@page "/calendar"
@page "/calendar/{YearMonth}"
@attribute [Authorize]
@rendermode InteractiveServer

@inject IWorkDayService WorkDayService
@inject IItalianFestivitySource FestivitySource
@inject NavigationManager Navigation

<PageTitle>Calendar</PageTitle>

<h1>Calendar</h1>

<div class="d-flex align-items-center gap-2 mb-3">
    <button class="btn btn-outline-secondary btn-sm" @onclick="PreviousMonth">&laquo; Prev</button>
    <h2 class="h5 mb-0">@firstOfMonth.ToString("MMMM yyyy")</h2>
    <button class="btn btn-outline-secondary btn-sm" @onclick="NextMonth">Next &raquo;</button>
</div>

@if (loading)
{
    <p><em>Loading...</em></p>
}
else
{
    <div class="table-responsive">
        <table class="table table-bordered calendar-table">
            <thead class="table-dark">
                <tr>
                    <th>Mon</th>
                    <th>Tue</th>
                    <th>Wed</th>
                    <th>Thu</th>
                    <th>Fri</th>
                    <th>Sat</th>
                    <th>Sun</th>
                </tr>
            </thead>
            <tbody>
                @foreach (var week in weeks)
                {
                    <tr>
                        @foreach (var cell in week)
                        {
                            @if (cell is null)
                            {
                                <td class="calendar-cell bg-light"></td>
                            }
                            else
                            {
                                <td class="calendar-cell @GetCellClass(cell)" @onclick="() => NavigateToDay(cell.Date)" role="button">
                                    <div class="calendar-day-number">@cell.Date.Day</div>
                                    @if (cell.Entry is not null)
                                    {
                                        <span class="badge @GetBadgeClass(cell.Entry.DayType)">@cell.Entry.DayType</span>
                                        <div class="calendar-hours">@cell.Entry.WorkedHoursFinal.ToString("N1")h</div>
                                    }
                                </td>
                            }
                        }
                    </tr>
                }
            </tbody>
        </table>
    </div>

    <div class="mt-3">
        <h3 class="h6">Legend</h3>
        <div class="d-flex flex-wrap gap-2">
            <span class="badge bg-primary">Work</span>
            <span class="badge bg-success">Home</span>
            <span class="badge bg-warning text-dark">Closure</span>
            <span class="badge bg-info text-dark">Illness</span>
            <span class="badge bg-secondary">DayOff</span>
            <span class="badge bg-danger">Holiday</span>
        </div>
    </div>
}

@code {
    [Parameter] public string? YearMonth { get; set; }

    private DateOnly firstOfMonth;
    private bool loading = true;
    private List<CalendarCell?[]> weeks = [];
    private IReadOnlyCollection<DateOnly> festivities = [];

    protected override async Task OnInitializedAsync()
    {
        if (!string.IsNullOrEmpty(YearMonth) && DateTime.TryParseExact(YearMonth, "yyyy-MM", null, System.Globalization.DateTimeStyles.None, out var parsed))
        {
            firstOfMonth = new DateOnly(parsed.Year, parsed.Month, 1);
        }
        else
        {
            firstOfMonth = new DateOnly(DateTime.Today.Year, DateTime.Today.Month, 1);
        }

        await LoadMonth();
    }

    private async Task LoadMonth()
    {
        loading = true;
        festivities = FestivitySource.GetFestivities(firstOfMonth.Year);

        var lastDay = firstOfMonth.AddMonths(1).AddDays(-1);
        var entries = await WorkDayService.GetRangeAsync(firstOfMonth, lastDay);
        var lookup = entries.ToDictionary(e => e.Date);

        // Build calendar grid (ISO weeks: Monday = 0)
        weeks = [];
        var currentWeek = new CalendarCell?[7];
        var dayOfWeek = ((int)firstOfMonth.DayOfWeek + 6) % 7; // Mon=0

        for (var d = firstOfMonth; d <= lastDay; d = d.AddDays(1))
        {
            currentWeek[dayOfWeek] = new CalendarCell
            {
                Date = d,
                IsWeekend = d.DayOfWeek is DayOfWeek.Saturday or DayOfWeek.Sunday,
                IsFestivity = festivities.Contains(d),
                Entry = lookup.GetValueOrDefault(d)
            };

            dayOfWeek++;
            if (dayOfWeek == 7)
            {
                weeks.Add(currentWeek);
                currentWeek = new CalendarCell?[7];
                dayOfWeek = 0;
            }
        }

        if (dayOfWeek > 0)
        {
            weeks.Add(currentWeek);
        }

        loading = false;
    }

    private async Task PreviousMonth()
    {
        firstOfMonth = firstOfMonth.AddMonths(-1);
        await LoadMonth();
    }

    private async Task NextMonth()
    {
        firstOfMonth = firstOfMonth.AddMonths(1);
        await LoadMonth();
    }

    private void NavigateToDay(DateOnly date) =>
        Navigation.NavigateTo($"/workday/{date:yyyy-MM-dd}");

    private string GetCellClass(CalendarCell cell)
    {
        if (cell.IsWeekend || cell.IsFestivity) return "calendar-weekend";
        if (cell.Entry is null) return "";
        return cell.Entry.DayType switch
        {
            DayType.Closure => "calendar-closure",
            DayType.Illness => "calendar-illness",
            DayType.DayOff => "calendar-dayoff",
            DayType.Holiday => "calendar-holiday",
            _ => ""
        };
    }

    private static string GetBadgeClass(DayType type) => type switch
    {
        DayType.Work => "bg-primary",
        DayType.Home => "bg-success",
        DayType.Closure => "bg-warning text-dark",
        DayType.Illness => "bg-info text-dark",
        DayType.DayOff => "bg-secondary",
        DayType.Holiday => "bg-danger",
        _ => "bg-light text-dark"
    };

    private sealed class CalendarCell
    {
        public DateOnly Date { get; set; }
        public bool IsWeekend { get; set; }
        public bool IsFestivity { get; set; }
        public WorkDayDocument? Entry { get; set; }
    }
}