part of '../slideshow_viewer.dart';

class _AppBar extends StatelessWidget {
  const _AppBar();

  @override
  Widget build(BuildContext context) {
    return Stack(
      children: [
        Container(
          // + status bar height
          height: kToolbarHeight + MediaQuery.of(context).padding.top,
          decoration: const BoxDecoration(
            gradient: LinearGradient(
              begin: Alignment.topCenter,
              end: Alignment.bottomCenter,
              colors: [
                Color.fromARGB(192, 0, 0, 0),
                Color.fromARGB(0, 0, 0, 0),
              ],
            ),
          ),
        ),
        AppBar(
          backgroundColor: Colors.transparent,
          elevation: 0,
          leading: IconButton(
            icon: const Icon(Icons.close),
            tooltip: MaterialLocalizations.of(context).closeButtonTooltip,
            onPressed: () {
              Navigator.of(context).pop();
            },
          ),
        ),
      ],
    );
  }
}

@npLog
class _Body extends StatelessWidget {
  const _Body();

  @override
  Widget build(BuildContext context) {
    return GestureDetector(
      onTap: () {
        context.addEvent(const _ToggleShowUi());
      },
      child: Stack(
        fit: StackFit.expand,
        children: [
          const ColoredBox(color: Colors.black),
          _BlocSelector<bool>(
            selector: (state) => state.hasInit,
            builder: (context, hasInit) =>
                hasInit ? const _PageViewer() : const SizedBox.shrink(),
          ),
          _BlocSelector<bool>(
            selector: (state) => state.isShowUi,
            builder: (context, isShowUi) => AnimatedVisibility(
              opacity: isShowUi ? 1 : 0,
              duration: k.animationDurationNormal,
              child: const Align(
                alignment: Alignment.topCenter,
                child: _AppBar(),
              ),
            ),
          ),
        ],
      ),
    );
  }
}

class _PageViewer extends StatefulWidget {
  const _PageViewer();

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

class _PageViewerState extends State<_PageViewer> {
  @override
  Widget build(BuildContext context) {
    return MultiBlocListener(
      listeners: [
        _BlocListenerT(
          selector: (state) => state.nextPage,
          listener: (context, state) {
            _controller.nextPage(
              duration: k.animationDurationLong,
              curve: Curves.easeInOut,
            );
          },
        ),
      ],
      child: HorizontalPageViewer(
        pageCount: context.bloc.pageCount,
        pageBuilder: (context, index) {
          return FractionallySizedBox(
            widthFactor: 1 / _viewportFraction,
            child: _PageView.ofPage(context, index),
          );
        },
        initialPage: context.bloc.initialPage,
        controller: _controller,
        viewportFraction: _viewportFraction,
        canSwitchPage: false,
        onPageChanged: (from, to) {
          context.addEvent(_SetCurrentPage(to));
        },
      ),
    );
  }

  final _controller = HorizontalPageViewerController();
}

@npLog
class _PageView extends StatelessWidget {
  const _PageView._({
    required this.page,
    required this.itemIndex,
  });

  factory _PageView.ofPage(BuildContext context, int page) => _PageView._(
        page: page,
        itemIndex: context.bloc.convertPageToFileIndex(page),
      );

  @override
  Widget build(BuildContext context) {
    final file = context.bloc.files[itemIndex];
    if (file_util.isSupportedImageFormat(file)) {
      return _ImagePageView(
        file: file,
        onLoaded: () {
          context.addEvent(_PreloadSidePages(page));
        },
      );
    } else if (file_util.isSupportedVideoFormat(file)) {
      return _VideoPageView(
        file: file,
        onCompleted: () {
          context.addEvent(_VideoCompleted(page));
        },
      );
    } else {
      _log.shout("[build] Unknown file format: ${file.fdMime}");
      return const SizedBox.shrink();
    }
  }

  final int page;
  final int itemIndex;
}

class _ImagePageView extends StatelessWidget {
  const _ImagePageView({
    required this.file,
    this.onLoaded,
  });

  @override
  Widget build(BuildContext context) {
    return RemoteImageViewer(
      account: context.bloc.account,
      file: file,
      canZoom: false,
      onLoaded: onLoaded,
    );
  }

  final FileDescriptor file;
  final VoidCallback? onLoaded;
}

class _VideoPageView extends StatelessWidget {
  const _VideoPageView({
    required this.file,
    this.onCompleted,
  });

  @override
  Widget build(BuildContext context) {
    return VideoViewer(
      account: context.bloc.account,
      file: file,
      onLoadFailure: () {
        // error, next
        Future.delayed(const Duration(seconds: 2), onCompleted);
      },
      onPause: () {
        // video ended
        Future.delayed(const Duration(seconds: 2), onCompleted);
      },
      isControlVisible: false,
      canLoop: false,
    );
  }

  final FileDescriptor file;
  final VoidCallback? onCompleted;
}

const _viewportFraction = 1.05;