@page "/calendar"
@attribute [Authorize]
@using WebApp.Components.Shared.Components
@using WebApp.Models
@using WebApp.Services
@using Heron.MudCalendar
@using Microsoft.Extensions.Logging
@inject IEventOccurrenceService EventOccurrenceService
@inject ILogger<Index> Logger

<PageHeader Title="Event Calendar" Description="View competition schedules and event occurrences" Icon="@AppIcons.EventCalendar">
    <ActionButtons>
        <MudButton StartIcon="@Icons.Material.Filled.ImportExport" Href="calendar/event-occurrences/import" Variant="Variant.Filled" Color="Color.Primary">Import</MudButton>
    </ActionButtons>
</PageHeader>

<MudPaper Elevation="2" Class="pa-3 pa-md-6">
    @if (_calendarItems == null)
    {
        <MudProgressLinear Indeterminate="true" />
        <MudText>Loading calendar events...</MudText>
    }
    else
    {
        <MudCalendar T="CalendarEventItem" 
                     Items="_calendarItems" 
                     View="CalendarView.Day"
                     CurrentDay="@_calendarDate"
                     />
    }
</MudPaper>

@code {
    private List<CalendarEventItem>? _calendarItems;
    private DateTime _calendarDate = DateTime.Today;

    protected override async Task OnInitializedAsync()
    {
        await LoadCalendarEvents();
    }

    private async Task LoadCalendarEvents()
    {
        try
        {
            Logger.LogInformation("Loading calendar events");
            var occurrences = await EventOccurrenceService.GetEventOccurrencesAsync();
            
            if (occurrences == null)
            {
                Logger.LogWarning("Service returned null occurrences");
                _calendarItems = new List<CalendarEventItem>();
                return;
            }

            Logger.LogDebug("Received {Count} occurrences from service", occurrences.Count());
            
            var items = new List<CalendarEventItem>();
            foreach (var occ in occurrences)
            {
                try
                {
                    if (occ == null)
                    {
                        Logger.LogWarning("Null occurrence found, skipping");
                        continue;
                    }
                    
                    if (string.IsNullOrEmpty(occ.Name))
                    {
                        Logger.LogWarning("Occurrence with Id={Id} has null or empty Name", occ.Id);
                    }
                    
                    var calendarItem = new CalendarEventItem(occ, occ.EventDefinition);
                    items.Add(calendarItem);
                }
                catch (Exception ex)
                {
                    Logger.LogError(ex, "Error creating CalendarEventItem for occurrence Id={Id}, Name={Name}", 
                        occ?.Id, occ?.Name);
                    // Continue processing other items
                }
            }
            
            _calendarItems = items;
            Logger.LogInformation("Created {Count} calendar items from {OccurrenceCount} occurrences", 
                _calendarItems.Count, occurrences.Count());

            // Find the next date with events
            _calendarDate = GetNextDateWithEvents();
        }
        catch (Exception ex)
        {
            Logger.LogError(ex, "Error loading calendar events");
            _calendarItems = new List<CalendarEventItem>();
        }
        finally
        {
            StateHasChanged();
        }
    }

    private DateTime GetNextDateWithEvents()
    {
        try
        {
            if (_calendarItems == null || !_calendarItems.Any())
            {
                Logger.LogDebug("No calendar items available, returning today's date");
                return DateTime.Today;
            }

            var today = DateTime.Today;
            var nextEvent = _calendarItems
                .Where(item => 
                {
                    try
                    {
                        return item != null && item.Start.Date >= today;
                    }
                    catch (Exception ex)
                    {
                        Logger.LogWarning(ex, "Error checking item date, skipping item");
                        return false;
                    }
                })
                .OrderBy(item => item.Start)
                .FirstOrDefault();

            if (nextEvent != null)
            {
                return nextEvent.Start.Date;
            }

            // Fallback to first event if no future events
            var firstEvent = _calendarItems
                .Where(item => item != null)
                .OrderBy(item => item.Start)
                .FirstOrDefault();
            
            if (firstEvent != null)
            {
                return firstEvent.Start.Date;
            }

            return DateTime.Today;
        }
        catch (Exception ex)
        {
            Logger.LogError(ex, "Error in GetNextDateWithEvents");
            return DateTime.Today;
        }
    }
}