feat: add diagnostic tools to identify student access issues

- Create migration utilities to query all notes and find orphaned data
- Add global statistics view to diagnostic page
- Show total notes, notes with subjects, orphaned notes, and invalid structure
- Enable identification of notes missing metadata that students cannot see
- Fix TypeScript configuration for better module resolution

Author: html-proof

.vscode/settings.json

@@ -1,4 +1,10 @@
 {
     "typescript.tsdk": "node_modules/typescript/lib",
-    "typescript.enablePromptUseWorkspaceTsdk": true
+    "typescript.enablePromptUseWorkspaceTsdk": true,
+    "typescript.preferences.importModuleSpecifier": "non-relative",
+    "typescript.updateImportsOnFileMove.enabled": "always",
+    "files.exclude": {
+        "**/.next": true,
+        "**/node_modules": true
+    }
 }

src/app/db-diagnostic/page.tsx

@@ -8,6 +8,7 @@ import {
     getSubjects,
     getNotes
 } from "@/lib/firebase/firestore";
+import { getAllNotes, getNoteStatistics, findOrphanedNotes } from "@/lib/firebase/migrations";
 
 export default function DBDiagnosticPage() {
     const [departments, setDepartments] = useState<any[]>([]);
@@ -22,6 +23,12 @@ export default function DBDiagnosticPage() {
     const [loading, setLoading] = useState(false);
     const [error, setError] = useState<string>("");
 
+    // Global diagnostics
+    const [allNotes, setAllNotes] = useState<any[]>([]);
+    const [statistics, setStatistics] = useState<any>(null);
+    const [orphanedNotes, setOrphanedNotes] = useState<any[]>([]);
+    const [showGlobalView, setShowGlobalView] = useState(false);
+
     useEffect(() => {
         loadDepartments();
     }, []);
@@ -40,6 +47,27 @@ export default function DBDiagnosticPage() {
         }
     }
 
+    async function loadGlobalStatistics() {
+        try {
+            setLoading(true);
+            setError("");
+            const [stats, orphaned, all] = await Promise.all([
+                getNoteStatistics(),
+                findOrphanedNotes(),
+                getAllNotes()
+            ]);
+            setStatistics(stats);
+            setOrphanedNotes(orphaned);
+            setAllNotes(all);
+            setShowGlobalView(true);
+        } catch (err: any) {
+            console.error("Error loading statistics:", err);
+            setError(err.message);
+        } finally {
+            setLoading(false);
+        }
+    }
+
     async function loadBatches(deptId: string) {
         try {
             setLoading(true);
@@ -122,7 +150,23 @@ export default function DBDiagnosticPage() {
 
     return (
         <div style={{ padding: "2rem", maxWidth: "1200px", margin: "0 auto" }}>
-            <h1 style={{ marginBottom: "2rem" }}>🔍 Firebase Database Diagnostic</h1>
+            <div style={{ display: "flex", justifyContent: "space-between", alignItems: "center", marginBottom: "2rem" }}>
+                <h1>🔍 Firebase Database Diagnostic</h1>
+                <button
+                    onClick={loadGlobalStatistics}
+                    style={{
+                        padding: "0.75rem 1.5rem",
+                        background: "#3b82f6",
+                        color: "white",
+                        border: "none",
+                        borderRadius: "6px",
+                        cursor: "pointer",
+                        fontWeight: "600"
+                    }}
+                >
+                    📊 Show Global Statistics
+                </button>
+            </div>
 
             {error && (
                 <div style={{
@@ -139,6 +183,80 @@ export default function DBDiagnosticPage() {
 
             {loading && <p>Loading...</p>}
 
+            {/* Global Statistics Panel */}
+            {showGlobalView && statistics && (
+                <div style={{ marginBottom: "2rem" }}>
+                    <div style={{ display: "flex", justifyContent: "space-between", alignItems: "center", marginBottom: "1rem" }}>
+                        <h2>📊 Global Database Statistics</h2>
+                        <button
+                            onClick={() => setShowGlobalView(false)}
+                            style={{
+                                padding: "0.5rem 1rem",
+                                background: "#6b7280",
+                                color: "white",
+                                border: "none",
+                                borderRadius: "6px",
+                                cursor: "pointer"
+                            }}
+                        >
+                            Hide
+                        </button>
+                    </div>
+
+                    {/* Statistics Cards */}
+                    <div style={{ display: "grid", gridTemplateColumns: "repeat(auto-fit, minmax(200px, 1fr))", gap: "1rem", marginBottom: "2rem" }}>
+                        <div style={{ background: "#eff6ff", padding: "1.5rem", borderRadius: "8px", border: "1px solid #bfdbfe" }}>
+                            <h3 style={{ fontSize: "2rem", marginBottom: "0.5rem", color: "#1e40af" }}>{statistics.total}</h3>
+                            <p style={{ color: "#3b82f6", fontWeight: "600" }}>Total Notes</p>
+                        </div>
+                        <div style={{ background: "#d1fae5", padding: "1.5rem", borderRadius: "8px", border: "1px solid #6ee7b7" }}>
+                            <h3 style={{ fontSize: "2rem", marginBottom: "0.5rem", color: "#065f46" }}>{statistics.withSubject}</h3>
+                            <p style={{ color: "#10b981", fontWeight: "600" }}>With Subject</p>
+                        </div>
+                        <div style={{ background: "#fee2e2", padding: "1.5rem", borderRadius: "8px", border: "1px solid #fca5a5" }}>
+                            <h3 style={{ fontSize: "2rem", marginBottom: "0.5rem", color: "#991b1b" }}>{statistics.orphaned}</h3>
+                            <p style={{ color: "#ef4444", fontWeight: "600" }}>Orphaned (No Subject)</p>
+                        </div>
+                        <div style={{ background: "#fef3c7", padding: "1.5rem", borderRadius: "8px", border: "1px solid #fcd34d" }}>
+                            <h3 style={{ fontSize: "2rem", marginBottom: "0.5rem", color: "#92400e" }}>{statistics.invalid}</h3>
+                            <p style={{ color: "#f59e0b", fontWeight: "600" }}>Invalid Structure</p>
+                        </div>
+                    </div>
+
+                    {/* Orphaned Notes Details */}
+                    {orphanedNotes.length > 0 && (
+                        <div style={{ background: "#fee2e2", padding: "1.5rem", borderRadius: "8px", marginBottom: "2rem" }}>
+                            <h3 style={{ color: "#991b1b", marginBottom: "1rem" }}>⚠️ Orphaned Notes ({orphanedNotes.length})</h3>
+                            <p style={{ marginBottom: "1rem", color: "#7f1d1d" }}>
+                                These files exist but are missing critical metadata. Students cannot see them.
+                            </p>
+                            <div style={{ maxHeight: "300px", overflow: "auto" }}>
+                                {orphanedNotes.map((note, idx) => (
+                                    <div key={note.id} style={{ background: "white", padding: "1rem", marginBottom: "0.5rem", borderRadius: "6px" }}>
+                                        <p style={{ fontWeight: "600", marginBottom: "0.5rem" }}>{idx + 1}. {note.title}</p>
+                                        <p style={{ fontSize: "0.85rem", color: "#6b7280" }}>
+                                            ID: {note.id}<br />
+                                            Missing: {!note.subjectId && "subjectId "}
+                                            {!note.departmentId && "departmentId "}
+                                            {!note.batchId && "batchId "}
+                                            {!note.semesterId && "semesterId"}
+                                        </p>
+                                    </div>
+                                ))}
+                            </div>
+                        </div>
+                    )}
+
+                    {/* All Notes */}
+                    <div style={{ background: "#f9fafb", padding: "1.5rem", borderRadius: "8px" }}>
+                        <h3 style={{ marginBottom: "1rem" }}>📄 All Notes in Database ({allNotes.length})</h3>
+                        <pre style={{ background: "#f5f5f5", padding: "1rem", borderRadius: "6px", overflow: "auto", maxHeight: "400px", fontSize: "0.85rem" }}>
+                            {JSON.stringify(allNotes, null, 2)}
+                        </pre>
+                    </div>
+                </div>
+            )}
+
             <div style={{ display: "grid", gap: "2rem" }}>
                 {/* Departments */}
                 <div>

src/lib/firebase/migrations.ts

@@ -0,0 +1,99 @@
+import { db } from "./config";
+import {
+    collection,
+    getDocs,
+    query,
+    where,
+    updateDoc,
+    doc
+} from "firebase/firestore";
+
+const NOTES = "notes";
+
+/**
+ * Get ALL notes in the database (no filtering)
+ * Useful for diagnostics and identifying orphaned data
+ */
+export const getAllNotes = async () => {
+    const snapshot = await getDocs(collection(db, NOTES));
+    return snapshot.docs.map(d => ({ id: d.id, ...d.data() } as any));
+};
+
+/**
+ * Get notes that are missing critical metadata fields
+ */
+export const findOrphanedNotes = async () => {
+    const allNotes = await getAllNotes();
+    return allNotes.filter((note: any) =>
+        !note.subjectId ||
+        !note.departmentId ||
+        !note.batchId ||
+        !note.semesterId
+    );
+};
+
+/**
+ * Validate note structure
+ */
+export const validateNoteStructure = (note: any) => {
+    const requiredFields = ['subjectId', 'departmentId', 'batchId', 'semesterId', 'title', 'fileUrl', 'fileType'];
+    const missingFields = requiredFields.filter(field => !note[field]);
+
+    return {
+        valid: missingFields.length === 0,
+        missingFields,
+        note
+    };
+};
+
+/**
+ * Get notes grouped by subject
+ */
+export const getNotesBySubject = async () => {
+    const allNotes = await getAllNotes();
+    const grouped = new Map<string, any[]>();
+
+    allNotes.forEach((note: any) => {
+        const subjectId = note.subjectId || 'orphaned';
+        if (!grouped.has(subjectId)) {
+            grouped.set(subjectId, []);
+        }
+        grouped.get(subjectId)!.push(note);
+    });
+
+    return Object.fromEntries(grouped);
+};
+
+/**
+ * Repair note metadata by updating missing fields
+ */
+export const repairNoteMetadata = async (noteId: string, metadata: {
+    subjectId?: string;
+    departmentId?: string;
+    batchId?: string;
+    semesterId?: string;
+}) => {
+    const noteRef = doc(db, NOTES, noteId);
+    await updateDoc(noteRef, metadata);
+    return { noteId, updated: metadata };
+};
+
+/**
+ * Get detailed statistics about notes
+ */
+export const getNoteStatistics = async () => {
+    const allNotes = await getAllNotes();
+    const orphaned = allNotes.filter((n: any) => !n.subjectId);
+    const withSubject = allNotes.filter((n: any) => n.subjectId);
+
+    const validationResults = allNotes.map(validateNoteStructure);
+    const invalid = validationResults.filter(r => !r.valid);
+
+    return {
+        total: allNotes.length,
+        withSubject: withSubject.length,
+        orphaned: orphaned.length,
+        invalid: invalid.length,
+        invalidNotes: invalid
+    };
+};