using System;
using System.Collections.Generic;
using System.Threading.Tasks;
using FluentValidation.Results;
using NLog;
using NzbDrone.Common.Disk;
using NzbDrone.Core.Configuration;
using NzbDrone.Core.Indexers;
using NzbDrone.Core.Parser.Model;
using NzbDrone.Core.ThingiProvider;
using NzbDrone.Core.Validation;

namespace NzbDrone.Core.Download
{
    public abstract class DownloadClientBase<TSettings> : IDownloadClient
        where TSettings : IProviderConfig, new()
    {
        protected readonly IConfigService _configService;
        protected readonly IDiskProvider _diskProvider;
        protected readonly Logger _logger;

        public abstract string Name { get; }

        public Type ConfigContract => typeof(TSettings);

        public virtual ProviderMessage Message => null;

        public IEnumerable<ProviderDefinition> DefaultDefinitions => new List<ProviderDefinition>();

        public ProviderDefinition Definition { get; set; }

        public virtual object RequestAction(string action, IDictionary<string, string> query)
        {
            return null;
        }

        protected TSettings Settings => (TSettings)Definition.Settings;

        protected DownloadClientBase(IConfigService configService,
            IDiskProvider diskProvider,
            Logger logger)
        {
            _configService = configService;
            _diskProvider = diskProvider;
            _logger = logger;
        }

        public override string ToString()
        {
            return GetType().Name;
        }

        public abstract DownloadProtocol Protocol
        {
            get;
        }

        public abstract Task<string> Download(ReleaseInfo release, bool redirect, IIndexer indexer);

        public ValidationResult Test()
        {
            var failures = new List<ValidationFailure>();

            try
            {
                Test(failures);
            }
            catch (Exception ex)
            {
                _logger.Error(ex, "Test aborted due to exception");
                failures.Add(new ValidationFailure(string.Empty, "Test was aborted due to an error: " + ex.Message));
            }

            return new ValidationResult(failures);
        }

        protected abstract void Test(List<ValidationFailure> failures);

        protected ValidationFailure TestFolder(string folder, string propertyName, bool mustBeWritable = true)
        {
            if (!_diskProvider.FolderExists(folder))
            {
                return new NzbDroneValidationFailure(propertyName, "Folder does not exist")
                {
                    DetailedDescription = string.Format("The folder you specified does not exist or is inaccessible. Please verify the folder permissions for the user account '{0}', which is used to execute Prowlarr.", Environment.UserName)
                };
            }

            if (mustBeWritable && !_diskProvider.FolderWritable(folder))
            {
                _logger.Error("Folder '{0}' is not writable.", folder);
                return new NzbDroneValidationFailure(propertyName, "Unable to write to folder")
                {
                    DetailedDescription = string.Format("The folder you specified is not writable. Please verify the folder permissions for the user account '{0}', which is used to execute Prowlarr.", Environment.UserName)
                };
            }

            return null;
        }
    }
}