From 30c9b3aa3de8122c171acd2b5e47d81293b22d98 Mon Sep 17 00:00:00 2001
From: Prev Wong <prevwong@gmail.com>
Date: Mon, 29 Apr 2024 18:45:18 +0800
Subject: [PATCH] feat(reka): implement getComponentSlots()

---
 .changeset/wise-points-teach.md |  5 +++
 packages/core/src/reka.ts       |  4 ++
 packages/core/src/resolver.ts   | 79 ++++++++++++++++++++++++++++++++-
 packages/core/src/scope.ts      | 15 +++++++
 4 files changed, 102 insertions(+), 1 deletion(-)
 create mode 100644 .changeset/wise-points-teach.md

diff --git a/.changeset/wise-points-teach.md b/.changeset/wise-points-teach.md
new file mode 100644
index 00000000..c56599e8
--- /dev/null
+++ b/.changeset/wise-points-teach.md
@@ -0,0 +1,5 @@
+---
+'@rekajs/core': patch
+---
+
+Implement getComponentSlots() to quickly get slots defined in a Reka Component
diff --git a/packages/core/src/reka.ts b/packages/core/src/reka.ts
index 897e013b..209d8e8a 100644
--- a/packages/core/src/reka.ts
+++ b/packages/core/src/reka.ts
@@ -433,6 +433,10 @@ export class Reka {
     );
   }
 
+  getComponentSlots(component: t.Component) {
+    return this.head.resolver.componentToSlotsMap.get(component) ?? [];
+  }
+
   /**
    * Create a new Reka instance
    */
diff --git a/packages/core/src/resolver.ts b/packages/core/src/resolver.ts
index 0e256d93..201739ec 100644
--- a/packages/core/src/resolver.ts
+++ b/packages/core/src/resolver.ts
@@ -1,4 +1,5 @@
 import * as t from '@rekajs/types';
+import { invariant } from '@rekajs/utils';
 import {
   computed,
   IComputedValue,
@@ -32,6 +33,8 @@ export class Resolver {
   identifiersToIdentifiable: Map<t.Identifier, t.Identifiable>;
   nodeToScope: Map<t.ASTNode, Scope>;
 
+  componentToSlotsMap: Map<t.Component, Map<string, Set<t.SlotTemplate>>>;
+
   private scope: Scope;
   private cachedComponentResolver: WeakMap<
     t.Component,
@@ -61,9 +64,12 @@ export class Resolver {
 
     this.nodeToScope = new Map();
 
+    this.componentToSlotsMap = new Map();
+
     makeObservable(this, {
       identifiersToIdentifiableDistance: observable,
       nodeToScope: observable,
+      componentToSlotsMap: observable,
     });
   }
 
@@ -116,6 +122,58 @@ export class Resolver {
     });
   }
 
+  private bindSlotToComponent(component: t.Component, slot: t.SlotTemplate) {
+    runInAction(() => {
+      const componentMap = this.componentToSlotsMap.get(component);
+
+      //TODO: support named slots
+      const slotName = 'children';
+
+      if (!componentMap) {
+        this.componentToSlotsMap.set(
+          component,
+          new Map([[slotName, new Set([slot])]])
+        );
+
+        return;
+      }
+
+      const slotSet = componentMap.get(slotName);
+
+      if (!slotSet) {
+        componentMap.set(slotName, new Set([slot]));
+        return;
+      }
+
+      slotSet.add(slot);
+    });
+  }
+
+  private unbindSlotToComponent(slot: t.SlotTemplate) {
+    const scope = this.nodeToScope.get(slot);
+    const slotName = 'children';
+
+    if (!scope) {
+      return;
+    }
+
+    const componentScope = scope.context?.component;
+    if (!componentScope) {
+      return;
+    }
+
+    const component = this.reka.getNodeFromId(
+      componentScope.id,
+      t.RekaComponent
+    );
+
+    this.componentToSlotsMap.get(component)?.get(slotName)?.delete(slot);
+
+    if (this.componentToSlotsMap.get(component)?.get(slotName)?.size === 0) {
+      this.componentToSlotsMap.get(component)?.delete(slotName);
+    }
+  }
+
   unbindIdentifierToIdentifiable(identifier: t.Identifier) {
     runInAction(() => {
       this.identifiersToIdentifiable.delete(identifier);
@@ -254,7 +312,7 @@ export class Resolver {
             });
 
             if (component.template) {
-            this.resolveTemplate(component.template, componentScope);
+              this.resolveTemplate(component.template, componentScope);
             }
           }),
           key: scope.toString(),
@@ -276,6 +334,15 @@ export class Resolver {
 
       this.bindNodeToScope(template, templateScope);
 
+      if (t.is(template, t.SlotTemplate)) {
+        const componentId = scope.context?.component.id;
+        invariant(componentId);
+
+        const component = this.reka.getNodeFromId(componentId, t.RekaComponent);
+
+        this.bindSlotToComponent(component, template);
+      }
+
       let eachIndex: string | null = null;
       let eachAliasName: string | null = null;
 
@@ -403,6 +470,16 @@ export class Resolver {
       return;
     }
 
+    if (t.is(node, t.Component)) {
+      runInAction(() => {
+        this.componentToSlotsMap.delete(node);
+      });
+    }
+
+    if (t.is(node, t.SlotTemplate)) {
+      this.unbindSlotToComponent(node);
+    }
+
     const scopeId = getKeyFromScopeDescription(scopeDescription);
 
     this.scopeRegistry.delete(scopeId);
diff --git a/packages/core/src/scope.ts b/packages/core/src/scope.ts
index d2675ceb..66785a96 100644
--- a/packages/core/src/scope.ts
+++ b/packages/core/src/scope.ts
@@ -98,6 +98,10 @@ export const getScopeDescriptionByNodeOwner = (
   return description;
 };
 
+export type ScopeContext = {
+  component?: t.Component;
+};
+
 export class Scope {
   identifiables: Map<string, t.Identifiable>;
 
@@ -105,6 +109,8 @@ export class Scope {
 
   path: string;
 
+  context: Record<string, ScopeDescription> | null;
+
   constructor(
     readonly resolver: Resolver,
     descriptionOrNode: ScopeDescription | t.ASTNode,
@@ -124,6 +130,15 @@ export class Scope {
 
     this.resolver.scopeRegistry.set(this.key, this);
 
+    this.context = null;
+
+    if (parent) {
+      this.context = {
+        ...(parent.context ?? {}),
+        [parent.description.level]: parent.description,
+      };
+    }
+
     makeObservable(this, {
       identifiables: observable,
       defineIdentifiable: action,