feat: extend tiles with Tiles.isLava and Tiles.isChasm

src/vaults.lua

@@ -0,0 +1,64 @@
+-- Lever-gated treasure rooms. A vault door only swings open once every lever
+-- sharing its id has been pulled; the builder places the door at a doorway
+-- pinch point and scatters its levers only on the side already reachable
+-- without crossing it, so the puzzle is always solvable and the reward
+-- sealed behind the door is always genuinely gated by it (see builder.lua's
+-- vault placement, drawn dead last so it never perturbs any earlier
+-- system's rng sequence).
+
+local Items = require("items")
+local Affixes = require("affixes")
+
+local Vaults = {}
+
+local treasureWeapons = {
+  { name = "vault greatsword", power = 7 },
+  { name = "vault warhammer",  power = 8 },
+}
+local treasureArmors = {
+  { name = "vault aegis", power = 6 },
+}
+
+-- A guaranteed affix on a base already well above anything the floor's own
+-- loot table can roll at this depth - the deterministic reward for solving
+-- the puzzle, distinct from a normal drop's coin-flip affix (see
+-- affixes.rollWeapon/rollArmor).
+function Vaults.treasure(rng, depth)
+  if rng:chance(1, 2) then
+    local base = treasureWeapons[rng:range(1, #treasureWeapons)]
+    local item = Items.weapon(base.name, base.power + depth // 3)
+    return Affixes.decorate(item, Affixes.weapon[rng:range(1, #Affixes.weapon)])
+  end
+  local base = treasureArmors[rng:range(1, #treasureArmors)]
+  local item = Items.armor(base.name, base.power + depth // 3)
+  return Affixes.decorate(item, Affixes.armor[rng:range(1, #Affixes.armor)])
+end
+
+function Vaults.doorFor(level, id)
+  for _, door in ipairs(level.vaultDoors) do
+    if door.id == id then return door end
+  end
+  return nil
+end
+
+local function allPulled(level, id)
+  for _, lever in ipairs(level.vaultLevers) do
+    if lever.id == id and not lever.pulled then return false end
+  end
+  return true
+end
+
+-- Pulls `lever`, an idempotent no-op returning false if it was already
+-- thrown. Returns (true, door) the instant this pull completes every lever
+-- sharing its id and the door has not opened yet, or (true, nil) for a pull
+-- that leaves the vault still sealed (or already open).
+function Vaults.pull(level, lever)
+  if lever.pulled then return false end
+  lever.pulled = true
+  if not allPulled(level, lever.id) then return true, nil end
+  local door = Vaults.doorFor(level, lever.id)
+  if door and not door.opened then return true, door end
+  return true, nil
+end
+
+return Vaults