feat: add Secrets.sweep and Secrets.revealAll

src/secrets.lua

@@ -0,0 +1,59 @@
+-- Secret doors: a wall tile that reads as ordinary rock (Tiles.WALL, same
+-- glyph, same isPassable/blocksSight as any other wall) until the player
+-- happens across it, gating a single hidden alcove otherwise unreachable
+-- from the rest of the floor (see builder.lua's dead-last placement).
+-- Detection is a passive roll against every still-hidden door within a
+-- step of the player, rolled once per player turn from Game:endPlayerTurn -
+-- the same shape disarm.lua's own trap sense already takes, and for the
+-- same reason: a once-per-round sweep rather than once per actor keeps a
+-- seeded run's discovery turn identical regardless of how many actors
+-- acted that round. Once found, the wall becomes a plain Tiles.DOOR_CLOSED -
+-- opened, from then on, through Game:openDoor exactly like any door the
+-- builder cut in the open, since nothing about a secret door's mechanics
+-- differs from an ordinary one once it is known to be there.
+
+local Tiles = require("tiles")
+
+local Secrets = {}
+
+Secrets.SEARCH_NUMERATOR = 1
+Secrets.SEARCH_DENOMINATOR = 5
+
+-- Sweeps every secret door within Chebyshev distance 1 of (px, py) that is
+-- not yet discovered, rolling each independently. Opens each newly-found
+-- door's map tile into a plain closed door on the spot and returns the
+-- doors discovered this call (in level.secretDoors order), so a caller only
+-- ever needs to report what was found.
+function Secrets.sweep(level, rng, px, py)
+  local found = {}
+  for _, door in ipairs(level.secretDoors) do
+    if not door.discovered
+      and math.max(math.abs(door.x - px), math.abs(door.y - py)) <= 1
+      and rng:chance(Secrets.SEARCH_NUMERATOR, Secrets.SEARCH_DENOMINATOR) then
+      door.discovered = true
+      level.map:set(door.x, door.y, Tiles.DOOR_CLOSED)
+      found[#found + 1] = door
+    end
+  end
+  return found
+end
+
+-- Discovers every still-hidden secret door on the floor outright, with no
+-- distance limit and no per-door roll - unlike Secrets.sweep's passive,
+-- one-step, one-in-five search above. Used only by captives.lua's
+-- interrogation, which trades a held captive for exactly this shortcut.
+-- Returns the doors this actually revealed (in level.secretDoors order), so
+-- a caller only ever needs to report what was found, same as Secrets.sweep.
+function Secrets.revealAll(level)
+  local found = {}
+  for _, door in ipairs(level.secretDoors) do
+    if not door.discovered then
+      door.discovered = true
+      level.map:set(door.x, door.y, Tiles.DOOR_CLOSED)
+      found[#found + 1] = door
+    end
+  end
+  return found
+end
+
+return Secrets