study-lib-backend/API/Controllers/GroupCandidatesController.cs

using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;
using Microsoft.EntityFrameworkCore;
using StudyLib.API.Data;
using StudyLib.API.Models;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;

namespace StudyLib.API.Controllers
{
    [Route("api/groupCandidates")]
    [Authorize]
    [ApiController]
    public class GroupCandidatesController : ControllerBase
    {
        private readonly StudyLibContext _context;

        public GroupCandidatesController(StudyLibContext context)
        {
            _context = context;
        }

        [HttpGet("list/{groupId}")]
        public async Task<ActionResult<IEnumerable<User>>> GetGroupCandidates(long groupId)
        {
            return await _context.GroupCandidates.Where(g => g.Group.ID == groupId).Include(g => g.User).Select(g => g.User).ToListAsync();
        }

        [HttpPost("join-request")]
        public async Task<IActionResult> GroupCandidate(GroupCandidateSaveModel groupCandidateSaveModel)
        {
            var user = await _context.Users.FindAsync(groupCandidateSaveModel.UserId);
            var group = await _context.Groups.FindAsync(groupCandidateSaveModel.GroupId);
            var groupCandidate = new GroupCandidate
            {
                GroupId = groupCandidateSaveModel.GroupId,
                Group = group,
                UserId = groupCandidateSaveModel.UserId,
                User = user
            };
            _context.GroupCandidates.Add(groupCandidate);
            await _context.SaveChangesAsync();

            return NoContent();
        }

        [HttpDelete("delete/{groupId}/{userId}")]
        public async Task<IActionResult> DeleteGroupCandidate(long groupId, string userId)
        {
            var groupCandidate = await _context.GroupCandidates.Where(g => g.Group.ID == groupId && g.User.Id == userId).FirstAsync();
            if (groupCandidate == null)
            {
                return NotFound();
            }

            _context.GroupCandidates.Remove(groupCandidate);
            await _context.SaveChangesAsync();

            return NoContent();
        }

        private bool GroupCandidateExists(long groupId, string userId)
        {
            return _context.GroupCandidates.Any(g => g.Group.ID == groupId && g.User.Id == userId);
        }
    }

}