chore(deps): Update dependencies and enhance API error handling

- Added '@vercel/analytics' to package.json for improved analytics tracking.
- Updated 'next' version from 15.0.2 to 15.0.3 to incorporate the latest features and fixes.
- Refactored API routes for invitations and studies to improve error handling and response structure.
- Enhanced permission checks in the invitations and studies API to ensure proper access control.
- Removed the participants dashboard page as part of a restructuring effort.
- Updated the database schema to include environment settings for users and studies.
- Improved the dashboard components to handle loading states and display statistics more effectively.

src/app/dashboard/studies/[id]/settings/page.tsx

@@ -1,201 +1,79 @@
 'use client';
 
-import { useEffect, useState } from "react";
-import { useParams } from "next/navigation";
-import { Card, CardContent, CardDescription, CardHeader, CardTitle } from "~/components/ui/card";
+import { useState } from "react";
+import { useParams, useRouter, useSearchParams } from "next/navigation";
 import { Tabs, TabsContent, TabsList, TabsTrigger } from "~/components/ui/tabs";
-import { InviteUserDialog } from "~/components/invite-user-dialog";
-import { Button } from "~/components/ui/button";
-import { Loader2 } from "lucide-react";
-import { useToast } from "~/hooks/use-toast";
+import { SettingsTab } from "~/components/studies/settings-tab";
+import { ParticipantsTab } from "~/components/studies/participants-tab";
+import { useEffect } from "react";
 
 interface Study {
   id: number;
   title: string;
-  description: string;
+  description: string | null;
+  permissions: string[];
 }
 
-interface Invitation {
-  id: string;
-  email: string;
-  roleName: string;
-  accepted: boolean;
-  expiresAt: string;
-}
-
-export default function StudySettingsPage() {
-  const params = useParams();
+export default function StudySettings() {
   const [study, setStudy] = useState<Study | null>(null);
-  const [invitations, setInvitations] = useState<Invitation[]>([]);
   const [isLoading, setIsLoading] = useState(true);
   const [error, setError] = useState<string | null>(null);
-  const { toast } = useToast();
-
-  const fetchStudyData = async () => {
-    try {
-      const response = await fetch(`/api/studies/${params.id}`);
-      if (!response.ok) throw new Error("Failed to fetch study");
-      const data = await response.json();
-      setStudy(data);
-    } catch (error) {
-      setError("Failed to load study details");
-      console.error("Error fetching study:", error);
-      toast({
-        title: "Error",
-        description: "Failed to load study details",
-        variant: "destructive",
-      });
-    }
-  };
-
-  const fetchInvitations = async () => {
-    try {
-      const response = await fetch(`/api/invitations?studyId=${params.id}`);
-      if (!response.ok) throw new Error("Failed to fetch invitations");
-      const data = await response.json();
-      setInvitations(data);
-    } catch (error) {
-      setError("Failed to load invitations");
-      console.error("Error fetching invitations:", error);
-      toast({
-        title: "Error",
-        description: "Failed to load invitations",
-        variant: "destructive",
-      });
-    } finally {
-      setIsLoading(false);
-    }
-  };
+  const { id } = useParams();
+  const router = useRouter();
+  const searchParams = useSearchParams();
+  const tab = searchParams.get('tab') || 'settings';
 
   useEffect(() => {
-    const loadData = async () => {
-      await Promise.all([fetchStudyData(), fetchInvitations()]);
-    };
-    loadData();
-  }, [params.id]); // eslint-disable-line react-hooks/exhaustive-deps
-
-  const handleDeleteInvitation = async (invitationId: string) => {
-    try {
-      const response = await fetch(`/api/invitations/${invitationId}`, {
-        method: "DELETE",
-      });
-
-      if (!response.ok) {
-        throw new Error("Failed to delete invitation");
+    const fetchStudy = async () => {
+      try {
+        const response = await fetch(`/api/studies/${id}`);
+        if (!response.ok) throw new Error("Failed to fetch study");
+        const data = await response.json();
+        setStudy(data.data);
+      } catch (error) {
+        console.error("Error fetching study:", error);
+        setError(error instanceof Error ? error.message : "Failed to load study");
+      } finally {
+        setIsLoading(false);
       }
+    };
 
-      // Update local state
-      setInvitations(invitations.filter(inv => inv.id !== invitationId));
-      
-      toast({
-        title: "Success",
-        description: "Invitation deleted successfully",
-      });
-    } catch (error) {
-      console.error("Error deleting invitation:", error);
-      toast({
-        title: "Error",
-        description: "Failed to delete invitation",
-        variant: "destructive",
-      });
-    }
+    fetchStudy();
+  }, [id]);
+
+  const handleTabChange = (value: string) => {
+    router.push(`/dashboard/studies/${id}/settings?tab=${value}`);
   };
 
   if (isLoading) {
-    return (
-      <div className="flex items-center justify-center min-h-[400px]">
-        <Loader2 className="h-8 w-8 animate-spin" />
-      </div>
-    );
+    return <div className="container py-6">Loading...</div>;
   }
 
-  if (error) {
-    return (
-      <div className="flex items-center justify-center min-h-[400px]">
-        <p className="text-red-500">{error}</p>
-      </div>
-    );
-  }
-
-  if (!study) {
-    return (
-      <div className="flex items-center justify-center min-h-[400px]">
-        <p className="text-gray-500">Study not found</p>
-      </div>
-    );
+  if (error || !study) {
+    return <div className="container py-6 text-destructive">{error || "Study not found"}</div>;
   }
 
   return (
     <div className="container py-6 space-y-6">
-      <div>
-        <h1 className="text-2xl font-bold">{study.title}</h1>
-        <p className="text-muted-foreground">{study.description}</p>
+      <div className="flex flex-col gap-2">
+        <h1 className="text-3xl font-bold tracking-tight">{study.title}</h1>
+        <p className="text-muted-foreground">
+          Manage study settings and participants
+        </p>
       </div>
 
-      <Tabs defaultValue="invites" className="space-y-4">
+      <Tabs value={tab} onValueChange={handleTabChange} className="space-y-6">
         <TabsList>
-          <TabsTrigger value="invites">Invites</TabsTrigger>
           <TabsTrigger value="settings">Settings</TabsTrigger>
+          <TabsTrigger value="participants">Participants</TabsTrigger>
         </TabsList>
-        
-        <TabsContent value="invites">
-          <Card>
-            <CardHeader>
-              <CardTitle>Manage Invitations</CardTitle>
-              <CardDescription>
-                Invite researchers and participants to collaborate on &ldquo;{study.title}&rdquo;
-              </CardDescription>
-            </CardHeader>
-            <CardContent className="space-y-6">
-              <div>
-                <InviteUserDialog studyId={study.id} onInviteSent={fetchInvitations} />
-              </div>
 
-              {invitations.length > 0 ? (
-                <div className="space-y-4">
-                  {invitations.map((invitation) => (
-                    <div
-                      key={invitation.id}
-                      className="flex items-center justify-between p-4 border rounded-lg bg-card"
-                    >
-                      <div>
-                        <p className="font-medium">{invitation.email}</p>
-                        <p className="text-sm text-muted-foreground">
-                          Role: {invitation.roleName}
-                          {invitation.accepted ? " • Accepted" : " • Pending"}
-                        </p>
-                      </div>
-                      {!invitation.accepted && (
-                        <Button
-                          variant="outline"
-                          size="sm"
-                          onClick={() => handleDeleteInvitation(invitation.id)}
-                        >
-                          Cancel
-                        </Button>
-                      )}
-                    </div>
-                  ))}
-                </div>
-              ) : (
-                <p className="text-muted-foreground">No invitations sent yet.</p>
-              )}
-            </CardContent>
-          </Card>
+        <TabsContent value="settings" className="space-y-6">
+          <SettingsTab study={study} />
         </TabsContent>
-        
-        <TabsContent value="settings">
-          <Card>
-            <CardHeader>
-              <CardTitle>Study Settings</CardTitle>
-              <CardDescription>
-                Configure study settings and permissions
-              </CardDescription>
-            </CardHeader>
-            <CardContent>
-              <p className="text-muted-foreground">Settings coming soon...</p>
-            </CardContent>
-          </Card>
+
+        <TabsContent value="participants" className="space-y-6">
+          <ParticipantsTab studyId={study.id} permissions={study.permissions} />
         </TabsContent>
       </Tabs>
     </div>

src/app/dashboard/studies/page.tsx

@@ -1,6 +1,6 @@
 'use client';
 
-import { useEffect, useState } from "react";
+import { useState } from "react";
 import { useRouter } from "next/navigation";
 import { PlusIcon, Trash2Icon, Settings2 } from "lucide-react";
 import { Button } from "~/components/ui/button";
@@ -9,73 +9,86 @@ import { Input } from "~/components/ui/input";
 import { Label } from "~/components/ui/label";
 import { Textarea } from "~/components/ui/textarea";
 import { useToast } from "~/hooks/use-toast";
+import { PERMISSIONS, hasPermission } from "~/lib/permissions-client";
+import {
+  AlertDialog,
+  AlertDialogAction,
+  AlertDialogCancel,
+  AlertDialogContent,
+  AlertDialogHeader,
+  AlertDialogTitle,
+  AlertDialogTrigger,
+  AlertDialogFooter
+} from "~/components/ui/alert-dialog";
+import { ROLES } from "~/lib/roles";
 
 interface Study {
   id: number;
   title: string;
-  description: string;
+  description: string | null;
   createdAt: string;
+  updatedAt: string | null;
+  userId: string;
+  permissions: string[];
+  roles: string[];
+}
+
+// Helper function to format role name
+function formatRoleName(role: string): string {
+  return role
+    .split('_')
+    .map(word => word.charAt(0).toUpperCase() + word.slice(1).toLowerCase())
+    .join(' ');
 }
 
 export default function Studies() {
   const [studies, setStudies] = useState<Study[]>([]);
-  const [newStudyTitle, setNewStudyTitle] = useState("");
-  const [newStudyDescription, setNewStudyDescription] = useState("");
-  const [loading, setLoading] = useState(true);
+  const [title, setTitle] = useState("");
+  const [description, setDescription] = useState("");
   const router = useRouter();
   const { toast } = useToast();
 
-  useEffect(() => {
-    fetchStudies();
-  }, []);
-
   const fetchStudies = async () => {
     try {
-      const response = await fetch('/api/studies');
+      const response = await fetch("/api/studies");
+      if (!response.ok) throw new Error("Failed to fetch studies");
       const data = await response.json();
-      setStudies(data);
+      setStudies(data.data || []);
     } catch (error) {
-      console.error('Error fetching studies:', error);
+      console.error("Error fetching studies:", error);
       toast({
         title: "Error",
         description: "Failed to load studies",
         variant: "destructive",
       });
-    } finally {
-      setLoading(false);
     }
   };
 
   const createStudy = async (e: React.FormEvent) => {
     e.preventDefault();
-    
     try {
-      const response = await fetch('/api/studies', {
-        method: 'POST',
+      const response = await fetch("/api/studies", {
+        method: "POST",
         headers: {
-          'Content-Type': 'application/json',
+          "Content-Type": "application/json",
         },
-        body: JSON.stringify({
-          title: newStudyTitle,
-          description: newStudyDescription,
-        }),
+        body: JSON.stringify({ title, description }),
       });
 
       if (!response.ok) {
-        throw new Error('Failed to create study');
+        throw new Error("Failed to create study");
       }
 
-      const newStudy = await response.json();
-      setStudies([...studies, newStudy]);
-      setNewStudyTitle("");
-      setNewStudyDescription("");
-      
+      const data = await response.json();
+      setStudies([...studies, data.data]);
+      setTitle("");
+      setDescription("");
       toast({
         title: "Success",
         description: "Study created successfully",
       });
     } catch (error) {
-      console.error('Error creating study:', error);
+      console.error("Error creating study:", error);
       toast({
         title: "Error",
         description: "Failed to create study",
@@ -87,11 +100,11 @@ export default function Studies() {
   const deleteStudy = async (id: number) => {
     try {
       const response = await fetch(`/api/studies/${id}`, {
-        method: 'DELETE',
+        method: "DELETE",
       });
 
       if (!response.ok) {
-        throw new Error('Failed to delete study');
+        throw new Error("Failed to delete study");
       }
 
       setStudies(studies.filter(study => study.id !== id));
@@ -100,7 +113,7 @@ export default function Studies() {
         description: "Study deleted successfully",
       });
     } catch (error) {
-      console.error('Error deleting study:', error);
+      console.error("Error deleting study:", error);
       toast({
         title: "Error",
         description: "Failed to delete study",
@@ -109,85 +122,128 @@ export default function Studies() {
     }
   };
 
-  if (loading) {
-    return (
-      <div className="flex items-center justify-center min-h-[400px]">
-        <div className="animate-spin h-8 w-8 border-4 border-primary border-t-transparent rounded-full" />
-      </div>
-    );
-  }
+  // Fetch studies on mount
+  useState(() => {
+    fetchStudies();
+  });
 
   return (
     <div className="container py-6 space-y-6">
-      <div>
-        <h1 className="text-2xl font-bold">Studies</h1>
-        <p className="text-muted-foreground">Manage your research studies</p>
+      <div className="flex flex-col gap-2">
+        <h1 className="text-3xl font-bold tracking-tight">Studies</h1>
+        <p className="text-muted-foreground">
+          Manage your research studies and experiments
+        </p>
       </div>
 
-      <Card>
-        <CardHeader>
-          <CardTitle>Create New Study</CardTitle>
-          <CardDescription>
-            Add a new research study to your collection
-          </CardDescription>
-        </CardHeader>
-        <CardContent>
-          <form onSubmit={createStudy} className="space-y-4">
-            <div className="space-y-2">
-              <Label htmlFor="title">Study Title</Label>
-              <Input
-                type="text"
-                id="title"
-                value={newStudyTitle}
-                onChange={(e) => setNewStudyTitle(e.target.value)}
-                placeholder="Enter study title"
-                required
-              />
-            </div>
-            <div className="space-y-2">
-              <Label htmlFor="description">Description</Label>
-              <Textarea
-                id="description"
-                value={newStudyDescription}
-                onChange={(e) => setNewStudyDescription(e.target.value)}
-                placeholder="Enter study description"
-                rows={3}
-              />
-            </div>
-            <Button type="submit">
-              <PlusIcon className="w-4 h-4 mr-2" />
-              Create Study
-            </Button>
-          </form>
-        </CardContent>
-      </Card>
+      {hasPermission(studies[0]?.permissions || [], PERMISSIONS.CREATE_STUDY) && (
+        <Card>
+          <CardHeader>
+            <CardTitle>Create New Study</CardTitle>
+            <CardDescription>Add a new research study to your collection</CardDescription>
+          </CardHeader>
+          <CardContent>
+            <form onSubmit={createStudy} className="space-y-4">
+              <div className="space-y-2">
+                <Label htmlFor="title">Study Title</Label>
+                <Input
+                  id="title"
+                  value={title}
+                  onChange={(e) => setTitle(e.target.value)}
+                  placeholder="Enter study title"
+                  required
+                />
+              </div>
+              <div className="space-y-2">
+                <Label htmlFor="description">Description</Label>
+                <Textarea
+                  id="description"
+                  value={description}
+                  onChange={(e) => setDescription(e.target.value)}
+                  placeholder="Enter study description"
+                />
+              </div>
+              <Button type="submit">
+                <PlusIcon className="w-4 h-4 mr-2" />
+                Create Study
+              </Button>
+            </form>
+          </CardContent>
+        </Card>
+      )}
 
       <div className="grid gap-4">
         {studies.length > 0 ? (
           studies.map((study) => (
-            <Card key={study.id}>
-              <CardHeader>
-                <CardTitle>{study.title}</CardTitle>
-                <CardDescription>{study.description}</CardDescription>
-              </CardHeader>
-              <CardContent>
-                <div className="flex items-center gap-2">
-                  <Button
-                    variant="outline"
-                    onClick={() => router.push(`/dashboard/studies/${study.id}/settings`)}
-                  >
-                    <Settings2 className="w-4 h-4 mr-2" />
-                    Settings
-                  </Button>
-                  <Button
-                    variant="outline"
-                    onClick={() => deleteStudy(study.id)}
-                  >
-                    <Trash2Icon className="w-4 h-4 mr-2" />
-                    Delete
-                  </Button>
+            <Card key={study.id} className="overflow-hidden">
+              <div className="p-6">
+                <div className="flex flex-col gap-1.5">
+                  <div className="flex items-start justify-between">
+                    <div className="space-y-1">
+                      <h3 className="font-semibold leading-none tracking-tight">
+                        {study.title}
+                      </h3>
+                      <p className="text-sm text-muted-foreground">
+                        {study.description || "No description provided."}
+                      </p>
+                      <p className="text-sm">
+                        <span className="text-muted-foreground">Your Roles: </span>
+                        <span className="text-foreground">
+                          {study.roles?.map(formatRoleName).join(", ")}
+                        </span>
+                      </p>
+                    </div>
+                    <div className="flex items-center gap-2">
+                      {(hasPermission(study.permissions, PERMISSIONS.EDIT_STUDY) || 
+                        hasPermission(study.permissions, PERMISSIONS.MANAGE_ROLES)) && (
+                        <Button
+                          variant="outline"
+                          size="sm"
+                          onClick={() => router.push(`/dashboard/studies/${study.id}/settings`)}
+                        >
+                          <Settings2 className="w-4 h-4 mr-2" />
+                          Settings
+                        </Button>
+                      )}
+                      {hasPermission(study.permissions, PERMISSIONS.MANAGE_SYSTEM_SETTINGS) && (
+                        <AlertDialog>
+                          <AlertDialogTrigger asChild>
+                            <Button variant="outline" size="sm">
+                              <Trash2Icon className="w-4 h-4 mr-2" />
+                              Delete
+                            </Button>
+                          </AlertDialogTrigger>
+                          <AlertDialogContent>
+                            <AlertDialogHeader>
+                              <AlertDialogTitle>Are you absolutely sure?</AlertDialogTitle>
+                              <div className="text-sm text-muted-foreground">
+                                <p className="mb-2">
+                                  This action cannot be undone. This will permanently delete the study
+                                  &quot;{study.title}&quot; and all associated data including:
+                                </p>
+                                <ul className="list-disc list-inside">
+                                  <li>All participant data</li>
+                                  <li>All user roles and permissions</li>
+                                  <li>All pending invitations</li>
+                                </ul>
+                              </div>
+                            </AlertDialogHeader>
+                            <AlertDialogFooter>
+                              <AlertDialogCancel>Cancel</AlertDialogCancel>
+                              <AlertDialogAction
+                                onClick={() => deleteStudy(study.id)}
+                                className="bg-destructive text-destructive-foreground hover:bg-destructive/90"
+                              >
+                                Delete Study
+                              </AlertDialogAction>
+                            </AlertDialogFooter>
+                          </AlertDialogContent>
+                        </AlertDialog>
+                      )}
+                    </div>
+                  </div>
                 </div>
-              </CardContent>
+              </div>
             </Card>
           ))
         ) : (