feat: Implement fuzzy matching for commands and input guardrails in whatsapp.ts

apps/api/src/services/whatsapp.ts

@@ -20,6 +20,39 @@ export class WhatsAppService {
         return 'UNKNOWN';
     }
 
+    private static levenshteinDistance(a: string, b: string): number {
+        const matrix: number[][] = [];
+        for (let i = 0; i <= b.length; i++) matrix[i] = [i];
+        for (let j = 0; j <= a.length; j++) matrix[0][j] = j;
+
+        for (let i = 1; i <= b.length; i++) {
+            for (let j = 1; j <= a.length; j++) {
+                if (b.charAt(i - 1) === a.charAt(j - 1)) {
+                    matrix[i][j] = matrix[i - 1][j - 1];
+                } else {
+                    matrix[i][j] = Math.min(
+                        matrix[i - 1][j - 1] + 1, // substitution
+                        matrix[i][j - 1] + 1,     // insertion
+                        matrix[i - 1][j] + 1      // deletion
+                    );
+                }
+            }
+        }
+        return matrix[b.length][a.length];
+    }
+
+    private static isFuzzyMatch(text: string, target: string, threshold = 0.8): boolean {
+        const normalized = text.trim().toUpperCase();
+        const tar = target.toUpperCase();
+        if (normalized === tar) return true;
+        if (normalized.includes(tar) || tar.includes(normalized)) return true;
+
+        const distance = this.levenshteinDistance(normalized, tar);
+        const maxLength = Math.max(normalized.length, tar.length);
+        const similarity = 1 - distance / maxLength;
+        return similarity >= threshold;
+    }
+
     static async handleIncomingMessage(phone: string, text: string, audioUrl?: string) {
         const traceId = audioUrl ? `[STT-FLOW-${phone.slice(-4)}]` : `[TXT-FLOW-${phone.slice(-4)}]`;
         const normalizedText = this.normalizeCommand(text);
@@ -29,7 +62,7 @@ export class WhatsAppService {
         let user = await prisma.user.findUnique({ where: { phone } });
 
         if (!user) {
-            const isInscription = normalizedText === 'INSCRIPTION' || normalizedText.includes('INSCRI');
+            const isInscription = this.isFuzzyMatch(normalizedText, 'INSCRIPTION') || normalizedText.includes('INSCRI');
 
             if (isInscription) {
                 console.log(`${traceId} New user registration triggered for ${phone}`);
@@ -69,7 +102,7 @@ export class WhatsAppService {
         }
 
         // 1.5. Testing / Cheat Codes (Only for registered users)
-        if (normalizedText === 'INSCRIPTION') {
+        if (this.isFuzzyMatch(normalizedText, 'INSCRIPTION')) {
             await prisma.enrollment.deleteMany({ where: { userId: user.id } });
             await prisma.userProgress.deleteMany({ where: { userId: user.id } });
             await prisma.response.deleteMany({ where: { userId: user.id } });
@@ -116,7 +149,7 @@ export class WhatsAppService {
             return;
         }
 
-        if (normalizedText === 'SEED') {
+        if (this.isFuzzyMatch(normalizedText, 'SEED')) {
             // Reply immediately so the webhook doesn't time out
             console.log(`[SEED] Triggered by user ${user.id}`);
             try {
@@ -307,8 +340,8 @@ export class WhatsAppService {
 
         if (activeEnrollment) {
             const intent = this.detectIntent(text);
-            const isSuite = normalizedText === 'SUITE' || normalizedText === '2';
-            const isApprofondir = normalizedText.includes('APPROFONDIR') || normalizedText === '1';
+            const isSuite = this.isFuzzyMatch(normalizedText, 'SUITE') || normalizedText === '2';
+            const isApprofondir = this.isFuzzyMatch(normalizedText, 'APPROFONDIR') || normalizedText === '1';
 
             // Handle SUITE Priority
             if (isSuite) {
@@ -464,7 +497,26 @@ export class WhatsAppService {
                 where: { trackId: activeEnrollment.trackId, dayNumber: activeEnrollment.currentDay }
             });
 
-            if (trackDayFallback && text.length > 3) {
+            if (trackDayFallback) {
+                // 🚨 Guardrail: Contenu Vide / Gibberish 🚨
+                const wordCount = text.trim().split(/\s+/).length;
+                if (wordCount < 3 || text.length < 5) {
+                    console.log(`${traceId} Guardrail: Input too short or potential gibberish: "${text}"`);
+                    await scheduleMessage(user.id, user.language === 'WOLOF'
+                        ? "Ma déggul li nga wax mbir mi... Mën nga ko gën a firi ci ab kàddu gatt (3-4 kàddu) ?"
+                        : "Je n'ai pas bien compris ton activité. Peux-tu me réexpliquer en quelques mots ce que tu vends et à qui ?");
+                    return;
+                }
+
+                // 🚨 Guardrail: Enrollment Priority 🚨
+                if (!user.activity || !user.language) {
+                    console.log(`${traceId} Blocking AI feedback: Enrollment incomplete for User ${user.id}`);
+                    await scheduleMessage(user.id, user.language === 'WOLOF'
+                        ? "Baax na, waaye laaj bi des na... Bindal 'INSCRIPTION' ngir tàmbali."
+                        : "C'est noté, mais il faut d'abord terminer ton inscription. Envoie 'INSCRIPTION' pour commencer.");
+                    return;
+                }
+
                 // Fetch previous responses to provide context to the AI Coach
                 const previousResponsesData = await prisma.response.findMany({
                     where: { userId: user.id, enrollmentId: activeEnrollment.id },