using System;
using System.Collections.Generic;
using System.Linq;
using System.Text.RegularExpressions;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Mvc.Filters;
using Microsoft.Extensions.Caching.Memory;
using Microsoft.Extensions.Logging;
using Org.BouncyCastle.Crypto.Digests;
using RocksDbSharp;
using Wabbajack.BuildServer;
using Wabbajack.Common;
using Wabbajack.Lib;
using Wabbajack.Lib.Downloaders;
using Wabbajack.Lib.ModListRegistry;
using Wabbajack.Lib.NexusApi;
using Wabbajack.Server.DataLayer;
using Wabbajack.Server.DTOs;

namespace Wabbajack.Server.Services
{
    public class ListValidator : AbstractService<ListValidator, int>
    {
        private SqlService _sql;
        private NexusApiClient _nexusClient;

        public IEnumerable<(ModListSummary Summary, DetailedStatus Detailed)> Summaries { get; private set; } =
            new (ModListSummary Summary, DetailedStatus Detailed)[0];


        public ListValidator(ILogger<ListValidator> logger, AppSettings settings, SqlService sql) 
            : base(logger, settings, TimeSpan.FromMinutes(10))
        {
            _sql = sql;
        }

        public override async Task<int> Execute()
        {
            var data = await _sql.GetValidationData();
            
            using var queue = new WorkQueue();

            var results = await data.ModLists.PMap(queue, async list =>
            {
                var (metadata, modList) = list;
                var archives = await modList.Archives.PMap(queue, async archive =>
                {
                    var (_, result) = await ValidateArchive(data, archive);
                    // TODO : auto-healing goes here
                    return (archive, result);
                });

                var failedCount = archives.Count(f => f.Item2 == ArchiveStatus.InValid);
                var passCount = archives.Count(f => f.Item2 == ArchiveStatus.Valid || f.Item2 == ArchiveStatus.Updated);
                var updatingCount = archives.Count(f => f.Item2 == ArchiveStatus.Updating);

                var summary =  new ModListSummary
                {
                    Checked = DateTime.UtcNow,
                    Failed = failedCount,
                    Passed = passCount,
                    Updating = updatingCount,
                    MachineURL = metadata.Links.MachineURL,
                    Name = metadata.Title,
                };

                var detailed = new DetailedStatus
                {
                    Name = metadata.Title,
                    Checked = DateTime.UtcNow,
                    DownloadMetaData = metadata.DownloadMetadata,
                    HasFailures = failedCount > 0,
                    MachineName = metadata.Links.MachineURL,
                    Archives = archives.Select(a => new DetailedStatusItem
                    {
                        Archive = a.Item1, IsFailing = a.Item2 == ArchiveStatus.InValid || a.Item2 == ArchiveStatus.Updating
                    }).ToList()
                };

                return (summary, detailed);
            });
            Summaries = results;
            return Summaries.Count(s => s.Summary.HasFailures);
        }
        
        private async Task<(Archive archive, ArchiveStatus)> ValidateArchive(ValidationData data, Archive archive)
        {
            switch (archive.State)
            {
                case GoogleDriveDownloader.State _:
                    // Disabled for now due to GDrive rate-limiting the build server
                    return (archive, ArchiveStatus.Valid);
                case NexusDownloader.State nexusState when data.NexusFiles.Contains((
                    nexusState.Game.MetaData().NexusGameId, nexusState.ModID, nexusState.FileID)):
                    return (archive, ArchiveStatus.Valid);
                case NexusDownloader.State ns:
                    return (archive, await SlowNexusModStats(data, ns));
                case ManualDownloader.State _:
                    return (archive, ArchiveStatus.Valid);
                default:
                {
                    if (data.ArchiveStatus.TryGetValue((archive.State.PrimaryKeyString, archive.Hash),
                        out bool isValid))
                    {
                        return isValid ? (archive, ArchiveStatus.Valid) : (archive, ArchiveStatus.InValid);
                    }

                    return (archive, ArchiveStatus.InValid);
                }
            }
        }

        
        private readonly AsyncLock _slowQueryLock = new AsyncLock();
        public async Task<ArchiveStatus> SlowNexusModStats(ValidationData data, NexusDownloader.State ns)
        {
            var gameId = ns.Game.MetaData().NexusGameId;
            //using var _ = await _slowQueryLock.WaitAsync();
            _logger.Log(LogLevel.Warning, $"Slow querying for {ns.Game} {ns.ModID} {ns.FileID}");


            if (data.NexusFiles.Contains((gameId, ns.ModID, ns.FileID)))
                return ArchiveStatus.Valid;

            if (data.NexusFiles.Contains((gameId, ns.ModID, -1)))
                return ArchiveStatus.InValid;

            if (data.SlowQueriedFor.Contains((ns.Game, ns.ModID)))
                return ArchiveStatus.InValid;
            
            var queryTime = DateTime.UtcNow;
            var regex_id = new Regex("(?<=[?;&]id\\=)\\d+");
            var regex_file_id = new Regex("(?<=[?;&]file_id\\=)\\d+");
            var client = new Common.Http.Client();
            var result =
                await client.GetHtmlAsync(
                    $"https://www.nexusmods.com/{ns.Game.MetaData().NexusName}/mods/{ns.ModID}/?tab=files");

            var fileIds = result.DocumentNode.Descendants()
                .Select(f => f.GetAttributeValue("href", ""))
                .Select(f =>
                {
                    var match = regex_id.Match(f);
                    if (match.Success)
                        return match.Value;
                    match = regex_file_id.Match(f);
                    if (match.Success)
                        return match.Value;
                    return null;
                })
                .Where(m => m != null)
                .Select(m => long.Parse(m))
                .Distinct()
                .ToList();
            
            _logger.Log(LogLevel.Warning, $"Slow queried {fileIds.Count} files");
            foreach (var id in fileIds)
            {
                await _sql.AddNexusModFileSlow(ns.Game, ns.ModID, id, queryTime);
                data.NexusFiles.Add((gameId, ns.ModID, id));
            }

            // Add in the default marker
            await _sql.AddNexusModFileSlow(ns.Game, ns.ModID, -1, queryTime);
            data.NexusFiles.Add((gameId, ns.ModID, -1));

            return fileIds.Contains(ns.FileID) ? ArchiveStatus.Valid : ArchiveStatus.InValid;
        }
        
        private async Task<ArchiveStatus> FastNexusModStats(NexusDownloader.State ns)
        {
            
            var mod = await _sql.GetNexusModInfoString(ns.Game, ns.ModID);
            var files = await _sql.GetModFiles(ns.Game, ns.ModID);

            try
            {
                if (mod == null)
                {
                    _nexusClient ??= await NexusApiClient.Get();
                    _logger.Log(LogLevel.Information, $"Found missing Nexus mod info {ns.Game} {ns.ModID}");
                    try
                    {
                        mod = await _nexusClient.GetModInfo(ns.Game, ns.ModID, false);
                    }
                    catch
                    {
                        mod = new ModInfo
                        {
                            mod_id = ns.ModID.ToString(), game_id = ns.Game.MetaData().NexusGameId, available = false
                        };
                    }

                    try
                    {
                        await _sql.AddNexusModInfo(ns.Game, ns.ModID, mod.updated_time, mod);
                    }
                    catch (Exception _)
                    {
                        // Could be a PK constraint failure
                    }

                }

                if (files == null)
                {
                    _logger.Log(LogLevel.Information, $"Found missing Nexus mod info {ns.Game} {ns.ModID}");
                    try
                    {
                        files = await _nexusClient.GetModFiles(ns.Game, ns.ModID, false);
                    }
                    catch
                    {
                        files = new NexusApiClient.GetModFilesResponse {files = new List<NexusFileInfo>()};
                    }

                    try
                    {
                        await _sql.AddNexusModFiles(ns.Game, ns.ModID, mod.updated_time, files);
                    }
                    catch (Exception _)
                    {
                        // Could be a PK constraint failure
                    }
                }
            }
            catch (Exception ex)
            {
                return ArchiveStatus.InValid;
            }

            if (mod.available && files.files.Any(f => !string.IsNullOrEmpty(f.category_name) && f.file_id == ns.FileID))
                return ArchiveStatus.Valid;
            return ArchiveStatus.InValid;

        }
    }
}