DrawMode is a fieldless two-variant enum — it is trivially bitwise-
copyable. Adding Copy + updating choose_winnable_seed to take the value
directly eliminates 13 superfluous .clone() calls across solitaire_core,
solitaire_engine, solitaire_assetgen, and solitaire_wasm.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
The H-key hint now asks the v0.15.0 Klondike solver for the actual
best first move from the current game state instead of the existing
heuristic. The heuristic stays as the fallback path so hints still
work when the solver bails Inconclusive on the player's budget.
solitaire_core::solver gains a path-recording variant. The internal
DFS already enumerated moves on each frame; recording the root_move
on the stack frame is +16 bytes and one unwrap_or per expansion —
the new-game retry loop sees no measurable slowdown.
New public API (additive — try_solve unchanged):
pub struct SolverMove { source, dest, count }
pub struct SolveOutcome { result: SolverResult, first_move: Option<SolverMove> }
pub fn try_solve_with_first_move(seed, draw_mode, &cfg) -> SolveOutcome
pub fn try_solve_from_state(&GameState, &cfg) -> SolveOutcome
The internal solver-move enum was renamed InternalMove so the public
SolverMove can use engine-friendly (source, dest, count) types
instead of the compact internal form.
Engine wiring: handle_keyboard_hint calls try_solve_from_state on
the live GameStateResource. On Winnable + first_move, the hint
surfaces that exact move (no cycling — a single, optimal hint).
Unwinnable or Inconclusive falls through to the existing all_hints
cycling heuristic so hints remain useful in deals the solver gives
up on.
A new HintSolverConfig resource lets tests inject tight budgets to
force the fallback path; production uses SolverConfig::default()
and median solve time stays at 2 ms per H press.
Six new tests pin the contract: 4 in solitaire_core (Winnable
returns first_move, Unwinnable returns None, deterministic, seed
and state forms agree); 2 in solitaire_engine (hint uses solver
when Winnable, falls back to heuristic when Inconclusive).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Closes Quat investigation #1. Today some Klondike deals are
unwinnable from the start and the player has no signal that the
deal they were given is solvable. A new Settings → Gameplay toggle
"Winnable deals only" (default off) makes the engine retry seeds
at deal-time until the solver returns Winnable, up to a cap.
Solver
solitaire_core::solver is a hand-rolled iterative-DFS solver with
memoisation on a 64-bit canonical state hash. Move enumeration is
priority-ordered: foundation moves first (zero choice when an Ace
or rank-up exists), inter-tableau moves second, waste-to-tableau
third, stock-draw last. The draw is skipped when the cycle counter
shows we've recirculated the entire stock without progress —
Klondike's deterministic stock cycle means further draws can't
unlock anything new.
Two budget knobs (move_budget = 100k, state_budget = 200k by
default) cap pathological cases at Inconclusive; the caller treats
Inconclusive as "winnable" so the player isn't penalised for the
solver giving up. Median solve time is 2 ms; pathological
inconclusives top out near 120 ms.
Switched from recursive to iterative DFS after a real-deal solve
overflowed Rust's default 8 MB thread stack. Behaviour identical;
the change is invisible to callers.
Pure logic — solitaire_core has no Bevy or I/O. Same input always
yields the same SolverResult.
Settings
Settings.winnable_deals_only is a #[serde(default)] bool; legacy
files load to false. SOLVER_DEAL_RETRY_CAP = 50 caps the retry
loop. The Settings → Gameplay toggle reads as "Winnable deals only"
with a "(may take a moment when on)" caption.
Engine integration
handle_new_game's seed-selection path now branches on the toggle.
When on AND mode is Classic AND no specific seed was requested
(daily challenges, replays, and explicit-seed requests bypass the
solver), choose_winnable_seed walks seed N, N+1, N+2, … calling
try_solve until it finds Winnable or Inconclusive. If the cap is
hit without a verdict, the latest tried seed is used so the player
always gets a deal rather than spinning forever.
19 new tests (11 solver, 3 settings, 5 engine including the
choose_winnable_seed unit). Two ignored bench/scan helpers
(solver_bench, find_unwinnable) for ad-hoc profiling.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
funman300