cozy-games/packages/mnswpr/adapters/replay-progress.js

57 lines
2.4 KiB
JavaScript

// @ts-check
import { MinesweeperRules } from '../core/minesweeper/rules.js'
/**
* @typedef {import('../core/minesweeper/rules.js').MoveEvent} MnswprMoveEvent
* @typedef {import('../core/minesweeper/board.js').Layout} Layout
*/
/**
* The percent-cleared progress reducer for Minesweeper — mnswpr's first concrete
* implementation of the replay engine's `ProgressReducer<MnswprMoveEvent>` seam
* (see `@cozy-games/replay` / replay-02). Given the ordered slice of move-events
* played so far, it returns completion as
* `revealed safe cells / total safe cells * 100`.
*
* Why it needs the board: a single `reveal` or `chord` event floods MANY cells,
* but the recorded move-event only carries `{ type, r, c }` — not how many cells
* opened. So the reducer takes the board as closure input (consistent with the
* interface design) and replays the moves through the pure core rules. That makes
* reveals flood, chords reveal via their (non-flagged) neighbors, and
* flags/unflags only gate chords — never advancing progress themselves — with no
* cell double-counted. The engine stays game-blind; all interpretation is here.
*
* @param {Layout} layout - the recorded board (as produced by `generateBoard`)
* @returns {(events: { event: MnswprMoveEvent }[]) => number} a reducer to `[0, 100]`
*/
export function createProgressReducer(layout) {
const totalSafe = layout.rows * layout.cols - layout.mines
return function progress(events) {
// A board with no safe cells is vacuously fully cleared (and avoids /0).
if (totalSafe === 0) return 100
let state = MinesweeperRules.fromLayout(layout)
for (const record of events) {
const move = toMove(record.event)
if (move) state = MinesweeperRules.apply(state, move).state
}
return (state.revealedSafe / totalSafe) * 100
}
}
/**
* Map a recorded move-event back to the rules move that produced it: `flag` and
* `unflag` are both the toggle move `flag`; `reveal` and `chord` pass through.
* Unknown kinds are ignored.
*
* @param {MnswprMoveEvent} e
* @returns {{ type: 'reveal' | 'flag' | 'chord', r: number, c: number } | null}
*/
function toMove(e) {
switch (e && e.type) {
case 'reveal': return { type: 'reveal', r: e.r, c: e.c }
case 'chord': return { type: 'chord', r: e.r, c: e.c }
case 'flag':
case 'unflag': return { type: 'flag', r: e.r, c: e.c }
default: return null
}
}