diff --git a/escape_wild/lib/core.dart b/escape_wild/lib/core.dart
index e1edc49..833b96a 100644
--- a/escape_wild/lib/core.dart
+++ b/escape_wild/lib/core.dart
@@ -8,6 +8,7 @@ export 'package:escape_wild/core/ecs/ecs.dart';
 export 'package:escape_wild/core/level.dart';
 export 'package:escape_wild/core/content.dart';
 export 'package:escape_wild/core/time.dart';
+export 'package:escape_wild/core/item_prop.dart';
 export 'package:escape_wild/core/craft.dart';
 export 'package:escape_wild/core/i18n.dart';
 export 'package:escape_wild/core/hardness.dart';
@@ -19,7 +20,7 @@ export 'package:escape_wild/core/data_class.dart';
 export 'package:escape_wild/core/player.dart';
 export 'package:escape_wild/core/route.dart';
 export 'package:escape_wild/core/campfire.dart';
-export 'package:escape_wild/core/cooking.dart';
+export 'package:escape_wild/core/cook/cook.dart';
 export 'package:escape_wild/core/item_pool.dart';
 export 'package:escape_wild/ambiguous.dart';
 
diff --git a/escape_wild/lib/core/campfire.dart b/escape_wild/lib/core/campfire.dart
index 8626cee..c5d4753 100644
--- a/escape_wild/lib/core/campfire.dart
+++ b/escape_wild/lib/core/campfire.dart
@@ -1,7 +1,9 @@
 import 'dart:math';
-
 import 'package:json_annotation/json_annotation.dart';
 
+import 'package:escape_wild/core.dart';
+import 'package:flutter/widgets.dart';
+
 part 'campfire.g.dart';
 
 @JsonSerializable()
@@ -36,3 +38,155 @@ class FireState {
         fuel: fuel ?? this.fuel,
       );
 }
+
+abstract class CampfirePlaceProtocol extends PlaceProtocol with ChangeNotifier {
+  FireState get fireState;
+
+  set fireState(FireState v);
+
+  List<ItemStack> get onCampfire;
+
+  set onCampfire(List<ItemStack> v);
+
+  List<ItemStack> get offCampfire;
+
+  set offCampfire(List<ItemStack> v);
+
+  void onResetCooking();
+}
+
+extension CampfireHolderProtocolX on CampfirePlaceProtocol {
+  bool get isCampfireHasAnyStack => onCampfire.isNotEmpty || offCampfire.isNotEmpty;
+}
+
+mixin CampfireCookingMixin on CampfirePlaceProtocol {
+  @JsonKey(fromJson: tsFromJson, toJson: tsToJson, includeIfNull: false)
+  Ts cookingTime = Ts.zero;
+  List<ItemStack> _onCampfire = [];
+
+  @override
+  @JsonKey(fromJson: campfireStackFromJson, toJson: campfireStackToJson, includeIfNull: false)
+  List<ItemStack> get onCampfire => _onCampfire;
+
+  @override
+  set onCampfire(List<ItemStack> v) {
+    _onCampfire = v;
+    notifyListeners();
+  }
+
+  List<ItemStack> _offCampfire = [];
+
+  @override
+  @JsonKey(fromJson: campfireStackFromJson, toJson: campfireStackToJson, includeIfNull: false)
+  List<ItemStack> get offCampfire => _offCampfire;
+
+  @override
+  set offCampfire(List<ItemStack> v) {
+    _offCampfire = v;
+    notifyListeners();
+  }
+
+  @CookRecipeProtocol.jsonKey
+  CookRecipeProtocol? recipe;
+
+  FireState _fireState = FireState.off;
+
+  @override
+  @JsonKey(fromJson: fireStateFromJson, toJson: fireStateStackToJson, includeIfNull: false)
+  FireState get fireState => _fireState;
+
+  @override
+  set fireState(FireState v) {
+    _fireState = v;
+    notifyListeners();
+  }
+
+  double get fuelCostPerMinute;
+
+  /// Call this after changing [onCampfire].
+  @override
+  void onResetCooking() {
+    cookingTime = Ts.zero;
+    final matched = matchCookRecipe(onCampfire);
+    recipe = matched;
+    if (matched != null) {
+      // for instant cooking
+      final changed = matched.onMatch(onCampfire, offCampfire);
+      if (changed) {
+        notifyListeners();
+      }
+    }
+  }
+
+  Future<void> onCampfirePass(Ts delta) async {
+    // update items the place holds
+    for (final stack in onCampfire) {
+      await stack.onPassTime(delta);
+    }
+    for (final stack in offCampfire) {
+      await stack.onPassTime(delta);
+    }
+    if (fireState.active) {
+      final cost = delta.minutes * fuelCostPerMinute;
+      fireState = _burningFuel(fireState, cost);
+    }
+    // only cooking when fire has fuel.
+    if (fireState.fuel <= 0) return;
+    if (onCampfire.isEmpty) return;
+    final recipe = this.recipe ??= matchCookRecipe(onCampfire);
+    if (recipe == null) {
+      cookingTime = Ts.zero;
+    } else {
+      cookingTime += delta;
+      final changed = recipe.updateCooking(onCampfire, offCampfire, cookingTime, delta);
+      if (changed) {
+        this.recipe = null;
+        cookingTime = Ts.zero;
+        notifyListeners();
+      }
+    }
+  }
+
+  Future<void> onFirePass(double fuelCostSpeed, Ts delta) async {
+    final fireState = this.fireState;
+    if (fireState.active) {
+      final cost = delta / actionStepTime * fuelCostSpeed;
+      this.fireState = _burningFuel(fireState, cost);
+    }
+  }
+
+  static List<ItemStack> campfireStackFromJson(dynamic json) =>
+      json == null ? [] : (json as List<dynamic>).map((e) => ItemStack.fromJson(e as Map<String, dynamic>)).toList();
+
+  static dynamic campfireStackToJson(List<ItemStack> list) => list.isEmpty ? null : list;
+
+  static Ts tsFromJson(dynamic json) => json == null ? Ts.zero : Ts.fromJson((json as num).toInt());
+
+  static dynamic tsToJson(Ts ts) => ts == Ts.zero ? null : ts;
+
+  static FireState fireStateFromJson(dynamic json) => json == null ? FireState.off : FireState.fromJson(json);
+
+  static dynamic fireStateStackToJson(FireState fire) => fire.isOff ? null : fire;
+}
+
+const _emberCostFactor = 5;
+
+// TODO: Better formula
+FireState _burningFuel(
+  FireState former,
+  double cost,
+) {
+  final curFuel = former.fuel;
+  var resFuel = curFuel;
+  var resEmber = former.ember;
+  if (curFuel <= cost) {
+    final costOverflow = cost - curFuel;
+    resFuel = 0;
+    resEmber += curFuel;
+    resEmber -= costOverflow * _emberCostFactor;
+  } else {
+    resFuel -= cost;
+    resEmber += cost;
+  }
+  return FireState(ember: resEmber, fuel: resFuel);
+}
diff --git a/escape_wild/lib/core/cook/container.dart b/escape_wild/lib/core/cook/container.dart
new file mode 100644
index 0000000..7010fd5
--- /dev/null
+++ b/escape_wild/lib/core/cook/container.dart
@@ -0,0 +1,33 @@
+import 'package:escape_wild/core.dart';
+import 'package:jconverter/jconverter.dart';
+
+/// [ContainerCookRecipe] will transform a certain [Item] that meets [inputTags] into [result] by a certain ratio.
+/// It only allow one input.
+///
+/// For example,
+class ContainerCookRecipe extends CookRecipeProtocol implements JConvertibleProtocol {
+  final List<String> inputTags;
+  final ItemGetter result;
+
+  ContainerCookRecipe(super.name, this.inputTags, this.result);
+
+  @override
+  bool match(List<ItemStack> inputs) {
+    throw UnimplementedError();
+  }
+
+  @override
+  bool updateCooking(
+    List<ItemStack> inputs,
+    List<ItemStack> outputs,
+    Ts totalTimePassed,
+    Ts delta,
+  ) {
+    throw UnimplementedError();
+  }
+
+  static const type = "ContainerCookRecipe";
+
+  @override
+  String get typeName => type;
+}
diff --git a/escape_wild/lib/core/cook/continuous.dart b/escape_wild/lib/core/cook/continuous.dart
new file mode 100644
index 0000000..62dde88
--- /dev/null
+++ b/escape_wild/lib/core/cook/continuous.dart
@@ -0,0 +1,87 @@
+import 'dart:math';
+
+import 'package:escape_wild/core.dart';
+import 'package:jconverter/jconverter.dart';
+import 'package:json_annotation/json_annotation.dart';
+
+part 'continuous.g.dart';
+
+/// [ContinuousCookRecipe] will continuously convert a certain [Item] that meets [ingredient] into [dish] by a certain ratio.
+/// - [ingredient] only matches one whose [Item.mergeable] is true.
+///
+/// It doesn't allow [Item.container].
+@JsonSerializable(createToJson: false)
+class ContinuousCookRecipe extends CookRecipeProtocol implements JConvertibleProtocol {
+  @JsonKey()
+  final Iterable<String> ingredient;
+  @itemGetterJsonKey
+  final ItemGetter dish;
+
+  /// [speed] is how much [ingredient] that will be transform to [dish] per minutes.
+  /// ```dart
+  /// int mass;
+  /// int minute;
+  /// speed = mass / minute;
+  /// ```
+  /// Unit: g/min
+  final double speed;
+
+  /// [ratio] works with [speed]. It's how much [dish] based on [speed]
+  /// ```dart
+  /// int transformedInput = speed * time;
+  /// int outputMass = transformedInput * ratio;
+  /// ```
+  ///
+  /// The default is 1.0
+  final double ratio;
+
+  ContinuousCookRecipe(
+    super.name, {
+    required this.ingredient,
+    required this.dish,
+    required this.speed,
+    this.ratio = 1.0,
+  }) {
+    assert(ingredient.isNotEmpty, "Input tags of $registerName is empty.");
+  }
+
+  @override
+  bool match(List<ItemStack> inputs) {
+    if (inputs.length != 1) return false;
+    final input = inputs.first;
+    if (!input.meta.mergeable) return false;
+    if (!input.meta.hasTags(ingredient)) return false;
+    return true;
+  }
+
+  @override
+  bool updateCooking(
+    List<ItemStack> inputs,
+    List<ItemStack> outputs,
+    Ts totalTimePassed,
+    Ts delta,
+  ) {
+    if (inputs.length != 1) return false;
+    final input = inputs.first;
+    if (!input.meta.mergeable) return false;
+    if (!input.meta.hasTags(ingredient)) return false;
+    double transformedInputF = min(speed * delta.minutes, input.stackMass.toDouble());
+    double outputMassF = transformedInputF * ratio;
+    // to avoid lose of precision.
+    int transformedInput = transformedInputF.toInt();
+    int outputMass = outputMassF.toInt();
+    input.mass = input.stackMass - transformedInput;
+    inputs.cleanEmptyStack();
+    final result = dish();
+    final resultStack = result.create(mass: outputMass);
+    outputs.addItemOrMerge(resultStack);
+    return true;
+  }
+
+  factory ContinuousCookRecipe.fromJson(Map<String, dynamic> json) => _$ContinuousCookRecipeFromJson(json);
+
+  static const type = "TransformCookRecipe";
+
+  @override
+  String get typeName => type;
+}
diff --git a/escape_wild/lib/core/cook/continuous.g.dart b/escape_wild/lib/core/cook/continuous.g.dart
new file mode 100644
index 0000000..c838523
--- /dev/null
+++ b/escape_wild/lib/core/cook/continuous.g.dart
@@ -0,0 +1,15 @@
+// GENERATED CODE - DO NOT MODIFY BY HAND
+
+part of 'continuous.dart';
+
+// **************************************************************************
+// JsonSerializableGenerator
+// **************************************************************************
+
+ContinuousCookRecipe _$ContinuousCookRecipeFromJson(Map<String, dynamic> json) => ContinuousCookRecipe(
+      json['name'] as String,
+      ingredient: (json['ingredient'] as List<dynamic>).map((e) => e as String),
+      dish: NamedItemGetter.create(json['dish'] as String),
+      speed: (json['speed'] as num).toDouble(),
+      ratio: (json['ratio'] as num?)?.toDouble() ?? 1.0,
+    )..mod = Moddable.modId2ModFunc(json['mod'] as String);
diff --git a/escape_wild/lib/core/cook/cook.dart b/escape_wild/lib/core/cook/cook.dart
new file mode 100644
index 0000000..4e3591b
--- /dev/null
+++ b/escape_wild/lib/core/cook/cook.dart
@@ -0,0 +1,5 @@
+export "container.dart";
+export "continuous.dart";
+export "instant.dart";
+export "protocol.dart";
+export "timed.dart";
diff --git a/escape_wild/lib/core/cook/instant.dart b/escape_wild/lib/core/cook/instant.dart
new file mode 100644
index 0000000..a9a3052
--- /dev/null
+++ b/escape_wild/lib/core/cook/instant.dart
@@ -0,0 +1,116 @@
+import 'package:escape_wild/core.dart';
+import 'package:jconverter/jconverter.dart';
+import 'package:json_annotation/json_annotation.dart';
+
+part 'instant.g.dart';
+
+/// [InstantConvertCookRecipe] will transform an [Item] to another one instantly.
+///
+/// It doesn't allow [Item.container].
+@JsonSerializable(createToJson: false)
+class InstantConvertCookRecipe extends CookRecipeProtocol implements JConvertibleProtocol {
+  /// the item as input
+  @itemGetterJsonKey
+  final ItemGetter input;
+
+  /// If [input] is mergeable, cooking will consume [inputMass] amount of [input].
+  final int? inputMass;
+
+  /// the item as output
+  @itemGetterJsonKey
+  final ItemGetter output;
+
+  /// If [output] is mergeable, cooking will create [outputMass] amount of [output].
+  final int? outputMass;
+  static const Set<ItemProp> kKeptProps = {
+    ItemProp.mass,
+    ItemProp.wetness,
+    ItemProp.durability,
+    ItemProp.freshness,
+  };
+  @JsonKey()
+  final Set<ItemProp> keptProps;
+
+  InstantConvertCookRecipe(
+    super.name, {
+    required this.input,
+    required this.output,
+    this.keptProps = InstantConvertCookRecipe.kKeptProps,
+    this.inputMass,
+    this.outputMass,
+  });
+
+  @override
+  bool match(List<ItemStack> inputs) {
+    if (inputs.length != 1) return false;
+    final meta = inputs.first.meta;
+    if (meta.isContainer) return false;
+    return meta == input();
+  }
+
+  @override
+  bool onMatch(List<ItemStack> inputs, List<ItemStack> outputs) {
+    if (inputs.length != 1) return false;
+    final input = inputs.first;
+    if (input.meta != this.input()) return false;
+    // handle input
+    int? outputMass = this.outputMass;
+    if (input.meta.mergeable) {
+      int? inputMass = this.inputMass;
+      assert(inputMass != null, "${input.meta} is mergeable but [inputMass] is not specified.");
+      if (inputMass == null) {
+        // if [inputMass] is empty, clear the input.
+        inputs.clear();
+      } else {
+        input.mass = input.stackMass - inputMass;
+        if (keptProps.contains(ItemProp.mass)) {
+          // when [ItemProp.mass] is kept
+          inputMass = input.stackMass;
+        }
+      }
+    } else {
+      inputs.clear();
+    }
+    // handle output
+    final outputStack = output().create(mass: outputMass);
+    _bakeOutput(input, outputStack);
+    outputs.addItemOrMerge(outputStack);
+    return true;
+  }
+
+  void _bakeOutput(ItemStack input, ItemStack output) {
+    for (final prop in keptProps) {
+      switch (prop) {
+        case ItemProp.wetness:
+          final inputComp = WetnessComp.of(input);
+          final outputComp = WetnessComp.of(output);
+          if (inputComp != null && outputComp != null) {
+            outputComp.setWetness(output, inputComp.getWetness(input));
+          }
+          break;
+        case ItemProp.durability:
+          final inputComp = DurabilityComp.of(input);
+          final outputComp = DurabilityComp.of(output);
+          if (inputComp != null && outputComp != null) {
+            outputComp.setDurability(output, inputComp.getDurability(input));
+          }
+          break;
+        case ItemProp.freshness:
+          final inputComp = FreshnessComp.of(input);
+          final outputComp = FreshnessComp.of(output);
+          if (inputComp != null && outputComp != null) {
+            outputComp.setFreshness(output, inputComp.getFreshness(input));
+          }
+          break;
+        default:
+      }
+    }
+  }
+
+  factory InstantConvertCookRecipe.fromJson(Map<String, dynamic> json) => _$InstantConvertCookRecipeFromJson(json);
+
+  static const type = "InstantConvertCookRecipe";
+
+  @override
+  String get typeName => type;
+}
diff --git a/escape_wild/lib/core/cooking.g.dart b/escape_wild/lib/core/cook/instant.g.dart
similarity index 51%
rename from escape_wild/lib/core/cooking.g.dart
rename to escape_wild/lib/core/cook/instant.g.dart
index 6f46e58..e98cdce 100644
--- a/escape_wild/lib/core/cooking.g.dart
+++ b/escape_wild/lib/core/cook/instant.g.dart
@@ -1,26 +1,11 @@
 // GENERATED CODE - DO NOT MODIFY BY HAND
 
-part of 'cooking.dart';
+part of 'instant.dart';
 
 // **************************************************************************
 // JsonSerializableGenerator
 // **************************************************************************
 
-TimedCookRecipe _$TimedCookRecipeFromJson(Map<String, dynamic> json) => TimedCookRecipe(
-      json['name'] as String,
-      ingredients: (json['ingredients'] as List<dynamic>).map(TagMassEntry.fromJson).toList(),
-      dishes: (json['dishes'] as List<dynamic>).map((e) => LazyItemStack.fromJson(e as Map<String, dynamic>)).toList(),
-      cookingTime: Ts.fromJson((json['cookingTime'] as num).toInt()),
-    )..mod = Moddable.modId2ModFunc(json['mod'] as String);
-
-ContinuousCookRecipe _$ContinuousCookRecipeFromJson(Map<String, dynamic> json) => ContinuousCookRecipe(
-      json['name'] as String,
-      ingredient: (json['ingredient'] as List<dynamic>).map((e) => e as String),
-      dish: NamedItemGetter.create(json['dish'] as String),
-      speed: (json['speed'] as num).toDouble(),
-      ratio: (json['ratio'] as num?)?.toDouble() ?? 1.0,
-    )..mod = Moddable.modId2ModFunc(json['mod'] as String);
-
 InstantConvertCookRecipe _$InstantConvertCookRecipeFromJson(Map<String, dynamic> json) => InstantConvertCookRecipe(
       json['name'] as String,
       input: NamedItemGetter.create(json['input'] as String),
diff --git a/escape_wild/lib/core/cook/protocol.dart b/escape_wild/lib/core/cook/protocol.dart
new file mode 100644
index 0000000..ec62ff1
--- /dev/null
+++ b/escape_wild/lib/core/cook/protocol.dart
@@ -0,0 +1,66 @@
+import 'package:escape_wild/core.dart';
+import 'package:json_annotation/json_annotation.dart';
+
+abstract class CookRecipeProtocol with Moddable {
+  /// The max cooking slot.
+  static const maxIngredient = 3;
+
+  @override
+  final String name;
+
+  CookRecipeProtocol(this.name);
+
+  /// ## Constrains
+  /// - [inputs] is in no order.
+  /// - [inputs.length] equals to [slotRequired].
+  /// - [inputs] is [Backpack.untracked].
+  bool match(@Backpack.untracked List<ItemStack> inputs);
+
+  /// Called as long as this is matched.
+  /// ## Constrains
+  /// - [inputs] is in no order.
+  /// - [inputs] is already matched.
+  /// - [inputs] is [Backpack.untracked].
+  /// - [outputs] is in no order.
+  /// - [outputs] is [Backpack.untracked].
+  /// - return whether [inputs] or [outputs] was changed.
+  /// ## Use cases
+  /// - Instant cooking: such as igniting a torch.
+  @Backpack.untracked
+  bool onMatch(
+    @Backpack.untracked List<ItemStack> inputs,
+    @Backpack.untracked List<ItemStack> outputs,
+  ) {
+    return false;
+  }
+
+  /// ## Constrains
+  /// - [inputs] is in no order.
+  /// - [inputs] is already matched.
+  /// - [inputs] is [Backpack.untracked].
+  /// - [outputs] is in no order.
+  /// - [outputs] is [Backpack.untracked].
+  /// - return whether [inputs] or [outputs] was changed.
+  @Backpack.untracked
+  bool updateCooking(
+    @Backpack.untracked List<ItemStack> inputs,
+    @Backpack.untracked List<ItemStack> outputs,
+    Ts totalTimePassed,
+    Ts delta,
+  ) {
+    return false;
+  }
+
+  static String? getNameOrNull(CookRecipeProtocol? recipe) => recipe?.name;
+  static const jsonKey = JsonKey(fromJson: Contents.getCookRecipesByName, toJson: getNameOrNull, includeIfNull: false);
+}
+
+CookRecipeProtocol? matchCookRecipe(List<ItemStack> stacks) {
+  if (stacks.isEmpty) return null;
+  for (final recipe in Contents.cookRecipes.name2FoodRecipe.values) {
+    if (recipe.match(stacks)) {
+      return recipe;
+    }
+  }
+  return null;
+}
diff --git a/escape_wild/lib/core/cook/timed.dart b/escape_wild/lib/core/cook/timed.dart
new file mode 100644
index 0000000..4ac4c76
--- /dev/null
+++ b/escape_wild/lib/core/cook/timed.dart
@@ -0,0 +1,99 @@
+import 'package:collection/collection.dart';
+import 'package:escape_wild/core.dart';
+import 'package:jconverter/jconverter.dart';
+import 'package:json_annotation/json_annotation.dart';
+
+import 'protocol.dart';
+
+part 'timed.g.dart';
+
+/// - [dishes] will be created as long as [cookingTime] is reached.
+///
+/// [Item.container] is not allowed.
+@JsonSerializable(createToJson: false)
+class TimedCookRecipe extends CookRecipeProtocol implements JConvertibleProtocol {
+  @JsonKey()
+  final List<TagMassEntry> ingredients;
+  @JsonKey()
+  final List<LazyItemStack> dishes;
+  @JsonKey()
+  final Ts cookingTime;
+
+  TimedCookRecipe(
+    super.name, {
+    required this.ingredients,
+    required this.dishes,
+    required this.cookingTime,
+  }) {
+    assert(ingredients.isNotEmpty, "Ingredients of $registerName is empty.");
+    assert(ingredients.length <= CookRecipeProtocol.maxIngredient,
+        "Ingredients of $registerName is > ${CookRecipeProtocol.maxIngredient}.");
+    assert(dishes.isNotEmpty, "Outputs of $registerName is empty.");
+  }
+
+  factory TimedCookRecipe.fromJson(Map<String, dynamic> json) => _$TimedCookRecipeFromJson(json);
+
+  @override
+  bool match(List<ItemStack> inputs) {
+    if (inputs.length != ingredients.length) return false;
+    // Container is not allowed.
+    if (inputs.any((input) => input.meta.isContainer)) return false;
+    final rest = Set.of(inputs);
+    for (final ingredient in ingredients) {
+      final matched = rest.firstWhereOrNull((input) => isMatched(input, ingredient));
+      if (matched == null) return false;
+      rest.remove(matched);
+    }
+    return rest.isEmpty;
+  }
+
+  bool isMatched(ItemStack input, TagMassEntry ingredient) {
+    if (!input.meta.hasTags(ingredient.tags)) return false;
+    final massReq = ingredient.mass;
+    // [massReq] is null, the input should be unmergeable.
+    // otherwise, [ItemStack.stackMass] should reach the [massReq].
+    if (massReq == null) {
+      return input.meta.mergeable;
+    } else {
+      return input.stackMass >= massReq;
+    }
+  }
+
+  @override
+  bool updateCooking(
+    List<ItemStack> inputs,
+    List<ItemStack> outputs,
+    Ts totalTimePassed,
+    Ts delta,
+  ) {
+    // It must reach the [cookingTime]
+    if (totalTimePassed < cookingTime) return false;
+    if (inputs.length != ingredients.length) return false;
+    // Cooked!
+    final rest = Set.of(inputs);
+    for (final ingredient in ingredients) {
+      final matched = rest.firstWhereOrNull((input) => isMatched(input, ingredient));
+      assert(matched != null, "$inputs should match $registerName in $updateCooking");
+      if (matched == null) return false;
+      rest.remove(matched);
+      if (matched.meta.mergeable) {
+        matched.mass = matched.stackMass - (ingredient.mass ?? 0);
+      } else {
+        inputs.removeStack(matched);
+      }
+    }
+    inputs.cleanEmptyStack();
+    for (final dish in dishes) {
+      final item = dish.item();
+      final mass = dish.mass;
+      final created = item.create(mass: mass);
+      outputs.addItemOrMerge(created);
+    }
+    return true;
+  }
+
+  static const type = "TimedCookRecipe";
+
+  @override
+  String get typeName => type;
+}
diff --git a/escape_wild/lib/core/cook/timed.g.dart b/escape_wild/lib/core/cook/timed.g.dart
new file mode 100644
index 0000000..199aa71
--- /dev/null
+++ b/escape_wild/lib/core/cook/timed.g.dart
@@ -0,0 +1,14 @@
+// GENERATED CODE - DO NOT MODIFY BY HAND
+
+part of 'timed.dart';
+
+// **************************************************************************
+// JsonSerializableGenerator
+// **************************************************************************
+
+TimedCookRecipe _$TimedCookRecipeFromJson(Map<String, dynamic> json) => TimedCookRecipe(
+      json['name'] as String,
+      ingredients: (json['ingredients'] as List<dynamic>).map(TagMassEntry.fromJson).toList(),
+      dishes: (json['dishes'] as List<dynamic>).map((e) => LazyItemStack.fromJson(e as Map<String, dynamic>)).toList(),
+      cookingTime: Ts.fromJson((json['cookingTime'] as num).toInt()),
+    )..mod = Moddable.modId2ModFunc(json['mod'] as String);
diff --git a/escape_wild/lib/core/cooking.dart b/escape_wild/lib/core/cooking.dart
deleted file mode 100644
index 85891d0..0000000
--- a/escape_wild/lib/core/cooking.dart
+++ /dev/null
@@ -1,543 +0,0 @@
-import 'dart:math';
-
-import 'package:collection/collection.dart';
-import 'package:escape_wild/core.dart';
-import 'package:flutter/widgets.dart';
-import 'package:jconverter/jconverter.dart';
-import 'package:json_annotation/json_annotation.dart';
-
-import 'item_comp/durability.dart';
-import 'item_comp/freshness.dart';
-import 'item_comp/wetness.dart';
-import 'item_prop.dart';
-
-part 'cooking.g.dart';
-
-abstract class CookRecipeProtocol with Moddable {
-  /// The max cooking slot.
-  static const maxIngredient = 3;
-
-  @override
-  final String name;
-
-  CookRecipeProtocol(this.name);
-
-  /// ## Constrains
-  /// - [inputs] is in no order.
-  /// - [inputs.length] equals to [slotRequired].
-  /// - [inputs] is [Backpack.untracked].
-  bool match(@Backpack.untracked List<ItemStack> inputs);
-
-  /// Called as long as this is matched.
-  /// ## Constrains
-  /// - [inputs] is in no order.
-  /// - [inputs] is already matched.
-  /// - [inputs] is [Backpack.untracked].
-  /// - [outputs] is in no order.
-  /// - [outputs] is [Backpack.untracked].
-  /// - return whether [inputs] or [outputs] was changed.
-  /// ## Use cases
-  /// - Instant cooking: such as igniting a torch.
-  @Backpack.untracked
-  bool onMatch(
-    @Backpack.untracked List<ItemStack> inputs,
-    @Backpack.untracked List<ItemStack> outputs,
-  ) {
-    return false;
-  }
-
-  /// ## Constrains
-  /// - [inputs] is in no order.
-  /// - [inputs] is already matched.
-  /// - [inputs] is [Backpack.untracked].
-  /// - [outputs] is in no order.
-  /// - [outputs] is [Backpack.untracked].
-  /// - return whether [inputs] or [outputs] was changed.
-  @Backpack.untracked
-  bool updateCooking(
-    @Backpack.untracked List<ItemStack> inputs,
-    @Backpack.untracked List<ItemStack> outputs,
-    Ts totalTimePassed,
-    Ts delta,
-  ) {
-    return false;
-  }
-
-  static String? getNameOrNull(CookRecipeProtocol? recipe) => recipe?.name;
-  static const jsonKey = JsonKey(fromJson: Contents.getCookRecipesByName, toJson: getNameOrNull, includeIfNull: false);
-}
-
-/// - [dishes] will be created as long as [cookingTime] is reached.
-///
-/// [Item.container] is not allowed.
-@JsonSerializable(createToJson: false)
-class TimedCookRecipe extends CookRecipeProtocol implements JConvertibleProtocol {
-  @JsonKey()
-  final List<TagMassEntry> ingredients;
-  @JsonKey()
-  final List<LazyItemStack> dishes;
-  @JsonKey()
-  final Ts cookingTime;
-
-  TimedCookRecipe(
-    super.name, {
-    required this.ingredients,
-    required this.dishes,
-    required this.cookingTime,
-  }) {
-    assert(ingredients.isNotEmpty, "Ingredients of $registerName is empty.");
-    assert(ingredients.length <= CookRecipeProtocol.maxIngredient,
-        "Ingredients of $registerName is > ${CookRecipeProtocol.maxIngredient}.");
-    assert(dishes.isNotEmpty, "Outputs of $registerName is empty.");
-  }
-
-  factory TimedCookRecipe.fromJson(Map<String, dynamic> json) => _$TimedCookRecipeFromJson(json);
-
-  @override
-  bool match(List<ItemStack> inputs) {
-    if (inputs.length != ingredients.length) return false;
-    // Container is not allowed.
-    if (inputs.any((input) => input.meta.isContainer)) return false;
-    final rest = Set.of(inputs);
-    for (final ingredient in ingredients) {
-      final matched = rest.firstWhereOrNull((input) => isMatched(input, ingredient));
-      if (matched == null) return false;
-      rest.remove(matched);
-    }
-    return rest.isEmpty;
-  }
-
-  bool isMatched(ItemStack input, TagMassEntry ingredient) {
-    if (!input.meta.hasTags(ingredient.tags)) return false;
-    final massReq = ingredient.mass;
-    // [massReq] is null, the input should be unmergeable.
-    // otherwise, [ItemStack.stackMass] should reach the [massReq].
-    if (massReq == null) {
-      return input.meta.mergeable;
-    } else {
-      return input.stackMass >= massReq;
-    }
-  }
-
-  @override
-  bool updateCooking(
-    List<ItemStack> inputs,
-    List<ItemStack> outputs,
-    Ts totalTimePassed,
-    Ts delta,
-  ) {
-    // It must reach the [cookingTime]
-    if (totalTimePassed < cookingTime) return false;
-    if (inputs.length != ingredients.length) return false;
-    // Cooked!
-    final rest = Set.of(inputs);
-    for (final ingredient in ingredients) {
-      final matched = rest.firstWhereOrNull((input) => isMatched(input, ingredient));
-      assert(matched != null, "$inputs should match $registerName in $updateCooking");
-      if (matched == null) return false;
-      rest.remove(matched);
-      if (matched.meta.mergeable) {
-        matched.mass = matched.stackMass - (ingredient.mass ?? 0);
-      } else {
-        inputs.removeStack(matched);
-      }
-    }
-    inputs.cleanEmptyStack();
-    for (final dish in dishes) {
-      final item = dish.item();
-      final mass = dish.mass;
-      final created = item.create(mass: mass);
-      outputs.addItemOrMerge(created);
-    }
-    return true;
-  }
-
-  static const type = "TimedCookRecipe";
-
-  @override
-  String get typeName => type;
-}
-
-/// [ContainerCookRecipe] will transform a certain [Item] that meets [inputTags] into [result] by a certain ratio.
-/// It only allow one input.
-///
-/// For example,
-class ContainerCookRecipe extends CookRecipeProtocol implements JConvertibleProtocol {
-  final List<String> inputTags;
-  final ItemGetter result;
-
-  ContainerCookRecipe(super.name, this.inputTags, this.result);
-
-  @override
-  bool match(List<ItemStack> inputs) {
-    throw UnimplementedError();
-  }
-
-  @override
-  bool updateCooking(
-    List<ItemStack> inputs,
-    List<ItemStack> outputs,
-    Ts totalTimePassed,
-    Ts delta,
-  ) {
-    throw UnimplementedError();
-  }
-
-  static const type = "ContainerCookRecipe";
-
-  @override
-  String get typeName => type;
-}
-
-/// [ContinuousCookRecipe] will continuously convert a certain [Item] that meets [ingredient] into [dish] by a certain ratio.
-/// - [ingredient] only matches one whose [Item.mergeable] is true.
-///
-/// It doesn't allow [Item.container].
-@JsonSerializable(createToJson: false)
-class ContinuousCookRecipe extends CookRecipeProtocol implements JConvertibleProtocol {
-  @JsonKey()
-  final Iterable<String> ingredient;
-  @itemGetterJsonKey
-  final ItemGetter dish;
-
-  /// [speed] is how much [ingredient] that will be transform to [dish] per minutes.
-  /// ```dart
-  /// int mass;
-  /// int minute;
-  /// speed = mass / minute;
-  /// ```
-  /// Unit: g/min
-  final double speed;
-
-  /// [ratio] works with [speed]. It's how much [dish] based on [speed]
-  /// ```dart
-  /// int transformedInput = speed * time;
-  /// int outputMass = transformedInput * ratio;
-  /// ```
-  ///
-  /// The default is 1.0
-  final double ratio;
-
-  ContinuousCookRecipe(
-    super.name, {
-    required this.ingredient,
-    required this.dish,
-    required this.speed,
-    this.ratio = 1.0,
-  }) {
-    assert(ingredient.isNotEmpty, "Input tags of $registerName is empty.");
-  }
-
-  @override
-  bool match(List<ItemStack> inputs) {
-    if (inputs.length != 1) return false;
-    final input = inputs.first;
-    if (!input.meta.mergeable) return false;
-    if (!input.meta.hasTags(ingredient)) return false;
-    return true;
-  }
-
-  @override
-  bool updateCooking(
-    List<ItemStack> inputs,
-    List<ItemStack> outputs,
-    Ts totalTimePassed,
-    Ts delta,
-  ) {
-    if (inputs.length != 1) return false;
-    final input = inputs.first;
-    if (!input.meta.mergeable) return false;
-    if (!input.meta.hasTags(ingredient)) return false;
-    double transformedInputF = min(speed * delta.minutes, input.stackMass.toDouble());
-    double outputMassF = transformedInputF * ratio;
-    // to avoid lose of precision.
-    int transformedInput = transformedInputF.toInt();
-    int outputMass = outputMassF.toInt();
-    input.mass = input.stackMass - transformedInput;
-    inputs.cleanEmptyStack();
-    final result = dish();
-    final resultStack = result.create(mass: outputMass);
-    outputs.addItemOrMerge(resultStack);
-    return true;
-  }
-
-  factory ContinuousCookRecipe.fromJson(Map<String, dynamic> json) => _$ContinuousCookRecipeFromJson(json);
-
-  static const type = "TransformCookRecipe";
-
-  @override
-  String get typeName => type;
-}
-
-/// [InstantConvertCookRecipe] will transform an [Item] to another one instantly.
-///
-/// It doesn't allow [Item.container].
-@JsonSerializable(createToJson: false)
-class InstantConvertCookRecipe extends CookRecipeProtocol implements JConvertibleProtocol {
-  /// the item as input
-  @itemGetterJsonKey
-  final ItemGetter input;
-
-  /// If [input] is mergeable, cooking will consume [inputMass] amount of [input].
-  final int? inputMass;
-
-  /// the item as output
-  @itemGetterJsonKey
-  final ItemGetter output;
-
-  /// If [output] is mergeable, cooking will create [outputMass] amount of [output].
-  final int? outputMass;
-  static const Set<ItemProp> kKeptProps = {
-    ItemProp.mass,
-    ItemProp.wetness,
-    ItemProp.durability,
-    ItemProp.freshness,
-  };
-  @JsonKey()
-  final Set<ItemProp> keptProps;
-
-  InstantConvertCookRecipe(
-    super.name, {
-    required this.input,
-    required this.output,
-    this.keptProps = InstantConvertCookRecipe.kKeptProps,
-    this.inputMass,
-    this.outputMass,
-  });
-
-  @override
-  bool match(List<ItemStack> inputs) {
-    if (inputs.length != 1) return false;
-    final meta = inputs.first.meta;
-    if (meta.isContainer) return false;
-    return meta == input();
-  }
-
-  @override
-  bool onMatch(List<ItemStack> inputs, List<ItemStack> outputs) {
-    if (inputs.length != 1) return false;
-    final input = inputs.first;
-    if (input.meta != this.input()) return false;
-    // handle input
-    int? outputMass = this.outputMass;
-    if (input.meta.mergeable) {
-      int? inputMass = this.inputMass;
-      assert(inputMass != null, "${input.meta} is mergeable but [inputMass] is not specified.");
-      if (inputMass == null) {
-        // if [inputMass] is empty, clear the input.
-        inputs.clear();
-      } else {
-        input.mass = input.stackMass - inputMass;
-        if (keptProps.contains(ItemProp.mass)) {
-          // when [ItemProp.mass] is kept
-          inputMass = input.stackMass;
-        }
-      }
-    } else {
-      inputs.clear();
-    }
-    // handle output
-    final outputStack = output().create(mass: outputMass);
-    _bakeOutput(input, outputStack);
-    outputs.addItemOrMerge(outputStack);
-    return true;
-  }
-
-  void _bakeOutput(ItemStack input, ItemStack output) {
-    for (final prop in keptProps) {
-      switch (prop) {
-        case ItemProp.wetness:
-          final inputComp = WetnessComp.of(input);
-          final outputComp = WetnessComp.of(output);
-          if (inputComp != null && outputComp != null) {
-            outputComp.setWetness(output, inputComp.getWetness(input));
-          }
-          break;
-        case ItemProp.durability:
-          final inputComp = DurabilityComp.of(input);
-          final outputComp = DurabilityComp.of(output);
-          if (inputComp != null && outputComp != null) {
-            outputComp.setDurability(output, inputComp.getDurability(input));
-          }
-          break;
-        case ItemProp.freshness:
-          final inputComp = FreshnessComp.of(input);
-          final outputComp = FreshnessComp.of(output);
-          if (inputComp != null && outputComp != null) {
-            outputComp.setFreshness(output, inputComp.getFreshness(input));
-          }
-          break;
-        default:
-      }
-    }
-  }
-
-  factory InstantConvertCookRecipe.fromJson(Map<String, dynamic> json) => _$InstantConvertCookRecipeFromJson(json);
-
-  static const type = "InstantConvertCookRecipe";
-
-  @override
-  String get typeName => type;
-}
-
-CookRecipeProtocol? _match(List<ItemStack> stacks) {
-  if (stacks.isEmpty) return null;
-  for (final recipe in Contents.cookRecipes.name2FoodRecipe.values) {
-    if (recipe.match(stacks)) {
-      return recipe;
-    }
-  }
-  return null;
-}
-
-abstract class CampfirePlaceProtocol extends PlaceProtocol with ChangeNotifier {
-  FireState get fireState;
-
-  set fireState(FireState v);
-
-  List<ItemStack> get onCampfire;
-
-  set onCampfire(List<ItemStack> v);
-
-  List<ItemStack> get offCampfire;
-
-  set offCampfire(List<ItemStack> v);
-
-  void onResetCooking();
-}
-
-extension CampfireHolderProtocolX on CampfirePlaceProtocol {
-  bool get isCampfireHasAnyStack => onCampfire.isNotEmpty || offCampfire.isNotEmpty;
-}
-
-mixin CampfireCookingMixin on CampfirePlaceProtocol {
-  @JsonKey(fromJson: tsFromJson, toJson: tsToJson, includeIfNull: false)
-  Ts cookingTime = Ts.zero;
-  List<ItemStack> _onCampfire = [];
-
-  @override
-  @JsonKey(fromJson: campfireStackFromJson, toJson: campfireStackToJson, includeIfNull: false)
-  List<ItemStack> get onCampfire => _onCampfire;
-
-  @override
-  set onCampfire(List<ItemStack> v) {
-    _onCampfire = v;
-    notifyListeners();
-  }
-
-  List<ItemStack> _offCampfire = [];
-
-  @override
-  @JsonKey(fromJson: campfireStackFromJson, toJson: campfireStackToJson, includeIfNull: false)
-  List<ItemStack> get offCampfire => _offCampfire;
-
-  @override
-  set offCampfire(List<ItemStack> v) {
-    _offCampfire = v;
-    notifyListeners();
-  }
-
-  @CookRecipeProtocol.jsonKey
-  CookRecipeProtocol? recipe;
-
-  FireState _fireState = FireState.off;
-
-  @override
-  @JsonKey(fromJson: fireStateFromJson, toJson: fireStateStackToJson, includeIfNull: false)
-  FireState get fireState => _fireState;
-
-  @override
-  set fireState(FireState v) {
-    _fireState = v;
-    notifyListeners();
-  }
-
-  double get fuelCostPerMinute;
-
-  /// Call this after changing [onCampfire].
-  @override
-  void onResetCooking() {
-    cookingTime = Ts.zero;
-    final matched = _match(onCampfire);
-    recipe = matched;
-    if (matched != null) {
-      // for instant cooking
-      final changed = matched.onMatch(onCampfire, offCampfire);
-      if (changed) {
-        notifyListeners();
-      }
-    }
-  }
-
-  Future<void> onCampfirePass(Ts delta) async {
-    // update items the place holds
-    for (final stack in onCampfire) {
-      await stack.onPassTime(delta);
-    }
-    for (final stack in offCampfire) {
-      await stack.onPassTime(delta);
-    }
-    if (fireState.active) {
-      final cost = delta.minutes * fuelCostPerMinute;
-      fireState = _burningFuel(fireState, cost);
-    }
-    // only cooking when fire has fuel.
-    if (fireState.fuel <= 0) return;
-    if (onCampfire.isEmpty) return;
-    final recipe = this.recipe ??= _match(onCampfire);
-    if (recipe == null) {
-      cookingTime = Ts.zero;
-    } else {
-      cookingTime += delta;
-      final changed = recipe.updateCooking(onCampfire, offCampfire, cookingTime, delta);
-      if (changed) {
-        this.recipe = null;
-        cookingTime = Ts.zero;
-        notifyListeners();
-      }
-    }
-  }
-
-  Future<void> onFirePass(double fuelCostSpeed, Ts delta) async {
-    final fireState = this.fireState;
-    if (fireState.active) {
-      final cost = delta / actionStepTime * fuelCostSpeed;
-      this.fireState = _burningFuel(fireState, cost);
-    }
-  }
-
-  static List<ItemStack> campfireStackFromJson(dynamic json) =>
-      json == null ? [] : (json as List<dynamic>).map((e) => ItemStack.fromJson(e as Map<String, dynamic>)).toList();
-
-  static dynamic campfireStackToJson(List<ItemStack> list) => list.isEmpty ? null : list;
-
-  static Ts tsFromJson(dynamic json) => json == null ? Ts.zero : Ts.fromJson((json as num).toInt());
-
-  static dynamic tsToJson(Ts ts) => ts == Ts.zero ? null : ts;
-
-  static FireState fireStateFromJson(dynamic json) => json == null ? FireState.off : FireState.fromJson(json);
-
-  static dynamic fireStateStackToJson(FireState fire) => fire.isOff ? null : fire;
-}
-
-const _emberCostFactor = 5;
-
-// TODO: Better formula
-FireState _burningFuel(
-  FireState former,
-  double cost,
-) {
-  final curFuel = former.fuel;
-  var resFuel = curFuel;
-  var resEmber = former.ember;
-  if (curFuel <= cost) {
-    final costOverflow = cost - curFuel;
-    resFuel = 0;
-    resEmber += curFuel;
-    resEmber -= costOverflow * _emberCostFactor;
-  } else {
-    resFuel -= cost;
-    resEmber += cost;
-  }
-  return FireState(ember: resEmber, fuel: resFuel);
-}
diff --git a/escape_wild/lib/core/ecs/tag.dart b/escape_wild/lib/core/ecs/tag.dart
index fae7d9d..5c7e41a 100644
--- a/escape_wild/lib/core/ecs/tag.dart
+++ b/escape_wild/lib/core/ecs/tag.dart
@@ -1,4 +1,3 @@
-
 import 'package:json_annotation/json_annotation.dart';
 
 mixin TagsMixin {
@@ -39,4 +38,4 @@ extension TagsMixinX<T extends TagsMixin> on T {
     }
     return false;
   }
-}
\ No newline at end of file
+}
diff --git a/escape_wild/lib/core/item.dart b/escape_wild/lib/core/item.dart
index bb81e02..6990a63 100644
--- a/escape_wild/lib/core/item.dart
+++ b/escape_wild/lib/core/item.dart
@@ -6,8 +6,6 @@ import 'package:flutter/foundation.dart';
 import 'package:jconverter/jconverter.dart';
 import 'package:json_annotation/json_annotation.dart';
 
-import 'ecs/ecs.dart';
-
 part 'item.g.dart';
 
 typedef ItemGetter = Item Function();