using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.IO;
using System.Linq;
using System.Net.Configuration;
using System.Net.Http;
using System.Reflection;
using System.Security.Cryptography;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
using ICSharpCode.SharpZipLib.BZip2;
using IniParser;
using Newtonsoft.Json;
using Newtonsoft.Json.Bson;
using File = Alphaleonis.Win32.Filesystem.File;
using FileInfo = Alphaleonis.Win32.Filesystem.FileInfo;
using Path = Alphaleonis.Win32.Filesystem.Path;

namespace Wabbajack.Common
{
    public static class Utils
    {
        public static string LogFile { get; private set; }
        static Utils()
        {
            var program_name = Assembly.GetEntryAssembly()?.Location ?? "Wabbajack";
            LogFile = program_name + ".log";
            _startTime = DateTime.Now;

            if (LogFile.FileExists())
                File.Delete(LogFile);
        }

        private static Action<string> _loggerFn;
        private static Action<string, int> _statusFn;

        private static readonly string[] Suffix = {"B", "KB", "MB", "GB", "TB", "PB", "EB"}; // Longs run out around EB

        public static void SetLoggerFn(Action<string> f)
        {
            _loggerFn = f;
        }

        public static void SetStatusFn(Action<string, int> f)
        {
            _statusFn = f;
        }

        private static object _lock = new object();
        private static DateTime _startTime;

        public static void Log(string msg)
        {
            lock (_lock)
            {
                msg = $"{(DateTime.Now - _startTime).TotalSeconds:0.##} - {msg}";

                File.AppendAllText(LogFile, msg + "\r\n");
            }
            _loggerFn?.Invoke(msg);
        }

        public static void Status(string msg, int progress = 0)
        {
            _statusFn?.Invoke(msg, progress);
        }


        /// <summary>
        ///     MurMur3 hashes the file pointed to by this string
        /// </summary>
        /// <param name="file"></param>
        /// <returns></returns>
        public static string FileSHA256(this string file)
        {
            var sha = new SHA256Managed();
            using (var o = new CryptoStream(Stream.Null, sha, CryptoStreamMode.Write))
            {
                using (var i = File.OpenRead(file))
                {
                    i.CopyToWithStatus(new FileInfo(file).Length, o, $"Hashing {Path.GetFileName(file)}");
                }
            }

            return sha.Hash.ToBase64();
        }

        public static void CopyToWithStatus(this Stream istream, long maxSize, Stream ostream, string status)
        {
            var buffer = new byte[1024 * 64];
            if (maxSize == 0) maxSize = 1;
            long total_read = 0;
            while (true)
            {
                var read = istream.Read(buffer, 0, buffer.Length);
                if (read == 0) break;
                total_read += read;
                ostream.Write(buffer, 0, read);
                Status(status, (int) (total_read * 100 / maxSize));
            }
        }

        public static string SHA256(this byte[] data)
        {
            return new SHA256Managed().ComputeHash(data).ToBase64();
        }

        /// <summary>
        ///     Returns a Base64 encoding of these bytes
        /// </summary>
        /// <param name="data"></param>
        /// <returns></returns>
        public static string ToBase64(this byte[] data)
        {
            return Convert.ToBase64String(data);
        }

        public static string ToHEX(this byte[] bytes)
        {
            var builder = new StringBuilder();
            for (var i = 0; i < bytes.Length; i++) builder.Append(bytes[i].ToString("x2"));
            return builder.ToString();
        }

        /// <summary>
        ///     Returns data from a base64 stream
        /// </summary>
        /// <param name="data"></param>
        /// <returns></returns>
        public static byte[] FromBase64(this string data)
        {
            return Convert.FromBase64String(data);
        }

        /// <summary>
        ///     Executes the action for every item in coll
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="coll"></param>
        /// <param name="f"></param>
        public static void Do<T>(this IEnumerable<T> coll, Action<T> f)
        {
            foreach (var i in coll) f(i);
        }

        public static void DoIndexed<T>(this IEnumerable<T> coll, Action<int, T> f)
        {
            var idx = 0;
            foreach (var i in coll)
            {
                f(idx, i);
                idx += 1;
            }
        }


        /// <summary>
        ///     Loads INI data from the given filename and returns a dynamic type that
        ///     can use . operators to navigate the INI.
        /// </summary>
        /// <param name="file"></param>
        /// <returns></returns>
        public static dynamic LoadIniFile(this string file)
        {
            return new DynamicIniData(new FileIniDataParser().ReadFile(file));
        }

        public static void ToJSON<T>(this T obj, string filename)
        {
            File.WriteAllText(filename,
                JsonConvert.SerializeObject(obj, Formatting.Indented,
                    new JsonSerializerSettings {TypeNameHandling = TypeNameHandling.Auto}));
        }

        public static void ToBSON<T>(this T obj, string filename)
        {
            using (var fo = File.OpenWrite(filename))
            using (var br = new BsonDataWriter(fo))
            {
                fo.SetLength(0);
                var serializer = JsonSerializer.Create(new JsonSerializerSettings
                    {TypeNameHandling = TypeNameHandling.Auto});
                serializer.Serialize(br, obj);
            }
        }

        public static ulong ToMilliseconds(this DateTime date)
        {
            return (ulong) (date - new DateTime(1970, 1, 1)).TotalMilliseconds;
        }

        public static string ToJSON<T>(this T obj)
        {
            return JsonConvert.SerializeObject(obj, Formatting.Indented,
                new JsonSerializerSettings {TypeNameHandling = TypeNameHandling.Auto});
        }

        public static T FromJSON<T>(this string filename)
        {
            return JsonConvert.DeserializeObject<T>(File.ReadAllText(filename),
                new JsonSerializerSettings {TypeNameHandling = TypeNameHandling.Auto});
        }

        public static T FromBSON<T>(this string filename, bool root_is_array = false)
        {
            using (var fo = File.OpenRead(filename))
            using (var br = new BsonDataReader(fo, root_is_array, DateTimeKind.Local))
            {
                var serializer = JsonSerializer.Create(new JsonSerializerSettings
                    {TypeNameHandling = TypeNameHandling.Auto});
                return serializer.Deserialize<T>(br);
            }
        }

        public static T FromJSONString<T>(this string data)
        {
            return JsonConvert.DeserializeObject<T>(data,
                new JsonSerializerSettings {TypeNameHandling = TypeNameHandling.Auto});
        }

        public static T FromJSON<T>(this Stream data)
        {
            var s = Encoding.UTF8.GetString(data.ReadAll());
            return JsonConvert.DeserializeObject<T>(s, 
                new JsonSerializerSettings { TypeNameHandling = TypeNameHandling.Auto });
        }

        public static bool FileExists(this string filename)
        {
            return File.Exists(filename);
        }

        public static string RelativeTo(this string file, string folder)
        {
            return file.Substring(folder.Length + 1);
        }

        /// <summary>
        ///     Returns the string compressed via BZip2
        /// </summary>
        /// <param name="data"></param>
        /// <returns></returns>
        public static byte[] BZip2String(this string data)
        {
            using (var os = new MemoryStream())
            {
                using (var bz = new BZip2OutputStream(os))
                {
                    using (var bw = new BinaryWriter(bz))
                    {
                        bw.Write(data);
                    }
                }

                return os.ToArray();
            }
        }

        public static void BZip2ExtractToFile(this Stream src, string dest)
        {
            using (var os = File.OpenWrite(dest))
            {
                os.SetLength(0);
                using (var bz = new BZip2InputStream(src))
                    bz.CopyTo(os);
            }
        }

        /// <summary>
        ///     Returns the string compressed via BZip2
        /// </summary>
        /// <param name="data"></param>
        /// <returns></returns>
        public static string BZip2String(this byte[] data)
        {
            using (var s = new MemoryStream(data))
            {
                using (var bz = new BZip2InputStream(s))
                {
                    using (var bw = new BinaryReader(bz))
                    {
                        return bw.ReadString();
                    }
                }
            }
        }

        public static byte[] ReadAll(this Stream ins)
        {
            using (var ms = new MemoryStream())
            {
                ins.CopyTo(ms);
                return ms.ToArray();
            }
        }

        public static List<TR> PMap<TI, TR>(this IEnumerable<TI> coll, Func<TI, TR> f)
        {
            var colllst = coll.ToList();
            Interlocked.Add(ref WorkQueue.MaxQueueSize, colllst.Count);
            //WorkQueue.CurrentQueueSize = 0;

            var remaining_tasks = colllst.Count;

            var tasks = coll.Select(i =>
            {
                var tc = new TaskCompletionSource<TR>();
                WorkQueue.QueueTask(() =>
                {
                    try
                    {
                        tc.SetResult(f(i));
                    }
                    catch (Exception ex)
                    {
                        tc.SetException(ex);
                    }

                    Interlocked.Increment(ref WorkQueue.CurrentQueueSize);
                    Interlocked.Decrement(ref remaining_tasks);
                    WorkQueue.ReportNow();
                });
                return tc.Task;
            }).ToList();

            // To avoid thread starvation, we'll start to help out in the work queue
            if (WorkQueue.WorkerThread)
                while (remaining_tasks > 0)
                    if (WorkQueue.Queue.TryTake(out var a, 500))
                        a();

            if (WorkQueue.CurrentQueueSize == WorkQueue.MaxQueueSize)
            {
                WorkQueue.MaxQueueSize = 0;
                WorkQueue.MaxQueueSize = 0;
            }

            return tasks.Select(t =>
            {
                t.Wait();
                if (t.IsFaulted)
                    throw t.Exception;
                return t.Result;
            }).ToList();
        }

        public static void PMap<TI>(this IEnumerable<TI> coll, Action<TI> f)
        {
            coll.PMap(i =>
            {
                f(i);
                return false;
            });
        }

        public static void DoProgress<T>(this IEnumerable<T> coll, string msg, Action<T> f)
        {
            var lst = coll.ToList();
            lst.DoIndexed((idx, i) =>
            {
                Status(msg, idx * 100 / lst.Count);
                f(i);
            });
        }

        public static void OnQueue(Action f)
        {
            new List<bool>().Do(_ => f());
        }

        public static HttpResponseMessage GetSync(this HttpClient client, string url)
        {
            var result = client.GetAsync(url, HttpCompletionOption.ResponseHeadersRead);
            result.Wait();
            return result.Result;
        }

        public static string GetStringSync(this HttpClient client, string url)
        {
            var result = client.GetStringAsync(url);
            result.Wait();
            return result.Result;
        }

        public static Stream GetStreamSync(this HttpClient client, string url)
        {
            var result = client.GetStreamAsync(url);
            result.Wait();
            return result.Result;
        }

        public static Stream PostStreamSync(this HttpClient client, string url, HttpContent content)
        {
            var result = client.PostAsync(url, content);
            result.Wait();
            var stream = result.Result.Content.ReadAsStreamAsync();
            stream.Wait();
            return stream.Result;
        }

        public static string ExceptionToString(this Exception ex)
        {
            var sb = new StringBuilder();
            while (ex != null)
            {
                sb.AppendLine(ex.Message);
                var st = new StackTrace(ex, true);
                foreach (var frame in st.GetFrames())
                    sb.AppendLine(
                        $"{frame.GetFileName()}:{frame.GetMethod().Name}:{frame.GetFileLineNumber()}:{frame.GetFileColumnNumber()}");
                ex = ex.InnerException;
            }


            return sb.ToString();
        }

        public static void CrashDump(Exception e)
        {
            File.WriteAllText($"{DateTime.Now.ToString("yyyyMMddTHHmmss_crash_log.txt")}", ExceptionToString(e));
        }

        public static IEnumerable<T> DistinctBy<T, V>(this IEnumerable<T> vs, Func<T, V> select)
        {
            var set = new HashSet<V>();
            foreach (var v in vs)
            {
                var key = select(v);
                if (set.Contains(key)) continue;
                yield return v;
            }
        }

        public static T Last<T>(this T[] a)
        {
            if (a == null || a.Length == 0)
                throw new InvalidDataException("null or empty array");
            return a[a.Length - 1];
        }

        public static V GetOrDefault<K, V>(this IDictionary<K, V> dict, K key)
        {
            if (dict.TryGetValue(key, out var v)) return v;
            return default;
        }

        public static string ToFileSizeString(this long byteCount)
        {
            if (byteCount == 0)
                return "0" + Suffix[0];
            var bytes = Math.Abs(byteCount);
            var place = Convert.ToInt32(Math.Floor(Math.Log(bytes, 1024)));
            var num = Math.Round(bytes / Math.Pow(1024, place), 1);
            return Math.Sign(byteCount) * num + Suffix[place];
        }

        public static string ToFileSizeString(this int byteCount)
        {
            return ToFileSizeString((long)byteCount);
        }

        public static void CreatePatch(byte[] a, byte[] b, Stream output)
        {
            var data_a = a.SHA256().FromBase64().ToHEX();
            var data_b = b.SHA256().FromBase64().ToHEX();
            var cache_file = Path.Combine("patch_cache", $"{data_a}_{data_b}.patch");
            if (!Directory.Exists("patch_cache"))
                Directory.CreateDirectory("patch_cache");

            while (true)
            {
                if (File.Exists(cache_file))
                {
                    using (var f = File.OpenRead(cache_file))
                    {
                        f.CopyTo(output);
                    }
                }
                else
                {
                    var tmp_name = Path.Combine("patch_cache", Guid.NewGuid() + ".tmp");

                    using (var f = File.OpenWrite(tmp_name))
                    {
                        BSDiff.Create(a, b, f);
                    }

                    File.Move(tmp_name, cache_file);
                    continue;
                }

                break;
            }
        }

        public static void TryGetPatch(string foundHash, string fileHash, out byte[] ePatch)
        {
            var patch_name = Path.Combine("patch_cache",
                $"{foundHash.FromBase64().ToHEX()}_{fileHash.FromBase64().ToHEX()}.patch");
            ePatch = File.Exists(patch_name) ? File.ReadAllBytes(patch_name) : null;
        }

        public static void Warning(string s)
        {
            Log($"WARNING: {s}");
        }

        public static TV GetOrDefault<TK, TV>(this Dictionary<TK, TV> dict, TK key)
        {
            return dict.TryGetValue(key, out var result) ? result : default;
        }

        public static IEnumerable<T> ButLast<T>(this IEnumerable<T> coll)
        {
            var lst = coll.ToList();
            return lst.Take(lst.Count() - 1);
        }

        public static byte[] ConcatArrays(this IEnumerable<byte[]> arrays)
        {
            var outarr = new byte[arrays.Sum(a => a.Length)];
            int offset = 0;
            foreach (var arr in arrays)
            {
                Array.Copy(arr, 0, outarr, offset, arr.Length);
                offset += arr.Length;
            }
            return outarr;
        }
    }
}