using System;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.Mvc;
using Website.Data;
using Website.Models;
using Website.ViewModels;

namespace Website.Controllers
{
	public class BlogController : Controller
	{
		private const int MaxPostsPerPage = 10;
		private readonly BlogRepository _repo;

		public BlogController(BlogRepository repo)
		{
			_repo = repo;
		}

		public async Task<IActionResult> Page(int page)
		{
			var offset = (page - 1) * MaxPostsPerPage;
			var posts = (await _repo.GetLatestPostsAsync(MaxPostsPerPage, offset)).Select(p => new BlogPostPreviewViewModel(p));
			var maxPages = (await _repo.GetCountAsync()) / MaxPostsPerPage;
			var model = new BlogViewModel(posts, page, maxPages);
			return View(model);
		}

		public async Task<IActionResult> Entry(string url)
		{
			try {
				var post = await _repo.GetPostByUrlAsync(url);
				var model = new BlogPostViewModel(post);
				return View(model);
			} catch (InvalidOperationException) {
				return NotFound();
			}
		}

		[Authorize]
		public async Task<IActionResult> Edit(int? id) {
			if (!id.HasValue)
				return View();

			try {
				var post = await _repo.GetPostByIdAsync(id.Value);
				var model = new BlogPostSubmission {
					Id = post.Id,
					Title = post.Title,
					Content = post.Draft
				};
				return View(model);
			}
			catch (InvalidOperationException) {
				return NotFound();
			}
		}

		[Authorize]
		[HttpPost]
		public async Task<IActionResult> Save(BlogPostSubmission submission) {
			var post = submission.Id.HasValue ? await _repo.GetPostByIdAsync(submission.Id.Value) : new BlogPost();

			post.UpdateTitle(submission.Title);
			post.UpdateDraft(submission.Content);

			var savedPost = await _repo.SavePost(post);

			return RedirectToAction(nameof(Edit), new{savedPost.Id});
		}

		[Authorize]
		public async Task<IActionResult> Manage() {
			var posts = await _repo.GetAllPostsAsync();
			var models = posts.OrderByDescending(post => post.Timestamp).Select(post => new BlogPostViewModel(post));
			return View(models);
		}

		[Authorize]
		public async Task<IActionResult> Publish(int id) {
			var post = await _repo.GetPostByIdAsync(id);
			post.Publish();
			await _repo.SavePost(post);

			return RedirectToAction(nameof(Manage));
		}

		[Authorize]
		public async Task<IActionResult> Delete(int id) {
			await _repo.DeletePostAsync(id);

			return RedirectToAction(nameof(Manage));
		}
	}
}