import 'package:flutter/material.dart';
import 'package:go_router/go_router.dart';
import 'package:outbag_app/backend/permissions.dart';
import 'package:outbag_app/backend/request.dart';
import 'package:outbag_app/backend/room.dart';
import 'package:outbag_app/backend/user.dart';
import 'package:outbag_app/components/category_chip.dart';
import 'package:outbag_app/components/labeled_divider.dart';
import 'package:outbag_app/components/value_unit_input.dart';
import 'package:outbag_app/tools/fetch_wrapper.dart';
import 'package:provider/provider.dart';
import 'package:flutter_gen/gen_l10n/app_localizations.dart';

class ShoppingListPage extends StatefulWidget {
  final RoomInfo? info;
  final Room? room;

  const ShoppingListPage(this.room, this.info, {super.key});

  @override
  State<StatefulWidget> createState() => _ShoppingListPageState();
}

class _ShoppingListPageState extends State<ShoppingListPage> {
  List<RoomItem> list = [];
  List<RoomItem> cart = [];
  Map<int, int> weights = {};
  Map<int?, RoomCategory> categories = {};
  List<RoomProduct> products = [];

  void fetchItems() {
    final user = context.read<User>();

    // TODO: load cached items first

    doNetworkRequest(ScaffoldMessenger.of(context),
        req: () => postWithCreadentials(
            credentials: user,
            target: user.server,
            path: 'getItems',
            body: {'room': widget.room?.id, 'server': widget.room?.serverTag}),
        onOK: (body) async {
          final resp = body['data']
              .map<RoomItem>((raw) => RoomItem.fromJSON(raw))
              .toList();

          final List<RoomItem> l = [];
          final List<RoomItem> c = [];

          for (RoomItem item in resp) {
            if (item.state == 0) {
              l.add(item);
            } else {
              c.add(item);
            }
          }

          // TODO: cache items

          if (mounted) {
            setState(() {
              list = l;
              cart = c;

              sortAll();
            });
          }
        });
  }

  void sortAll() {
    for (List<RoomItem> input in [list, cart]) {
      setState(() {
        input.sort((a, b) {
          if (a.category == b.category) {
            return 0;
          }
          if (a.category == null) {
            // b should be below
            return -1;
          }
          if (b.category == null) {
            // a should be below
            return 1;
          }

          final weightA = weights[a.category];
          final weightB = weights[b.category];
          // both could be null now,
          // so we have to check agein
          if (weightA == weightB) {
            return 0;
          }
          if (weightA == null) {
            // b should be below
            return -1;
          }
          if (weightB == null) {
            // a should be below
            return 1;
          }

          return weightA.compareTo(weightB);
        });
      });
    }
  }

  void fetchCategories() {
    final user = context.read<User>();

    // TODO: load cached categories first

    doNetworkRequest(ScaffoldMessenger.of(context),
        req: () => postWithCreadentials(
            credentials: user,
            target: user.server,
            path: 'getCategories',
            body: {'room': widget.room?.id, 'server': widget.room?.serverTag}),
        onOK: (body) async {
          final resp = body['data']
              .map<RoomCategory>((raw) => RoomCategory.fromJSON(
                  widget.room?.serverTag ?? "", widget.room?.id ?? "", raw))
              .toList();

          Map<int, int> map = {};
          Map<int?, RoomCategory> cat = {};
          for (int i = 0; i < resp.length; i++) {
            map[resp[i].id] = i;
            cat[resp[i].id] = resp[i];
          }

          if (mounted) {
            setState(() {
              weights = map;
              categories = cat;
              sortAll();
            });
          }
        });
  }

  void fetchProducts() {
    final user = context.read<User>();

    // TODO: load cached products first

    doNetworkRequest(ScaffoldMessenger.of(context),
        req: () => postWithCreadentials(
            credentials: user,
            target: user.server,
            path: 'getProducts',
            body: {'room': widget.room?.id, 'server': widget.room?.serverTag}),
        onOK: (body) async {
          final resp = body['data']
              .map<RoomProduct>((raw) => RoomProduct.fromJSON(raw))
              .toList();

          if (mounted) {
            setState(() {
              products = resp;
            });
          }
        });
  }

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

    WidgetsBinding.instance.addPostFrameCallback((_) {
      fetchItems();
      fetchCategories();
      fetchProducts();
    });
  }

  void changeItemState(RoomItem item) {
    final user = context.read<User>();
    doNetworkRequest(ScaffoldMessenger.of(context),
        req: () => postWithCreadentials(
                credentials: user,
                target: user.server,
                path: 'changeItemState',
                body: {
                  'room': widget.room?.id,
                  'server': widget.room?.serverTag,
                  'listItemID': item.id,
                  'state': item.state
                }));
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Center(
          child: Padding(
              padding: const EdgeInsets.all(14),
              child: ConstrainedBox(
                  constraints: const BoxConstraints(maxWidth: 600),
                  child: ListView(children: [
                    LabeledDivider(AppLocalizations.of(context)!.shoppingList),
                    ListView.builder(
                      shrinkWrap: true,
                      physics: const ClampingScrollPhysics(),
                      itemCount: list.length,
                      itemBuilder: (context, index) {
                        final item = list[index];
                        final cat = categories[item.category] ??
                            RoomCategory.other(widget.room?.serverTag ?? "",
                                widget.room?.id ?? "", context);
                        return ShoppingListItem(
                            name: item.name,
                            server: widget.room!.serverTag,
                            room: widget.room!.id,
                            description: item.description,
                            category: cat,
                            key: Key(item.id.toString()),
                            inCart: item.state != 0,
                            onDismiss: () {
                              // move to cart
                              item.state = 1;

                              setState(() {
                                list.removeAt(index);
                                cart.add(item);
                                sortAll();
                              });

                              // network request
                              // NOTE: for now we do not care if it is successfull,
                              // because the shopping cart is supposed to work even
                              // without network
                              changeItemState(item);
                            },
                            onTap: () {
                              // TODO: show modal bottom sheet
                              // containing
                              // - item info
                              // - option to view linked product (if available)
                              // - edit item (if allowed)
                              // - delete item (if allowed)
                              // - move to/from shopping cart?
                              showModalBottomSheet(
                                  context: context,
                                  builder: (context) => ShoppingListItemInfo(
                                      products: products,
                                      category: cat,
                                      info: widget.info,
                                      item: item,
                                      room: widget.room!.id,
                                      server: widget.room!.serverTag));
                            });
                      },
                    ),
                    LabeledDivider(AppLocalizations.of(context)!.shoppingCart),
                    ListView.builder(
                      itemCount: cart.length,
                      shrinkWrap: true,
                      physics: const ClampingScrollPhysics(),
                      itemBuilder: (context, index) {
                        final item = cart[index];
                        final cat = categories[item.category] ??
                            RoomCategory.other(widget.room!.serverTag,
                                widget.room!.id, context);

                        return ShoppingListItem(
                            server: widget.room!.serverTag,
                            room: widget.room!.id,
                            name: item.name,
                            description: item.description,
                            category: cat,
                            key: Key(item.id.toString()),
                            inCart: item.state != 0,
                            onDismiss: () {
                              // move back to list
                              item.state = 0;
                              setState(() {
                                cart.removeAt(index);
                                list.add(item);
                                sortAll();
                              });

                              // network request
                              // NOTE: for now we do not care if it is successfull,
                              // because the shopping cart is supposed to work even
                              // without network
                              changeItemState(item);
                            },
                            onTap: () {
                              // show modal bottom sheet
                              // containing
                              // - item info
                              // - option to view linked product (if available)
                              // - edit item (if allowed)
                              // - delete item (if allowed)
                              // - move to/from shopping cart?
                              showModalBottomSheet(
                                  context: context,
                                  builder: (context) => ShoppingListItemInfo(
                                      products: products,
                                      category: cat,
                                      item: item,
                                      info: widget.info,
                                      room: widget.room!.id,
                                      server: widget.room!.serverTag));
                            });
                      },
                    )
                  ])))),
      floatingActionButton: (widget.info != null &&
              ((widget.info?.isAdmin ?? false) ||
                  (widget.info?.isOwner ?? false) ||
                  ((widget.info?.permissions)! &
                          RoomPermission.addShoppingListItems !=
                      0)))
          ? FloatingActionButton.extended(
              icon: const Icon(Icons.add),
              label: Text(AppLocalizations.of(context)!.newItemShort),
              tooltip: AppLocalizations.of(context)!.newItemLong,
              onPressed: () {
                // show new category popup
                context.pushNamed('new-item', params: {
                  'server': widget.room!.serverTag,
                  'id': widget.room!.id,
                });
              },
            )
          : null,
    );
  }
}

class ShoppingListItem extends StatelessWidget {
  final String name;
  final RoomCategory category;
  final String description;
  final bool inCart;
  final Key _key;
  final Function()? onDismiss;
  final Function()? onTap;
  final String server;
  final String room;

  const ShoppingListItem(
      {required this.name,
      required this.category,
      required this.inCart,
      required this.description,
      required this.server,
      required this.room,
      required key,
      this.onDismiss,
      this.onTap})
      : _key = key;

  @override
  Widget build(BuildContext context) {
    return Dismissible(
      key: Key('item-$_key'),
      dismissThresholds: const {
        // NOTE: value might need updating
        // maybe we could calculate this using the screen width
        DismissDirection.horizontal: 500.0,
      },
      confirmDismiss: (_) async {
        if (onDismiss != null) {
          onDismiss!();
        }

        // keep item in list
        // NOTE: might want to set this to true/variable
        // if in-shopping-cart items have a second screen
        return true;
      },
      background:
          Icon(!inCart ? Icons.shopping_cart : Icons.remove_shopping_cart),
      child: Opacity(
          opacity: inCart ? 0.5 : 1.0,
          child: ListTile(
            title: Text(name),
            subtitle: Text(description),
            trailing: CategoryChip(
              server: server,
              room: room,
              category: category,
            ),
            onTap: () {
              if (onTap != null) {
                onTap!();
              }
            },
          )),
    );
  }
}

class ShoppingListItemInfo extends StatelessWidget {
  final RoomItem item;
  final String server;
  final String room;
  final RoomInfo? info;
  final RoomCategory category;
  final List<RoomProduct> products;

  const ShoppingListItemInfo(
      {super.key,
      this.info,
      required this.item,
      required this.server,
      required this.room,
      required this.category,
      required this.products});

  @override
  Widget build(BuildContext context) {
    final textTheme = Theme.of(context).textTheme;
    return BottomSheet(
      onClosing: () {},
      builder: (context) => Column(
        children: [
          Padding(
              padding: const EdgeInsets.all(14),
              child: Center(
                  child: Column(children: [
                Text(item.name, style: textTheme.headlineLarge),
                Text(item.description, style: textTheme.titleMedium),
                CategoryChip(
                  server: server,
                  room: room,
                  category: category,
                ),
                Text(Unit.fromId(item.unit).display(context, item.value))
              ]))),
          ...(item.link != null)
              ? [
                  ListTile(
                    title: Text(AppLocalizations.of(context)!
                        .itemShowLinkedProductTitle),
                    subtitle: Text(AppLocalizations.of(context)!
                        .itemShowLinkedProductSubtitle),
                    trailing: const Icon(Icons.chevron_right),
                    onTap: () {
                      // launch "view-product" page for specific product
                      context.pushNamed('view-product', params: {
                        'server': server,
                        'id': room,
                        'product': item.link.toString()
                      });
                    },
                  )
                ]
              : [],
          ...(info != null &&
                  ((info?.isAdmin ?? false) ||
                      (info?.isOwner ?? false) ||
                      ((info?.permissions)! &
                              RoomPermission.addShoppingListItems !=
                          0)))
              ? [
                  ListTile(
                    title: Text(AppLocalizations.of(context)!.editItem),
                    subtitle: Text(AppLocalizations.of(context)!.editItemLong),
                    trailing: const Icon(Icons.chevron_right),
                    onTap: () {
                      context.pushNamed('edit-item', params: {
                        'server': server,
                        'id': room,
                        'item': item.id.toString()
                      });
                    },
                  ),
                  ListTile(
                      title:
                          Text(AppLocalizations.of(context)!.deleteItemTitle),
                      subtitle: Text(
                          AppLocalizations.of(context)!.deleteItemSubtitle),
                      trailing: const Icon(Icons.chevron_right),
                      onTap: () {
                        // show popup
                        showDialog(
                            context: context,
                            builder: (ctx) => AlertDialog(
                                  icon: const Icon(Icons.delete),
                                  title: Text(
                                      AppLocalizations.of(context)!.deleteItem),
                                  content: Text(AppLocalizations.of(context)!
                                      .deleteItemConfirm(item.name)),
                                  actions: [
                                    TextButton(
                                      onPressed: () {
                                        // close popup
                                        Navigator.of(ctx).pop();
                                      },
                                      child: Text(
                                          AppLocalizations.of(context)!.cancel),
                                    ),
                                    FilledButton(
                                      onPressed: () async {
                                        // send request
                                        final scaffMgr =
                                            ScaffoldMessenger.of(ctx);
                                        // popup context
                                        final navInner = Navigator.of(ctx);
                                        // bottomsheet context
                                        final nav = Navigator.of(context);
                                        final user = context.read<User>();

                                        doNetworkRequest(scaffMgr,
                                            req: () => postWithCreadentials(
                                                path: 'deleteItem',
                                                target: user.server,
                                                body: {
                                                  'room': room,
                                                  'server': server,
                                                  'listItemID': item.id
                                                },
                                                credentials: user),
                                            onOK: (_) async {
                                              // TODO: remove cached item
                                            },
                                            after: () {
                                              // close popup
                                              navInner.pop();
                                              // close modal bottom sheet
                                              nav.pop();
                                            });
                                      },
                                      child: Text(AppLocalizations.of(context)!
                                          .deleteItem),
                                    )
                                  ],
                                ));
                      }),
                ]
              : [],
          ListTile(
              title: Text(item.state == 0
                  ? AppLocalizations.of(context)!.moveItemToCartTitle
                  : AppLocalizations.of(context)!.moveItemToCartSubtitle),
              subtitle: Text(item.state == 0
                  ? AppLocalizations.of(context)!.removeItemFromCartTitle
                  : AppLocalizations.of(context)!.removeItemFromCartSubtitle),
              onTap: () {
                // flip state
                item.state = (item.state - 1).abs();
                final user = context.read<User>();
                doNetworkRequest(ScaffoldMessenger.of(context),
                    req: () => postWithCreadentials(
                            credentials: user,
                            target: user.server,
                            path: 'changeItemState',
                            body: {
                              'room': room,
                              'server': server,
                              'listItemID': item.id,
                              'state': item.state
                            }));
              })
        ],
      ),
    );
  }
}