auto-claude: subtask-4-3 - Create Supabase chat database operations module

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/lib/supabase/chat.ts

@@ -0,0 +1,334 @@
+import { createClient as createServerClient } from '@supabase/supabase-js';
+
+// Type definitions for chat tables
+export type ChatRole = 'user' | 'assistant' | 'system';
+
+export interface ChatSession {
+  id: string;
+  created_at: string;
+  visitor_id: string;
+  metadata: Record<string, unknown>;
+}
+
+export interface ChatMessage {
+  id: string;
+  session_id: string;
+  role: ChatRole;
+  content: string;
+  created_at: string;
+}
+
+// Input types for creating records
+export interface CreateChatSessionInput {
+  visitor_id: string;
+  metadata?: Record<string, unknown>;
+}
+
+export interface CreateChatMessageInput {
+  session_id: string;
+  role: ChatRole;
+  content: string;
+}
+
+// Create a Supabase client with service role key for server-side operations
+// This bypasses RLS for administrative operations
+function createServiceClient() {
+  const supabaseUrl = process.env.NEXT_PUBLIC_SUPABASE_URL;
+  const serviceRoleKey = process.env.SUPABASE_SERVICE_ROLE_KEY;
+
+  if (!supabaseUrl || !serviceRoleKey) {
+    throw new Error(
+      'Missing Supabase environment variables: NEXT_PUBLIC_SUPABASE_URL or SUPABASE_SERVICE_ROLE_KEY'
+    );
+  }
+
+  return createServerClient(supabaseUrl, serviceRoleKey, {
+    auth: {
+      autoRefreshToken: false,
+      persistSession: false,
+    },
+  });
+}
+
+// ============================================
+// Chat Session Operations
+// ============================================
+
+/**
+ * Create a new chat session for a visitor
+ */
+export async function createChatSession(
+  input: CreateChatSessionInput
+): Promise<ChatSession> {
+  const supabase = createServiceClient();
+
+  const { data, error } = await supabase
+    .from('chat_sessions')
+    .insert({
+      visitor_id: input.visitor_id,
+      metadata: input.metadata ?? {},
+    })
+    .select()
+    .single();
+
+  if (error) {
+    throw new Error(`Failed to create chat session: ${error.message}`);
+  }
+
+  return data as ChatSession;
+}
+
+/**
+ * Get a chat session by ID
+ */
+export async function getChatSession(
+  sessionId: string
+): Promise<ChatSession | null> {
+  const supabase = createServiceClient();
+
+  const { data, error } = await supabase
+    .from('chat_sessions')
+    .select()
+    .eq('id', sessionId)
+    .single();
+
+  if (error) {
+    if (error.code === 'PGRST116') {
+      // No rows found
+      return null;
+    }
+    throw new Error(`Failed to get chat session: ${error.message}`);
+  }
+
+  return data as ChatSession;
+}
+
+/**
+ * Get or create a chat session for a visitor
+ * Useful for maintaining session continuity
+ */
+export async function getOrCreateChatSession(
+  visitorId: string,
+  metadata?: Record<string, unknown>
+): Promise<ChatSession> {
+  const supabase = createServiceClient();
+
+  // First, try to find an existing active session for this visitor
+  // Get the most recent session from the last 24 hours
+  const twentyFourHoursAgo = new Date(
+    Date.now() - 24 * 60 * 60 * 1000
+  ).toISOString();
+
+  const { data: existingSession, error: findError } = await supabase
+    .from('chat_sessions')
+    .select()
+    .eq('visitor_id', visitorId)
+    .gte('created_at', twentyFourHoursAgo)
+    .order('created_at', { ascending: false })
+    .limit(1)
+    .single();
+
+  if (existingSession && !findError) {
+    return existingSession as ChatSession;
+  }
+
+  // No existing session found, create a new one
+  return createChatSession({
+    visitor_id: visitorId,
+    metadata,
+  });
+}
+
+/**
+ * Update session metadata
+ */
+export async function updateSessionMetadata(
+  sessionId: string,
+  metadata: Record<string, unknown>
+): Promise<ChatSession> {
+  const supabase = createServiceClient();
+
+  const { data, error } = await supabase
+    .from('chat_sessions')
+    .update({ metadata })
+    .eq('id', sessionId)
+    .select()
+    .single();
+
+  if (error) {
+    throw new Error(`Failed to update session metadata: ${error.message}`);
+  }
+
+  return data as ChatSession;
+}
+
+// ============================================
+// Chat Message Operations
+// ============================================
+
+/**
+ * Add a message to a chat session
+ */
+export async function addChatMessage(
+  input: CreateChatMessageInput
+): Promise<ChatMessage> {
+  const supabase = createServiceClient();
+
+  const { data, error } = await supabase
+    .from('chat_messages')
+    .insert({
+      session_id: input.session_id,
+      role: input.role,
+      content: input.content,
+    })
+    .select()
+    .single();
+
+  if (error) {
+    throw new Error(`Failed to add chat message: ${error.message}`);
+  }
+
+  return data as ChatMessage;
+}
+
+/**
+ * Get all messages for a chat session
+ * Returns messages in chronological order
+ */
+export async function getChatMessages(
+  sessionId: string
+): Promise<ChatMessage[]> {
+  const supabase = createServiceClient();
+
+  const { data, error } = await supabase
+    .from('chat_messages')
+    .select()
+    .eq('session_id', sessionId)
+    .order('created_at', { ascending: true });
+
+  if (error) {
+    throw new Error(`Failed to get chat messages: ${error.message}`);
+  }
+
+  return (data ?? []) as ChatMessage[];
+}
+
+/**
+ * Get the last N messages for a session
+ * Useful for maintaining context window limits
+ */
+export async function getRecentMessages(
+  sessionId: string,
+  limit: number = 20
+): Promise<ChatMessage[]> {
+  const supabase = createServiceClient();
+
+  const { data, error } = await supabase
+    .from('chat_messages')
+    .select()
+    .eq('session_id', sessionId)
+    .order('created_at', { ascending: false })
+    .limit(limit);
+
+  if (error) {
+    throw new Error(`Failed to get recent messages: ${error.message}`);
+  }
+
+  // Reverse to get chronological order
+  return ((data ?? []) as ChatMessage[]).reverse();
+}
+
+/**
+ * Delete all messages for a session (clear history)
+ */
+export async function clearChatMessages(sessionId: string): Promise<void> {
+  const supabase = createServiceClient();
+
+  const { error } = await supabase
+    .from('chat_messages')
+    .delete()
+    .eq('session_id', sessionId);
+
+  if (error) {
+    throw new Error(`Failed to clear chat messages: ${error.message}`);
+  }
+}
+
+/**
+ * Delete a chat session and all its messages
+ * Messages are deleted automatically via ON DELETE CASCADE
+ */
+export async function deleteChatSession(sessionId: string): Promise<void> {
+  const supabase = createServiceClient();
+
+  const { error } = await supabase
+    .from('chat_sessions')
+    .delete()
+    .eq('id', sessionId);
+
+  if (error) {
+    throw new Error(`Failed to delete chat session: ${error.message}`);
+  }
+}
+
+// ============================================
+// Utility Functions
+// ============================================
+
+/**
+ * Get conversation history formatted for AI context
+ * Converts database messages to the format expected by chat completion APIs
+ */
+export async function getConversationHistory(
+  sessionId: string,
+  maxMessages: number = 20
+): Promise<Array<{ role: ChatRole; content: string }>> {
+  const messages = await getRecentMessages(sessionId, maxMessages);
+
+  return messages.map((msg) => ({
+    role: msg.role,
+    content: msg.content,
+  }));
+}
+
+/**
+ * Save a conversation turn (user message + assistant response)
+ * Convenience function for typical chat flow
+ */
+export async function saveConversationTurn(
+  sessionId: string,
+  userMessage: string,
+  assistantResponse: string
+): Promise<{ userMsg: ChatMessage; assistantMsg: ChatMessage }> {
+  const userMsg = await addChatMessage({
+    session_id: sessionId,
+    role: 'user',
+    content: userMessage,
+  });
+
+  const assistantMsg = await addChatMessage({
+    session_id: sessionId,
+    role: 'assistant',
+    content: assistantResponse,
+  });
+
+  return { userMsg, assistantMsg };
+}
+
+// Default export for convenience
+export default {
+  // Session operations
+  createChatSession,
+  getChatSession,
+  getOrCreateChatSession,
+  updateSessionMetadata,
+  deleteChatSession,
+  // Message operations
+  addChatMessage,
+  getChatMessages,
+  getRecentMessages,
+  clearChatMessages,
+  // Utility functions
+  getConversationHistory,
+  saveConversationTurn,
+};