using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Utils.Security;

namespace Utils.Files
{
	public class SafeConfig
	{
		/// <summary>
		/// 向指定的加密文件中添加键值对。
		/// <para>如果键已经存在，则为更新</para>
		/// <para>如果文件不存在，则创建一个。路径必须存在</para>
		/// </summary>
		/// <param name="fileName_pathAndFileName">路径与文件名</param>
		/// <param name="password">密码。8位：不够则补全，多了则截断</param>
		/// <param name="key">键</param>
		/// <param name="value">值</param>
		public static void AddAndSaveConfig(string fileName_pathAndFileName, string password, string key, string value)
		{
			password = CheckPassword(password);
			var configs = GetAllConfigs(fileName_pathAndFileName, password);
			if (configs.Keys.Contains(key))
				configs[key] = value;
			else
				configs.Add(key, value);
			Save(configs, fileName_pathAndFileName, password);
		}

		/// <summary>
		/// 向指定的加密文件中添加键值对。
		/// <para>如果键已经存在，则为更新</para>
		/// <para>如果文件不存在，则创建一个。路径必须存在</para>
		/// </summary>
		/// <param name="fileName_pathAndFileName">路径与文件名</param>
		/// <param name="password">密码。8位：不够则补全，多了则截断</param>
		/// <param name="configs">要添加的键值对</param>
		public static void AddAndSaveConfig(string fileName_pathAndFileName, string password, Dictionary<string, string> configs)
		{
			password = CheckPassword(password);
			var all = GetAllConfigs(fileName_pathAndFileName, password);
			foreach (var item in configs) {
				if (all.Keys.Contains(item.Key))
					all[item.Key] = item.Value;
				else
					all.Add(item.Key, item.Value);
			}
			Save(all, fileName_pathAndFileName, password);
		}

		/// <summary>
		/// 获取加密文件的键值对信息。【文件可以不存在】
		/// </summary>
		/// <param name="fileName_pathAndFileName">文件路径和文件名</param>
		/// <param name="password">密码。8位：不够则补全，多了则截断</param>
		/// <returns>键值对信息</returns>
		public static Dictionary<string, string> GetAllConfigs(string fileName_pathAndFileName, string password)
		{
			Dictionary<string, string> all = new Dictionary<string, string>();
			var value = GetDecryptConfigFile(fileName_pathAndFileName, password);
			var configs = value.Split(new string[] { Environment.NewLine }, StringSplitOptions.RemoveEmptyEntries);
			foreach (var item in configs) {
				if (item.StartsWith(Separator))//忽略键为空的行
					continue;
				if (!item.Contains(Separator))//忽略没有分隔符的行
					continue;
				var pairs = item.Split(new string[] { Separator }, StringSplitOptions.RemoveEmptyEntries);
				if (pairs.Count() > 0) {
					all.Add(pairs.ElementAt(0), pairs.Count() > 1 ? pairs.ElementAt(1) : string.Empty);
				}
			}
			return all;
		}

		/// <summary>
		/// 将键值对加密后保存。密码必须为8位。
		/// <para>文件不存在则创建。路径必须存在。</para>
		/// </summary>
		/// <param name="configs">键值对</param>
		/// <param name="fileName_pathAndFileName">文件路径和文件名</param>
		/// <param name="password">8位密码</param>
		private static void Save(Dictionary<string, string> configs, string fileName_pathAndFileName, string password)
		{
			string file = string.Empty;
			foreach (var item in configs) {
				file += item.Key + Separator + item.Value + Environment.NewLine;
			}
			EncryptSave(fileName_pathAndFileName, password, file);
		}

		/// <summary>
		/// 获取解密文件
		/// </summary>
		/// <param name="fileName_pathAndFileName">文件路径和文件名</param>
		/// <param name="password">密码。8位：不够则补全，多了则截断</param>
		/// <returns>解密后的文件</returns>
		public static string GetDecryptConfigFile(string fileName_pathAndFileName, string password)
		{
			password = CheckPassword(password);
			var source = ReadWriteFile.ReadFile(fileName_pathAndFileName);
			if (string.IsNullOrEmpty(source))
				return string.Empty;
			return SecurityUtil.ChangeBack(source, password);
		}

		/// <summary>
		/// 将指定内容，加密后保存为一个文件(如果存在，则重写；否则新建)
		/// </summary>
		/// <param name="fileName_pathAndFileName">文件路径和文件名</param>
		/// <param name="password">密码。8位：不够则补全，多了则截断</param>
		/// <param name="content">要加密并保存的文件</param>
		public static void EncryptSave(string fileName_pathAndFileName, string password, string content)
		{
			var saveFile = SecurityUtil.Change(content, password);
			ReadWriteFile.WriteFile(fileName_pathAndFileName, saveFile);
		}

		private static string CheckPassword(string password)
		{
			if (string.IsNullOrEmpty(password))
				return DefaultPassword;
			if (password.Length == 8)
				return password;
			if (password.Length > 8)
				return password.Substring(0, 8);
			return password + DefaultPassword.Substring(0, 8 - password.Length);
		}

		private static string DefaultPassword = "ρ☉〩＄℡№◆↙";//必须为8位。一经使用，不许更改

		private static string Separator = "⊙丷▼☆↘ωα";
	}
}