feat(channels): add category creation modal and sidebar action

components/modals/CreateCategoryModal.tsx

@@ -0,0 +1,133 @@
+/**
+ * @file components/modals/CreateCategoryModal.tsx
+ * @description Modal dialog component for creating a new channel category within a server.
+ */
+
+"use client";
+
+import { useState } from "react";
+import { X } from "lucide-react";
+import { useActiveServer } from "@/lib/context/ServerContext";
+import { ActionButton } from "../ui/ActionButton";
+
+interface CreateCategoryModalProps {
+  isOpen: boolean;
+  onClose: () => void;
+  serverId: string;
+}
+
+/** Renders a modal dialog allowing users to create a new category in a server. */
+export function CreateCategoryModal({
+  isOpen,
+  onClose,
+  serverId,
+}: CreateCategoryModalProps) {
+  const [name, setName] = useState("");
+  const [isLoading, setIsLoading] = useState(false);
+  const [error, setError] = useState<string | null>(null);
+
+  const { addCategory } = useActiveServer();
+
+  if (!isOpen) return null;
+
+  const isValid = name.trim().length !== 0;
+  const canSave = isValid && !isLoading;
+
+  /** Handles form submission to create a new category via the API. */
+  const handleSubmit = async (e: React.SubmitEvent) => {
+    e.preventDefault();
+    if (!name.trim() || isLoading) return;
+
+    try {
+      setIsLoading(true);
+      setError(null);
+
+      const response = await fetch("/api/categories", {
+        method: "POST",
+        headers: { "Content-Type": "application/json" },
+        body: JSON.stringify({ name, serverId }),
+      });
+
+      if (!response.ok) {
+        throw new Error("Failed to create category.");
+      }
+
+      const newCategory = await response.json();
+
+      addCategory(newCategory);
+      setName("");
+      onClose();
+    } catch (err: unknown) {
+      setError(err instanceof Error ? err.message : "Something went wrong.");
+    } finally {
+      setIsLoading(false);
+    }
+  };
+
+  return (
+    <div
+      onClick={onClose}
+      className="fixed inset-0 z-50 bg-black/70 flex items-center justify-center p-4"
+    >
+      <div
+        onClick={(e) => e.stopPropagation()}
+        className="bg-surface border border-surface/50 rounded-2xl w-full max-w-md p-6 shadow-2xl relative animate-in fade-in zoom-in-95 duration-150"
+      >
+        <button
+          type="button"
+          onClick={onClose}
+          disabled={isLoading}
+          className="absolute top-4 right-4 text-muted hover:text-white transition-colors cursor-pointer"
+        >
+          <X className="w-5 h-5" />
+        </button>
+
+        <h2 className="text-xl font-bold text-white mb-1">Create Category</h2>
+        <p className="text-sm text-muted mb-6">
+          Create a category to group channels together in this server.
+        </p>
+
+        <form onSubmit={handleSubmit} className="space-y-4">
+          <div>
+            <label className="block text-xs font-semibold text-muted uppercase tracking-wider mb-2">
+              Category Name
+            </label>
+            <input
+              type="text"
+              required
+              value={name}
+              maxLength={32}
+              onChange={(e) => setName(e.target.value)}
+              placeholder="NEW CATEGORY"
+              disabled={isLoading}
+              autoFocus
+              className="w-full bg-background border border-surface/80 rounded-xl px-3.5 py-2.5 text-sm text-white placeholder:text-muted focus:outline-none focus:ring-2 focus:ring-accent transition-all disabled:opacity-50"
+            />
+          </div>
+
+          {error && <p className="text-xs text-red-400 mt-2">{error}</p>}
+
+          <div className="flex items-center justify-end gap-3 pt-4">
+            <ActionButton
+              type="button"
+              variant="secondary"
+              onClick={onClose}
+              disabled={isLoading}
+            >
+              Cancel
+            </ActionButton>
+
+            <ActionButton
+              type="submit"
+              variant="primary"
+              isLoading={isLoading}
+              disabled={!canSave}
+            >
+              Save
+            </ActionButton>
+          </div>
+        </form>
+      </div>
+    </div>
+  );
+}

components/sidebar/ChannelSidebar.tsx

@@ -10,10 +10,12 @@ import { useParams } from "next/navigation";
 import { useActiveServer } from "@/lib/context/ServerContext";
 import { useSidebarStore } from "@/lib/stores/useSidebarStore";
 import { CreateChannelModal } from "@/components/modals/CreateChannelModal";
+import { CreateCategoryModal } from "@/components/modals/CreateCategoryModal";
 import { EditChannelModal } from "@/components/modals/EditChannelModal";
 import {
   ChevronDown,
   ChevronRight,
+  FolderPlus,
   PanelLeftClose,
   Plus,
   Settings,
@@ -24,6 +26,8 @@ import Link from "next/link";
 /** Renders the channel navigation sidebar for the active server. */
 export function ChannelSidebar() {
   const [isCreateModalOpen, setIsCreateModalOpen] = useState(false);
+  const [isCreateCategoryModalOpen, setIsCreateCategoryModalOpen] =
+    useState(false);
   const [editingChannel, setEditingChannel] = useState<Channel | null>(null);
   const [selectedCategoryId, setSelectedCategoryId] = useState<string | null>(
     null,
@@ -119,14 +123,24 @@ export function ChannelSidebar() {
         {/* Server Header */}
         <div className="h-14 border-b border-background flex items-center justify-between px-4 font-bold text-white shadow-sm shrink-0">
           <span className="truncate">{activeServer.name}</span>
-          <button
-            type="button"
-            onClick={toggleNav}
-            title="Collapse the sidebar"
-            className="p-1.5 rounded-md text-muted hover:text-white hover:bg-surface transition-colors cursor-pointer shrink-0"
-          >
-            <PanelLeftClose className="w-5 h-5" />
-          </button>
+          <div className="flex items-center gap-1">
+            <button
+              type="button"
+              onClick={() => setIsCreateCategoryModalOpen(true)}
+              title="Create Category"
+              className="p-1.5 rounded-md text-muted hover:text-white hover:bg-surface transition-colors cursor-pointer shrink-0"
+            >
+              <FolderPlus className="w-4 h-4" />
+            </button>
+            <button
+              type="button"
+              onClick={toggleNav}
+              title="Collapse the sidebar"
+              className="p-1.5 rounded-md text-muted hover:text-white hover:bg-surface transition-colors cursor-pointer shrink-0"
+            >
+              <PanelLeftClose className="w-5 h-5" />
+            </button>
+          </div>
         </div>
 
         {/* Channel List */}
@@ -205,6 +219,12 @@ export function ChannelSidebar() {
       </div>
 
       {/* Modals */}
+      <CreateCategoryModal
+        isOpen={isCreateCategoryModalOpen}
+        onClose={() => setIsCreateCategoryModalOpen(false)}
+        serverId={activeServer.id}
+      />
+
       <CreateChannelModal
         isOpen={isCreateModalOpen}
         onClose={() => setIsCreateModalOpen(false)}