import 'dart:convert';

import 'package:flutter/material.dart';
import 'package:http/http.dart' as http;

import '../config/environment.dart';
import '../service/token_storage_service.dart';

class NhanceTopBar extends StatefulWidget implements PreferredSizeWidget {
  const NhanceTopBar({super.key});

  @override
  Size get preferredSize => const Size.fromHeight(64);

  @override
  State<NhanceTopBar> createState() => _NhanceTopBarState();
}

class _NhanceTopBarState extends State<NhanceTopBar> {
  final tokenStorage = TokenStorageService();

  List<Map<String, dynamic>> branches = [];
  Map<String, dynamic>? selectedBranch;

  /// client_id → logo URL
  final Map<String, String> _logoByClientId = {};

  @override
  void initState() {
    super.initState();
    _loadBranches();
  }

  void _loadBranches() {
    branches = tokenStorage.getCombinedBranches();
    selectedBranch = tokenStorage.getSelectedBranch();
    setState(() {});
    _loadBranchLogos();
  }

  String _clientKey(Map<String, dynamic> branch) {
    return (branch['client_id'] ?? branch['id'] ?? '').toString();
  }

  String? _logoFromBranch(Map<String, dynamic> branch) {
    final candidates = [
      branch['client_logo'],
      branch['logo'],
      branch['clientLogo'],
    ];
    for (final value in candidates) {
      final url = value?.toString().trim() ?? '';
      if (url.isNotEmpty) return url;
    }
    return null;
  }

  Map<String, dynamic>? _decodeBranchToken(String token) {
    try {
      final parts = token.split('.');
      if (parts.length != 3) return null;

      final payload = base64Url.normalize(parts[1]);
      final decoded = utf8.decode(base64Url.decode(payload));
      final parsed = json.decode(decoded);
      if (parsed is Map<String, dynamic>) return parsed;
      if (parsed is Map) return Map<String, dynamic>.from(parsed);
      return null;
    } catch (_) {
      return null;
    }
  }

  /// Read post/pre client + branch ids from selected branch JWT payload.
  Map<String, String>? _clientDetailsParamsFromBranch(
    Map<String, dynamic> branch,
  ) {
    final token = branch['token']?.toString() ??
        tokenStorage.getCurrentToken() ??
        '';
    if (token.isEmpty) return null;

    final decoded = _decodeBranchToken(token);
    if (decoded == null) return null;

    final postClientId = decoded['post_client_id']?.toString().trim() ?? '';
    final postBranchId = decoded['post_branch_id']?.toString().trim() ?? '';
    final preClientId = decoded['pre_client_id']?.toString().trim() ?? '';
    final preBranchId = decoded['pre_branch_id']?.toString().trim() ?? '';

    if (postClientId.isEmpty &&
        postBranchId.isEmpty &&
        preClientId.isEmpty &&
        preBranchId.isEmpty) {
      return null;
    }

    return {
      'post_client_id': postClientId,
      'post_branch_id': postBranchId,
      'pre_client_id': preClientId,
      'pre_branch_id': preBranchId,
    };
  }

  Future<void> _loadBranchLogos() async {
    final uniqueBranches = <String, Map<String, dynamic>>{};
    for (final branch in branches) {
      final key = _clientKey(branch);
      if (key.isEmpty) continue;
      uniqueBranches.putIfAbsent(key, () => branch);
    }

    for (final entry in uniqueBranches.entries) {
      final key = entry.key;
      if (_logoByClientId.containsKey(key)) continue;

      final fromBranch = _logoFromBranch(entry.value);
      if (fromBranch != null) {
        if (!mounted) return;
        setState(() => _logoByClientId[key] = fromBranch);
        continue;
      }

      final logoUrl = await _fetchClientLogoUrl(entry.value);
      if (!mounted) return;
      if (logoUrl != null && logoUrl.isNotEmpty) {
        setState(() => _logoByClientId[key] = logoUrl);
      }
    }
  }

  Future<String?> _fetchClientLogoUrl(Map<String, dynamic> branch) async {
    try {
      final token = branch['token']?.toString() ??
          tokenStorage.getCurrentToken() ??
          '';
      if (token.isEmpty) return null;

      final params = _clientDetailsParamsFromBranch(branch);
      if (params == null) return null;

      final url = Uri.parse('${Environment.apiUrl}getClientDetails').replace(
        queryParameters: params,
      );

      final response = await http.get(
        url,
        headers: {
          'Authorization': 'Bearer $token',
          'APP-SIGNATURE':
              'nhance-2025-signature-T8f6gV9k5fK2wf5V5c4vId3b0J8z6cAm2x8Y',
        },
      );

      if (response.statusCode != 200) return null;
      final data = jsonDecode(response.body);
      if (data is! Map || data['status'] != 'success') return null;

      final logo = data['data']?['client']?['client_logo']?.toString().trim();
      if (logo == null || logo.isEmpty) return null;
      return logo;
    } catch (_) {
      return null;
    }
  }

  Future<String> _getBranchSwitchRoute() async {
    final postRaw = await tokenStorage.readValue('empAllowed_modules');
    final postModules = postRaw != null && postRaw.isNotEmpty
        ? List<int>.from(jsonDecode(postRaw))
        : <int>[];

    if (postModules.isNotEmpty && postModules.contains(5)) {
      return 'claimsOverviewDashboard';
    }
    return 'policies';
  }

  Future<void> _onBranchSelected(Map<String, dynamic> branch) async {
    final tokenStorage = TokenStorageService();

    await tokenStorage.resetSessionAndSwitchBranch(branch);

    if (!mounted) return;

    _loadBranches();

    final route = await _getBranchSwitchRoute();

    if (!mounted) return;
    Navigator.pushReplacementNamed(context, route);
  }

  @override
  Widget build(BuildContext context) {
    final selectedLogo = selectedBranch == null
        ? null
        : _logoByClientId[_clientKey(selectedBranch!)];

    return AppBar(
      automaticallyImplyLeading: false,
      backgroundColor: const Color(0xFFBFEFEF),
      elevation: 0,
      title: Row(
        children: [
          Image.asset('assets/nhance_client_logo.png', height: 32),
          const Spacer(),
          if (selectedBranch != null)
            _BranchPopup(
              clientName: selectedBranch!['client_name']?.toString() ?? '',
              branchName: selectedBranch!['branch_name']?.toString() ?? '',
              selectedLogoUrl: selectedLogo,
              branches: branches,
              logoByClientId: _logoByClientId,
              clientKeyBuilder: _clientKey,
              onSelected: _onBranchSelected,
            ),
        ],
      ),
    );
  }
}

class _BranchPopup extends StatelessWidget {
  final String clientName;
  final String branchName;
  final String? selectedLogoUrl;
  final List<Map<String, dynamic>> branches;
  final Map<String, String> logoByClientId;
  final String Function(Map<String, dynamic>) clientKeyBuilder;
  final Function(Map<String, dynamic>) onSelected;

  const _BranchPopup({
    required this.clientName,
    required this.branchName,
    required this.selectedLogoUrl,
    required this.branches,
    required this.logoByClientId,
    required this.clientKeyBuilder,
    required this.onSelected,
  });

  @override
  Widget build(BuildContext context) {
    return PopupMenuButton<Map<String, dynamic>>(
      tooltip: '',
      offset: const Offset(0, 48),
      onSelected: onSelected,
      itemBuilder: (context) {
        return branches.map((branch) {
          final logoUrl = logoByClientId[clientKeyBuilder(branch)];
          return PopupMenuItem<Map<String, dynamic>>(
            value: branch,
            child: Row(
              children: [
                _BranchLogo(logoUrl: logoUrl, size: 24),
                const SizedBox(width: 8),
                Expanded(
                  child: Text(
                    branch['client_name']?.toString() ?? '',
                    style: const TextStyle(fontSize: 13),
                    overflow: TextOverflow.ellipsis,
                  ),
                ),
                const SizedBox(width: 10),
                const Icon(Icons.location_on, size: 14, color: Colors.grey),
                const SizedBox(width: 4),
                Flexible(
                  child: Text(
                    branch['branch_name']?.toString() ?? '',
                    style: const TextStyle(
                      fontSize: 12,
                      color: Colors.grey,
                    ),
                    overflow: TextOverflow.ellipsis,
                  ),
                ),
              ],
            ),
          );
        }).toList();
      },
      child: Row(
        mainAxisSize: MainAxisSize.min,
        children: [
          _BranchLogo(logoUrl: selectedLogoUrl, size: 32),
          const SizedBox(width: 8),
          Container(
            height: 40,
            padding: const EdgeInsets.symmetric(horizontal: 12),
            decoration: BoxDecoration(
              color: Colors.white,
              borderRadius: BorderRadius.circular(22),
              boxShadow: [
                BoxShadow(
                  color: Colors.black.withOpacity(0.08),
                  blurRadius: 8,
                  offset: const Offset(0, 2),
                ),
              ],
            ),
            child: Row(
              children: [
                Text(
                  clientName,
                  style: const TextStyle(
                    fontSize: 14,
                    fontWeight: FontWeight.w500,
                  ),
                ),
                const SizedBox(width: 8),
                Row(
                  children: [
                    const Icon(
                      Icons.location_on,
                      size: 14,
                      color: Colors.grey,
                    ),
                    const SizedBox(width: 4),
                    Text(
                      branchName,
                      style: const TextStyle(
                        fontSize: 12,
                        color: Colors.grey,
                      ),
                    ),
                  ],
                ),
                const SizedBox(width: 6),
                const Icon(
                  Icons.keyboard_arrow_down,
                  size: 20,
                  color: Colors.orange,
                ),
              ],
            ),
          ),
        ],
      ),
    );
  }
}

class _BranchLogo extends StatelessWidget {
  final String? logoUrl;
  final double size;

  const _BranchLogo({
    required this.logoUrl,
    required this.size,
  });

  @override
  Widget build(BuildContext context) {
    final url = logoUrl?.trim() ?? '';
    if (url.isEmpty) {
      return _placeholder();
    }

    return ClipRRect(
      borderRadius: BorderRadius.circular(4),
      child: Image.network(
        url,
        width: size,
        height: size,
        fit: BoxFit.contain,
        errorBuilder: (_, __, ___) => _placeholder(),
        loadingBuilder: (context, child, progress) {
          if (progress == null) return child;
          return SizedBox(
            width: size,
            height: size,
            child: const Padding(
              padding: EdgeInsets.all(4),
              child: CircularProgressIndicator(strokeWidth: 1.5),
            ),
          );
        },
      ),
    );
  }

  Widget _placeholder() {
    return Container(
      width: size,
      height: size,
      decoration: BoxDecoration(
        color: const Color(0xFFE8F5F5),
        borderRadius: BorderRadius.circular(4),
        border: Border.all(color: const Color(0xFFBFEFEF)),
      ),
      child: Icon(
        Icons.business,
        size: size * 0.6,
        color: const Color(0xFF00999E),
      ),
    );
  }
}