diff --git a/app/courrier/page.tsx b/app/courrier/page.tsx
index 46733579..ae3397d0 100644
--- a/app/courrier/page.tsx
+++ b/app/courrier/page.tsx
@@ -41,12 +41,16 @@ import EmailDetailView from '@/components/email/EmailDetailView';
 import ComposeEmail from '@/components/email/ComposeEmail';
 import { DeleteConfirmDialog } from '@/components/email/EmailDialogs';
 
-// Import the custom hook
+// Import the custom hooks
 import { useCourrier, EmailData } from '@/hooks/use-courrier';
+import { useEmailState } from '@/hooks/use-email-state';
 
 // Import the prefetching function
 import { prefetchFolderEmails } from '@/lib/services/prefetch-service';
 
+// Import Account type from the reducer
+import { Account } from '@/lib/reducers/emailReducer';
+
 // Simplified version for this component
 function SimplifiedLoadingFix() {
   // In production, don't render anything
@@ -62,14 +66,6 @@ function SimplifiedLoadingFix() {
   );
 }
 
-interface Account {
-  id: string;
-  name: string;
-  email: string;
-  color: string;
-  folders: string[];
-}
-
 interface EmailWithFlags {
   id: string;
   read?: boolean;
diff --git a/hooks/use-email-state.ts b/hooks/use-email-state.ts
new file mode 100644
index 00000000..7a8ae259
--- /dev/null
+++ b/hooks/use-email-state.ts
@@ -0,0 +1,585 @@
+import { useReducer, useCallback, useEffect } from 'react';
+import { useSession } from 'next-auth/react';
+import { useToast } from './use-toast';
+import { 
+  emailReducer, 
+  initialState, 
+  EmailState, 
+  EmailAction,
+  normalizeFolderAndAccount,
+  Account
+} from '@/lib/reducers/emailReducer';
+import { 
+  getCachedEmailsWithTimeout, 
+  refreshEmailsInBackground 
+} from '@/lib/services/prefetch-service';
+import { Email, EmailData } from './use-courrier';
+import { formatEmailForReplyOrForward } from '@/lib/utils/email-formatter';
+
+export const useEmailState = () => {
+  const [state, dispatch] = useReducer(emailReducer, initialState);
+  const { data: session } = useSession();
+  const { toast } = useToast();
+
+  // Helper function to log operations
+  const logEmailOp = useCallback((operation: string, details: string, data?: any) => {
+    const timestamp = new Date().toISOString().split('T')[1].substring(0, 12);
+    console.log(`[${timestamp}][EMAIL-STATE][${operation}] ${details}`);
+    if (data) {
+      console.log(`[${timestamp}][EMAIL-STATE][DATA]`, data);
+    }
+  }, []);
+
+  // Load emails from the server
+  const loadEmails = useCallback(async (isLoadMore = false, accountId?: string) => {
+    if (!session?.user?.id) return;
+    
+    dispatch({ type: 'SET_LOADING', payload: true });
+    
+    try {
+      // Get normalized parameters using helper function
+      const { normalizedFolder, effectiveAccountId, prefixedFolder } = 
+        normalizeFolderAndAccount(state.currentFolder, accountId);
+      
+      logEmailOp('LOAD_EMAILS', `Loading emails for ${prefixedFolder} (account: ${effectiveAccountId})`);
+      
+      // Construct query parameters
+      const queryParams = new URLSearchParams({
+        folder: normalizedFolder,
+        page: state.page.toString(),
+        perPage: state.perPage.toString(),
+        accountId: effectiveAccountId
+      });
+      
+      // Try to get cached emails first
+      logEmailOp('CACHE_CHECK', `Checking cache for ${prefixedFolder}, page: ${state.page}`);
+      const cachedEmails = await getCachedEmailsWithTimeout(
+        session.user.id,
+        prefixedFolder,
+        state.page,
+        state.perPage,
+        100,
+        effectiveAccountId
+      );
+      
+      if (cachedEmails) {
+        logEmailOp('CACHE_HIT', `Using cached data for ${prefixedFolder}`);
+        
+        // Ensure cached data has emails array property
+        if (Array.isArray(cachedEmails.emails)) {
+          // Dispatch appropriate action based on if we're loading more
+          dispatch({ 
+            type: isLoadMore ? 'APPEND_EMAILS' : 'SET_EMAILS', 
+            payload: cachedEmails.emails 
+          });
+          
+          // Set pagination info from cache if available
+          if (cachedEmails.totalEmails) {
+            dispatch({ type: 'SET_TOTAL_EMAILS', payload: cachedEmails.totalEmails });
+          }
+          
+          if (cachedEmails.totalPages) {
+            dispatch({ type: 'SET_TOTAL_PAGES', payload: cachedEmails.totalPages });
+          }
+          
+          // Update available mailboxes if provided
+          if (cachedEmails.mailboxes && cachedEmails.mailboxes.length > 0) {
+            dispatch({ type: 'SET_MAILBOXES', payload: cachedEmails.mailboxes });
+          }
+        }
+        
+        // Still refresh in background for fresh data
+        logEmailOp('BACKGROUND_REFRESH', `Starting background refresh for ${prefixedFolder}`);
+        refreshEmailsInBackground(
+          session.user.id,
+          normalizedFolder,
+          state.page,
+          state.perPage,
+          effectiveAccountId
+        ).catch(err => {
+          console.error('Background refresh error:', err);
+        });
+        
+        return;
+      }
+      
+      // Fetch emails from API if no cache hit
+      logEmailOp('API_FETCH', `Fetching emails from API: ${queryParams.toString()}`);
+      const response = await fetch(`/api/courrier?${queryParams.toString()}`);
+      
+      if (!response.ok) {
+        const errorData = await response.json();
+        throw new Error(errorData.error || 'Failed to fetch emails');
+      }
+      
+      const data = await response.json();
+      
+      // Ensure all emails have proper account ID and folder format
+      if (Array.isArray(data.emails)) {
+        data.emails.forEach((email: Email) => {
+          // If email doesn't have an accountId, set it to the effective one
+          if (!email.accountId) {
+            email.accountId = effectiveAccountId;
+          }
+          
+          // Ensure folder has the proper prefix format
+          if (email.folder && !email.folder.includes(':')) {
+            email.folder = `${email.accountId}:${email.folder}`;
+          }
+        });
+      }
+      
+      // Update state with fetched data
+      dispatch({ 
+        type: isLoadMore ? 'APPEND_EMAILS' : 'SET_EMAILS', 
+        payload: Array.isArray(data.emails) ? data.emails : [] 
+      });
+      
+      if (data.totalEmails) {
+        dispatch({ type: 'SET_TOTAL_EMAILS', payload: data.totalEmails });
+      }
+      
+      if (data.totalPages) {
+        dispatch({ type: 'SET_TOTAL_PAGES', payload: data.totalPages });
+      }
+      
+      // Update available mailboxes if provided
+      if (data.mailboxes && data.mailboxes.length > 0) {
+        dispatch({ type: 'SET_MAILBOXES', payload: data.mailboxes });
+      }
+    } catch (err) {
+      logEmailOp('ERROR', `Failed to load emails: ${err instanceof Error ? err.message : String(err)}`);
+      dispatch({ 
+        type: 'SET_ERROR', 
+        payload: err instanceof Error ? err.message : 'Failed to load emails' 
+      });
+      toast({
+        variant: "destructive",
+        title: "Error",
+        description: err instanceof Error ? err.message : 'Failed to load emails'
+      });
+    }
+  }, [session?.user?.id, state.currentFolder, state.page, state.perPage, toast, logEmailOp]);
+
+  // Change folder
+  const changeFolder = useCallback(async (folder: string, accountId?: string) => {
+    logEmailOp('CHANGE_FOLDER', `Changing to folder ${folder} with account ${accountId || 'default'}`);
+    
+    try {
+      // This will handle all the state updates in a single atomic operation
+      dispatch({ 
+        type: 'CHANGE_FOLDER', 
+        payload: { folder, accountId: accountId || 'default' } 
+      });
+      
+      // After dispatch, the state will be updated with consistent values
+      // We'll load emails in the useEffect that watches for folder changes
+    } catch (error) {
+      logEmailOp('ERROR', `Failed to change folder: ${error instanceof Error ? error.message : String(error)}`);
+      dispatch({ 
+        type: 'SET_ERROR', 
+        payload: error instanceof Error ? error.message : 'Failed to change folder' 
+      });
+    }
+  }, [logEmailOp]);
+
+  // Select account
+  const selectAccount = useCallback((account: Account) => {
+    logEmailOp('SELECT_ACCOUNT', `Selecting account: ${account.email} (${account.id})`);
+    
+    // Handle the entire account selection in a single atomic operation
+    dispatch({ type: 'SELECT_ACCOUNT', payload: account });
+    
+    // The folder loading will be triggered by the useEffect watching for currentFolder changes
+  }, [logEmailOp]);
+
+  // Handle email selection
+  const handleEmailSelect = useCallback(async (emailId: string, accountId: string, folder: string) => {
+    logEmailOp('SELECT_EMAIL', `Selecting email ${emailId} from account ${accountId} in folder ${folder}`);
+    
+    if (!emailId) {
+      dispatch({ 
+        type: 'SELECT_EMAIL', 
+        payload: { emailId: '', accountId: '', folder: '', email: null } 
+      });
+      return;
+    }
+    
+    try {
+      // Find the email in the current list
+      const existingEmail = state.emails.find(e => e.id === emailId);
+      
+      if (existingEmail && existingEmail.contentFetched) {
+        // Use the existing email if it has content already
+        dispatch({ 
+          type: 'SELECT_EMAIL',
+          payload: { emailId, accountId, folder, email: existingEmail }
+        });
+        
+        // Mark as read if not already
+        if (!existingEmail.flags.seen) {
+          markEmailAsRead(emailId, true, accountId);
+        }
+        
+        return;
+      }
+      
+      // Need to fetch the email content
+      dispatch({ type: 'SET_LOADING', payload: true });
+      
+      // Extract account ID from folder name if present and none was explicitly provided
+      const { normalizedFolder, effectiveAccountId } = normalizeFolderAndAccount(folder, accountId);
+      
+      // Fetch email content from API
+      const response = await fetch(`/api/courrier/${emailId}?folder=${normalizedFolder}&accountId=${effectiveAccountId}`);
+      
+      if (!response.ok) {
+        throw new Error(`Failed to fetch email content: ${response.status}`);
+      }
+      
+      const emailData = await response.json();
+      
+      // Mark the email as read on the server
+      markEmailAsRead(emailId, true, effectiveAccountId);
+      
+      // Select the email
+      dispatch({ 
+        type: 'SELECT_EMAIL',
+        payload: { emailId, accountId: effectiveAccountId, folder, email: emailData }
+      });
+    } catch (error) {
+      logEmailOp('ERROR', `Failed to select email: ${error instanceof Error ? error.message : String(error)}`);
+      dispatch({ 
+        type: 'SET_ERROR', 
+        payload: error instanceof Error ? error.message : 'Failed to select email' 
+      });
+    } finally {
+      dispatch({ type: 'SET_LOADING', payload: false });
+    }
+  }, [state.emails, logEmailOp]);
+
+  // Toggle email selection for multi-select
+  const toggleEmailSelection = useCallback((emailId: string) => {
+    dispatch({ type: 'TOGGLE_EMAIL_SELECTION', payload: emailId });
+  }, []);
+
+  // Toggle select all
+  const toggleSelectAll = useCallback(() => {
+    dispatch({ type: 'TOGGLE_SELECT_ALL' });
+  }, []);
+
+  // Mark email as read/unread
+  const markEmailAsRead = useCallback(async (emailId: string, isRead: boolean, accountId?: string) => {
+    try {
+      // Find the email to get its account ID if not provided
+      const email = state.emails.find(e => e.id === emailId);
+      const effectiveAccountId = accountId || email?.accountId || 'default';
+      const folder = email?.folder || state.currentFolder;
+      
+      // Extract normalized folder
+      const { normalizedFolder } = normalizeFolderAndAccount(folder, effectiveAccountId);
+      
+      logEmailOp('MARK_READ', `Marking email ${emailId} as ${isRead ? 'read' : 'unread'} in ${normalizedFolder}`);
+      
+      // Update UI state immediately (optimistic update)
+      dispatch({
+        type: 'MARK_EMAIL_AS_READ',
+        payload: { emailId, isRead, accountId: effectiveAccountId }
+      });
+      
+      // Make API call to update on server
+      const response = await fetch(`/api/courrier/${emailId}/mark-read`, {
+        method: 'POST',
+        headers: { 'Content-Type': 'application/json' },
+        body: JSON.stringify({
+          isRead,
+          folder: normalizedFolder,
+          accountId: effectiveAccountId
+        })
+      });
+      
+      if (!response.ok) {
+        throw new Error('Failed to mark email as read');
+      }
+      
+      return true;
+    } catch (error) {
+      logEmailOp('ERROR', `Failed to mark email as read: ${error instanceof Error ? error.message : String(error)}`);
+      toast({
+        variant: "destructive",
+        title: "Error",
+        description: 'Failed to update email read status'
+      });
+      return false;
+    }
+  }, [state.emails, state.currentFolder, toast, logEmailOp]);
+
+  // Toggle starred status
+  const toggleStarred = useCallback(async (emailId: string) => {
+    try {
+      // Find the email in current list
+      const email = state.emails.find(e => e.id === emailId);
+      if (!email) {
+        throw new Error('Email not found');
+      }
+      
+      const newFlaggedStatus = !email.flags.flagged;
+      logEmailOp('TOGGLE_STAR', `Setting starred status to ${newFlaggedStatus} for email ${emailId}`);
+      
+      // TODO: Implement optimistic update
+      
+      // Make API call
+      const response = await fetch(`/api/courrier/${emailId}/flag`, {
+        method: 'POST',
+        headers: { 'Content-Type': 'application/json' },
+        body: JSON.stringify({
+          flagged: newFlaggedStatus,
+          folder: email.folder,
+          accountId: email.accountId
+        })
+      });
+      
+      if (!response.ok) {
+        throw new Error('Failed to update star status');
+      }
+      
+      // Reload emails to get updated state
+      loadEmails();
+      
+      return true;
+    } catch (error) {
+      logEmailOp('ERROR', `Failed to toggle star: ${error instanceof Error ? error.message : String(error)}`);
+      toast({
+        variant: "destructive",
+        title: "Error",
+        description: 'Failed to update star status'
+      });
+      return false;
+    }
+  }, [state.emails, toast, loadEmails, logEmailOp]);
+
+  // Delete emails
+  const deleteEmails = useCallback(async (emailIds: string[]) => {
+    if (emailIds.length === 0) return;
+    
+    dispatch({ type: 'SET_LOADING', payload: true });
+    
+    try {
+      logEmailOp('DELETE', `Deleting ${emailIds.length} emails`);
+      
+      // Find the first email to get account ID and folder
+      const firstEmail = state.emails.find(e => e.id === emailIds[0]);
+      const accountId = firstEmail?.accountId || 'default';
+      const folder = firstEmail?.folder || state.currentFolder;
+      const { normalizedFolder } = normalizeFolderAndAccount(folder, accountId);
+      
+      // Make API call to delete emails
+      const response = await fetch('/api/courrier/delete', {
+        method: 'POST',
+        headers: { 'Content-Type': 'application/json' },
+        body: JSON.stringify({
+          emailIds,
+          folder: normalizedFolder,
+          accountId
+        })
+      });
+      
+      if (!response.ok) {
+        throw new Error('Failed to delete emails');
+      }
+      
+      // Clear selections
+      dispatch({ type: 'CLEAR_SELECTED_EMAILS' });
+      
+      // Reload emails to get updated list
+      loadEmails();
+      
+      toast({
+        title: "Emails Deleted",
+        description: `${emailIds.length} email(s) moved to trash`
+      });
+      
+      return true;
+    } catch (error) {
+      logEmailOp('ERROR', `Failed to delete emails: ${error instanceof Error ? error.message : String(error)}`);
+      toast({
+        variant: "destructive",
+        title: "Error",
+        description: 'Failed to delete emails'
+      });
+      return false;
+    } finally {
+      dispatch({ type: 'SET_LOADING', payload: false });
+    }
+  }, [state.emails, state.currentFolder, toast, loadEmails, logEmailOp]);
+
+  // Send email
+  const sendEmail = useCallback(async (emailData: EmailData) => {
+    dispatch({ type: 'SET_LOADING', payload: true });
+    
+    try {
+      logEmailOp('SEND', `Sending email to ${emailData.to}`);
+      
+      // Make API call to send email
+      const response = await fetch('/api/courrier/send', {
+        method: 'POST',
+        headers: { 'Content-Type': 'application/json' },
+        body: JSON.stringify(emailData)
+      });
+      
+      if (!response.ok) {
+        const errorData = await response.json();
+        throw new Error(errorData.error || 'Failed to send email');
+      }
+      
+      const result = await response.json();
+      
+      toast({
+        title: "Email Sent",
+        description: "Your message has been sent successfully"
+      });
+      
+      // Refresh emails to show the sent email
+      loadEmails();
+      
+      return { success: true, ...result };
+    } catch (error) {
+      logEmailOp('ERROR', `Failed to send email: ${error instanceof Error ? error.message : String(error)}`);
+      toast({
+        variant: "destructive",
+        title: "Error",
+        description: error instanceof Error ? error.message : 'Failed to send email'
+      });
+      return { success: false, error: error instanceof Error ? error.message : 'Failed to send email' };
+    } finally {
+      dispatch({ type: 'SET_LOADING', payload: false });
+    }
+  }, [toast, loadEmails, logEmailOp]);
+  
+  // Search emails
+  const searchEmails = useCallback(async (query: string) => {
+    // Set loading state
+    dispatch({ type: 'SET_LOADING', payload: true });
+    
+    try {
+      if (!session?.user?.id) return;
+      
+      logEmailOp('SEARCH', `Searching for "${query}" in ${state.currentFolder}`);
+      
+      // Extract account ID from current folder
+      const { normalizedFolder, effectiveAccountId } = normalizeFolderAndAccount(state.currentFolder);
+      
+      // Construct query params for search
+      const queryParams = new URLSearchParams({
+        folder: normalizedFolder,
+        search: query,
+        accountId: effectiveAccountId
+      });
+      
+      // Call API for search
+      const response = await fetch(`/api/courrier/search?${queryParams.toString()}`);
+      
+      if (!response.ok) {
+        const errorData = await response.json();
+        throw new Error(errorData.error || 'Failed to search emails');
+      }
+      
+      const results = await response.json();
+      
+      // Update emails with search results
+      dispatch({ type: 'SET_EMAILS', payload: results.emails || [] });
+      
+      if (results.totalEmails) {
+        dispatch({ type: 'SET_TOTAL_EMAILS', payload: results.totalEmails });
+      }
+      
+      if (results.totalPages) {
+        dispatch({ type: 'SET_TOTAL_PAGES', payload: results.totalPages });
+      }
+    } catch (error) {
+      logEmailOp('ERROR', `Search failed: ${error instanceof Error ? error.message : String(error)}`);
+      dispatch({ 
+        type: 'SET_ERROR', 
+        payload: error instanceof Error ? error.message : 'Failed to search emails' 
+      });
+      toast({
+        variant: "destructive",
+        title: "Error",
+        description: 'Failed to search emails'
+      });
+    } finally {
+      dispatch({ type: 'SET_LOADING', payload: false });
+    }
+  }, [session?.user?.id, state.currentFolder, toast, logEmailOp]);
+  
+  // Format email for reply, reply all, or forward
+  const formatEmailForAction = useCallback((email: any, type: 'reply' | 'reply-all' | 'forward') => {
+    return formatEmailForReplyOrForward(email, type);
+  }, []);
+
+  // Update page
+  const setPage = useCallback((page: number) => {
+    dispatch({ type: 'SET_PAGE', payload: page });
+  }, []);
+
+  // Set emails directly
+  const setEmails = useCallback((emails: Email[]) => {
+    dispatch({ type: 'SET_EMAILS', payload: emails });
+  }, []);
+
+  // Handle loading more emails
+  const handleLoadMore = useCallback(() => {
+    if (state.page < state.totalPages && !state.isLoading) {
+      dispatch({ type: 'INCREMENT_PAGE' });
+    }
+  }, [state.page, state.totalPages, state.isLoading]);
+
+  // Effect to load emails when folder changes
+  useEffect(() => {
+    if (session?.user?.id && state.currentFolder) {
+      // Extract account ID from folder for consistent loading
+      const { effectiveAccountId } = normalizeFolderAndAccount(state.currentFolder);
+      
+      logEmailOp('FOLDER_CHANGE', `Loading emails for folder ${state.currentFolder} with account ${effectiveAccountId}`);
+      
+      // Load emails with the correct account ID
+      loadEmails(false, effectiveAccountId);
+    }
+  }, [session?.user?.id, state.currentFolder, loadEmails, logEmailOp]);
+
+  // Effect to load more emails when page changes
+  useEffect(() => {
+    if (session?.user?.id && state.page > 1) {
+      // Extract account ID for consistency
+      const { effectiveAccountId } = normalizeFolderAndAccount(state.currentFolder);
+      
+      logEmailOp('PAGINATION', `Loading page ${state.page} for ${state.currentFolder} with account ${effectiveAccountId}`);
+      
+      // Load more emails with the correct account ID
+      loadEmails(true, effectiveAccountId);
+    }
+  }, [session?.user?.id, state.page, state.currentFolder, loadEmails, logEmailOp]);
+
+  // Return all state values and actions
+  return {
+    // State values
+    ...state,
+    
+    // Actions
+    loadEmails,
+    handleEmailSelect,
+    toggleEmailSelection,
+    toggleSelectAll,
+    markEmailAsRead,
+    toggleStarred,
+    changeFolder,
+    deleteEmails,
+    sendEmail,
+    searchEmails,
+    formatEmailForAction,
+    setPage,
+    setEmails,
+    selectAccount,
+    handleLoadMore
+  };
+}; 
\ No newline at end of file
diff --git a/lib/reducers/emailReducer.ts b/lib/reducers/emailReducer.ts
new file mode 100644
index 00000000..e8bbf802
--- /dev/null
+++ b/lib/reducers/emailReducer.ts
@@ -0,0 +1,324 @@
+import { Email } from '@/hooks/use-courrier';
+
+// Define all possible state types
+export interface Account {
+  id: string;
+  name: string;
+  email: string;
+  color: string;
+  folders: string[];
+}
+
+export interface EmailState {
+  accounts: Account[];
+  selectedAccount: Account | null;
+  selectedFolders: Record<string, string>;
+  currentFolder: string;
+  emails: Email[];
+  selectedEmail: Email | null;
+  selectedEmailIds: string[];
+  isLoading: boolean;
+  error: string | null;
+  page: number;
+  perPage: number;
+  totalPages: number;
+  totalEmails: number;
+  mailboxes: string[];
+  unreadCountMap: Record<string, Record<string, number>>;
+  showFolders: boolean;
+}
+
+// Define all possible action types
+export type EmailAction = 
+  | { type: 'SET_ACCOUNTS', payload: Account[] }
+  | { type: 'SELECT_ACCOUNT', payload: Account }
+  | { type: 'CHANGE_FOLDER', payload: { folder: string, accountId: string } }
+  | { type: 'SET_EMAILS', payload: Email[] }
+  | { type: 'APPEND_EMAILS', payload: Email[] }
+  | { type: 'SELECT_EMAIL', payload: { emailId: string, accountId: string, folder: string, email: Email | null } }
+  | { type: 'TOGGLE_EMAIL_SELECTION', payload: string }
+  | { type: 'TOGGLE_SELECT_ALL' }
+  | { type: 'CLEAR_SELECTED_EMAILS' }
+  | { type: 'SET_LOADING', payload: boolean }
+  | { type: 'SET_ERROR', payload: string | null }
+  | { type: 'SET_PAGE', payload: number }
+  | { type: 'INCREMENT_PAGE' }
+  | { type: 'SET_TOTAL_PAGES', payload: number }
+  | { type: 'SET_TOTAL_EMAILS', payload: number }
+  | { type: 'SET_MAILBOXES', payload: string[] }
+  | { type: 'UPDATE_UNREAD_COUNT', payload: { accountId: string, folder: string, count: number } }
+  | { type: 'TOGGLE_SHOW_FOLDERS', payload: boolean }
+  | { type: 'MARK_EMAIL_AS_READ', payload: { emailId: string, isRead: boolean, accountId?: string } };
+
+// Initial state
+export const initialState: EmailState = {
+  accounts: [],
+  selectedAccount: null,
+  selectedFolders: {},
+  currentFolder: 'INBOX',
+  emails: [],
+  selectedEmail: null,
+  selectedEmailIds: [],
+  isLoading: false,
+  error: null,
+  page: 1,
+  perPage: 20,
+  totalPages: 0,
+  totalEmails: 0,
+  mailboxes: [],
+  unreadCountMap: {},
+  showFolders: false
+};
+
+// Helper functions for consistency
+export const normalizeFolderAndAccount = (folder: string, accountId?: string) => {
+  let normalizedFolder: string;
+  let effectiveAccountId: string = accountId || 'default';
+  
+  // First, handle the folder format
+  if (folder.includes(':')) {
+    // Extract parts if folder already has a prefix
+    const parts = folder.split(':');
+    const folderAccountId = parts[0];
+    normalizedFolder = parts[1];
+    
+    // If explicit accountId is provided, it ALWAYS takes precedence
+    if (accountId) {
+      console.log(`Using provided accountId (${accountId}) over folder prefix (${folderAccountId})`);
+      effectiveAccountId = accountId;
+    } else {
+      effectiveAccountId = folderAccountId;
+    }
+  } else {
+    // No folder prefix, use the folder name as is
+    normalizedFolder = folder;
+  }
+  
+  return {
+    normalizedFolder,
+    effectiveAccountId,
+    prefixedFolder: `${effectiveAccountId}:${normalizedFolder}`
+  };
+};
+
+// Reducer function
+export function emailReducer(state: EmailState, action: EmailAction): EmailState {
+  console.log(`[EMAIL_REDUCER] Action: ${action.type}`, action);
+  
+  switch (action.type) {
+    case 'SET_ACCOUNTS':
+      return {
+        ...state,
+        accounts: action.payload
+      };
+    
+    case 'SELECT_ACCOUNT': {
+      // This is a critical action that needs special handling
+      const account = action.payload;
+      const inboxFolder = `${account.id}:INBOX`;
+      
+      console.log(`[EMAIL_REDUCER] Selecting account: ${account.email} (${account.id})`);
+      
+      // Return a completely new state that's atomically consistent
+      return {
+        ...state,
+        selectedAccount: account,
+        currentFolder: inboxFolder,
+        selectedFolders: {
+          ...state.selectedFolders,
+          [account.id]: inboxFolder
+        },
+        // Clear email selections as part of the atomic account switch
+        selectedEmail: null,
+        selectedEmailIds: [],
+        emails: [],
+        isLoading: true,
+        showFolders: true,
+        page: 1
+      };
+    }
+    
+    case 'CHANGE_FOLDER': {
+      const { folder, accountId } = action.payload;
+      
+      // Use our helper to ensure consistent folder/account handling
+      const { normalizedFolder, effectiveAccountId, prefixedFolder } = 
+        normalizeFolderAndAccount(folder, accountId);
+      
+      console.log(`[EMAIL_REDUCER] Changing folder to: ${prefixedFolder} (account: ${effectiveAccountId})`);
+      
+      // Return a new state with consistent folder and account info
+      return {
+        ...state,
+        currentFolder: prefixedFolder,
+        selectedFolders: {
+          ...state.selectedFolders,
+          [effectiveAccountId]: prefixedFolder
+        },
+        // Clear email-specific state when changing folders
+        selectedEmail: null,
+        selectedEmailIds: [],
+        emails: [],
+        isLoading: true,
+        page: 1
+      };
+    }
+    
+    case 'SET_EMAILS':
+      return {
+        ...state,
+        emails: action.payload,
+        isLoading: false
+      };
+    
+    case 'APPEND_EMAILS': {
+      // Create a set of existing email IDs to avoid duplicates
+      const existingIds = new Set(state.emails.map(email => email.id));
+      
+      // Filter out any duplicates before appending
+      const newEmails = action.payload.filter(email => !existingIds.has(email.id));
+      
+      // Combine and sort emails by date (newest first)
+      const combinedEmails = [...state.emails, ...newEmails].sort(
+        (a, b) => new Date(b.date).getTime() - new Date(a.date).getTime()
+      );
+      
+      return {
+        ...state,
+        emails: combinedEmails,
+        isLoading: false
+      };
+    }
+    
+    case 'SELECT_EMAIL':
+      return {
+        ...state,
+        selectedEmail: action.payload.email,
+        // If an email is selected, add it to the selectedEmailIds if not already there
+        selectedEmailIds: action.payload.email && !state.selectedEmailIds.includes(action.payload.emailId)
+          ? [...state.selectedEmailIds, action.payload.emailId]
+          : state.selectedEmailIds
+      };
+    
+    case 'TOGGLE_EMAIL_SELECTION': {
+      const emailId = action.payload;
+      const isSelected = state.selectedEmailIds.includes(emailId);
+      
+      return {
+        ...state,
+        selectedEmailIds: isSelected
+          ? state.selectedEmailIds.filter(id => id !== emailId)
+          : [...state.selectedEmailIds, emailId]
+      };
+    }
+    
+    case 'TOGGLE_SELECT_ALL': {
+      // If all emails are already selected, clear the selection
+      const allEmailIds = state.emails.map(email => email.id);
+      const allSelected = allEmailIds.every(id => state.selectedEmailIds.includes(id));
+      
+      return {
+        ...state,
+        selectedEmailIds: allSelected ? [] : allEmailIds
+      };
+    }
+    
+    case 'CLEAR_SELECTED_EMAILS':
+      return {
+        ...state,
+        selectedEmailIds: [],
+        selectedEmail: null
+      };
+    
+    case 'SET_LOADING':
+      return {
+        ...state,
+        isLoading: action.payload
+      };
+    
+    case 'SET_ERROR':
+      return {
+        ...state,
+        error: action.payload,
+        isLoading: false
+      };
+    
+    case 'SET_PAGE':
+      return {
+        ...state,
+        page: action.payload
+      };
+    
+    case 'INCREMENT_PAGE':
+      return {
+        ...state,
+        page: state.page + 1
+      };
+    
+    case 'SET_TOTAL_PAGES':
+      return {
+        ...state,
+        totalPages: action.payload
+      };
+    
+    case 'SET_TOTAL_EMAILS':
+      return {
+        ...state,
+        totalEmails: action.payload
+      };
+    
+    case 'SET_MAILBOXES':
+      return {
+        ...state,
+        mailboxes: action.payload
+      };
+    
+    case 'UPDATE_UNREAD_COUNT': {
+      const { accountId, folder, count } = action.payload;
+      
+      return {
+        ...state,
+        unreadCountMap: {
+          ...state.unreadCountMap,
+          [accountId]: {
+            ...(state.unreadCountMap[accountId] || {}),
+            [folder]: count
+          }
+        }
+      };
+    }
+    
+    case 'TOGGLE_SHOW_FOLDERS':
+      return {
+        ...state,
+        showFolders: action.payload
+      };
+    
+    case 'MARK_EMAIL_AS_READ': {
+      const { emailId, isRead, accountId } = action.payload;
+      
+      // Update emails list
+      const updatedEmails = state.emails.map(email => 
+        (email.id === emailId && (!accountId || email.accountId === accountId))
+          ? { ...email, flags: { ...email.flags, seen: isRead } }
+          : email
+      );
+      
+      // Update selected email if it matches
+      const updatedSelectedEmail = state.selectedEmail && 
+        state.selectedEmail.id === emailId && 
+        (!accountId || state.selectedEmail.accountId === accountId)
+          ? { ...state.selectedEmail, flags: { ...state.selectedEmail.flags, seen: isRead } }
+          : state.selectedEmail;
+      
+      return {
+        ...state,
+        emails: updatedEmails,
+        selectedEmail: updatedSelectedEmail
+      };
+    }
+    
+    default:
+      return state;
+  }
+} 
\ No newline at end of file