chapter-organizer/WebApp/Services/EventOccurrenceService.cs

using Core.Entities;
using Data;
using Microsoft.EntityFrameworkCore;

namespace WebApp.Services;

public class EventOccurrenceService : IEventOccurrenceService
{
    private readonly AppDbContext _context;

    public EventOccurrenceService(AppDbContext context)
    {
        _context = context;
    }

    public async Task<IEnumerable<EventOccurrence>> GetEventOccurrencesAsync()
    {
        return await _context.EventOccurrences
            .Include(eo => eo.EventDefinition)
            .OrderBy(eo => eo.StartTime)
            .ToListAsync();
    }

    public async Task<IEnumerable<EventOccurrence>> GetEventOccurrencesForDateRangeAsync(DateTime start, DateTime end)
    {
        return await _context.EventOccurrences
            .Include(eo => eo.EventDefinition)
            .Where(eo => eo.StartTime.Date >= start.Date && eo.StartTime.Date <= end.Date)
            .OrderBy(eo => eo.StartTime)
            .ToListAsync();
    }

    public async Task<Dictionary<int, List<Team>>> GetTeamsByEventDefinitionIdsAsync(IEnumerable<int> eventDefinitionIds)
    {
        var ids = eventDefinitionIds.Where(id => id > 0).Distinct().ToList();
        if (!ids.Any())
        {
            return new Dictionary<int, List<Team>>();
        }

        var teams = await _context.Teams
            .Include(t => t.Event)
            .Include(t => t.Students)
            .Include(t => t.Captain)
            .Where(t => t.Event != null && ids.Contains(t.Event.Id))
            .ToListAsync();

        return teams
            .GroupBy(t => t.Event!.Id)
            .ToDictionary(g => g.Key, g => g.ToList());
    }
}