using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Mvc;
using Microsoft.EntityFrameworkCore;

namespace ScrumTaskboard.Controllers
{
    /// <summary>
    /// This is a controller of Sprints class includes all API's related to the Sprints.
    /// </summary>
    [Route("[controller]")]
    [ApiController]
    public class SprintsController : ControllerBase
    {
        private readonly TaskContext _context;

        /// <summary>
        /// Initializes a new instance of the class.
        /// </summary>
        /// <param name="context"></param>
        public SprintsController(TaskContext context)
        {
            _context = context;
        }

        // GET: api/sprint
        #nullable enable
        [HttpGet]
        public async Task<ActionResult<IEnumerable<ScrumSprint>>> GetSprint([FromQuery]string? title, [FromQuery]int? projectid, [FromQuery]DateTime? startDate, [FromQuery]DateTime? endDate)
        {
            var filtered = _context.Sprints.AsQueryable();

            if (title != null)
            {
                filtered = filtered.Where<ScrumSprint>(s => s.Title.Contains(title));
            }
            if (projectid != null)
            {
                filtered = filtered.Where<ScrumSprint>(s => s.ProjectId == projectid);
            }
            if (startDate != null)
            {
                filtered = filtered.Where<ScrumSprint>(s => s.StartDate == startDate);
            }
            if (endDate != null)
            {
                filtered = filtered.Where<ScrumSprint>(s => s.EndDate == endDate);
            }

            return await filtered.ToListAsync();
        }
        #nullable disable

        // GET: api/sprint/5
        [HttpGet("{id}")]
        public async Task<ActionResult<ScrumSprint>> GetSprint(int id)
        {
            var sprint = await _context.Sprints.FindAsync(id);

            if (sprint == null)
            {
                return NotFound();
            }

            return sprint;
        }

        // PUT: api/sprint/5
        [HttpPut("{id}")]
        public async Task<IActionResult> PutSprint(int id, ScrumSprint sprint)
        {
            // The sprint's ID must not be changed
            if (id != sprint.Id)
            {
                return BadRequest();
            }

            // Save the changed sprint in the context
            _context.Entry(sprint).State = EntityState.Modified;

            try
            {
                // Apply the changes to the database
                await _context.SaveChangesAsync();
            }
            catch (DbUpdateConcurrencyException)
            {
                // If the sprint does not exist, return status code 404
                if (!SprintExists(id))
                {
                    return NotFound();
                }
                else
                {
                    throw;
                }
            }

            return NoContent();
        }

        // POST: api/Sprint
        [HttpPost]
        public async Task<ActionResult<ScrumSprint>> PostSprint(ScrumSprint sprint)
        {
            _context.Sprints.Add(sprint);
            await _context.SaveChangesAsync();

            // The new sprint has been created and can be called up using the GetSprint method
            return CreatedAtAction("GetSprint", new { id = sprint.Id }, sprint);
        }

        // DELETE: api/Sprint/5
        [HttpDelete("{id}")]
        public async Task<ActionResult<ScrumSprint>> DeleteSprint(int id)
        {
            var scrumSprint = await _context.Sprints.FindAsync(id);
            if (scrumSprint == null)
            {
                return NotFound();
            }

            // Remove the sprint from the context
            _context.Sprints.Remove(scrumSprint);
            // Save the changes in the database
            await _context.SaveChangesAsync();

            return scrumSprint;
        }

        /// <summary>
        /// Checks whether a sprint with the specified ID already exists.
        /// </summary>
        private bool SprintExists(int id)
        {
            return _context.Sprints.Any(e => e.Id == id);
        }
    }
}