add endpoint Matriculate

Tsi1.Api/Tsi1.Api/Controllers/CourseController.cs

@@ -57,5 +57,21 @@ namespace Tsi1.Api.Controllers
 
             return Ok();
         }
+
+
+        [Authorize(Roles = UserTypes.Student)]
+        [HttpPost("Matriculate/{courseId}")]
+        public async Task<IActionResult> Matriculate(int courseId)
+        {
+            var userId = int.Parse(HttpContext.User.Claims.FirstOrDefault(x => x.Type == "Id").Value);
+
+            var result = await _courseService.Matriculate(userId, courseId);
+            if (result.HasError)
+            {
+                return BadRequest(result.Message);
+            }
+
+            return Ok();
+        }
     }
 }

Tsi1.Api/Tsi1.BusinessLayer/Interfaces/ICourseService.cs

@@ -13,5 +13,7 @@ namespace Tsi1.BusinessLayer.Interfaces
         Task<ServiceResult<List<CoursePreviewDto>>> GetCoursePreviews(string userType, int tenantId);
 
         Task<ServiceResult<Course>> Create(CourseCreateDto newCourse);
+
+        Task<ServiceResult<bool>> Matriculate(int userId, int courseId);
     }
 }

Tsi1.Api/Tsi1.BusinessLayer/Services/CourseService.cs

 using AutoMapper;
 using Microsoft.EntityFrameworkCore;
+using Microsoft.Extensions.FileProviders;
 using System;
 using System.Collections.Generic;
 using System.Linq;
@@ -32,8 +33,17 @@ namespace Tsi1.BusinessLayer.Services
             var course = _mapper.Map<Course>(newCourse);
                 
             _context.Courses.Add(course);
-            await _context.SaveChangesAsync();
-
+            try
+            {
+                await _context.SaveChangesAsync();
+            }
+            catch (DbUpdateException)
+            {
+                result.HasError = true;
+                result.Message = string.Format(ErrorMessages.DuplicateCourseName, newCourse.Name);
+                return result;
+            }
+            
             result.Data = course;
             return result;
         }
@@ -65,5 +75,42 @@ namespace Tsi1.BusinessLayer.Services
 
             return result;
         }
+
+        public async Task<ServiceResult<bool>> Matriculate(int userId, int courseId)
+        {
+            var result = new ServiceResult<bool>();
+
+            var user = await _context.Users
+                .Include(x => x.Student)
+                .FirstOrDefaultAsync(x => x.Id == userId);
+
+            if (user == null || user.Student == null)
+            {
+                result.HasError = true;
+                result.Message = string.Format(ErrorMessages.UserDoesNotExist, userId);
+                return result;
+            }
+
+            var course = await _context.Courses.FirstOrDefaultAsync(x => x.Id == courseId);
+
+            if (course == null)
+            {
+                result.HasError = true;
+                result.Message = string.Format(ErrorMessages.CourseDoesNotExist, courseId);
+                return result;
+            }
+
+            var studentCourse = new StudentCourse
+            {
+                CourseId = courseId,
+                StudentId = user.Student.Id
+            };
+
+            _context.StudentCourses.Add(studentCourse);
+
+            await _context.SaveChangesAsync();
+
+            return result;
+        }
     }
 }