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 Projects class includes all API's related to the Projects.
    /// </summary>
    [Route("[controller]")]
    [ApiController]
    public class ProjectsController : ControllerBase
    {
        private readonly TaskContext _context;

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

        // GET: api/projects
        /// <summary>
        /// Retrieve all Projects in DB.
        /// Result can be filtered using the Params.
        /// </summary>
        /// <param name="title">string value</param>
        /// <param name="isprivate">boolean value</param>
        /// <returns>JSON list of all matching Projects</returns>
#nullable enable
        [HttpGet]
        public async Task<ActionResult<IEnumerable<ScrumProject>>> GetProject([FromQuery]string? title, [FromQuery]bool? isprivate)
        {
            var filtered = _context.Projects.AsQueryable();

            if (title != null)
            {
                filtered = filtered.Where<ScrumProject>(t => t.Title.Contains(title));
            }
            if (isprivate != null)
            {
                filtered = filtered.Where<ScrumProject>(t => t.IsPrivate == isprivate);
            }

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

        // GET: api/projects/5
        /// <summary>
        /// Retrieve the Project by it's ID.
        /// </summary>
        /// <param name="id">ID of searched Project</param>
        /// <returns>JSON object</returns>
        [HttpGet("{id}")]
        public async Task<ActionResult<ScrumProject>> GetProjects(int id)
        {
            var project = await _context.Projects.FindAsync(id);

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

            return project;
        }

        // PUT: api/Project/5
        /// <summary>
        /// Update the Project identified by it's ID.
        /// </summary>
        /// <param name="id">to edit Project's ID</param>
        /// <param name="projects">modified Project</param>
        /// <returns>the proper status code</returns>
        [HttpPut("{id}")]
        public async Task<IActionResult> PutProject(int id, ScrumProject projects)
        {
            // The project's ID must not be changed
            if (id != projects.Id)
            {
                return BadRequest();
            }

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

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

            return NoContent();
        }

        // POST: api/Project
        /// <summary>
        /// Create a new Project.
        /// </summary>
        /// <param name="projects">new Project</param>
        /// <returns>the proper status code</returns>
        [HttpPost]
        public async Task<ActionResult<ScrumProject>> PostProject(ScrumProject projects)
        {
            _context.Projects.Add(projects);
            await _context.SaveChangesAsync();

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

        // DELETE: api/Project/5
        /// <summary>
        /// Delete a Project identified by it's ID.
        /// </summary>
        /// <param name="id">to delete Project's ID</param>
        /// <returns>the proper status code</returns>
        [HttpDelete("{id}")]
        public async Task<ActionResult<ScrumProject>> DeleteProject(int id)
        {
            var scrumProject = await _context.Projects.FindAsync(id);
            if (scrumProject == null)
            {
                return NotFound();
            }

            // Remove the project from the context
            _context.Projects.Remove(scrumProject);
            // Save the changes in the database
            await _context.SaveChangesAsync();

            return scrumProject;
        }

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