// =====================================================================================
//  NEW WORKFLOW: Draggable bottom sheet with paginated + searchable + multi-select assets.
//
//  Controlled from `MapTrackingPage` via `showAsDraggableSheet`.
//  This file is fully self-contained (own paging/search/selection state, own API call)
//  so it doesn't touch the existing "Assets on the floor" expansion-tile workflow.
//  To roll back: set `showAsDraggableSheet = false` (or delete this file + its usages).
//
//  Data flow (no duplicate API calls):
//    "View" pressed -> AssetTrackingSheetLauncher creates an [AssetSheetPager] and loads page 1
//                      (bar shows `totalRows`).
//    Bar tapped     -> the SAME pager is handed to the sheet, which renders the cached pages.
//    Scroll         -> pager loads pageNumber + 1, ...
//    Re-open sheet  -> still the same pager: already loaded pages are reused, no new request.
// =====================================================================================

import 'dart:async';
import 'dart:convert';

import 'package:flutter/material.dart';
import 'package:test_sa/controllers/api_routes/api_manager.dart';
import 'package:test_sa/controllers/api_routes/urls.dart';
import 'package:test_sa/new_views/app_style/app_color.dart';
import 'package:test_sa/views/widgets/item_views/info_text_widget.dart';

import 'asset_tracking_item_view.dart';
import 'models/asset_tracking_model.dart';

/// Snapshot of the Site / Building / Floor selection at the time "View" was pressed.
/// [requestId] changes on every "View" press so a fresh pager (page 1) is created.
class AssetSheetQuery {
  final int requestId;
  final int siteId;
  final int buildingId;
  final int? floorId;

  const AssetSheetQuery({required this.requestId, required this.siteId, required this.buildingId, this.floorId});

  /// "Floor" when a floor is selected, otherwise "Building".
  String get scopeLabel => floorId != null ? "Floor" : "Building";
}

// =====================================================================================
//  Pager: single source of truth for paging/search. Shared by the bar and the sheet.
// =====================================================================================

class AssetSheetPager extends ChangeNotifier {
  AssetSheetPager(this.query);

  final AssetSheetQuery query;
  static const int pageSize = 20;

  final List<AssetTrackingModel> assets = [];
  int pageNumber = 0; // last loaded page
  int totalRows = 0; // total for the current search
  int? unfilteredTotal; // total without search (shown on the bar); null until first load
  String search = "";

  bool isLoading = false; // first page
  bool isLoadingMore = false; // next pages
  bool hasLoaded = false;
  String? error;

  int _activeRequest = 0; // discards responses of outdated requests (e.g. fast typing)
  bool _disposed = false;

  bool get hasMore => assets.length < totalRows;

  /// Loads page 1 (optionally with a new [newSearch]) and replaces the current list.
  Future<void> loadFirstPage({String? newSearch}) async {
    if (newSearch != null) search = newSearch.trim();
    final requestId = ++_activeRequest;
    isLoading = true;
    isLoadingMore = false;
    error = null;
    assets.clear();
    pageNumber = 0;
    totalRows = 0;
    _notify();
    await _fetchPage(1, requestId);
  }

  /// Loads `pageNumber + 1` and appends it.
  Future<void> loadNextPage() async {
    if (isLoading || isLoadingMore || !hasMore) return;
    isLoadingMore = true;
    error = null;
    _notify();
    await _fetchPage(pageNumber + 1, _activeRequest);
  }

  Future<void> _fetchPage(int page, int requestId) async {
    final body = <String, dynamic>{
      "campusId": query.siteId,
      "venueIds": [query.buildingId],
      if (query.floorId != null) "floorIds": [query.floorId],
      "pageSize": pageSize,
      "pageNumber": page,
      if (search.isNotEmpty) "searchString": search,
    };

    try {
      final response = await ApiManager.instance.post(URLs.getAssetsFromPenguin, body: body);
      if (_disposed || requestId != _activeRequest) return; // outdated response

      if (response.statusCode >= 200 && response.statusCode < 300) {
        final Map<String, dynamic> jsonData = json.decode(response.body);
        final List list = jsonData["data"] ?? [];
        final pageAssets = list.map((item) => AssetTrackingModel.fromJson(item)).toList();
        assets.addAll(pageAssets);
        pageNumber = page;
        totalRows = (jsonData["totalRows"] as int?) ?? assets.length;
        if (pageAssets.isEmpty) totalRows = assets.length; // safety: stop paging on empty page
        if (search.isEmpty) unfilteredTotal = totalRows;
        hasLoaded = true;
      } else {
        error = "Failed to load assets (${response.statusCode})";
      }
    } catch (_) {
      if (_disposed || requestId != _activeRequest) return;
      error = "Failed to load assets";
    }

    if (_disposed || requestId != _activeRequest) return;
    isLoading = false;
    isLoadingMore = false;
    _notify();
  }

  void _notify() {
    if (!_disposed) notifyListeners();
  }

  @override
  void dispose() {
    _disposed = true;
    super.dispose();
  }
}

// =====================================================================================
//  Draggable sheet
// =====================================================================================

class AssetTrackingDraggableSheet extends StatefulWidget {
  final AssetSheetQuery query;

  /// Shared pager (from [AssetTrackingSheetLauncher]). If null, the sheet creates its own.
  final AssetSheetPager? pager;

  /// Called with the selected assets when the user taps "Show on map" (or clears selection).
  final ValueChanged<List<AssetTrackingModel>> onShowOnMap;

  /// Assets that should appear already checked (e.g. selection from a previous opening).
  final List<AssetTrackingModel> initialSelection;

  /// true  -> hosted inside a modal bottom sheet (see [showAssetTrackingSheet]).
  /// false -> embedded directly in a Stack above the map.
  final bool asModal;

  const AssetTrackingDraggableSheet({
    Key? key,
    required this.query,
    required this.onShowOnMap,
    this.pager,
    this.initialSelection = const [],
    this.asModal = false,
  }) : super(key: key);

  @override
  State<AssetTrackingDraggableSheet> createState() => _AssetTrackingDraggableSheetState();
}

class _AssetTrackingDraggableSheetState extends State<AssetTrackingDraggableSheet> {
  double get _minSize => widget.asModal ? 0.3 : 0.12;

  double get _initialSize => widget.asModal ? 0.6 : 0.35;

  double get _maxSize => widget.asModal ? 0.92 : 0.85;

  final DraggableScrollableController _sheetController = DraggableScrollableController();
  late final TextEditingController _searchController;
  Timer? _debounce;

  late final AssetSheetPager _pager;
  late final bool _ownsPager;

  // Selection (kept across pages & searches, keyed by asset id)
  final Map<int, AssetTrackingModel> _selected = {};

  @override
  void initState() {
    super.initState();
    _ownsPager = widget.pager == null;
    _pager = widget.pager ?? AssetSheetPager(widget.query);
    _pager.addListener(_onPagerChanged);
    _searchController = TextEditingController(text: _pager.search);

    for (final asset in widget.initialSelection) {
      if (asset.id != null) _selected[asset.id!] = asset;
    }

    // Reuse already-loaded data; only call the API if nothing was loaded yet.
    if (!_pager.hasLoaded && !_pager.isLoading) _pager.loadFirstPage();
  }

  @override
  void dispose() {
    _debounce?.cancel();
    _pager.removeListener(_onPagerChanged);
    if (_ownsPager) _pager.dispose();
    _searchController.dispose();
    _sheetController.dispose();
    super.dispose();
  }

  void _onPagerChanged() {
    if (mounted) setState(() {});
  }

  // ---------------------------------------------------------------------------
  // Search
  // ---------------------------------------------------------------------------

  void _applySearch() {
    _debounce?.cancel();
    final text = _searchController.text.trim();
    if (text == _pager.search && _pager.hasLoaded) return; // nothing changed -> no API call
    _pager.loadFirstPage(newSearch: text);
  }

  void _onSearchChanged(String _) {
    _debounce?.cancel();
    _debounce = Timer(const Duration(milliseconds: 500), _applySearch);
    setState(() {}); // refresh clear icon
  }

  // ---------------------------------------------------------------------------
  // Selection
  // ---------------------------------------------------------------------------

  void _toggle(AssetTrackingModel asset) {
    final id = asset.id;
    if (id == null) return;
    setState(() => _selected.containsKey(id) ? _selected.remove(id) : _selected[id] = asset);
  }

  void _clearSelection() {
    setState(_selected.clear);
    widget.onShowOnMap(const []);
  }

  void _showSelectedOnMap() {
    widget.onShowOnMap(_selected.values.toList());
    if (widget.asModal) {
      Navigator.of(context).pop();
      return;
    }
    if (_sheetController.isAttached) {
      _sheetController.animateTo(_minSize, duration: const Duration(milliseconds: 250), curve: Curves.easeOut);
    }
  }

  // ---------------------------------------------------------------------------
  // UI
  // ---------------------------------------------------------------------------

  /// Lets the (non-scrolling) header drag the sheet as well.
  void _onHeaderDrag(DragUpdateDetails details) {
    if (!_sheetController.isAttached) return;
    final height = MediaQuery.of(context).size.height;
    final newSize = (_sheetController.size - details.delta.dy / height).clamp(_minSize, _maxSize);
    _sheetController.jumpTo(newSize);
  }

  @override
  Widget build(BuildContext context) {
    return DraggableScrollableSheet(
      controller: _sheetController,
      minChildSize: _minSize,
      initialChildSize: _initialSize,
      maxChildSize: _maxSize,
      expand: !widget.asModal, // modal: size to the sheet so tapping the barrier closes it
      snap: true,
      snapSizes: [_initialSize],
      builder: (context, scrollController) {
        return Container(
          decoration: BoxDecoration(
            color: AppColor.background(context),
            borderRadius: const BorderRadius.vertical(top: Radius.circular(20)),
            boxShadow: [BoxShadow(color: Colors.black.withValues(alpha: 0.15), blurRadius: 12, offset: const Offset(0, -2))],
          ),
          child: Column(
            children: [
              GestureDetector(
                behavior: HitTestBehavior.opaque,
                onVerticalDragUpdate: _onHeaderDrag,
                child: _buildHeader(context),
              ),
              Expanded(child: _buildList(context, scrollController)),
            ],
          ),
        );
      },
    );
  }

  Widget _buildHeader(BuildContext context) {
    final textColor = AppColor.textColor(context);
    final scope = widget.query.scopeLabel.toLowerCase();
    final title = _pager.isLoading && _pager.assets.isEmpty ? "Loading assets…" : "${_pager.totalRows} Assets found on this $scope";

    return Padding(
      padding: const EdgeInsets.fromLTRB(16, 8, 16, 8),
      child: Column(
        mainAxisSize: MainAxisSize.min,
        crossAxisAlignment: CrossAxisAlignment.stretch,
        children: [
          Center(
            child: Container(
              width: 40,
              height: 5,
              decoration: BoxDecoration(color: AppColor.neutral10, borderRadius: BorderRadius.circular(8)),
            ),
          ),
          const SizedBox(height: 10),
          Text(title, style: TextStyle(fontSize: 16, fontWeight: FontWeight.w600, color: textColor)),
          const SizedBox(height: 10),
          TextField(
            controller: _searchController,
            onChanged: _onSearchChanged,
            textInputAction: TextInputAction.search,
            onSubmitted: (_) => _applySearch(),
            style: TextStyle(color: textColor),
            decoration: InputDecoration(
              isDense: true,
              hintText: "Search By Label or Serial Number",
              prefixIcon: const Icon(Icons.search),
              suffixIcon: _searchController.text.isEmpty
                  ? null
                  : IconButton(
                      icon: const Icon(Icons.close),
                      onPressed: () {
                        _searchController.clear();
                        _applySearch();
                        setState(() {});
                      },
                    ),
              border: OutlineInputBorder(borderRadius: BorderRadius.circular(12)),
            ),
          ),
          if (_selected.isNotEmpty) ...[
            const SizedBox(height: 8),
            Row(
              children: [
                Expanded(
                  child: Text("${_selected.length} selected", style: TextStyle(color: textColor, fontWeight: FontWeight.w500)),
                ),
                TextButton(onPressed: _clearSelection, child: const Text("Clear")),
                const SizedBox(width: 4),
                FilledButton.icon(
                  onPressed: _showSelectedOnMap,
                  icon: const Icon(Icons.location_pin, size: 18),
                  label: const Text("Show on map"),
                ),
              ],
            ),
          ],
        ],
      ),
    );
  }

  Widget _buildList(BuildContext context, ScrollController scrollController) {
    final assets = _pager.assets;

    // Note: the list MUST use [scrollController] so dragging the list also drags the sheet.
    if (_pager.isLoading && assets.isEmpty) {
      return ListView(controller: scrollController, children: const [
        Padding(padding: EdgeInsets.all(24), child: Center(child: CircularProgressIndicator())),
      ]);
    }

    if (assets.isEmpty) {
      return ListView(controller: scrollController, children: [
        Padding(
          padding: const EdgeInsets.all(24),
          child: Column(
            children: [
              Text(_pager.error ?? "No assets found", textAlign: TextAlign.center, style: TextStyle(color: AppColor.textColor(context))),
              if (_pager.error != null) TextButton(onPressed: () => _pager.loadFirstPage(), child: const Text("Retry")),
            ],
          ),
        ),
      ]);
    }

    return NotificationListener<ScrollNotification>(
      onNotification: (info) {
        // Auto-load next page near the bottom (not while showing an error -> user taps retry).
        if (_pager.error == null && info.metrics.pixels >= info.metrics.maxScrollExtent - 200) {
          _pager.loadNextPage();
        }
        return false;
      },
      child: ListView.separated(
        controller: scrollController,
        padding: const EdgeInsets.fromLTRB(16, 4, 16, 24),
        itemCount: assets.length + 1, // +1 footer (loader / retry / end)
        separatorBuilder: (_, __) => const SizedBox(height: 12),
        itemBuilder: (context, index) {
          if (index == assets.length) return _buildFooter(context);
          final asset = assets[index];
          final isSelected = asset.id != null && _selected.containsKey(asset.id);
          return InkWell(
            borderRadius: BorderRadius.circular(12),
            onTap: () => _toggle(asset),
            child: Stack(
              children: [
                AssetTrackingListItemView(asset, false, showViewOnMap: false),
                PositionedDirectional(
                  top: 4,
                  end: 4,
                  child: Checkbox(value: isSelected, onChanged: (_) => _toggle(asset)),
                ),
              ],
            ),
          );
        },
      ),
    );
  }

  Widget _buildFooter(BuildContext context) {
    if (_pager.isLoadingMore) {
      return const Padding(padding: EdgeInsets.all(12), child: Center(child: CircularProgressIndicator()));
    }
    if (_pager.error != null && _pager.hasMore) {
      return Center(child: TextButton(onPressed: _pager.loadNextPage, child: const Text("Retry loading more")));
    }
    if (!_pager.hasMore) {
      return Padding(
        padding: const EdgeInsets.all(8),
        child: Center(child: Text("Showing all ${_pager.assets.length} assets", style: const TextStyle(color: AppColor.neutral20))),
      );
    }
    return const SizedBox(height: 24);
  }
}

// =====================================================================================
//  Bottom bar shown in place of the old "Assets found on this floor" expansion tile.
//  Tapping it opens [AssetTrackingDraggableSheet] as a modal draggable bottom sheet.
// =====================================================================================

/// Opens the paginated assets sheet as a modal draggable bottom sheet.
Future<void> showAssetTrackingSheet(
  BuildContext context, {
  required AssetSheetQuery query,
  required ValueChanged<List<AssetTrackingModel>> onShowOnMap,
  AssetSheetPager? pager,
  List<AssetTrackingModel> initialSelection = const [],
}) {
  return showModalBottomSheet(
    context: context,
    isScrollControlled: true,
    useSafeArea: true,
    backgroundColor: Colors.transparent,
    builder: (_) => AssetTrackingDraggableSheet(
      query: query,
      pager: pager,
      onShowOnMap: onShowOnMap,
      initialSelection: initialSelection,
      asModal: true,
    ),
  );
}

class AssetTrackingSheetLauncher extends StatefulWidget {
  final AssetSheetQuery query;
  final ValueChanged<List<AssetTrackingModel>> onShowOnMap;

  const AssetTrackingSheetLauncher({Key? key, required this.query, required this.onShowOnMap}) : super(key: key);

  @override
  State<AssetTrackingSheetLauncher> createState() => _AssetTrackingSheetLauncherState();
}

class _AssetTrackingSheetLauncherState extends State<AssetTrackingSheetLauncher> {
  late final AssetSheetPager _pager;
  List<AssetTrackingModel> _selection = const [];

  @override
  void initState() {
    super.initState();
    // One pager per "View": page 1 loaded here is reused by the sheet.
    _pager = AssetSheetPager(widget.query)..addListener(_onPagerChanged);
    _pager.loadFirstPage();
  }

  @override
  void dispose() {
    _pager.removeListener(_onPagerChanged);
    _pager.dispose();
    super.dispose();
  }

  void _onPagerChanged() {
    if (mounted) setState(() {});
  }

  void _open() {
    showAssetTrackingSheet(
      context,
      query: widget.query,
      pager: _pager,
      initialSelection: _selection,
      onShowOnMap: (assets) {
        _selection = assets; // remember selection for the next opening
        widget.onShowOnMap(assets);
        if (mounted) setState(() {});
      },
    );
  }

  @override
  Widget build(BuildContext context) {
    final total = _pager.unfilteredTotal; // null until the first (unfiltered) page arrives
    final failed = total == null && _pager.error != null && !_pager.isLoading;
    if (total == 0) return const SizedBox(); // same as old tile: hidden when no assets

    final scope = widget.query.scopeLabel.toLowerCase();
    final label = failed
        ? "Failed to load assets, tap to retry"
        : total == null
            ? "Loading assets…"
            : "$total Assets found on this $scope";

    return SafeArea(
      top: false,
      child: Container(
        margin: const EdgeInsets.all(16),
        decoration: BoxDecoration(
          color: AppColor.tabBarBackground(context),
          border: Border.all(color: AppColor.tabBarBorder(context)),
          borderRadius: BorderRadius.circular(20),
        ),
        child: InkWell(
          borderRadius: BorderRadius.circular(20),
          onTap: failed ? () => _pager.loadFirstPage() : (total == null ? null : _open),
          child: Padding(
            padding: const EdgeInsets.all(16),
            child: Row(
              children: [
                Expanded(child: InfoTextLabelWidget(label: label)),
                if (_selection.isNotEmpty)
                  Padding(
                    padding: const EdgeInsetsDirectional.only(end: 8),
                    child: Text("${_selection.length} pinned", style: const TextStyle(color: AppColor.neutral20, fontSize: 12)),
                  ),
                Icon(failed ? Icons.refresh : Icons.expand_less),
              ],
            ),
          ),
        ),
      ),
    );
  }
}