using System;
using System.Collections.Generic;
using System.Globalization;
using Avalonia;
using Avalonia.Controls;
using Avalonia.Media;
using Avalonia.Threading;
using LanMontainDesktop.Services;

namespace LanMontainDesktop.Views.Components;

public partial class DateWidget : UserControl
{
    private readonly DispatcherTimer _timer = new()
    {
        Interval = TimeSpan.FromMinutes(1)
    };
    private static readonly LunarCalendarService LunarCalendarService = new();

    private static readonly string[] ZhWeekdayHeaders = ["日", "一", "二", "三", "四", "五", "六"];
    private static readonly string[] EnWeekdayHeaders = ["S", "M", "T", "W", "T", "F", "S"];

    private TimeZoneService? _timeZoneService;
    private double _currentCellSize = 64;
    private double _calendarDayFontSize = 14;
    private double _calendarTodayDotSize = 28;

    public DateWidget()
    {
        InitializeComponent();

        _timer.Tick += OnTimerTick;
        AttachedToVisualTree += OnAttachedToVisualTree;
        DetachedFromVisualTree += OnDetachedFromVisualTree;
        SizeChanged += OnSizeChanged;
        UpdateDate();
    }

    public void SetTimeZoneService(TimeZoneService timeZoneService)
    {
        if (_timeZoneService != null)
        {
            _timeZoneService.TimeZoneChanged -= OnTimeZoneChanged;
        }

        _timeZoneService = timeZoneService;
        _timeZoneService.TimeZoneChanged += OnTimeZoneChanged;
        UpdateDate();
    }

    private void OnAttachedToVisualTree(object? sender, VisualTreeAttachmentEventArgs e)
    {
        UpdateDate();
        _timer.Start();
    }

    private void OnDetachedFromVisualTree(object? sender, VisualTreeAttachmentEventArgs e)
    {
        _timer.Stop();
    }

    private void OnSizeChanged(object? sender, SizeChangedEventArgs e)
    {
        ApplyCellSize(_currentCellSize);
    }

    private void OnTimerTick(object? sender, EventArgs e)
    {
        UpdateDate();
    }

    private void OnTimeZoneChanged(object? sender, EventArgs e)
    {
        UpdateDate();
    }

    private void UpdateDate()
    {
        var now = _timeZoneService?.GetCurrentTime() ?? DateTime.Now;
        var culture = CultureInfo.CurrentCulture;
        var isZh = culture.TwoLetterISOLanguageName.Equals("zh", StringComparison.OrdinalIgnoreCase);
        var lunar = LunarCalendarService.GetLunarInfo(now);

        GregorianHeadlineTextBlock.Text = isZh
            ? $"{now.Month}月{now.Day}日 {ToChineseWeekday(now.DayOfWeek)}"
            : now.ToString("MMM d ddd", culture);

        if (isZh)
        {
            LunarDateTextBlock.Text = $"农历 {lunar.LunarDateZh}";
            LunarMetaTextBlock.Text = $"{lunar.GanzhiYearZh}年（{lunar.ZodiacZh}年）";
            YiLabelTextBlock.Text = "宜";
            JiLabelTextBlock.Text = "忌";
            YiItemsTextBlock.Text = "祭祀 祈福 出行 会友";
            JiItemsTextBlock.Text = "动土 诉讼 远航 争执";
        }
        else
        {
            LunarDateTextBlock.Text = $"Lunar {lunar.LunarDateEn}";
            LunarMetaTextBlock.Text = $"Ganzhi year: {lunar.GanzhiYearEn} ({lunar.ZodiacEn})";
            YiLabelTextBlock.Text = "Do";
            JiLabelTextBlock.Text = "Avoid";
            YiItemsTextBlock.Text = "Worship Blessing Travel Meet";
            JiItemsTextBlock.Text = "Groundwork Lawsuit Voyage Dispute";
        }

        UpdateWeekdayHeaders(isZh);
        GenerateCalendar(now);
    }

    private static string ToChineseWeekday(DayOfWeek dayOfWeek)
    {
        return dayOfWeek switch
        {
            DayOfWeek.Sunday => "周日",
            DayOfWeek.Monday => "周一",
            DayOfWeek.Tuesday => "周二",
            DayOfWeek.Wednesday => "周三",
            DayOfWeek.Thursday => "周四",
            DayOfWeek.Friday => "周五",
            _ => "周六"
        };
    }

    private void UpdateWeekdayHeaders(bool isZh)
    {
        var headers = isZh ? ZhWeekdayHeaders : EnWeekdayHeaders;
        WeekdayText0.Text = headers[0];
        WeekdayText1.Text = headers[1];
        WeekdayText2.Text = headers[2];
        WeekdayText3.Text = headers[3];
        WeekdayText4.Text = headers[4];
        WeekdayText5.Text = headers[5];
        WeekdayText6.Text = headers[6];
    }

    private void GenerateCalendar(DateTime currentDate)
    {
        var removeList = new List<Control>();
        foreach (var child in CalendarGrid.Children)
        {
            if (child is Control control && control.Tag is string tag &&
                (tag == "day" || tag == "today-dot"))
            {
                removeList.Add(control);
            }
        }

        foreach (var child in removeList)
        {
            CalendarGrid.Children.Remove(child);
        }

        var year = currentDate.Year;
        var month = currentDate.Month;
        var today = currentDate.Day;

        var firstDayOfMonth = new DateTime(year, month, 1);
        var daysInMonth = DateTime.DaysInMonth(year, month);
        var startDayOfWeek = (int)firstDayOfMonth.DayOfWeek;

        for (var day = 1; day <= daysInMonth; day++)
        {
            var row = (day + startDayOfWeek - 1) / 7;
            var col = (day + startDayOfWeek - 1) % 7;
            if (row > 4)
            {
                continue;
            }

            var dayText = new TextBlock
            {
                Text = day.ToString(CultureInfo.CurrentCulture),
                HorizontalAlignment = Avalonia.Layout.HorizontalAlignment.Center,
                VerticalAlignment = Avalonia.Layout.VerticalAlignment.Center,
                FontSize = _calendarDayFontSize,
                FontWeight = FontWeight.SemiBold,
                Tag = "day"
            };

            if (day == today)
            {
                var accentBrush = this.TryFindResource("AdaptiveAccentBrush", out var accent)
                    ? accent as IBrush
                    : Brushes.Blue;
                var onAccentBrush = this.TryFindResource("AdaptiveOnAccentBrush", out var onAccent)
                    ? onAccent as IBrush
                    : Brushes.White;

                dayText.Foreground = onAccentBrush;
                var dot = new Border
                {
                    Width = _calendarTodayDotSize,
                    Height = _calendarTodayDotSize,
                    CornerRadius = new CornerRadius(_calendarTodayDotSize * 0.5),
                    Background = accentBrush,
                    HorizontalAlignment = Avalonia.Layout.HorizontalAlignment.Center,
                    VerticalAlignment = Avalonia.Layout.VerticalAlignment.Center,
                    Child = dayText,
                    Tag = "today-dot"
                };

                Grid.SetRow(dot, row);
                Grid.SetColumn(dot, col);
                CalendarGrid.Children.Add(dot);
            }
            else
            {
                var isWeekend = col is 0 or 6;
                dayText.Foreground = isWeekend
                    ? GetThemeBrush("AdaptiveTextSecondaryBrush", 0.82)
                    : GetThemeBrush("AdaptiveTextPrimaryBrush", 0.92);
                Grid.SetRow(dayText, row);
                Grid.SetColumn(dayText, col);
                CalendarGrid.Children.Add(dayText);
            }
        }
    }

    public void ApplyCellSize(double cellSize)
    {
        _currentCellSize = Math.Max(1, cellSize);
        var scale = ResolveScale();

        RootBorder.CornerRadius = new CornerRadius(Math.Clamp(28 * scale, 16, 40));
        RootBorder.Padding = new Thickness(Math.Clamp(12 * scale, 8, 18));

        LeftPanelGrid.RowSpacing = Math.Clamp(8 * scale, 5, 14);
        RightPanelGrid.RowSpacing = Math.Clamp(10 * scale, 6, 16);
        LunarCardBorder.CornerRadius = new CornerRadius(Math.Clamp(24 * scale, 14, 34));
        LunarCardBorder.Padding = new Thickness(Math.Clamp(14 * scale, 9, 20));

        GregorianHeadlineTextBlock.FontSize = Math.Clamp(22 * scale, 14, 34);
        WeekdayText0.FontSize = Math.Clamp(13 * scale, 9, 18);
        WeekdayText1.FontSize = WeekdayText0.FontSize;
        WeekdayText2.FontSize = WeekdayText0.FontSize;
        WeekdayText3.FontSize = WeekdayText0.FontSize;
        WeekdayText4.FontSize = WeekdayText0.FontSize;
        WeekdayText5.FontSize = WeekdayText0.FontSize;
        WeekdayText6.FontSize = WeekdayText0.FontSize;

        LunarDateTextBlock.FontSize = Math.Clamp(28 * scale, 17, 44);
        LunarMetaTextBlock.FontSize = Math.Clamp(14 * scale, 10, 22);
        YiLabelTextBlock.FontSize = Math.Clamp(18 * scale, 12, 28);
        JiLabelTextBlock.FontSize = YiLabelTextBlock.FontSize;
        YiItemsTextBlock.FontSize = Math.Clamp(16 * scale, 11, 24);
        JiItemsTextBlock.FontSize = YiItemsTextBlock.FontSize;

        _calendarDayFontSize = Math.Clamp(14 * scale, 9, 22);
        _calendarTodayDotSize = Math.Clamp(28 * scale, 17, 38);

        UpdateDate();
    }

    private double ResolveScale()
    {
        var cellScale = Math.Clamp(_currentCellSize / 48d, 0.72, 1.55);
        var heightScale = Bounds.Height > 1 ? Math.Clamp(Bounds.Height / 220d, 0.65, 1.65) : 1;
        var widthScale = Bounds.Width > 1 ? Math.Clamp(Bounds.Width / 460d, 0.65, 1.65) : 1;
        return Math.Clamp(Math.Min(cellScale, Math.Min(heightScale, widthScale) * 1.08), 0.65, 1.6);
    }

    private IBrush GetThemeBrush(string key, double opacity)
    {
        if (this.TryFindResource(key, out var value) && value is IBrush brush)
        {
            if (brush is ISolidColorBrush solid)
            {
                return new SolidColorBrush(solid.Color, opacity);
            }

            return brush;
        }

        return new SolidColorBrush(Colors.Gray, opacity);
    }
}