import 'package:flutter/cupertino.dart';
import 'package:get/get.dart';
import 'package:isekai_wiki/api/mw/list.dart';
import 'package:isekai_wiki/api/mw/mw_api.dart';
import 'package:isekai_wiki/api/response/page_info.dart';
import 'package:isekai_wiki/components/page_card.dart';
import 'package:isekai_wiki/models/favorite_list.dart';
import 'package:isekai_wiki/models/user.dart';
import 'package:isekai_wiki/pages/home.dart';

class RecentPageListController extends GetxController {
  Function? _handleReload;
  ScrollController? scrollController;
  UserController? uc;
  FavoriteListController? flc;

  var shouldRefresh = true;

  var pageList = RxList<PageInfo>();
  var continueInfo = RxMap<String, String>();
  var errorList = RxList<MWError>();

  var hasNextPage = true.obs;
  var isLoading = false.obs;

  RecentPageListController({this.scrollController});

  @override
  void onInit() {
    scrollController?.addListener(() {
      if (scrollController!.position.pixels > scrollController!.position.maxScrollExtent - 10) {
        // 滚动到底部
        if (hasNextPage.value && !isLoading.value) {
          loadNextPages();
        }
      }
    });

    super.onInit();

    uc = Get.find<UserController>();
    flc = Get.find<FavoriteListController>();

    loadNextPages();

    var homeController = Get.find<HomeController>();
    homeController.onRefresh = refreshPages;
  }

  @override
  void dispose() {
    var homeController = Get.find<HomeController>();
    homeController.onRefresh = refreshPages;

    super.dispose();
  }

  Future<void> refreshPages() async {
    continueInfo.clear();
    errorList.clear();
    hasNextPage.value = true;
    shouldRefresh = true;

    await loadNextPages();
  }

  Future<void> loadNextPages() async {
    // 如果没有下一页，则阻止加载
    if (!hasNextPage.value) return;

    isLoading.value = true;

    var rcListRes = await MWApiList.getMixedRecentChanges(
        limit: 10, continueInfo: continueInfo.isNotEmpty ? continueInfo : null);
    if (!rcListRes.ok) {
      // 发生错误，展示错误列表
      errorList.value = rcListRes.errorList ?? [];
      isLoading.value = false;
      hasNextPage.value = false;
      if (shouldRefresh) {
        pageList.clear();
      }
      return;
    }

    var pageIds = rcListRes.data!.map((rcInfo) => rcInfo.pageid).toList();
    var pageListRes = await MWApiList.getPageInfoList(
        pageids: pageIds, extractChars: 515, getInWatchlist: uc!.isLoggedIn);
    if (!pageListRes.ok) {
      // 发生错误，展示错误列表
      errorList.value = pageListRes.errorList ?? [];
      isLoading.value = false;
      hasNextPage.value = false;
      if (shouldRefresh) {
        pageList.clear();
      }
      return;
    }

    if (uc!.isLoggedIn) {
      // 更新收藏列表信息
      flc!.updateFromPageList(pageListRes.data!);
    }

    // 加载完成，设置信息
    if (shouldRefresh) {
      // 初次加载，替换全部数据
      pageList.value = pageListRes.data!;
      shouldRefresh = false;
    } else {
      pageList.addAll(pageListRes.data!);
    }
    hasNextPage.value = rcListRes.continueInfo != null;
    continueInfo.value = rcListRes.continueInfo ?? {};
    isLoading.value = false;
  }

  Future<void> reload() async {
    if (_handleReload != null) {
      await _handleReload!();
    }
  }

  void setReloadHandler(Function? reloadHandler) {
    _handleReload = reloadHandler;
  }
}

class RecentPageList extends StatelessWidget {
  final ScrollController? scrollController;

  const RecentPageList({
    super.key,
    this.scrollController,
  });

  Widget _buildSkeletonList() {
    return Column(
      key: key,
      children: [
        for (var i = 0; i < 6; i++) PageCard(key: ValueKey("rpl-card-$i"), isLoading: true),
      ],
    );
  }

  Widget _buildPageCard(
      int index, PageInfo pageInfo, RecentPageListController c, FavoriteListController fc) {
    return PageCard(
      key: ValueKey("rpl-card-$index"),
      pageInfo: c.pageList[index],
      isFavorite: fc.isFavorite(c.pageList[index]),
      onSetFavorite: fc.setFavorite,
    );
  }

  SliverChildBuilderDelegate _buildPageListDelegate() {
    var c = Get.find<RecentPageListController>();
    var flc = Get.find<FavoriteListController>();

    return SliverChildBuilderDelegate(
      childCount: c.pageList.length + 1,
      (context, index) {
        if (index == 0) {
          // 第一页数据，直接加载
          if (c.pageList.isEmpty) {
            return _buildSkeletonList();
          } else {
            return _buildPageCard(index, c.pageList[index], c, flc);
          }
        }

        // 后续页数据
        if (index < c.pageList.length) {
          return _buildPageCard(index, c.pageList[index], c, flc);
        } else if (index == c.pageList.length) {
          // 显示加载动画
          return Padding(
            padding: const EdgeInsets.symmetric(vertical: 12),
            child: Center(
              child: c.isLoading.value
                  ? const CupertinoActivityIndicator(
                      radius: 14,
                    )
                  : const SizedBox(
                      width: 28,
                      height: 28,
                    ),
            ),
          );
        }

        return null;
      },
    );
  }

  @override
  Widget build(BuildContext context) {
    Get.put(RecentPageListController(scrollController: scrollController));

    return Obx(
      () => SliverList(
        delegate: _buildPageListDelegate(),
      ),
    );
  }
}