shoc-backend/SeaHaven.DataServices/Implementation/UserDataService.cs

using Data.SeaHavenIndustries;
using Microsoft.EntityFrameworkCore;
using SeaHaven.DataServices.Interfaces;

namespace SeaHaven.DataServices.Implementation
{
    public class UserDataService : IUserDataService
    {
        private readonly ApplicationDbContext _context;

        public UserDataService(ApplicationDbContext context)
        {
            _context = context;
        }

        public async Task<ApplicationUser?> GetByIdAsync(string id)
        {
            return await _context.Users.FindAsync(id);
        }

        public async Task<IEnumerable<ApplicationUser>> GetAllAsync()
        {
            return await _context.Users.ToListAsync();
        }

        public async Task<ApplicationUser?> GetByEmailAsync(string email)
        {
            return await _context.Users
                .FirstOrDefaultAsync(u => u.Email == email);
        }

        public async Task<bool> ExistsAsync(string id)
        {
            return await _context.Users.AnyAsync(u => u.Id == id);
        }

        public async Task<IReadOnlyDictionary<string, string>> GetDisplayNamesByIdsAsync(IEnumerable<string> ids)
        {
            var idList = ids
                .Where(id => !string.IsNullOrWhiteSpace(id))
                .Distinct(StringComparer.Ordinal)
                .ToList();

            if (idList.Count == 0)
                return new Dictionary<string, string>(StringComparer.Ordinal);

            var users = await _context.Users
                .AsNoTracking()
                .Where(u => idList.Contains(u.Id))
                .Select(u => new { u.Id, u.FirstName, u.LastName })
                .ToListAsync();

            return users.ToDictionary(
                u => u.Id,
                u => $"{u.FirstName ?? ""} {u.LastName ?? ""}".Trim(),
                StringComparer.Ordinal);
        }
    }
}