From ce8362d0f69307f0daead241beda29cd8a493da3 Mon Sep 17 00:00:00 2001
From: DualFroz <me@dualfroz.com>
Date: Thu, 27 Aug 2026 11:44:00 +0200
Subject: [PATCH] feat(level): add floor contents and exploration state

---
 src/level.lua | 113 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 113 insertions(+)
 create mode 100644 src/level.lua

diff --git a/src/level.lua b/src/level.lua
new file mode 100644
index 0000000..994e2ee
--- /dev/null
+++ b/src/level.lua
@@ -0,0 +1,113 @@
+-- One dungeon floor: its map plus the mutable contents that live on it -
+-- monsters, dropped items, traps, light emitters and what the player has
+-- explored. Levels are cached by the dungeon so revisiting one restores its
+-- exact state, dead monsters and all.
+
+local Map = require("map")
+local Entity = require("entity")
+
+local Level = {}
+Level.__index = Level
+
+function Level.new(fields)
+  return setmetatable({
+    depth = fields.depth,
+    generator = fields.generator,
+    map = fields.map,
+    entities = fields.entities or {},
+    floorItems = fields.floorItems or {},
+    traps = fields.traps or {},
+    lights = fields.lights or {},
+    dark = fields.dark or false,
+    explored = fields.explored or {},
+    upX = fields.upX, upY = fields.upY,
+    downX = fields.downX, downY = fields.downY,
+  }, Level)
+end
+
+function Level:entityAt(x, y)
+  for _, monster in ipairs(self.entities) do
+    if monster:isAlive() and monster.x == x and monster.y == y then
+      return monster
+    end
+  end
+  return nil
+end
+
+function Level:trapAt(x, y)
+  for _, trap in ipairs(self.traps) do
+    if trap.x == x and trap.y == y then return trap end
+  end
+  return nil
+end
+
+function Level:itemsAt(x, y)
+  local here = {}
+  for _, ground in ipairs(self.floorItems) do
+    if ground.x == x and ground.y == y then here[#here + 1] = ground end
+  end
+  return here
+end
+
+function Level:removeDead()
+  for i = #self.entities, 1, -1 do
+    if not self.entities[i]:isAlive() then
+      table.remove(self.entities, i)
+    end
+  end
+end
+
+function Level:markExplored(idx)
+  self.explored[idx] = true
+end
+
+function Level:toData()
+  local monsters = {}
+  for i, monster in ipairs(self.entities) do
+    monsters[i] = monster:toData()
+  end
+  local explored = {}
+  for idx in pairs(self.explored) do
+    explored[#explored + 1] = idx
+  end
+  table.sort(explored)
+  return {
+    depth = self.depth,
+    generator = self.generator,
+    map = self.map:toData(),
+    entities = monsters,
+    floorItems = self.floorItems,
+    traps = self.traps,
+    lights = self.lights,
+    dark = self.dark,
+    explored = explored,
+    upX = self.upX, upY = self.upY,
+    downX = self.downX, downY = self.downY,
+  }
+end
+
+function Level.fromData(snapshot)
+  local entities = {}
+  for i, monsterData in ipairs(snapshot.entities) do
+    entities[i] = Entity.fromData(monsterData)
+  end
+  local explored = {}
+  for _, idx in ipairs(snapshot.explored) do
+    explored[idx] = true
+  end
+  return Level.new({
+    depth = snapshot.depth,
+    generator = snapshot.generator,
+    map = Map.fromData(snapshot.map),
+    entities = entities,
+    floorItems = snapshot.floorItems,
+    traps = snapshot.traps,
+    lights = snapshot.lights,
+    dark = snapshot.dark,
+    explored = explored,
+    upX = snapshot.upX, upY = snapshot.upY,
+    downX = snapshot.downX, downY = snapshot.downY,
+  })
+end
+
+return Level