import 'dart:async';
import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import '../../../core/theme/theme_extensions.dart';
import '../../../services/map/map_provider_interface.dart';
import '../../../services/routes/route_provider.dart';
import '../../../services/routes/route_providers.dart';

/// Reusable address and place autocomplete field for MotorSignal.
///
/// Integrates with [RouteProvider] (Stadia Maps / Pelias) to provide:
/// - 350ms debounced search
/// - Sequence-guarded asynchronous responses to prevent stale data
/// - Immediate resolution when coordinates are present in search results
/// - Invalidation of previous resolution upon text modification
/// - Accessible suggestions list with loading, no-results, and error states
class AddressAutocompleteField extends ConsumerStatefulWidget {
  final String labelText;
  final String? hintText;
  final ResolvedPlace? initialPlace;
  final String? initialQuery;
  final ValueChanged<ResolvedPlace?> onPlaceResolved;
  final AppLatLng? nearLocation;
  final String? Function(String?)? validator;
  final bool enabled;
  final bool autofocus;
  final FocusNode? focusNode;
  final TextEditingController? controller;
  final Widget? prefixIcon;
  final bool showAttribution;
  final VoidCallback? onClear;
  final bool isRequired;

  const AddressAutocompleteField({
    super.key,
    required this.labelText,
    this.hintText,
    this.initialPlace,
    this.initialQuery,
    required this.onPlaceResolved,
    this.nearLocation,
    this.validator,
    this.enabled = true,
    this.autofocus = false,
    this.focusNode,
    this.controller,
    this.prefixIcon,
    this.showAttribution = true,
    this.onClear,
    this.isRequired = false,
  });

  @override
  ConsumerState<AddressAutocompleteField> createState() =>
      _AddressAutocompleteFieldState();
}

class _AddressAutocompleteFieldState
    extends ConsumerState<AddressAutocompleteField> {
  late final TextEditingController _controller;
  late final FocusNode _focusNode;
  bool _internalController = false;
  bool _internalFocusNode = false;

  ResolvedPlace? _resolvedPlace;
  List<PlaceSearchResult> _suggestions = const [];
  bool _isLoading = false;
  bool _isResolving = false;
  String? _errorMessage;
  Timer? _debounceTimer;
  int _searchSequence = 0;
  bool _showDropdown = false;
  bool _hasSearched = false;

  String _lastText = '';

  @override
  void initState() {
    super.initState();
    if (widget.controller != null) {
      _controller = widget.controller!;
    } else {
      _controller = TextEditingController(
        text: _displayText(widget.initialPlace) ?? widget.initialQuery ?? '',
      );
      _internalController = true;
    }

    if (widget.focusNode != null) {
      _focusNode = widget.focusNode!;
    } else {
      _focusNode = FocusNode();
      _internalFocusNode = true;
    }

    _resolvedPlace = widget.initialPlace;
    _lastText = _controller.text;

    _focusNode.addListener(_handleFocusChange);
    _controller.addListener(_handleControllerChange);
  }

  void _handleControllerChange() {
    if (_controller.text != _lastText) {
      _lastText = _controller.text;
      _onTextChanged(_controller.text);
    }
  }

  @override
  void didUpdateWidget(covariant AddressAutocompleteField oldWidget) {
    super.didUpdateWidget(oldWidget);
    if (widget.initialPlace != oldWidget.initialPlace) {
      _resolvedPlace = widget.initialPlace;
      final newText = _displayText(widget.initialPlace) ?? '';
      if (_controller.text != newText) {
        WidgetsBinding.instance.addPostFrameCallback((_) {
          if (mounted && _controller.text != newText) {
            _lastText = newText;
            _controller.text = newText;
          }
        });
      }
    }
  }

  String? _displayText(ResolvedPlace? place) {
    final formatted = place?.formattedAddress?.trim();
    return formatted == null || formatted.isEmpty
        ? place?.displayName
        : formatted;
  }

  @override
  void dispose() {
    _debounceTimer?.cancel();
    _controller.removeListener(_handleControllerChange);
    _focusNode.removeListener(_handleFocusChange);
    if (_internalFocusNode) {
      _focusNode.dispose();
    }
    if (_internalController) {
      _controller.dispose();
    }
    super.dispose();
  }

  void _handleFocusChange() {
    if (!_focusNode.hasFocus) {
      // Delay closing dropdown slightly so tap on suggestion can register
      Future.delayed(const Duration(milliseconds: 200), () {
        if (mounted && !_focusNode.hasFocus) {
          setState(() {
            _showDropdown = false;
          });
        }
      });
    }
  }

  void _onTextChanged(String text) {
    // If the text was previously resolved, modifying text invalidates the resolution
    if (_resolvedPlace != null) {
      _resolvedPlace = null;
      widget.onPlaceResolved(null);
    }

    _debounceTimer?.cancel();

    final trimmed = text.trim();
    if (trimmed.length < 2) {
      setState(() {
        _suggestions = const [];
        _isLoading = false;
        _showDropdown = false;
        _errorMessage = null;
        _hasSearched = false;
      });
      return;
    }

    _debounceTimer = Timer(const Duration(milliseconds: 350), () {
      _performSearch(trimmed);
    });
  }

  Future<void> _performSearch(String query) async {
    final seq = ++_searchSequence;
    setState(() {
      _isLoading = true;
      _errorMessage = null;
      _hasSearched = true;
      _showDropdown = true;
    });

    try {
      final provider = ref.read(activeRouteCalculationProvider);
      final results = await provider.searchPlaces(
        query,
        nearLocation: widget.nearLocation,
      );

      if (!mounted || seq != _searchSequence) return;

      setState(() {
        _suggestions = results;
        _isLoading = false;
      });
    } catch (e) {
      if (!mounted || seq != _searchSequence) return;

      final msg = e is RouteProviderException
          ? e.message
          : e
                .toString()
                .replaceAll('RouteProviderException: ', '')
                .replaceAll('Exception: ', '');

      final userMessage = msg.contains('STADIA_API_KEY')
          ? 'Address search is unavailable. The routing server needs a Stadia Maps API key.'
          : msg;

      setState(() {
        _isLoading = false;
        _errorMessage = userMessage.isNotEmpty
            ? userMessage
            : 'Unable to search addresses.';
      });
    }
  }

  Future<void> _selectSuggestion(PlaceSearchResult suggestion) async {
    // If coordinates are already present in search result, resolve immediately without secondary call
    if (suggestion.hasCoordinates) {
      final place = suggestion.toResolvedPlace()!;
      _applyResolvedPlace(place);
      return;
    }

    // Fallback: resolve via provider
    setState(() {
      _isResolving = true;
      _errorMessage = null;
    });

    try {
      final provider = ref.read(activeRouteCalculationProvider);
      final place = await provider.resolvePlace(suggestion.providerId);
      if (!mounted) return;
      _applyResolvedPlace(place);
    } catch (e) {
      if (!mounted) return;
      setState(() {
        _isResolving = false;
        _errorMessage = 'Failed to resolve location coordinates.';
      });
    }
  }

  void _applyResolvedPlace(ResolvedPlace place) {
    _resolvedPlace = place;
    final displayText = _displayText(place) ?? place.displayName;
    _lastText = displayText;
    _controller.text = displayText;
    setState(() {
      _isResolving = false;
      _suggestions = const [];
      _showDropdown = false;
      _errorMessage = null;
    });
    _focusNode.unfocus();
    widget.onPlaceResolved(place);
  }

  void _clear() {
    _lastText = '';
    _controller.clear();
    _resolvedPlace = null;
    _suggestions = const [];
    _showDropdown = false;
    _errorMessage = null;
    _hasSearched = false;
    setState(() {});
    widget.onPlaceResolved(null);
    widget.onClear?.call();
  }

  @override
  Widget build(BuildContext context) {
    final colors = context.motorColors;
    final theme = Theme.of(context);
    final onSurface = theme.colorScheme.onSurface;
    final onSurfaceVariant = theme.colorScheme.onSurfaceVariant;
    final isResolved = _resolvedPlace != null;

    return Column(
      mainAxisSize: MainAxisSize.min,
      crossAxisAlignment: CrossAxisAlignment.stretch,
      children: [
        TextFormField(
          controller: _controller,
          focusNode: _focusNode,
          enabled: widget.enabled && !_isResolving,
          autofocus: widget.autofocus,
          scrollPadding: const EdgeInsets.only(bottom: 120, top: 24),
          style: TextStyle(color: onSurface, fontSize: 14),
          onChanged: _onTextChanged,
          validator: (val) {
            if (widget.isRequired && (val == null || val.trim().isEmpty)) {
              return 'This location is required';
            }
            if (widget.isRequired && _resolvedPlace == null) {
              return 'Please select a valid address from the suggestions';
            }
            if (widget.validator != null) {
              return widget.validator!(val);
            }
            return null;
          },
          decoration: InputDecoration(
            labelText: widget.labelText,
            hintText: widget.hintText ?? 'Type address or place name...',
            labelStyle: TextStyle(
              color: isResolved ? colors.launchGreen : onSurfaceVariant,
              fontSize: 13,
            ),
            hintStyle: TextStyle(color: onSurfaceVariant.withValues(alpha: 0.5), fontSize: 13),
            filled: true,
            fillColor: colors.surfaceContainerHigh,
            prefixIcon:
                widget.prefixIcon ??
                (isResolved
                    ? Icon(
                        Icons.check_circle,
                        color: colors.launchGreen,
                        size: 20,
                      )
                    : Icon(Icons.search, color: colors.cyberCyan, size: 20)),
            suffixIcon: _isResolving
                ? Padding(
                    padding: const EdgeInsets.all(12),
                    child: SizedBox(
                      width: 16,
                      height: 16,
                      child: CircularProgressIndicator(
                        strokeWidth: 2,
                        color: colors.cyberCyan,
                      ),
                    ),
                  )
                : _controller.text.isNotEmpty
                ? IconButton(
                    icon: Icon(
                      Icons.clear,
                      size: 18,
                      color: onSurfaceVariant,
                    ),
                    onPressed: _clear,
                    tooltip: 'Clear location',
                  )
                : null,
            border: OutlineInputBorder(
              borderRadius: BorderRadius.circular(8),
              borderSide: BorderSide(
                color: isResolved ? colors.launchGreen : colors.outlineVariant,
              ),
            ),
            enabledBorder: OutlineInputBorder(
              borderRadius: BorderRadius.circular(8),
              borderSide: BorderSide(
                color: isResolved
                    ? colors.launchGreen.withValues(alpha: 0.6)
                    : colors.outlineVariant,
              ),
            ),
            focusedBorder: OutlineInputBorder(
              borderRadius: BorderRadius.circular(8),
              borderSide: BorderSide(
                color: isResolved ? colors.launchGreen : colors.cyberCyan,
                width: 1.5,
              ),
            ),
            errorBorder: OutlineInputBorder(
              borderRadius: BorderRadius.circular(8),
              borderSide: BorderSide(color: colors.raceRed),
            ),
          ),
        ),
        if (_showDropdown) ...[
          const SizedBox(height: 4),
          _buildDropdownPanel(colors),
        ],
      ],
    );
  }

  Widget _buildDropdownPanel(MotorSignalThemeColors colors) {
    final theme = Theme.of(context);
    final onSurface = theme.colorScheme.onSurface;
    final onSurfaceVariant = theme.colorScheme.onSurfaceVariant;

    return Material(
      color: colors.surfaceContainerHighest,
      borderRadius: BorderRadius.circular(8),
      elevation: 4,
      child: Container(
        constraints: const BoxConstraints(maxHeight: 200),
        decoration: BoxDecoration(
          borderRadius: BorderRadius.circular(8),
          border: Border.all(color: colors.outlineVariant),
        ),
        child: ClipRRect(
          borderRadius: BorderRadius.circular(8),
          child: SingleChildScrollView(
            child: Column(
              mainAxisSize: MainAxisSize.min,
              crossAxisAlignment: CrossAxisAlignment.stretch,
              children: [
                if (_isLoading)
                  Padding(
                    padding: const EdgeInsets.all(16),
                    child: Row(
                      mainAxisAlignment: MainAxisAlignment.center,
                      children: [
                        SizedBox(
                          width: 16,
                          height: 16,
                          child: CircularProgressIndicator(
                            strokeWidth: 2,
                            color: colors.cyberCyan,
                          ),
                        ),
                        const SizedBox(width: 12),
                        Text(
                          'Searching addresses...',
                          style: TextStyle(color: onSurfaceVariant, fontSize: 12),
                        ),
                      ],
                    ),
                  )
                else if (_errorMessage != null)
                  Padding(
                    padding: const EdgeInsets.all(12),
                    child: Row(
                      children: [
                        Icon(
                          Icons.warning_amber_rounded,
                          color: colors.warningAmber,
                          size: 18,
                        ),
                        const SizedBox(width: 8),
                        Expanded(
                          child: Text(
                            _errorMessage!,
                            style: TextStyle(
                              color: onSurfaceVariant,
                              fontSize: 12,
                            ),
                          ),
                        ),
                        TextButton(
                          onPressed: () =>
                              _performSearch(_controller.text.trim()),
                          child: Text(
                            'RETRY',
                            style: TextStyle(
                              color: colors.cyberCyan,
                              fontSize: 11,
                            ),
                          ),
                        ),
                      ],
                    ),
                  )
                else if (_hasSearched && _suggestions.isEmpty)
                  Padding(
                    padding: const EdgeInsets.all(16),
                    child: Row(
                      mainAxisAlignment: MainAxisAlignment.center,
                      children: [
                        Icon(
                          Icons.location_off,
                          color: onSurfaceVariant.withValues(alpha: 0.5),
                          size: 16,
                        ),
                        const SizedBox(width: 8),
                        Text(
                          'No matching addresses found',
                          style: TextStyle(color: onSurfaceVariant, fontSize: 12),
                        ),
                      ],
                    ),
                  )
                else
                  for (int i = 0; i < _suggestions.length; i++) ...[
                    if (i > 0) Divider(height: 1, color: colors.outlineVariant),
                    ListTile(
                      dense: true,
                      contentPadding: const EdgeInsets.symmetric(
                        horizontal: 12,
                        vertical: 2,
                      ),
                      leading: Icon(
                        Icons.place_outlined,
                        color: colors.cyberCyan,
                        size: 20,
                      ),
                      title: Text(
                        _suggestions[i].primaryText,
                        style: TextStyle(
                          color: onSurface,
                          fontSize: 13,
                          fontWeight: FontWeight.w600,
                        ),
                        maxLines: 1,
                        overflow: TextOverflow.ellipsis,
                      ),
                      subtitle: _suggestions[i].secondaryText.isNotEmpty
                          ? Text(
                              _suggestions[i].secondaryText,
                              style: TextStyle(
                                color: onSurfaceVariant,
                                fontSize: 11,
                              ),
                              maxLines: 1,
                              overflow: TextOverflow.ellipsis,
                            )
                          : null,
                      onTap: () => _selectSuggestion(_suggestions[i]),
                    ),
                  ],
                if (widget.showAttribution)
                  Builder(
                    builder: (context) {
                      const attributionText =
                          'Search powered by Amazon Location Service • © AWS, HERE';
                      return Container(
                        padding: const EdgeInsets.symmetric(
                          horizontal: 10,
                          vertical: 4,
                        ),
                        color: colors.surfaceContainer,
                        child: Text(
                          attributionText,
                          style: TextStyle(
                            color: onSurfaceVariant.withValues(alpha: 0.6),
                            fontSize: 9,
                            letterSpacing: 0.2,
                          ),
                          textAlign: TextAlign.center,
                        ),
                      );
                    },
                  ),
              ],
            ),
          ),
        ),
      ),
    );
  }
}