import 'package:InvenTree/api.dart';
import 'package:InvenTree/inventree/stock.dart';
import 'package:InvenTree/widget/drawer.dart';
import 'package:InvenTree/widget/stock_display.dart';
import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';
import 'package:flutter/foundation.dart';
import 'package:font_awesome_flutter/font_awesome_flutter.dart';

class LocationDisplayWidget extends StatefulWidget {

  LocationDisplayWidget(this.location, {Key key}) : super(key: key);

  final InvenTreeStockLocation location;

  final String title = "Location";

  @override
  _LocationDisplayState createState() => _LocationDisplayState(location);
}


class _LocationDisplayState extends State<LocationDisplayWidget> {

  _LocationDisplayState(this.location) {
    _requestData();
  }

  final InvenTreeStockLocation location;

  List<InvenTreeStockLocation> _sublocations = List<InvenTreeStockLocation>();

  String _locationFilter = '';

  List<InvenTreeStockLocation> get sublocations {
    
    if (_locationFilter.isEmpty || _sublocations.isEmpty) {
      return _sublocations;
    } else {
      return _sublocations.where((loc) => loc.filter(_locationFilter)).toList();
    }
  }

  List<InvenTreeStockItem> _items = List<InvenTreeStockItem>();

  String get _title {

    if (location == null) {
      return "Stock Locations";
    } else {
      return "Stock Location - ${location.name}";
    }
  }

  /*
   * Request data from the server.
   * It will be displayed once loaded
   *
   * - List of sublocations under this one
   * - List of stock items at this location
   */
  void _requestData() {

    int pk = location?.pk ?? -1;

    // Request a list of sub-locations under this one
    InvenTreeStockLocation().list(filters: {"parent": "$pk"}).then((var locs) {
      _sublocations.clear();

      for (var loc in locs) {
        if (loc is InvenTreeStockLocation) {
          _sublocations.add(loc);
        }
      }

      setState(() {});

    // Request a list of stock-items under this one
    InvenTreeStockItem().list(filters: {"location": "$pk"}).then((var items) {
      _items.clear();

      for (var item in items) {
        if (item is InvenTreeStockItem) {
          _items.add(item);
        }
      }

      setState(() {});
    });

    });
  }

  bool _locationListExpanded = false;
  bool _stockListExpanded = true;

  Widget locationDescriptionCard() {
    if (location == null) {
      return Card(
        child: ListTile(
          title: Text("Stock Locations"),
          subtitle: Text("Top level stock location")
        )
      );
    } else {
      return Card(
        child: Column(
          children: <Widget> [
            ListTile(
              title: Text("${location.name}"),
              subtitle: Text("${location.description}"),
              trailing: IconButton(
                icon: FaIcon(FontAwesomeIcons.edit),
                onPressed: null,
              ),
            ),
            ListTile(
              title: Text("Parent Category"),
              subtitle: Text("${location.parentpathstring}"),
              onTap: () {
                if (location.parentId < 0) {
                  Navigator.push(context, MaterialPageRoute(builder: (context) => LocationDisplayWidget(null)));
                } else {
                  InvenTreeStockLocation().get(location.parentId).then((var loc) {
                    if (loc is InvenTreeStockLocation) {
                      Navigator.push(context, MaterialPageRoute(builder: (context) => LocationDisplayWidget(loc)));
                    }
                  });
                }
              },
            )
          ]
        )
      );
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(_title),
      ),
      drawer: new InvenTreeDrawer(context),
      body: ListView(
        children: <Widget> [
          locationDescriptionCard(),
          ExpansionPanelList(
            expansionCallback: (int index, bool isExpanded) {
              setState(() {
                switch (index) {
                  case 0:
                    _locationListExpanded = !isExpanded;
                    break;
                  case 1:
                    _stockListExpanded = !isExpanded;
                    break;
                  default:
                    break;
                }
              });

            },
            children: <ExpansionPanel> [
              ExpansionPanel(
                headerBuilder: (BuildContext context, bool isExpanded) {
                  return ListTile(
                    title: Text("Sublocations"),
                    leading: FaIcon(FontAwesomeIcons.mapMarkerAlt),
                    trailing: Text("${_sublocations.length}"),
                    onTap: () {
                      setState(() {
                        _locationListExpanded = !_locationListExpanded;
                      });
                    },
                  );
                },
                body: SublocationList(_sublocations),
                isExpanded: _locationListExpanded,
              ),
              ExpansionPanel(
                headerBuilder: (BuildContext context, bool isExpanded) {
                  return ListTile(
                    title: Text("Stock Items"),
                    leading: FaIcon(FontAwesomeIcons.boxes),
                    trailing: Text("${_items.length}"),
                    onTap: () {
                      setState(() {
                        _stockListExpanded = !_stockListExpanded;
                      });
                    },
                  );
                },
                body: StockList(_items),
                isExpanded: _stockListExpanded,
              )
            ]
          ),
        ]
      )
    );
  }
}


class SublocationList extends StatelessWidget {
  final List<InvenTreeStockLocation> _locations;

  SublocationList(this._locations);

  void _openLocation(BuildContext context, int pk) {

    InvenTreeStockLocation().get(pk).then((var loc) {
      if (loc is InvenTreeStockLocation) {

        Navigator.push(context, MaterialPageRoute(builder: (context) => LocationDisplayWidget(loc)));
      }
    });
  }

  Widget _build(BuildContext context, int index) {
    InvenTreeStockLocation loc = _locations[index];

    return ListTile(
      title: Text('${loc.name}'),
      subtitle: Text("${loc.description}"),
      trailing: Text("${loc.itemcount}"),
      onTap: () {
        _openLocation(context, loc.pk);
      },
    );
  }

  @override
  Widget build(BuildContext context) {
    return ListView.builder(
        shrinkWrap: true,
        physics: ClampingScrollPhysics(),
        itemBuilder: _build, itemCount: _locations.length);
  }
}

class StockList extends StatelessWidget {
  final List<InvenTreeStockItem> _items;

  StockList(this._items);

  void _openItem(BuildContext context, int pk) {
    InvenTreeStockItem().get(pk).then((var item) {
      if (item is InvenTreeStockItem) {
        Navigator.push(context, MaterialPageRoute(builder: (context) => StockItemDisplayWidget(item)));
      }
    });
  }

  Widget _build(BuildContext context, int index) {
    InvenTreeStockItem item = _items[index];

    return ListTile(
      title: Text("${item.partName}"),
      subtitle: Text("${item.partDescription}"),
      leading: Image(
        image: InvenTreeAPI().getImage(item.partThumbnail),
        width: 48,
      ),
      trailing: Text("${item.displayQuantity}",
        style: TextStyle(fontWeight: FontWeight.bold),
      ),
      onTap: () {
        _openItem(context, item.pk);
      },
    );
  }

  @override
  Widget build(BuildContext context) {
    return ListView.builder(
        shrinkWrap: true,
        physics: ClampingScrollPhysics(),
        itemBuilder: _build, itemCount: _items.length);
  }
}