import 'package:flutter/material.dart';
import 'package:go_router/go_router.dart';
import 'package:intl/intl.dart';

import '../../../utils/definitions/color_pair.dart';
import '../../../utils/logic/preferences_service.dart'; // Correct the path as necessary

class CalendarWidget extends StatefulWidget {
  final DateTime currentDate;

  const CalendarWidget({Key? key, required this.currentDate}) : super(key: key);

  @override
  State<CalendarWidget> createState() => _CalendarWidget();
}

class _CalendarWidget extends State<CalendarWidget> {
  List<DateTime> dateList = []; // Initialized immediately as an empty list
  Map<String, DiaryEntry?> diaryEntries = {}; // Holds diary entries by date
  late ColorPair currentColorPair; // Holds the current color pair

  @override
  void initState() {
    super.initState();
    dateList = _generateDateList(widget.currentDate); // Ensured initialization
    _loadColorPairAndDiaryData();
  }

  void _loadColorPairAndDiaryData() async {
    // Load color pair
    currentColorPair = await PreferencesService().loadColorPair();

    // Generate date list
    //dateList = _generateDateList(widget.currentDate);

    // Load diary entries for each date
    for (DateTime date in dateList) {
      DiaryEntry? entry = await PreferencesService().getDiaryEntryByDate(date);
      String key = DateFormat('yyyy-MM-dd').format(date);
      diaryEntries[key] = entry;
    }
    setState(() {}); // Update the state to reflect new data
  }

  List<DateTime> _generateDateList(DateTime date) {
    List<DateTime> list = [];
    DateTime firstOfMonth = DateTime(date.year, date.month, 1);
    int dayOfWeek = firstOfMonth.weekday;

    // Adjust to Monday start
    int startDay = dayOfWeek - 1;
    if (startDay < 0) startDay = 6;

    // Dates from previous month to fill the first row
    for (int i = startDay; i > 0; i--) {
      list.add(firstOfMonth.subtract(Duration(days: i)));
    }

    // Dates of current month up to the current date
    int daysInMonth = DateUtils.getDaysInMonth(date.year, date.month);
    DateTime today = DateTime.now();
    for (int i = 0; i < daysInMonth; i++) {
      DateTime current = DateTime(date.year, date.month, i + 1);
      if (current.isAfter(today)) break; // Stop adding dates after today
      list.add(current);
    }

    // Add dates of the next month to complete the week, if necessary
    DateTime firstOfNextMonth = DateTime(date.year, date.month + 1, 1);
    while (list.length % 7 != 0 && !firstOfNextMonth.isAfter(DateTime.now())) {
      list.add(firstOfNextMonth);
      firstOfNextMonth = firstOfNextMonth.add(const Duration(days: 1));
    }

    return list;
  }

  @override
  Widget build(BuildContext context) {
    double addon = dateList.length > 35 ? 50 : 0;
    String monthName = DateFormat("MMMM yyyy").format(widget.currentDate); // For month header

    return FutureBuilder<ColorPair>(
        future: PreferencesService().loadColorPair(),
        builder: (context, snapshot) {
          if (!snapshot.hasData) {
            return const Center(child: CircularProgressIndicator());
          }
          ColorPair colorPair = snapshot.data!;

          return SizedBox(
            height: 360 + addon,
            child: Column(
              crossAxisAlignment: CrossAxisAlignment.start,
              children: [
                Padding(
                  padding: const EdgeInsets.symmetric(vertical: 8.0, horizontal: 30),
                  child: Text(monthName, style: const TextStyle(fontSize: 20, fontWeight: FontWeight.bold)), // Month Header
                ),
                Expanded(
                  child: Padding(
                    padding: const EdgeInsets.fromLTRB(25, 0, 25, 0),
                    child: GridView.builder(
                      physics: const NeverScrollableScrollPhysics(),
                      gridDelegate: const SliverGridDelegateWithFixedCrossAxisCount(
                        crossAxisCount: 7,
                      ),
                      itemBuilder: (context, index) {
                        DateTime date = dateList[index];
                        bool isCurrentMonth = date.month == widget.currentDate.month;
                        double opacity = isCurrentMonth ? 1.0 : 0.15;

                        // Fetching diary entry percentage value
                        DiaryEntry? entry = diaryEntries[DateFormat('yyyy-MM-dd').format(date)];
                        double fillPercentage = entry != null ? entry.percentValue / 100.0 : 0.0;

                        return Center(
                          child: GestureDetector(
                            onTap: () {
                              DiaryEntry? entry = diaryEntries[DateFormat('yyyy-MM-dd').format(date)];
                              if (entry != null) {
                                context.go('/entry', extra: date);
                              } else {
                                ScaffoldMessenger.of(context).showSnackBar(
                                  const SnackBar(
                                    content: Text("no entry there :("),
                                    duration: Duration(seconds: 2),
                                  ),
                                );
                              }
                            },
                            child: Container(
                              width: 50,
                              height: 50,
                              decoration: BoxDecoration(
                                shape: BoxShape.circle,
                                border: Border.all(color: Colors.black, width: 1),
                                color: DateTime.now().day == date.day && DateTime.now().month == date.month && DateTime.now().year == date.year
                                    ? Colors.transparent // Setting background color for current day
                                    : isCurrentMonth
                                        ? Colors.transparent
                                        : Colors.grey.withOpacity(opacity),
                              ),
                              child: Stack(
                                alignment: Alignment.center,
                                children: [
                                  CircleWidget(
                                      radius: 25 * fillPercentage, color: fillPercentage > 0 ? colorPair.backgroundColor : Colors.teal.withOpacity(opacity)),
                                  Text(
                                    DateTime.now().day == date.day && DateTime.now().month == date.month && DateTime.now().year == date.year
                                        ? "today"
                                        : DateFormat("d").format(date),
                                    style: const TextStyle(color: Colors.black, fontSize: 16),
                                  ),
                                ],
                              ),
                            ),
                          ),
                        );
                      },
                      itemCount: dateList.length,
                    ),
                  ),
                ),
              ],
            ),
          );
        });
  }
}

class CircleWidget extends StatelessWidget {
  final double radius;
  final Color color;

  const CircleWidget({Key? key, required this.radius, required this.color}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return Container(
      width: radius * 2,
      height: radius * 2,
      decoration: BoxDecoration(
        shape: BoxShape.circle,
        color: color,
      ),
    );
  }
}