@page "/"
@using BlazorSvgComponents.Models
@using HotMap.Services
@using HotMap.Utils
@inject HeatMapService HeatMapInstance

<PageTitle>Heat Map!</PageTitle>


<div class="w-full">
    <p class="text-2xl">
        Heat map below:
    </p>
    <div>
        <SvgContainer Width="800" Height="400" ViewBox="@GetHeatMapViewBox()">
            <SvgGroup Transform="@(SvgTransform.CreateBuilder().Translate(23, 10).Build())">
                @foreach ((int i, string text) in _monthIndexes)
                {
                    <SvgText Content="@text" Transform="@MonthTextTransform(i)" Class="text-[10px]"/>
                }
            </SvgGroup>
            <SvgGroup Transform="@(SvgTransform.CreateBuilder().Translate(2, 24).Build())">
                @foreach ((string text, int i) in Weekdays.Select((s, i) => (s, i)))
                {
                    <SvgText Content="@text" Transform="@(DayTextTransform(i))" Class="text-[10px]"/>
                }
            </SvgGroup>
            <SvgGroup Transform="@(SvgTransform.CreateBuilder().Translate(25, 15).Build())">
                @foreach ((HeatMapGroupByWeek itemsByItem, int i) in _groupsByWeek.WithIndex())
                {
                    <SvgGroup Transform="@(WeekGridTransform(i))">
                        @foreach ((HeatMapItem item, int j) in itemsByItem.Items.WithIndex())
                        {
                            <Rectangle Width="@Width" Height="@Width" Transform="@(WeekdayGridTransform(j))"
                                       Class="@(GetColorByContribution(item.Contributions))"/>
                        }
                    </SvgGroup>
                }
            </SvgGroup>
        </SvgContainer>
    </div>
</div>

@code {
    private const int Width = 10;
    private const int Spacing = 2;

    private readonly record struct MonthIndex(int Pos, string Month);

    private readonly List<MonthIndex> _monthIndexes = [];
    private readonly List<HeatMapGroupByWeek> _groupsByWeek = [];

    protected override void OnInitialized()
    {
        base.OnInitialized();

        _groupsByWeek.AddRange(HeatMapInstance.GetItemsByWeek());

        // To get the last item, we skip the first item.
        // So index of current item is i + 1, and index of last item is i.
        foreach ((HeatMapGroupByWeek group, int i) in _groupsByWeek.Skip(1).WithIndex())
        {
            if (group.Monday.Month == _groupsByWeek[i].Monday.Month)
            {
                continue;
            }

            // If current week item is not in the same month as the last week item.
            _monthIndexes.Add(new MonthIndex(i + 1, Months[group.Monday.Month - 1]));
        }
    }

    private SvgViewBox GetHeatMapViewBox()
    {
        int width = 25 + Width * _groupsByWeek.Count + Spacing * (_groupsByWeek.Count - 1);
        int height = 15 + Width * 7 + Spacing * 6;

        // Add an extra 10 pixels to make sure nothing is hidden.
        return new SvgViewBox(0, 0, width + 10, height + 10);
    }

    private static readonly List<string> Months =
    [
        "1月", "2月", "3月", "4月", "5月", "6月",
        "7月", "8月", "9月", "10月", "11月", "12月"
    ];

    // private static readonly List<string> Weekdays = ["周一", "周二", "周三", "周四", "周五", "周六", "周日"];
    private static readonly List<string> Weekdays = ["周一", "周三", "周五"];

    private static SvgTransform WeekdayGridTransform(int y)
    {
        return SvgTransform.CreateBuilder().Translate(0, y * (Width + Spacing)).Build();
    }

    private static SvgTransform WeekGridTransform(int x)
    {
        return SvgTransform.CreateBuilder().Translate(x * (Width + Spacing)).Build();
    }

    private static SvgTransform MonthTextTransform(int x)
    {
        return SvgTransform.CreateBuilder().Translate(x * (Width + Spacing)).Build();
    }

    private static SvgTransform DayTextTransform(int y)
    {
        // We only show Monday, Wednesday and Friday, so there are two days between texts.
        return SvgTransform.CreateBuilder().Translate(0, y * 2 * (Width + Spacing)).Build();
    }

    private static string GetColorByContribution(int contribution)
    {
        return contribution switch
        {
            0 => "fill-gray-200",
            1 or 2 => "fill-blue-100",
            3 or 4 => "fill-blue-300",
            5 or 6 => "fill-blue-500",
            7 or 8 => "fill-blue-700",
            _ => "fill-blue-800"
        };
    }

}