using Microsoft.Data.Sqlite;
using Microsoft.Extensions.Configuration;
using MySql.Data.MySqlClient;
using Npgsql;
using Oracle.ManagedDataAccess.Client;
using System;
using System.Collections.Generic;
using System.Data;
using System.Data.SqlClient;
using System.Reflection;
using Znyc.Recruitment.Admin.Commons.Encrypt;
using Znyc.Recruitment.Admin.Commons.Enums;
using Znyc.Recruitment.Admin.Commons.Extensions;

namespace Znyc.Recruitment.Admin.Commons.Core.DataManager
{
    /// <summary>
    ///     数据库服务提供者
    /// </summary>
    public class DBServerProvider
    {
        /// <summary>
        ///     数据库配置名称
        /// </summary>
        private static string dbConfigName = "";

        /// <summary>
        ///     数据库连接
        /// </summary>
        private static IDbConnection dbConnection;

        #region Dapper Context

        /// <summary>
        ///     获取默认数据库连接
        /// </summary>
        /// <returns></returns>
        public static string GetConnectionString()
        {
            return GetConnectionString(dbConfigName);
        }

        /// <summary>
        /// </summary>
        /// <param name="key"></param>
        /// <returns></returns>
        public static string GetConnectionString(string key)
        {
            return dbConfigName = key ?? dbConfigName;
        }

        /// <summary>
        ///     获取数据库连接
        /// </summary>
        /// <param name="masterDb">是否访问主库，默认为是，否则访问从库即只读数据库</param>
        /// <returns></returns>
        public static IDbConnection GetDBConnection<TEntity>(bool masterDb = true)
        {
            DbConnectionOptions connectionOptions = GeDbConnectionOptions<TEntity>(masterDb);
            string defaultSqlConnectionString = connectionOptions.ConnectionString;
            DatabaseType dbType = connectionOptions.DatabaseType;
            if (dbType == DatabaseType.SqlServer)
            {
                dbConnection = new SqlConnection(defaultSqlConnectionString);
            }
            else if (dbType == DatabaseType.MySql)
            {
                dbConnection = new MySqlConnection(defaultSqlConnectionString);
            }
            else if (dbType == DatabaseType.Oracle)
            {
                dbConnection = new OracleConnection(defaultSqlConnectionString);
            }
            else if (dbType == DatabaseType.SQLite)
            {
                dbConnection = new SqliteConnection(defaultSqlConnectionString);
            }
            else if (dbType == DatabaseType.Npgsql)
            {
                dbConnection = new NpgsqlConnection(defaultSqlConnectionString);
            }
            else
            {
                throw new NotSupportedException("The database is not supported");
            }

            return dbConnection;
        }

        /// <summary>
        ///     获取数据库连接
        /// </summary>
        /// <param name="masterDb">是否访问主库，默认为是，否则访问从库即只读数据库</param>
        /// <returns></returns>
        public static IDbConnection GetDBConnection(bool masterDb = true)
        {
            DbConnectionOptions connectionOptions = GeDbConnectionOptions(masterDb);
            string defaultSqlConnectionString = connectionOptions.ConnectionString;
            DatabaseType dbType = connectionOptions.DatabaseType;
            if (dbType == DatabaseType.SqlServer)
            {
                dbConnection = new SqlConnection(defaultSqlConnectionString);
            }
            else if (dbType == DatabaseType.MySql)
            {
                dbConnection = new MySqlConnection(defaultSqlConnectionString);
            }
            else if (dbType == DatabaseType.Oracle)
            {
                dbConnection = new OracleConnection(defaultSqlConnectionString);
            }
            else if (dbType == DatabaseType.SQLite)
            {
                dbConnection = new SqliteConnection(defaultSqlConnectionString);
            }
            else if (dbType == DatabaseType.Npgsql)
            {
                dbConnection = new NpgsqlConnection(defaultSqlConnectionString);
            }
            else
            {
                throw new NotSupportedException("The database is not supported");
            }

            return dbConnection;
        }

        /// <summary>
        ///     获取数据库连接连接配置
        /// </summary>
        /// <typeparam name="TEntity">数据实体</typeparam>
        /// <param name="masterDb">是否访问主库，默认为是，否则访问从库即只读数据库</param>
        /// <returns></returns>
        public static DbConnectionOptions GeDbConnectionOptions<TEntity>(bool masterDb = true)
        {
            dbConfigName = typeof(TEntity).GetCustomAttribute<AppDBContextAttribute>(false)?.DbConfigName ??
                           dbConfigName;
            bool conStringEncrypt = Configs.GetConfigurationValue("AppSetting", "ConStringEncrypt").ToBool();
            if (string.IsNullOrEmpty(dbConfigName))
            {
                dbConfigName = Configs.GetConfigurationValue("AppSetting", "DefaultDataBase");
            }

            Dictionary<string, DbConnectionOptions> dictRead = Configs.GetSection("DbConnections:" + dbConfigName + ":ReadDb")
                .Get<Dictionary<string, DbConnectionOptions>>();

            DbConnectionOptions dbConnectionOptions = new DbConnectionOptions();
            bool isDBReadWriteSeparate = Configs.GetConfigurationValue("AppSetting", "IsDBReadWriteSeparate").ToBool();
            if (masterDb || !isDBReadWriteSeparate)
            {
                dbConnectionOptions.ConnectionString =
                    Configs.GetConfigurationValue("DbConnections:" + dbConfigName + ":MasterDB", "ConnectionString");
                dbConnectionOptions.DatabaseType = (DatabaseType)Enum.Parse(typeof(DatabaseType),
                    Configs.GetConfigurationValue("DbConnections:" + dbConfigName + ":MasterDB", "DatabaseType"));
            }
            else
            {
                dbConnectionOptions = GetReadConn(dictRead);
            }

            if (conStringEncrypt)
            {
                dbConnectionOptions.ConnectionString = DEncrypt.Decrypt(dbConnectionOptions.ConnectionString);
            }

            return dbConnectionOptions;
        }

        /// <summary>
        ///     获取数据库连接连接配置
        /// </summary>
        /// <param name="masterDb">是否访问主库，默认为是，否则访问从库即只读数据库</param>
        /// <returns></returns>
        public static DbConnectionOptions GeDbConnectionOptions(bool masterDb = true)
        {
            bool conStringEncrypt = Configs.GetConfigurationValue("AppSetting", "ConStringEncrypt").ToBool();
            if (string.IsNullOrEmpty(dbConfigName))
            {
                dbConfigName = Configs.GetConfigurationValue("AppSetting", "DefaultDataBase");
            }

            Dictionary<string, DbConnectionOptions> dictRead = Configs.GetSection("DbConnections:" + dbConfigName + ":ReadDb")
                .Get<Dictionary<string, DbConnectionOptions>>();

            DbConnectionOptions dbConnectionOptions = new DbConnectionOptions();
            bool isDBReadWriteSeparate = Configs.GetConfigurationValue("AppSetting", "IsDBReadWriteSeparate").ToBool();
            if (masterDb || !isDBReadWriteSeparate)
            {
                dbConnectionOptions.ConnectionString =
                    Configs.GetConfigurationValue("DbConnections:" + dbConfigName + ":MasterDB", "ConnectionString");
                dbConnectionOptions.DatabaseType = (DatabaseType)Enum.Parse(typeof(DatabaseType),
                    Configs.GetConfigurationValue("DbConnections:" + dbConfigName + ":MasterDB", "DatabaseType"));
            }
            else
            {
                dbConnectionOptions = GetReadConn(dictRead);
            }

            if (conStringEncrypt)
            {
                dbConnectionOptions.ConnectionString = DEncrypt.Decrypt(dbConnectionOptions.ConnectionString);
            }

            return dbConnectionOptions;
        }

        /// <summary>
        ///     按从库数据库连接的策略进行返回连接对象，实现从库的负载均衡
        /// </summary>
        /// <param name="slaveData"></param>
        /// <returns></returns>
        private static DbConnectionOptions GetReadConn(Dictionary<string, DbConnectionOptions> slaveData)
        {
            DbConnectionOptions connectionOptions = new DbConnectionOptions();
            string queryDBStrategy = Configs.GetConfigurationValue("AppSetting", "QueryDBStrategy");
            if (queryDBStrategy == "Random") //随机策略
            {
                int index = new Random().Next(0, slaveData.Count - 1);
                connectionOptions = slaveData[index.ToString()];
            }
            else if (queryDBStrategy == "Polling") //轮询策略
            {
            }

            return connectionOptions;
        }

        #endregion Dapper Context
    }
}