using Newtonsoft.Json;
using Newtonsoft.Json.Bson;
using System.Collections.Generic;
using System.IO;
using System.Linq;

namespace Muchinfo.PC.Common.Bosn
{
    public class BsonHelper
    {
        /// <summary>
        /// Loads the data.
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="filePath">The file path.</param>
        /// <returns>List{``0}.</returns>
        public static List<T> LoadData<T>(string filePath)
        {
            var result = new List<T>();
            if (!File.Exists(filePath)) return result;

            try
            {
                using (var stream = new FileStream(filePath, FileMode.Open, FileAccess.ReadWrite))
                {
                    using (var memory = new MemoryStream())
                    {
                        ZipHelper.Decompress(stream, memory);
                        using (var reader = new BsonReader(memory))
                        {
                            //反序列化集合必须设置此值
                            reader.ReadRootValueAsArray = true;
                            var serializer = new JsonSerializer();
                            result = serializer.Deserialize<List<T>>(reader).ToList();
                        }
                    }
                }

                return result;
            }
            catch
            {
                return null;
            }
        }

        /// <summary>
        /// Saves the data.
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="filePath">The file path.</param>
        /// <param name="source">The source.</param>
        /// <param name="comparer">The comparer.</param>
        /// <param name="isOverride">if set to <c>true</c> [is override].</param>
        public static void SaveData<T>(string filePath, T source, IEqualityComparer<T> comparer, bool isOverride = false)
        {
            if (null == source) return;
            var list = new List<T>() { source };
            SaveData(filePath, list, comparer, isOverride);
        }

        /// <summary>
        /// Saves the data.
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="filePath">The file path.</param>
        /// <param name="list">The list.</param>
        /// <param name="comparer">The comparer.</param>
        /// <param name="isOverride">if set to <c>true</c> [is override].</param>
        public static void SaveData<T>(string filePath, List<T> list, IEqualityComparer<T> comparer, bool isOverride = false)
        {

            if (null == list) return;

            var folderPath = Path.GetDirectoryName(filePath);
            if (string.IsNullOrWhiteSpace(folderPath)) return;
            if (!Directory.Exists(folderPath)) Directory.CreateDirectory(folderPath);

            List<T> data;
            if (isOverride && File.Exists(filePath))
            {
                File.Delete(filePath);
                data = list;
            }
            else
            {
                data = LoadData<T>(filePath) ?? new List<T>();
                data = list.Union(data, comparer).ToList();
            }

            using (var stream = new FileStream(filePath, FileMode.OpenOrCreate, FileAccess.ReadWrite, FileShare.Read))
            {
                using (var memory = new MemoryStream())
                {
                    using (var writer = new BsonWriter(memory))
                    {
                        var settings = new JsonSerializerSettings
                        {
                            NullValueHandling = NullValueHandling.Ignore
                        };
                        var serializer = JsonSerializer.Create(settings);
                        serializer.Formatting = Formatting.None;
                        serializer.Serialize(writer, data);
                        memory.Seek(0, SeekOrigin.Begin);
                        ZipHelper.Compress(memory, stream);
                    }
                }
            }
        }
    }
}