using System.Collections.Generic;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
using InternshipSystem.Api.Queries;
using InternshipSystem.Api.Security;
using InternshipSystem.Core;
using InternshipSystem.Repository;
using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.Mvc;
using Microsoft.EntityFrameworkCore;

namespace InternshipSystem.Api.Controllers
{
    [Route("students")]
    [ApiController]
    public class StudentsController : ControllerBase
    {
        private readonly InternshipDbContext _context;

        public StudentsController(InternshipDbContext context)
        {
            _context = context;
        }

        [HttpGet("current")]
        [Authorize]
        public async Task<ActionResult<Student>> GetCurrentStudentData([FromServices] User user, CancellationToken cancellationToken)
        {
            return await _context.Students.FindAsync(user.PersonNumber);
        }
        
        [HttpPut("current")]
        [Authorize]
        public async Task<ActionResult> UpdateCurrentStudentData([FromBody] CurrentStudentForm studentNewData, [FromServices] User user, CancellationToken cancellationToken)
        {
            var currentStudent = await _context.Students.FindAsync(user.PersonNumber);

            currentStudent.AlbumNumber = studentNewData.AlbumNumber ?? currentStudent.AlbumNumber;
            currentStudent.FirstName = string.IsNullOrEmpty(studentNewData.FirstName) ? currentStudent.FirstName : studentNewData.FirstName;
            currentStudent.LastName = string.IsNullOrEmpty(studentNewData.LastName) ? currentStudent.LastName : studentNewData.LastName;
            currentStudent.Email = string.IsNullOrEmpty(studentNewData.Email) ? currentStudent.Email : studentNewData.Email;
            currentStudent.Course = string.IsNullOrEmpty(studentNewData.Course) ? currentStudent.Course : studentNewData.Course;
            currentStudent.Semester = studentNewData.Semester ?? currentStudent.Semester;

            await _context.SaveChangesAsync(cancellationToken);
            
            return Ok($"Student updated successfully");
        }

        [HttpGet("{studentPersonNumber}")]
        [Authorize]
        public async Task<ActionResult<Student>> GetStudentByPersonNumber(long studentPersonNumber, CancellationToken cancellationToken) => 
            await _context.Students.FindAsync(studentPersonNumber);

        [HttpGet]
        [Authorize]
        public async Task<ActionResult<IReadOnlyCollection<Student>>> GetStudents([FromBody] StudentSearchQuery searchQuery, CancellationToken cancellationToken) =>
            await _context.Students
                .Where(s => !searchQuery.AlbumNumber.HasValue || s.AlbumNumber.Equals(searchQuery.AlbumNumber))
                .Where(s => string.IsNullOrEmpty(searchQuery.FirstName) || s.FirstName.ToLower().Contains(searchQuery.FirstName.ToLower()))
                .Where(s => string.IsNullOrEmpty(searchQuery.LastName) || s.LastName.ToLower().Contains(searchQuery.LastName.ToLower()))
                .OrderBy(s => s.AlbumNumber)
                .Skip(searchQuery.Page * searchQuery.PerPage)
                .Take(searchQuery.PerPage)
                .ToListAsync(cancellationToken);

        [HttpPut]
        [Authorize]
        public async Task<ActionResult> UpdateStudentData([FromBody] StudentForm studentNewData, CancellationToken cancellationToken)
        {
            var validator = new StudentForm.Validator();
            var validationResult = await validator.ValidateAsync(studentNewData, cancellationToken);

            if (!validationResult.IsValid)
            {
                return BadRequest(validationResult.ToString());
            }
            
            var currentStudent = await _context.Students.FindAsync(studentNewData.Id);

            if (currentStudent == null)
            {
                return NotFound($"Student with id: {studentNewData.Id} does not exist");
            }
            
            currentStudent.AlbumNumber = studentNewData.AlbumNumber ?? currentStudent.AlbumNumber;
            currentStudent.FirstName = string.IsNullOrEmpty(studentNewData.FirstName) ? currentStudent.FirstName : studentNewData.FirstName;
            currentStudent.LastName = string.IsNullOrEmpty(studentNewData.LastName) ? currentStudent.LastName : studentNewData.LastName;
            currentStudent.Email = string.IsNullOrEmpty(studentNewData.Email) ? currentStudent.Email : studentNewData.Email;
            currentStudent.Course = string.IsNullOrEmpty(studentNewData.Course) ? currentStudent.Course : studentNewData.Course;
            currentStudent.Semester = studentNewData.Semester ?? currentStudent.Semester;

            await _context.SaveChangesAsync(cancellationToken);
            
            return Ok($"Student updated successfully");
        }
    }
}