using Microsoft.AspNetCore.Mvc;
using AS1024.GeoFeed.Interfaces;
using AS1024.GeoFeed.GeoFeedBuilder;
using Microsoft.Extensions.Caching.Memory;
using AS1024.GeoFeed.Models;
using System.Text;
using AS1024.GeoFeed.GeoFeedLocalCache;

namespace AS1024.GeoFeed.Controllers
{
    [ApiController]
    [Route("[controller]")]
    [Route("[controller].csv")]

    public class GeofeedController : ControllerBase
    {
        private readonly IGeoFeedProvider builder;
        private readonly IMemoryCache memoryCache;
        private readonly IWebHostEnvironment environment;
        private readonly ILogger<GeofeedController> logger;
        private readonly GeoFeedCacheDbContext dbContext;
        private const string GeoFeedCacheKey = "GeoFeedData";

        public GeofeedController(IGeoFeedProvider builder,
            IMemoryCache memoryCache,
            IWebHostEnvironment environment,
            ILogger<GeofeedController> logger,
            GeoFeedCacheDbContext dbContext) {
            this.logger = logger;
            this.dbContext = dbContext;
            this.builder = builder;
            this.memoryCache = memoryCache;
            this.environment = environment;
        }

        [HttpGet]
        [Route("")]
        public async Task<IActionResult> Get()
        {
            try
            {
                if (!memoryCache.TryGetValue(GeoFeedCacheKey, out List<IPGeoFeed>? feed))
                {
                    feed = await builder.GetGeoFeedData();
                    if (environment.IsProduction())
                    {
                        MemoryCacheEntryOptions cacheEntryOptions = new MemoryCacheEntryOptions()
                            .SetSlidingExpiration(TimeSpan.FromMinutes(15));
                        memoryCache.Set(GeoFeedCacheKey, feed, cacheEntryOptions);
                    }
                }

                return ReturnFile(feed);
            } catch (HttpRequestException ex)
            {
                logger.LogWarning($"Temporary failure of retrieving GeoData from upstream. {ex}");
                var results = 
                    dbContext.GeoFeedCacheEntries.ToList();
                List<IPGeoFeed> cachedData = [];
                results.ForEach(cachedData.Add);
                return ReturnFile(cachedData);
            }

            catch (Exception ex)
            {
                logger.LogError($"Geofeed generation failed. Exception: {ex}");
                return StatusCode(500);
            }

        }

        [NonAction]
        private IActionResult ReturnFile(List<IPGeoFeed>? feed)
        {
            string csvContent = feed.ToGeoFeedCsv(); // Assuming ToGeoFeedCsv() returns a string in CSV format.
            byte[] contentBytes = Encoding.UTF8.GetBytes(csvContent);
            string contentType = "text/csv";

            return new FileContentResult(contentBytes, contentType)
            {
                FileDownloadName = "geofeed.csv"
            };
        }
    }
}