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

namespace YTManager.Controllers {
    [Produces("application/json")]
    [Route("api/Videos")]
    public class VideosController : Controller {
        // Custom return type for API accesses. Done this way to ensure we
        // always return the expected data regardless of the underlying model.
        struct Video_ForAPI {
            // Title of the video.
            public string Title;

            // Description of the video.
            public string Description;

            // Youtube ID of the video.
            public string ID;

            // Thumbnail URL.
            public string Thumbnail;

            // Channel youtube ID.
            public string Channel;

            // Populate this struct using a model video.
            public Video_ForAPI(Models.Video video) {
                Title = video.Title;
                Description = video.Description;
                ID = video.YoutubeID;
                Thumbnail = video.ThumbnailURL;
                Channel = video.channel?.YoutubeID;
            }
        }

        // Maximum number of entries to return per query.
        private readonly int max_per_query = 20;

        // DB context used for all these calls.
        private readonly MediaDB db;

        // Constructor to fetch the db context.
        public VideosController(MediaDB context) => db = context;

        // Returns the most recent videos.
        [HttpGet]
        public async Task<IActionResult> GetVideos() {
            // Get all the relevant videos.
            var vids = await db.Videos
                .OrderByDescending(i => i.AddedtoDB)
                .Take(max_per_query)
                .ToListAsync();

            // Convert them to what we will send out.
            var converted = vids
                .Select(v => new Video_ForAPI(v))
                .ToList();

            // Convert all the videos to what we will send back.
            return Ok(converted);
        }

        // Returns the most recent videos of a channel.
        [HttpGet("fromchannel/{channelID}")]
        public async Task<IActionResult> Get_Channel_Videos([FromRoute] string channelID) {
            // Get all the relevant videos.
            var vids = await db.Videos
                .Include(v => v.channel)
                .Where(v => v.channel.YoutubeID == channelID)
                .OrderByDescending(i => i.AddedtoDB)
                .Take(max_per_query)
                .ToListAsync();

            // Convert them to what we will send out.
            var converted = vids
                .Select(v => new Video_ForAPI(v))
                .ToList();

            // Convert all the videos to what we will send back.
            return Ok(converted);
        }
    }
}