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

namespace InternshipSystem.Api.Controllers
{
    [ApiController]
    [Route("staticPage")]
    public class StaticPagesController : ControllerBase
    {
        public StaticPagesController(InternshipDbContext context)
        {
            Context = context;
        }
        private InternshipDbContext Context { get; }

        /// <summary>
        /// Get all static pages, only available for coordinator
        /// </summary>
        /// <returns>List of static pages with titles and content</returns>
        /// <response code="200">Static pages list returned successfully</response>
        [HttpGet]
        [ProducesResponseType(StatusCodes.Status200OK)]
        public async Task<ActionResult<IList<StaticPage>>> GetStaticPages(CancellationToken cancellationToken) =>
            await Context.StaticPages
                .ToListAsync(cancellationToken);

        /// <summary>
        /// Get static page, only available for coordinator
        /// </summary>
        /// <param name="accessName">Name of page</param>
        /// <returns>Static page title and content</returns>
        /// <response code="200">Static page returned successfully</response>
        /// <response code="404">Static page with given access name do not exist</response>
        [HttpGet("{accessName}")]
        [ProducesResponseType(StatusCodes.Status200OK)]
        [ProducesResponseType(StatusCodes.Status404NotFound)]
        public async Task<ActionResult<StaticPage>> GetStaticPage(string accessName, CancellationToken cancellationToken)
        {
            var page = 
                await Context.StaticPages
                    .Where(p => p.AccessName.Trim().ToLower().Equals(accessName.Trim().ToLower()))
                    .FirstOrDefaultAsync(cancellationToken);

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

            return Ok(page);
        }

        /// <summary>
        /// Add or update static page, only available for coordinator
        /// </summary>
        /// <response code="200">Static page updated successfully</response>
        /// <response code="400">Static page form is not valid</response>
        /// <response code="401">This action is only available for authorized internship admin</response>
        /// <response code="404">Static page with given id do not exist</response>
        [HttpPut]
        [ProducesResponseType(StatusCodes.Status200OK)]
        [ProducesResponseType(StatusCodes.Status400BadRequest)]
        [ProducesResponseType(StatusCodes.Status401Unauthorized)]
        [ProducesResponseType(StatusCodes.Status404NotFound)]
        [Authorize]
        public async Task<ActionResult> UpdateStaticPage([FromBody] StaticPageForm staticPageForm, CancellationToken cancellationToken)
        {
            var validator = new StaticPageForm.Validator();
            var validationResult = await validator.ValidateAsync(staticPageForm, cancellationToken);

            if (!validationResult.IsValid)
            {
                return BadRequest(validationResult.ToString());
            }

            if (staticPageForm.Id.HasValue)
            {
                var pageToUpdate = await Context.StaticPages.FindAsync(staticPageForm.Id);

                if (pageToUpdate == null)
                {
                    return NotFound($"Static page with id: {staticPageForm.Id} does not exist");
                }
                
                if (!string.IsNullOrEmpty(staticPageForm.AccessName))
                {
                    var pageWithSameAccessName = await Context.StaticPages
                        .FirstOrDefaultAsync(sp => sp.AccessName.ToLower().Trim().Equals(staticPageForm.AccessName.ToLower().Trim()), cancellationToken: cancellationToken);

                    if (pageWithSameAccessName != null && !pageWithSameAccessName.Id.Equals(pageToUpdate.Id))
                    {
                        return BadRequest($"Static page with access name: {staticPageForm.AccessName} already exist");
                    }
                }

                pageToUpdate.AccessName = string.IsNullOrEmpty(staticPageForm.AccessName) ? pageToUpdate.AccessName : staticPageForm.AccessName;
                pageToUpdate.Title = string.IsNullOrEmpty(staticPageForm.Title) ? pageToUpdate.Title : staticPageForm.Title;
                pageToUpdate.TitleEng = string.IsNullOrEmpty(staticPageForm.TitleEng) ? pageToUpdate.TitleEng : staticPageForm.TitleEng;
                pageToUpdate.Content = string.IsNullOrEmpty(staticPageForm.Content) ? pageToUpdate.Content : staticPageForm.Content;
                pageToUpdate.ContentEng = string.IsNullOrEmpty(staticPageForm.ContentEng) ? pageToUpdate.ContentEng : staticPageForm.ContentEng;
            }
            else
            {
                var pageWithSameAccessName = await Context.StaticPages
                    .FirstOrDefaultAsync(sp => sp.AccessName.ToLower().Trim().Equals(staticPageForm.AccessName.ToLower().Trim()), cancellationToken: cancellationToken);

                if (pageWithSameAccessName != null)
                {
                    return BadRequest($"Static page with access name: {staticPageForm.AccessName} already exist");
                }
                
                var newStaticPage = new StaticPage
                {
                    AccessName = staticPageForm.AccessName.ToLower().Trim(),
                    Title = staticPageForm.Title,
                    TitleEng = staticPageForm.Title,
                    Content = staticPageForm.Content,
                    ContentEng = staticPageForm.ContentEng,
                };
                await Context.StaticPages.AddAsync(newStaticPage, cancellationToken);
            }

            await Context.SaveChangesAsync(cancellationToken);
            
            return Ok($"Static page updated successfully");
        }
        
        /// <summary>
        /// Delete static page, only available for coordinator
        /// </summary>
        /// <response code="200">Static page deleted successfully</response>
        /// <response code="401">This action is only available for authorized internship admin</response>
        /// <response code="404">Static page with given access name do not exist</response>
        [HttpDelete("{accessName}")]
        [ProducesResponseType(StatusCodes.Status200OK)]
        [ProducesResponseType(StatusCodes.Status400BadRequest)]
        [ProducesResponseType(StatusCodes.Status401Unauthorized)]
        [ProducesResponseType(StatusCodes.Status404NotFound)]
        [Authorize]
        public async Task<ActionResult> DeleteStaticPage(string accessName, CancellationToken cancellationToken)
        {
            var pageToDelete = await Context.StaticPages
                .FirstOrDefaultAsync(sp => sp.AccessName.ToLower().Trim().Equals(accessName.ToLower().Trim()), cancellationToken: cancellationToken);

            if (pageToDelete == null)
            {
                return NotFound($"Static page with access name: {accessName} does not exist");
            }

            Context.StaticPages.Attach(pageToDelete);
            Context.StaticPages.Remove(pageToDelete);
            await Context.SaveChangesAsync(cancellationToken);
            return Ok($"Static page with access name: {accessName} deleted successfully");
        }
    }
}