players[0]) is None


def test_the_same_diagonal_station_is_reachable_from_the_near_corner() -> None:
    state = make_state(
        stations=(fixture(kind=StationKind.STOVE, x=6, y=6),),
        players=(cook("p0", pos=Vec2(5.65, 5.65), facing=Facing.RIGHT),),
    )
    target = select_target(state, state.players[0])
    assert isinstance(target, StationTarget)
    assert target.station.id == "stove-6-6"


def test_an_out_of_reach_diagonal_is_skipped_so_the_tile_underfoot_still_wins() -> None:
    state = make_state(
        stations=(
            fixture(kind=StationKind.STOVE, x=6, y=6),  # candidate 3, out of reach here
            fixture(kind=StationKind.SINK, x=5, y=5),  # candidate 4, underfoot, in reach
        ),
        players=(cook("p0", pos=Vec2(5.35, 5.35), facing=Facing.RIGHT),),
    )
    target = select_target(state, state.players[0])
    assert isinstance(target, StationTarget)
    assert target.station.kind is StationKind.SINK


# --- select_target: priority ----------------------------------------------------------------


def test_a_ready_fixture_with_contents_yields_the_item_to_a_free_hand() -> None:
    ready = fixture(state=StationState.READY, contents=(tomato(ItemForm.CHOPPED),))
    state = make_state(stations=(ready,), players=(cook("p0"),))
    target = select_target(state, state.players[0])
    assert isinstance(target, ItemTarget)
    assert target.item.form is ItemForm.CHOPPED
    assert target.on_station_id == ready.id
    assert target.at == Vec2(5.5, 4.5)


def test_a_full_hand_skips_the_item_and_gets_the_fixture_instead() -> None:
    ready = fixture(state=StationState.READY, contents=(tomato(ItemForm.CHOPPED),))
    state = make_state(
        stations=(ready,),
        players=(
            cook(
                "p0",
                carrying=Item(kind=ItemKind.LETTUCE, form=ItemForm.RAW),
            ),
        ),
    )
    target = select_target(state, state.players[0])
    assert isinstance(target, StationTarget)
    assert target.station is ready


def test_a_spawn_shelf_hands_stock_even_while_idle() -> None:
    shelf = fixture(kind=StationKind.SPAWN_SHELF, contents=(tomato(),))
    state = make_state(stations=(shelf,), players=(cook("p0"),))
    target = select_target(state, state.players[0])
    assert isinstance(target, ItemTarget)
    assert target.item.kind is ItemKind.TOMATO


def test_a_spawn_shelf_with_no_stock_is_a_plain_fixture() -> None:
    shelf = fixture(kind=StationKind.SPAWN_SHELF)
    state = make_state(stations=(shelf,), players=(cook("p0"),))
    target = select_target(state, state.players[0])
    assert isinstance(target, StationTarget)


def test_a_non_ready_fixture_holds_its_contents() -> None:
    working = fixture(
        kind=StationKind.CHOP_BOARD,
        state=StationState.WORKING,
        contents=(tomato(),),
        worker_id="p0",
    )
    state = make_state(stations=(working,), players=(cook("p0"),))
    target = select_target(state, state.players[0])
    assert isinstance(target, StationTarget)  # the onion is *to be chopped*, not grabbable


def test_a_ready_fixture_with_empty_contents_is_a_plain_fixture() -> None:
    ready = fixture(state=StationState.READY)
    state = make_state(stations=(ready,), players=(cook("p0"),))
    target = select_target(state, state.players[0])
    assert isinstance(target, StationTarget)


def test_a_serve_window_is_a_serve_target_not_a_station_target() -> None:
    window = fixture(kind=StationKind.SERVE)
    state = make_state(stations=(window,), players=(cook("p0"),))
    target = select_target(state, state.players[0])
    assert isinstance(target, ServeTarget)
    assert target.station is window


def test_nothing_in_the_zone_is_none() -> None:
    state = make_state(players=(cook("p0"),))
    assert select_target(state, state.players[0]) is None


def test_a_station_two_tiles_away_is_never_a_candidate_even_beside_a_wall() -> None:
    # The wall fills the front tile; the stove is beyond it. The cell walk has
    # no "through the wall" mode, so the stove is simply not a candidate and
    # the press cannot land on it.
    state = make_state(
        stations=(fixture(kind=StationKind.STOVE, x=5, y=3),),
        players=(cook("p0"),),
        tile_overrides={(5, 4): TileKind.WALL},
    )
    assert select_target(state, state.players[0]) is None


def test_the_front_tile_outranks_a_diagonal_one() -> None:
    state = make_state(
        stations=(
            fixture(kind=StationKind.STOVE, x=6, y=4),  # diagonal (candidate 3 for UP)
            fixture(kind=StationKind.CHOP_BOARD, x=5, y=4),  # front (candidate 1)
        ),
        players=(cook("p0"),),
    )
    target = select_target(state, state.players[0])
    assert isinstance(target, StationTarget)
    assert target.station.kind is StationKind.CHOP_BOARD


def test_station_cells_keys_fixtures_by_their_authored_tile() -> None:
    state = make_state(
        stations=(
            fixture(kind=StationKind.STOVE, x=3, y=2),
            fixture(kind=StationKind.SINK, x=7, y=1),
        )
    )
    cells = station_cells(state)
    assert set(cells) == {(3, 2), (7, 1)}
    assert cells[(3, 2)].kind is StationKind.STOVE


# --- facing: the half-plane, not an angle ---------------------------------------------------


def test_faces_target_refuses_a_target_behind_the_cook() -> None:
    state = make_state(stations=(fixture(kind=StationKind.SERVE, x=5, y=6),))
    player = cook("p0", pos=Vec2(5.5, 5.5), facing=Facing.UP)
    assert faces_target(state, player, StationTarget(state.stations[0])) is False


def test_faces_target_accepts_a_target_level_with_the_cook() -> None:
    state = make_state(stations=(fixture(kind=StationKind.SERVE, x=4, y=5),))
    player = cook("p0", pos=Vec2(5.5, 5.5), facing=Facing.UP)
    # `along` is 0 for a target on the cook's own row, so a serve window the
    # cook is standing beside is not refused.
    assert faces_target(state, player, StationTarget(state.stations[0])) is True


# --- the STUNNED denial ---------------------------------------------------------------------


def test_a_stunned_cook_is_refused_before_the_target_is_even_read() -> None:
    state = make_state(
        stations=(fixture(kind=StationKind.SPAWN_SHELF),),
        players=(cook("p0", stun=0.3),),
    )
    target = select_target(state, state.players[0])
    verb, denial = select_verb(state, state.players[0], target)
    assert (verb, denial) == (Verb.NONE, DeniedReason.STUNNED)


def test_the_stunned_state_flag_alone_is_enough() -> None:
    state = make_state(
        stations=(fixture(kind=StationKind.SPAWN_SHELF),),
        players=(cook("p0", state=PlayerState.STUNNED, stun=0.0),),
    )
    target = select_target(state, state.players[0])
    verb, denial = select_verb(state, state.players[0], target)
    assert (verb, denial) == (Verb.NONE, DeniedReason.STUNNED)


# --- one press, one event (through the full kernel) -------------------------------------------


def test_a_do_nothing_press_emits_exactly_one_denied_not_one_per_tick() -> None:
    state = make_state(players=(cook("p0"),))
    frame = PlayerInput(player_id="p0", seq=0, action=True, received_at_tick=0)
    first_before_hash = state.state_hash()

    first, events = step(state, STEP_DT, (frame,))
    assert len(events) == 1
    assert events[0].kind is EventKind.DENIED
    assert dict(events[0].payload) == {
        "player_id": "p0",
        "reason": "nothing_here",
        "verb": "none",
    }
    assert (events[0].x, events[0].y) == (5.5, 5.5)
    assert first.players[0].action_held_ticks == 1
    assert first.players[0].action_pressed_tick == 0

    # The same frame on the next tick continues the press: no new edge, no new
    # event, the hold just gets longer.
    second, held_events = step(first, STEP_DT, (frame,))
    assert held_events == ()
    assert second.players[0].action_held_ticks == 2
    assert second.players[0].action_pressed_tick == 0

    # One call that runs two substeps: still exactly one press.
    batched, batched_events = step(state, MAX_DT, (frame,))
    assert sum(event.kind is EventKind.DENIED for event in batched_events) == 1
    assert batched.players[0].action_held_ticks == 2

    # Releasing the button clears the counters and the next press is a new one.
    released, released_events = step(
        second, STEP_DT, (PlayerInput(player_id="p0", seq=1, action=False),)
    )
    assert released_events == ()
    assert released.players[0].action_held_ticks == 0
    assert released.players[0].action_pressed_tick == 0
    # Purity: the state the first press was handed is still exactly what it was.
    assert state.state_hash() == first_before_hash
    assert state.players[0].action_held_ticks == 0


def test_a_press_at_a_station_out_of_reach_is_one_named_refusal() -> None:
    state = make_state(
        stations=(fixture(kind=StationKind.STOVE, x=5, y=3),),
        players=(cook("p0"),),
        tile_overrides={(5, 4): TileKind.WALL},
    )
    frame = PlayerInput(player_id="p0", seq=0, action=True, received_at_tick=0)
    first, events = step(state, STEP_DT, (frame,))
    assert len(events) == 1
    assert events[0].kind is EventKind.DENIED
    # The discrete zone has no "through the wall" mode, so the press surfaces as
    # nothing_here: the one effect, named, at the cook.
    assert dict(events[0].payload)["reason"] == "nothing_here"
    assert first.players[0].action_held_ticks == 1