// SPDX-FileCopyrightText: 2022 Iconica
//
// SPDX-License-Identifier: BSD-3-Clause

import 'package:flutter/material.dart';
import 'package:flutter_agenda/src/models/agenda_event.dart';
import 'package:flutter_agenda/src/models/agenda_theme.dart';
import 'package:flutter_date_time_picker/flutter_date_time_picker.dart';
import 'package:flutter_timetable/flutter_timetable.dart';

class AgendaWidget extends StatefulWidget {
  /// [AgendaWidget] is a widget that displays a timetable with events.
  /// It is stateful and sorts the events based on the selected date.
  /// All styling can be configured through the [AgendaTheme] class.
  const AgendaWidget({
    required this.blocks,
    this.tableDirection = Axis.vertical,
    this.size,
    this.highlightedDates = const [],
    this.disabledDates = const [],
    this.initialDate,
    this.alwaysUse24HourFormat,
    this.header,
    this.childIfEmptyRoster,
    this.scrollController,
    this.scrollPhysics,
    this.onTapDay,
    this.tableTopPadding = 0,
    this.datePickerExpansion = 0,
    this.startHour = 0,
    this.endHour = 24,
    this.hourDimension = 80,
    this.highlightToday = true,
    this.updateEmptyChildPosition = true,
    this.blockDimension = 50,
    this.blockColor = const Color(0x80FF0000),
    this.theme = const AgendaTheme(),
    super.key,
  });

  /// The [Axis] along which the timetable markings are lined out
  final Axis tableDirection;

  /// Header widget that is displayed above the datepicker.
  final Widget? header;

  /// The Widget displayed instead of the timetable when no events are available
  final Widget? childIfEmptyRoster;

  /// Whether to change the position of the Empty Child Widget
  /// when the datepicker is opened
  final bool updateEmptyChildPosition;

  /// The blocks that are displayed in the agenda
  final List<AgendaEvent> blocks;

  /// The highlighted dates that are displayed in the agenda
  final List<DateTime> highlightedDates;

  /// The disabled dates that are displayed in the agenda
  final List<DateTime> disabledDates;

  /// The date that is initially selected.
  final DateTime? initialDate;

  /// Function called when the user taps on a day in the datepicker.
  final Function(DateTime)? onTapDay;

  /// Whether to highlight the current date in the agenda.
  final bool highlightToday;

  /// Hour at which the timetable starts.
  final int startHour;

  /// Hour at which the timetable ends.
  final int endHour;

  /// The amount of pixels above the timetable
  final double tableTopPadding;

  /// The extra height of the datePicker when it is expanded
  final double datePickerExpansion;

  /// [bool] to set the clock on [TimePickerDialog] to a fixed 24 format.
  /// By default this gets determined by the settings on the user device.
  final bool? alwaysUse24HourFormat;

  /// The dimension in pixels of one hour in the timetable.
  final double hourDimension;

  /// The dimension in pixels of the rosterItem if there is no child
  final double blockDimension;

  /// The color of the agendaItem if there is no child
  final Color blockColor;

  /// The theme used by the agenda.
  /// The [TableTheme] used by the timetable is included.
  final AgendaTheme theme;

  /// The [Size] of the timetable.
  final Size? size;

  /// The scroll controller to control the scrolling of the timetable.
  final ScrollController? scrollController;

  /// The scroll physics used for the SinglechildScrollView.
  final ScrollPhysics? scrollPhysics;

  @override
  State<AgendaWidget> createState() => _AgendaWidgetState();
}

class _AgendaWidgetState extends State<AgendaWidget> {
  late DateTime _selectedDate;
  double _scrollOffset = 0.0;

  @override
  void initState() {
    super.initState();
    _selectedDate = widget.initialDate ?? DateTime.now();
  }

  @override
  Widget build(BuildContext context) {
    var events = _filterEventsOnDay(widget.blocks, _selectedDate);
    return DragDownDateTimePicker(
      alwaysUse24HourFormat: widget.alwaysUse24HourFormat,
      initialDate: _selectedDate,
      pickTime: false,
      highlightToday: widget.highlightToday,
      header: widget.header,
      onTapDay: (selected) {
        widget.onTapDay?.call(selected);
        setState(() {
          _selectedDate = selected;
        });
      },
      onTimerPickerSheetChange: (p0) {
        if (widget.updateEmptyChildPosition) {
          setState(() {
            _scrollOffset = p0 - widget.tableTopPadding;
          });
        }
      },
      disabledDates: widget.disabledDates,
      markedDates: widget.highlightedDates,
      dateTimePickerTheme: widget.theme.timePickerTheme,
      child: Column(
        children: [
          SizedBox(
            height: widget.tableTopPadding,
          ),
          SizedBox(
            height: (widget.size != null)
                ? widget.size!.height - widget.tableTopPadding
                : null,
            width: (widget.size != null) ? widget.size!.width : null,
            child: (widget.childIfEmptyRoster != null && events.isEmpty)
                ? Column(
                    crossAxisAlignment: CrossAxisAlignment.center,
                    children: [
                      // add empty space between the top of the widget
                      //and the child if the datepicker is expanded
                      SizedBox(
                        height: _scrollOffset,
                      ),
                      widget.childIfEmptyRoster!,
                    ],
                  )
                : Timetable(
                    tableDirection: widget.tableDirection,
                    scrollPhysics: widget.scrollPhysics,
                    scrollController: widget.scrollController,
                    blockColor: widget.blockColor,
                    blockDimension: widget.blockDimension,
                    hourDimension: widget.hourDimension,
                    startHour: widget.startHour,
                    endHour: widget.endHour,
                    timeBlocks: events,
                    theme: widget.theme.tableTheme,
                    combineBlocks: true,
                    mergeBlocks: true,
                    size: (widget.size != null)
                        ? Size(
                            widget.size!.width,
                            widget.size!.height - widget.tableTopPadding,
                          )
                        : null,
                  ),
          ),
        ],
      ),
    );
  }

  List<TimeBlock> _filterEventsOnDay(List<AgendaEvent> events, DateTime day) {
    return events
        .where(
          (e) =>
              (e.start.day == day.day &&
                  e.start.month == day.month &&
                  e.start.year == day.year) ||
              (e.end.day == day.day &&
                  e.end.month == day.month &&
                  e.end.year == day.year),
        )
        .map(
          (e) => TimeBlock(
            start: (e.start.day != day.day)
                ? TimeOfDay(hour: widget.startHour, minute: 0)
                : TimeOfDay(
                    hour: e.start.hour,
                    minute: e.start.minute,
                  ),
            end: (e.end.day != day.day)
                ? TimeOfDay(hour: widget.endHour, minute: 0)
                : TimeOfDay(
                    hour: e.end.hour,
                    minute: e.end.minute,
                  ),
            id: e.id ?? 0,
            childDimension: e.childDimension,
            child: e.content,
          ),
        )
        .toList();
  }
}