/// A widget that displays the account content page for the travel expense app.
///
/// This component manages the display of user accounts (groups) and provides
/// navigation to group expense management. It handles loading account data,
/// error states, and navigation to the group expenses page.
///
/// Features:
/// - **Account Loading**: Automatically loads accounts for the current user
/// - **Error Handling**: Displays error states with retry functionality
/// - **Navigation**: Navigates to group expense management pages
/// - **Real-time Updates**: Uses BLoC pattern for reactive state management
/// - **Pull to Refresh**: Allows users to refresh account data
///
/// Dependencies:
/// - [UserBloc]: For current user state management
/// - [AccountBloc]: For account data management
/// - [GroupRepository]: For group data operations
///
/// The component automatically loads account data when initialized and
/// provides a clean interface for managing group-based expenses.
library;
import 'package:flutter/material.dart';
import 'package:travel_mate/blocs/user/user_bloc.dart';
import '../../models/account.dart';
import '../../blocs/account/account_bloc.dart';
import '../../blocs/account/account_event.dart';
import '../../blocs/account/account_state.dart';
import 'package:flutter_bloc/flutter_bloc.dart';
import 'package:travel_mate/components/error/error_content.dart';
import '../../blocs/user/user_state.dart' as user_state;
import '../../repositories/group_repository.dart'; // Ajouter cet import
import 'group_expenses_page.dart'; // Ajouter cet import

/// Widget that displays the account content page with account management functionality.
class AccountContent extends StatefulWidget {
  const AccountContent({super.key});

  @override
  State<AccountContent> createState() => _AccountContentState();
}

/// State class for AccountContent that manages account loading and navigation.
class _AccountContentState extends State<AccountContent> {
  /// Repository for group data operations used for navigation
  final _groupRepository = GroupRepository(); // Ajouter cette ligne

  @override 
  void initState() {
    super.initState();
    
    // Load immediately without waiting for the next frame
    WidgetsBinding.instance.addPostFrameCallback((_) {
      _loadInitialData();
    });
  }

  /// Loads the initial account data for the current user.
  /// 
  /// Retrieves the current user from UserBloc and loads their accounts
  /// using the AccountBloc. Handles errors gracefully with error display.
  void _loadInitialData() {
    try {
      final userState = context.read<UserBloc>().state;
      
      if (userState is user_state.UserLoaded) {
        final userId = userState.user.id;
        context.read<AccountBloc>().add(LoadAccountsByUserId(userId));
      } else {
        throw Exception('User not connected');
      }
    } catch (e) {
      ErrorContent(
        message: 'Error loading accounts: $e',
        onRetry: () {},
      );
    }
  }

  /// Navigates to the group expenses page for a specific account.
  /// 
  /// Retrieves the group associated with the account and navigates to
  /// the group expenses management page. Shows error messages if the
  /// group cannot be found or if navigation fails.
  /// 
  /// Args:
  ///   [account]: The account to navigate to for expense management
  Future<void> _navigateToGroupExpenses(Account account) async {
    try {
      // Retrieve the group associated with the account
      final group = await _groupRepository.getGroupByTripId(account.tripId);
      
      if (group != null && mounted) {
        Navigator.push(
          context,
          MaterialPageRoute(
            builder: (context) => GroupExpensesPage(
              account: account,
              group: group,
            ),
          ),
        );
      } else {
        if (mounted) {
          ScaffoldMessenger.of(context).showSnackBar(
            const SnackBar(
              content: Text('Group not found for this account'),
              backgroundColor: Colors.red,
            ),
          );
        }
      }
    } catch (e) {
      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(
            content: Text('Error loading group: $e'),
            backgroundColor: Colors.red,
          ),
        );
      }
    }
  }

  /// Builds the main widget for the account content page.
  /// 
  /// Creates a responsive UI that handles different user and account states:
  /// - Shows loading indicator for user authentication
  /// - Displays error content for user errors
  /// - Builds account content based on account loading states
  /// 
  /// Returns:
  ///   Widget representing the complete account page UI
  @override
  Widget build(BuildContext context) {
    return BlocBuilder<UserBloc, user_state.UserState>(
      builder: (context, userState) {
        if (userState is user_state.UserLoading) {
          return const Scaffold(
            body: Center(child: CircularProgressIndicator()),
          );
        }

        if (userState is user_state.UserError) {
          return ErrorContent(
            message: 'User error: ${userState.message}',
            onRetry: () {},
          ); 
        }

        if (userState is! user_state.UserLoaded) {
          return const Scaffold(
            body: Center(child: Text('User not connected')),
          );
        }
        final user = userState.user;

        return BlocConsumer<AccountBloc, AccountState>(
          listener: (context, accountState) {
            if (accountState is AccountError) {
              ErrorContent(
                message: 'Account loading error: ${accountState.message}',
                onRetry: () {
                  context.read<AccountBloc>().add(LoadAccountsByUserId(user.id));
                },
              );
            }
          },
          builder: (context, accountState) {
            return Scaffold(
                body: SafeArea(child: _buildContent(accountState, user.id))
              );
          },
        );
      },    
    );
  }

  /// Builds the main content based on the current account state.
  /// 
  /// Handles different account loading states and renders appropriate UI:
  /// - Loading: Shows circular progress indicator with loading message
  /// - Error: Displays error content with retry functionality
  /// - Loaded: Renders the accounts list or empty state message
  /// 
  /// Args:
  ///   [accountState]: Current state of account loading
  ///   [userId]: ID of the current user for reload operations
  /// 
  /// Returns:
  ///   Widget representing the account content UI
  Widget _buildContent(AccountState accountState, String userId) {
    if (accountState is AccountLoading) {
      return const Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            CircularProgressIndicator(),
            SizedBox(height: 16),
            Text('Loading accounts...'),
          ],        
        ),     
      );
    } 
    
    if (accountState is AccountError) {
      return ErrorContent(
        message: 'Account loading error...',
        onRetry: () {
          context.read<AccountBloc>().add(LoadAccountsByUserId(userId));
        },
      );
    }

    if (accountState is AccountsLoaded) {
      if (accountState.accounts.isEmpty) {
        return _buildEmptyState();
      }

      return _buildAccountsList(accountState.accounts, userId);
    }
    return Center(
      child: Column(
        mainAxisAlignment: MainAxisAlignment.center,
        children: [
          const Text('Unknown state'),
          const SizedBox(height: 16),
          ElevatedButton(
            onPressed: () {
              context.read<AccountBloc>().add(LoadAccountsByUserId(userId));
            },
            child: const Text('Load accounts'),
          ),
        ],
      ),
    );    
  }

  /// Builds the empty state widget when no accounts are found.
  /// 
  /// Displays a user-friendly message explaining that accounts are
  /// automatically created when trips are created. Shows an icon
  /// and informative text to guide the user.
  /// 
  /// Returns:
  ///   Widget representing the empty accounts state
  Widget _buildEmptyState() {
    return Center(
      child: Padding(
        padding: const EdgeInsets.all(32),
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            const Icon(Icons.account_balance_wallet, size: 80, color: Colors.grey),
            const SizedBox(height: 16),
            const Text(
              'No accounts found',
              style: TextStyle(fontSize: 20, fontWeight: FontWeight.bold),
            ),
            const SizedBox(height: 8),
            const Text(
              'Accounts are automatically created when you create a trip',
              style: TextStyle(fontSize: 14, color: Colors.grey),
              textAlign: TextAlign.center,
            ),
          ],
        ),
      ),
    );
  }

  /// Builds a scrollable list of user accounts with pull-to-refresh functionality.
  /// 
  /// Creates a RefreshIndicator-wrapped ListView that displays all user accounts
  /// in card format. Includes a header with title and description, and renders
  /// each account using the _buildSimpleAccountCard method.
  /// 
  /// Args:
  ///   [accounts]: List of accounts to display
  ///   [userId]: Current user ID for refresh operations
  /// 
  /// Returns:
  ///   Widget containing the accounts list with pull-to-refresh capability
  Widget _buildAccountsList(List<Account> accounts, String userId) {
    return RefreshIndicator(
      onRefresh: () async {
        context.read<AccountBloc>().add(LoadAccountsByUserId(userId));
        await Future.delayed(const Duration(milliseconds: 500));
      },
      child: ListView(
        padding: const EdgeInsets.all(16),
        children: [
          const Text(
            'My accounts',
            style: TextStyle(fontSize: 28, fontWeight: FontWeight.bold),
          ),
          const SizedBox(height: 8),
          Text(
            'Manage your travel accounts',
            style: TextStyle(fontSize: 14, color: Colors.grey[600]),
          ),
          const SizedBox(height: 24),
          
          ...accounts.map((account) {
            return Padding(
              padding: const EdgeInsets.only(bottom: 12),
              child: _buildSimpleAccountCard(account),
            );
          })
        ],
      )
    );
  }
  
  /// Builds an individual account card with account information.
  /// 
  /// Creates a Material Design card displaying account details including:
  /// - Account name with color-coded avatar
  /// - Member count and member names (up to 2 displayed)
  /// - Navigation capability to group expenses
  /// - Error handling for card rendering issues
  /// 
  /// Args:
  ///   [account]: Account object containing account details
  /// 
  /// Returns:
  ///   Widget representing a single account card
  Widget _buildSimpleAccountCard(Account account) {
    try {
      final colors = [Colors.blue, Colors.purple, Colors.green, Colors.orange];
      final color = colors[account.name.hashCode.abs() % colors.length];

      String memberInfo = '${account.members.length} member${account.members.length > 1 ? 's' : ''}';

      if(account.members.isNotEmpty){
        final names = account.members
            .take(2)
            .map((m) => m.pseudo.isNotEmpty ? m.pseudo : m.firstName)
            .join(', ');
        memberInfo += '\n$names';
      }

      return Card(
        elevation: 2,
        child: ListTile(
          leading: CircleAvatar(
            backgroundColor: color,
            child: const Icon(Icons.account_balance_wallet, color: Colors.white),
          ),
          title: Text(
            account.name,
            style: const TextStyle(fontWeight: FontWeight.bold),
          ), 
          subtitle: Text(memberInfo),
          trailing: const Icon(Icons.chevron_right),
          onTap: () => _navigateToGroupExpenses(account), // Navigate to group expenses
        ),
      );
    } catch (e) {
      return Card(
        color: Colors.red,
        child: const ListTile(
          leading: Icon(Icons.error, color: Colors.red),
          title: Text('Display error'),
        )
      );
    }
  }
}