import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';
import 'package:flutter_bloc/flutter_bloc.dart';
import 'package:intl/intl.dart';
import 'package:logger/logger.dart';
import 'package:paperless_mobile/features/logging/cubit/app_logs_cubit.dart';
import 'package:paperless_mobile/features/logging/models/parsed_log_message.dart';
import 'package:paperless_mobile/core/extensions/dart_extensions.dart';
import 'package:paperless_mobile/core/extensions/flutter_extensions.dart';
import 'package:paperless_mobile/generated/l10n/app_localizations.dart';

class AppLogsPage extends StatefulWidget {
  const AppLogsPage({super.key});

  @override
  State<AppLogsPage> createState() => _AppLogsPageState();
}

class _AppLogsPageState extends State<AppLogsPage> {
  final ScrollController _scrollController = ScrollController();

  bool autoScroll = true;

  @override
  Widget build(BuildContext context) {
    final locale = Localizations.localeOf(context).toString();
    final theme = Theme.of(context);
    return BlocBuilder<AppLogsCubit, AppLogsState>(
      builder: (context, state) {
        final formattedDate = DateFormat.yMMMd(locale).format(state.date);
        return Scaffold(
          bottomNavigationBar: BottomAppBar(
            child: Row(
              mainAxisAlignment: MainAxisAlignment.start,
              children: switch (state) {
                AppLogsStateInitial() => [],
                AppLogsStateLoading() => [],
                AppLogsStateLoaded() => [
                    IconButton(
                      tooltip: S.of(context)!.copyToClipboard,
                      onPressed: () {
                        context
                            .read<AppLogsCubit>()
                            .copyToClipboard(state.date);
                      },
                      icon: const Icon(Icons.copy),
                    ).padded(),
                    IconButton(
                      tooltip: S.of(context)!.saveLogsToFile,
                      onPressed: () {
                        context
                            .read<AppLogsCubit>()
                            .saveLogs(state.date, locale);
                      },
                      icon: const Icon(Icons.download),
                    ).padded(),
                    IconButton(
                      tooltip: S.of(context)!.clearLogs(formattedDate),
                      onPressed: () {
                        context.read<AppLogsCubit>().clearLogs(state.date);
                      },
                      icon: Icon(
                        Icons.delete_sweep,
                        color: Theme.of(context).colorScheme.error,
                      ),
                    ).padded(),
                  ],
                _ => [],
              },
            ),
          ),
          appBar: AppBar(
            title: Text(S.of(context)!.appLogs(formattedDate)),
            actions: [
              if (state is AppLogsStateLoaded)
                IconButton(
                  tooltip: MaterialLocalizations.of(context).datePickerHelpText,
                  onPressed: () async {
                    final selectedDate = await showDatePicker(
                      context: context,
                      initialDate: state.date,
                      firstDate: state.availableLogs.first,
                      lastDate: state.availableLogs.last,
                      selectableDayPredicate: (day) => state.availableLogs
                          .any((date) => day.isOnSameDayAs(date)),
                      initialEntryMode: DatePickerEntryMode.calendarOnly,
                    );
                    if (selectedDate != null) {
                      context.read<AppLogsCubit>().loadLogs(selectedDate);
                    }
                  },
                  icon: const Icon(Icons.calendar_today),
                ).padded(),
            ],
          ),
          body: switch (state) {
            AppLogsStateLoaded(
              logs: var logs,
            ) =>
              Builder(
                builder: (context) {
                  if (state.logs.isEmpty) {
                    return Center(
                      child: Text(S.of(context)!.noLogsFoundOn(formattedDate)),
                    );
                  }
                  return ListView.builder(
                    reverse: true,
                    controller: _scrollController,
                    itemBuilder: (context, index) {
                      if (index == 0) {
                        return Center(
                          child: Text(S.of(context)!.logfileBottomReached,
                              style: theme.textTheme.bodySmall?.copyWith(
                                color: theme.disabledColor,
                              )),
                        ).padded(24);
                      }
                      final messages = state.logs;
                      final logMessage = messages[index - 1];
                      final altColor = CupertinoDynamicColor.withBrightness(
                        color: Colors.grey.shade200,
                        darkColor: Colors.grey.shade800,
                      ).resolveFrom(context);
                      return ParsedLogMessageTile(
                        message: logMessage,
                        backgroundColor: (index % 2 == 0)
                            ? theme.colorScheme.background
                            : altColor,
                      );
                    },
                    itemCount: logs.length + 1,
                  );
                },
              ),
            AppLogsStateError() => Center(
                child:
                    Text(S.of(context)!.couldNotLoadLogfileFrom(formattedDate)),
              ),
            _ => _buildLoadingLogs(state.date)
          },
        );
      },
    );
  }

  Widget _buildLoadingLogs(DateTime date) {
    final formattedDate =
        DateFormat.yMd(Localizations.localeOf(context).toString()).format(date);
    return Center(
      child: Column(
        mainAxisSize: MainAxisSize.min,
        children: [
          const CircularProgressIndicator(),
          Text(S.of(context)!.loadingLogsFrom(formattedDate)),
        ],
      ),
    );
  }
}

class ParsedLogMessageTile extends StatelessWidget {
  final ParsedLogMessage message;
  final Color backgroundColor;

  const ParsedLogMessageTile({
    super.key,
    required this.message,
    required this.backgroundColor,
  });

  @override
  Widget build(BuildContext context) {
    return switch (message) {
      ParsedFormattedLogMessage m => FormattedLogMessageWidget(
          message: m,
          backgroundColor: backgroundColor,
        ),
      UnformattedLogMessage(message: var m) => Text(m),
    };
  }
}

class FormattedLogMessageWidget extends StatelessWidget {
  final ParsedFormattedLogMessage message;
  final Color backgroundColor;
  const FormattedLogMessageWidget(
      {super.key, required this.message, required this.backgroundColor});
  static final _timeFormat = DateFormat("HH:mm:ss.SSS");
  @override
  Widget build(BuildContext context) {
    final c = Theme.of(context).colorScheme;

    final icon = switch (message.level) {
      Level.trace => Icons.troubleshoot,
      Level.debug => Icons.bug_report,
      Level.info => Icons.info_outline,
      Level.warning => Icons.warning,
      Level.error => Icons.error,
      Level.fatal => Icons.error_outline,
      _ => null,
    };
    final color = switch (message.level) {
      Level.trace => c.onBackground.withOpacity(0.75),
      Level.warning => Colors.yellow.shade600,
      Level.error => Colors.red,
      Level.fatal => Colors.red.shade900,
      Level.info => Colors.blue,
      _ => c.onBackground,
    };

    final logStyle = Theme.of(context).textTheme.bodyMedium?.copyWith(
          fontFamily: 'monospace',
          fontSize: 12,
        );
    final formattedMethodName =
        message.methodName != null ? '${message.methodName!.trim()}()' : '';
    final source = switch (message.className) {
      '' || null => formattedMethodName,
      String className => '$className.$formattedMethodName',
    };
    return Material(
      color: backgroundColor,
      child: ExpansionTile(
        leading: Text(
          _timeFormat.format(message.timestamp),
          style: logStyle?.copyWith(color: color),
        ),
        title: Text(
          message.message,
          style: logStyle?.copyWith(color: color),
        ),
        trailing: Icon(
          icon,
          color: color,
        ),
        expandedCrossAxisAlignment: CrossAxisAlignment.start,
        childrenPadding: const EdgeInsets.fromLTRB(16, 8, 16, 8),
        expandedAlignment: Alignment.topLeft,
        children: source.isNotEmpty
            ? [
                Row(
                  children: [
                    const Icon(Icons.arrow_right),
                    Flexible(
                      child: Text(
                        'In $source',
                        style: logStyle?.copyWith(fontSize: 14),
                      ),
                    ),
                  ],
                ),
                ..._buildErrorWidgets(context),
              ]
            : _buildErrorWidgets(context),
      ),
    );
  }

  List<Widget> _buildErrorWidgets(BuildContext context) {
    if (message.error != null) {
      return [
        Divider(),
        Text(
          message.error!.error,
          style: TextStyle(color: Colors.red),
        ).padded(),
        if (message.error?.stackTrace != null) ...[
          Text(
            message.error!.stackTrace!,
            style: Theme.of(context).textTheme.bodySmall?.copyWith(
                  fontFamily: 'monospace',
                  fontSize: 10,
                ),
          ).paddedOnly(left: 8),
        ],
      ];
    } else {
      return [];
    }
  }
}