using System.Globalization;
using Elternbeirat.Contracts;
using Elternbeirat.PocketBase;
using Microsoft.AspNetCore.Components;

namespace Elternbeirat.Web.Features.Events;

public partial class EventList
{
    private static readonly CultureInfo German = CultureInfo.GetCultureInfo("de-DE");

    [LoggerMessage(Level = LogLevel.Warning, Message = "Could not load events from PocketBase.")]
    private static partial void LogLoadFailed(ILogger logger, Exception exception);

    [Inject]
    private PocketBaseClient PocketBase { get; set; } = default!;

    [Inject]
    private ILogger<EventList> Logger { get; set; } = default!;

    private IReadOnlyList<Event> _upcoming = [];
    private IReadOnlyList<Event> _past = [];

    protected override async Task OnInitializedAsync()
    {
        IReadOnlyList<Event> events;
        try
        {
            events = await PocketBase.GetEventsAsync();
        }
        catch (HttpRequestException ex)
        {
            // Source unreachable -> show empty sections instead of a 500. The page
            // stays up; the "keine Termine" note is rendered.
            LogLoadFailed(Logger, ex);
            return;
        }

        // Split into upcoming and past by date, so an event earlier today still
        // counts as upcoming. Upcoming earliest first, past most recent first.
        var today = DateOnly.FromDateTime(DateTime.Today);
        _upcoming = events
            .Where(e => DateOnly.FromDateTime(e.Start) >= today)
            .OrderBy(e => e.Start)
            .ToList();
        _past = events
            .Where(e => DateOnly.FromDateTime(e.Start) < today)
            .OrderByDescending(e => e.Start)
            .ToList();
    }

    // An event counts as all-day when its start carries no wall-clock time
    // (00:00); PocketBase has no separate flag.
    private static bool HasTime(Event ev) => ev.Start.TimeOfDay != TimeSpan.Zero;

    // Formats the entry's date range for display: a single day, a date with a
    // time, or a span across days.
    private static string Format(Event ev)
    {
        var start = HasTime(ev)
            ? ev.Start.ToString("dddd, d. MMMM yyyy, HH:mm", German) + " Uhr"
            : ev.Start.ToString("dddd, d. MMMM yyyy", German);

        if (ev.End is not { } end)
        {
            return start;
        }

        // Same day: append just the end time. Different days: append the full
        // end date.
        if (end.Date == ev.Start.Date)
        {
            return HasTime(ev)
                ? start + "–" + end.ToString("HH:mm", German) + " Uhr"
                : start;
        }

        var endText = HasTime(ev)
            ? end.ToString("d. MMMM yyyy, HH:mm", German) + " Uhr"
            : end.ToString("d. MMMM yyyy", German);
        return start + " – " + endText;
    }
}