feat(channel): add channel creation with API, modal UI, and context state update

app/api/channels/route.ts

@@ -0,0 +1,73 @@
+/**
+ * @file app/api/channels/route.ts
+ * @description API route handler for creating new channels within a server.
+ */
+
+import { auth } from "@/auth";
+import { db } from "@/db";
+import { channels, members } from "@/db/schema";
+import { and, eq } from "drizzle-orm";
+import { NextResponse } from "next/server";
+
+/**
+ * Handles the POST request to create a new channel within a specific server.
+ *
+ * @async
+ * @function POST
+ * @param {Request} req - The incoming HTTP request containing JSON payload with `name` and `serverId`.
+ * @returns {Promise<NextResponse>} The created channel object with status 201, or an error response (401, 400, 403, 500).
+ */
+export async function POST(req: Request) {
+  try {
+    const session = await auth();
+
+    if (!session?.user?.id) {
+      return NextResponse.json({ error: "Unauthorized" }, { status: 401 });
+    }
+
+    const { name, serverId } = await req.json();
+
+    if (!name?.trim() || !serverId) {
+      return NextResponse.json(
+        { error: "Name and server ID are required" },
+        { status: 400 },
+      );
+    }
+
+    // Check if the user is a member of the server
+    const [member] = await db
+      .select()
+      .from(members)
+      .where(
+        and(
+          eq(members.userId, session.user.id),
+          eq(members.serverId, serverId),
+        ),
+      )
+      .limit(1);
+
+    if (!member) {
+      return NextResponse.json(
+        { error: "Access denied to this server" },
+        { status: 403 },
+      );
+    }
+
+    // Create the channel in the database
+    const [newChannel] = await db
+      .insert(channels)
+      .values({
+        name: name.trim().toLowerCase().replace(/\s+/g, "-"),
+        serverId,
+      })
+      .returning();
+
+    return NextResponse.json(newChannel, { status: 201 });
+  } catch (error) {
+    console.error("API Channel POST error:", error);
+    return NextResponse.json(
+      { error: "Internal server error" },
+      { status: 500 },
+    );
+  }
+}

components/modals/CreateChannelModal.tsx

@@ -0,0 +1,160 @@
+/**
+ * @file components/modals/CreateChannelModal.tsx
+ * @description Modal dialog component for creating a new text channel within a server.
+ */
+
+"use client";
+
+import { useState } from "react";
+import { useRouter } from "next/navigation";
+import { X, Loader2 } from "lucide-react";
+import { useActiveServer } from "@/lib/context/ServerContext";
+
+/**
+ * Properties for the CreateChannelModal component.
+ *
+ * @interface CreateChannelModalProps
+ * @property {boolean} isOpen - Determines whether the modal is visible.
+ * @property {() => void} onClose - Callback function executed to close the modal.
+ * @property {string} serverId - The unique identifier of the target server where the channel is created.
+ */
+interface CreateChannelModalProps {
+  isOpen: boolean;
+  onClose: () => void;
+  serverId: string;
+}
+
+/**
+ * Renders a modal dialog allowing users to input a name and create a new server channel.
+ *
+ * @param {CreateChannelModalProps} props - The component props.
+ * @param {boolean} props.isOpen - Determines whether the modal is visible.
+ * @param {() => void} props.onClose - Callback function executed to close the modal.
+ * @param {string} props.serverId - The unique identifier of the target server where the channel is created.
+ * @returns {JSX.Element | null} The rendered modal component or null if closed.
+ */
+export function CreateChannelModal({
+  isOpen,
+  onClose,
+  serverId,
+}: CreateChannelModalProps) {
+  const [name, setName] = useState("");
+  const [isLoading, setIsLoading] = useState(false);
+  const [error, setError] = useState<string | null>(null);
+
+  const router = useRouter();
+  const { addChannel } = useActiveServer();
+
+  if (!isOpen) return null;
+
+  /**
+   * Handles form submission to create a new channel via the API.
+   *
+   * @async
+   * @function handleSubmit
+   * @param {React.FormEvent} e - The form submission event.
+   * @returns {Promise<void>} Resolves when the channel creation request completes.
+   */
+  const handleSubmit = async (e: React.FormEvent) => {
+    e.preventDefault();
+    if (!name.trim() || isLoading) return;
+
+    try {
+      setIsLoading(true);
+      setError(null);
+
+      const response = await fetch("/api/channels", {
+        method: "POST",
+        headers: { "Content-Type": "application/json" },
+        body: JSON.stringify({ name, serverId }),
+      });
+
+      if (!response.ok) {
+        throw new Error("Failed to create channel.");
+      }
+
+      const newChannel = await response.json();
+
+      addChannel(newChannel);
+
+      setName("");
+      onClose();
+
+      router.push(`/servers/${serverId}/channels/${newChannel.id}`);
+    } 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 Channel</h2>
+        <p className="text-sm text-muted mb-6">
+          Create a new text channel for messaging 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">
+              Channel Name
+            </label>
+            <div className="relative flex items-center">
+              <span className="absolute left-3.5 text-muted text-sm font-semibold">
+                #
+              </span>
+              <input
+                type="text"
+                required
+                value={name}
+                onChange={(e) => setName(e.target.value)}
+                placeholder="new-channel"
+                disabled={isLoading}
+                autoFocus
+                className="w-full bg-background border border-surface/80 rounded-xl pl-8 pr-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>
+          </div>
+
+          {error && <p className="text-xs text-red-400 mt-2">{error}</p>}
+
+          <div className="flex items-center justify-end gap-3 pt-4">
+            <button
+              type="button"
+              onClick={onClose}
+              disabled={isLoading}
+              className="px-4 py-2 text-sm font-medium text-muted hover:text-white transition-colors cursor-pointer"
+            >
+              Cancel
+            </button>
+            <button
+              type="submit"
+              disabled={isLoading || !name.trim()}
+              className="px-5 py-2 bg-accent text-white font-medium text-sm rounded-xl hover:bg-accent/90 transition-all disabled:opacity-50 flex items-center gap-2 cursor-pointer"
+            >
+              {isLoading && <Loader2 className="w-4 h-4 animate-spin" />}
+              Create
+            </button>
+          </div>
+        </form>
+      </div>
+    </div>
+  );
+}

components/sidebar/ChannelSidebar.tsx

@@ -1,31 +1,36 @@
 /**
  * @file components/sidebar/ChannelSidebar.tsx
- * @description Sidebar component listing channels for the active server, or rendering direct messages when no server is active.
+ * @description Sidebar component displaying server channels, navigation toggles, and modal triggers.
  */
 
 "use client";
 
+import { useState } from "react";
 import Link from "next/link";
 import { useParams } from "next/navigation";
 import { useActiveServer } from "@/lib/context/ServerContext";
 import { DirectMessageSidebar } from "@/components/sidebar/DirectMessageSidebar";
 import { useSidebarStore } from "@/lib/stores/useSidebarStore";
-import { PanelLeftClose } from "lucide-react";
+import { CreateChannelModal } from "@/components/modals/CreateChannelModal";
+import { PanelLeftClose, Plus } from "lucide-react";
 
 /**
- * Renders the channel sidebar for the active server or defaults to the direct message view.
+ * Renders the channel sidebar for active servers, allowing users to navigate channels or create new ones.
- * Handles responsive sidebar toggling and highlights active channels based on URL parameters.
  *
- * @returns {JSX.Element} The rendered channel sidebar or direct message sidebar component.
+ * @returns {JSX.Element} The rendered channel sidebar container.
  */
 export function ChannelSidebar() {
+  const [isModalOpen, setIsModalOpen] = useState(false);
   const params = useParams();
   const currentChannelId = params?.channelId as string;
   const { activeServer } = useActiveServer();
   const { closeNav, toggleNav } = useSidebarStore();
 
   /**
-   * Closes the mobile navigation drawer when a channel link is selected on viewports smaller than 768px.
+   * Handles channel selection clicks, closing the mobile navigation sidebar on smaller viewports.
+   *
+   * @function handleChannelClick
+   * @returns {void}
    */
   const handleChannelClick = () => {
     if (!window.matchMedia("(min-width: 768px)").matches) {
@@ -38,6 +43,7 @@ export function ChannelSidebar() {
   }
 
   return (
+    <>
       <div className="flex-1 w-full md:w-72 bg-surface/50 border-r border-background flex flex-col h-full shrink-0">
         {/* Server Header */}
         <div className="h-14 border-b border-background flex items-center justify-between px-4 font-bold text-white shadow-sm">
@@ -56,6 +62,14 @@ export function ChannelSidebar() {
         <div className="flex-1 overflow-y-auto p-3 space-y-1">
           <div className="flex items-center justify-between text-xs font-semibold text-muted px-2 py-1 uppercase tracking-wider">
             <span>Text Channels</span>
+            <button
+              type="button"
+              onClick={() => setIsModalOpen(true)}
+              className="p-1 rounded text-muted hover:text-white hover:bg-surface transition-colors cursor-pointer"
+              aria-label="Create channel"
+            >
+              <Plus className="w-4 h-4" />
+            </button>
           </div>
 
           <div className="space-y-0.5">
@@ -84,5 +98,12 @@ export function ChannelSidebar() {
           </div>
         </div>
       </div>
+
+      <CreateChannelModal
+        isOpen={isModalOpen}
+        onClose={() => setIsModalOpen(false)}
+        serverId={activeServer.id}
+      />
+    </>
   );
 }

lib/context/ServerContext.tsx

@@ -39,6 +39,7 @@ export interface ServerMember {
 interface ServerContextType {
   activeServer: ServerWithChannels | null;
   setActiveServer: (server: ServerWithChannels | null) => void;
+  addChannel: (channel: Channel) => void;
   members: ServerMember[];
   setMembers: (members: ServerMember[]) => void;
 }
@@ -46,6 +47,7 @@ interface ServerContextType {
 const ServerContext = createContext<ServerContextType>({
   activeServer: null,
   setActiveServer: () => {},
+  addChannel: () => {},
   members: [],
   setMembers: () => {},
 });
@@ -63,21 +65,31 @@ export function ServerProvider({ children }: { children: React.ReactNode }) {
   );
   const [members, setMembers] = useState<ServerMember[]>([]);
 
+  const addChannel = (channel: Channel) => {
+    setActiveServer((prev) => {
+      if (!prev || prev.id !== channel.serverId) return prev;
+      return {
+        ...prev,
+        channels: [...prev.channels, channel],
+      };
+    });
+  };
+
   return (
     <ServerContext.Provider
-      value={{ activeServer, setActiveServer, members, setMembers }}
+      value={{
+        activeServer,
+        setActiveServer,
+        addChannel,
+        members,
+        setMembers,
+      }}
     >
       {children}
     </ServerContext.Provider>
   );
 }
 
-/**
- * Custom hook to access the current ServerContext state.
- *
- * @throws {Error} Throws an error if used outside of a `ServerProvider`.
- * @returns {ServerContextType} The server context value containing active server state and member management functions.
- */
 export function useActiveServer() {
   const context = useContext(ServerContext);
   if (!context) {