import 'dart:math';

import 'package:flutter/material.dart';
import 'package:flutter_bloc/flutter_bloc.dart';
import 'package:lightmeter/data/models/exposure_pair.dart';
import 'package:lightmeter/data/models/film.dart';
import 'package:lightmeter/data/models/metering_screen_layout_config.dart';
import 'package:lightmeter/features.dart';
import 'package:lightmeter/platform_config.dart';
import 'package:lightmeter/providers/user_preferences_provider.dart';
import 'package:lightmeter/res/dimens.dart';
import 'package:lightmeter/screens/metering/components/camera_container/bloc_container_camera.dart';
import 'package:lightmeter/screens/metering/components/camera_container/components/camera_controls/widget_camera_controls.dart';
import 'package:lightmeter/screens/metering/components/camera_container/components/camera_controls_placeholder/widget_placeholder_camera_controls.dart';
import 'package:lightmeter/screens/metering/components/camera_container/components/camera_preview/widget_camera_preview.dart';
import 'package:lightmeter/screens/metering/components/camera_container/event_container_camera.dart';
import 'package:lightmeter/screens/metering/components/camera_container/models/camera_error_type.dart';
import 'package:lightmeter/screens/metering/components/camera_container/state_container_camera.dart';
import 'package:lightmeter/screens/metering/components/shared/exposure_pairs_list/widget_list_exposure_pairs.dart';
import 'package:lightmeter/screens/metering/components/shared/metering_top_bar/widget_top_bar_metering.dart';
import 'package:lightmeter/screens/metering/components/shared/readings_container/widget_container_readings.dart';
import 'package:m3_lightmeter_resources/m3_lightmeter_resources.dart';

class CameraContainer extends StatelessWidget {
  final ExposurePair? fastest;
  final ExposurePair? slowest;
  final Film film;
  final IsoValue iso;
  final NdValue nd;
  final ValueChanged<Film> onFilmChanged;
  final ValueChanged<IsoValue> onIsoChanged;
  final ValueChanged<NdValue> onNdChanged;
  final List<ExposurePair> exposurePairs;

  const CameraContainer({
    required this.fastest,
    required this.slowest,
    required this.film,
    required this.iso,
    required this.nd,
    required this.onFilmChanged,
    required this.onIsoChanged,
    required this.onNdChanged,
    required this.exposurePairs,
    super.key,
  });

  @override
  Widget build(BuildContext context) {
    final double meteringContainerHeight = _meteringContainerHeight(context);
    final double cameraPreviewHeight = _cameraPreviewHeight(context);
    final double topBarOverflow = meteringContainerHeight - cameraPreviewHeight;

    return Stack(
      children: [
        Positioned(
          left: 0,
          top: 0,
          right: 0,
          child: MeteringTopBar(
            readingsContainer: ReadingsContainer(
              fastest: fastest,
              slowest: slowest,
              film: film,
              iso: iso,
              nd: nd,
              onFilmChanged: onFilmChanged,
              onIsoChanged: onIsoChanged,
              onNdChanged: onNdChanged,
            ),
            appendixHeight: topBarOverflow,
            preview: const _CameraViewBuilder(),
          ),
        ),
        SafeArea(
          bottom: false,
          child: Column(
            children: [
              SizedBox(
                height: min(meteringContainerHeight, cameraPreviewHeight) + Dimens.paddingM * 2,
              ),
              Expanded(
                child: Padding(
                  padding: const EdgeInsets.symmetric(horizontal: Dimens.paddingM),
                  child: Row(
                    children: [
                      Expanded(
                        child: Padding(
                          padding: EdgeInsets.only(top: topBarOverflow >= 0 ? topBarOverflow : 0),
                          child: ExposurePairsList(exposurePairs),
                        ),
                      ),
                      const SizedBox(width: Dimens.grid8),
                      Expanded(
                        child: Padding(
                          padding: EdgeInsets.only(top: topBarOverflow <= 0 ? -topBarOverflow : 0),
                          child: const _CameraControlsBuilder(),
                        ),
                      ),
                    ],
                  ),
                ),
              ),
            ],
          ),
        )
      ],
    );
  }

  double _meteringContainerHeight(BuildContext context) {
    double enabledFeaturesHeight = 0;
    if (FeaturesConfig.equipmentProfilesEnabled) {
      enabledFeaturesHeight += Dimens.readingContainerSingleValueHeight;
      enabledFeaturesHeight += Dimens.paddingS;
    }
    if (UserPreferencesProvider.meteringScreenFeatureOf(
      context,
      MeteringScreenLayoutFeature.extremeExposurePairs,
    )) {
      enabledFeaturesHeight += Dimens.readingContainerDoubleValueHeight;
      enabledFeaturesHeight += Dimens.paddingS;
    }
    if (UserPreferencesProvider.meteringScreenFeatureOf(
      context,
      MeteringScreenLayoutFeature.filmPicker,
    )) {
      enabledFeaturesHeight += Dimens.readingContainerSingleValueHeight;
      enabledFeaturesHeight += Dimens.paddingS;
    }

    return enabledFeaturesHeight + Dimens.readingContainerSingleValueHeight; // ISO & ND
  }

  double _cameraPreviewHeight(BuildContext context) {
    return ((MediaQuery.of(context).size.width - Dimens.grid8 - 2 * Dimens.paddingM) / 2) /
        PlatformConfig.cameraPreviewAspectRatio;
  }
}

class _CameraViewBuilder extends StatelessWidget {
  const _CameraViewBuilder();

  @override
  Widget build(BuildContext context) {
    return BlocBuilder<CameraContainerBloc, CameraContainerState>(
      buildWhen: (previous, current) => current is! CameraActiveState,
      builder: (context, state) => CameraPreview(
        controller: state is CameraInitializedState ? state.controller : null,
        error: state is CameraErrorState ? state.error : null,
      ),
    );
  }
}

class _CameraControlsBuilder extends StatelessWidget {
  const _CameraControlsBuilder();

  @override
  Widget build(BuildContext context) {
    return Padding(
      padding: const EdgeInsets.symmetric(vertical: Dimens.paddingM),
      child: BlocBuilder<CameraContainerBloc, CameraContainerState>(
        builder: (context, state) {
          late final Widget child;
          if (state is CameraActiveState) {
            child = CameraControls(
              exposureOffsetRange: state.exposureOffsetRange,
              exposureOffsetValue: state.currentExposureOffset,
              onExposureOffsetChanged: (value) {
                context.read<CameraContainerBloc>().add(ExposureOffsetChangedEvent(value));
              },
              zoomRange: state.zoomRange,
              zoomValue: state.currentZoom,
              onZoomChanged: (value) {
                context.read<CameraContainerBloc>().add(ZoomChangedEvent(value));
              },
            );
          } else if (state is CameraErrorState) {
            child = CameraControlsPlaceholder(
              error: state.error,
              onReset: () {
                context.read<CameraContainerBloc>().add(
                      state.error == CameraErrorType.permissionNotGranted
                          ? const OpenAppSettingsEvent()
                          : const InitializeEvent(),
                    );
              },
            );
          } else {
            child = const Column(
              children: [Expanded(child: SizedBox.shrink())],
            );
          }

          return AnimatedSwitcher(
            duration: Dimens.switchDuration,
            child: child,
          );
        },
      ),
    );
  }
}