using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data.SQLite;
using System.Data;

namespace CNAS_DBSync
{

    public static class SQLiteHelper
    {
        private static log4net.ILog log = log4net.LogManager.GetLogger("SQLiteHelper");
        private static string connectionString = string.Empty;

        /// <summary>
        /// 根据数据源、密码、版本号设置连接字符串。
        /// </summary>
        /// <param name="datasource">数据源。</param>
        /// <param name="password">密码。</param>
        /// <param name="version">版本号（缺省为3）。</param>
        public static void SetConnectionString(string datasource, string password, int version = 3)
        {
            connectionString = string.Format("Data Source={0};Version={1};password={2}",
                datasource, version, password);
        }

        /// <summary>
        /// 创建一个数据库文件。如果存在同名数据库文件，则会覆盖。
        /// </summary>
        /// <param name="dbName">数据库文件名。为null或空串时不创建。</param>
        /// <param name="password">（可选）数据库密码，默认为空。</param>
        /// <exception cref="Exception"></exception>
        public static void CreateDB(string dbName)
        {
            if (!string.IsNullOrEmpty(dbName))
            {
                try { SQLiteConnection.CreateFile(dbName); }
                catch (Exception) { throw; }
            }
        }

        /// <summary> 
        /// 对SQLite数据库执行增删改操作，返回受影响的行数。 
        /// </summary> 
        /// <param name="sql">要执行的增删改的SQL语句。</param> 
        /// <param name="parameters">执行增删改语句所需要的参数，参数必须以它们在SQL语句中的顺序为准。</param> 
        /// <returns></returns> 
        /// <exception cref="Exception"></exception>
        public static int ExecuteNonQuery(string sql, params SQLiteParameter[] parameters)
        {
            int affectedRows = 0;
            using (SQLiteConnection connection = new SQLiteConnection(connectionString))
            {
                using (SQLiteCommand command = new SQLiteCommand(connection))
                {
                    try
                    {
                        connection.Open();
                        command.CommandText = sql;
                        if (parameters.Length != 0)
                        {
                            command.Parameters.AddRange(parameters);
                        }
                        affectedRows = command.ExecuteNonQuery();
                    }
                    catch (Exception) { throw; }
                }
            }
            return affectedRows;
        }

        /// <summary>
        /// 批量处理数据操作语句。
        /// </summary>
        /// <param name="list">SQL语句集合。</param>
        /// <exception cref="Exception"></exception>
        public static void ExecuteNonQueryBatch(List<KeyValuePair<string, SQLiteParameter[]>> list)
        {
            using (SQLiteConnection conn = new SQLiteConnection(connectionString))
            {
                try { conn.Open(); }
                catch { throw; }
                using (SQLiteTransaction tran = conn.BeginTransaction())
                {
                    using (SQLiteCommand cmd = new SQLiteCommand(conn))
                    {
                        try
                        {
                            foreach (var item in list)
                            {
                                cmd.CommandText = item.Key;
                                if (item.Value != null)
                                {
                                    cmd.Parameters.AddRange(item.Value);
                                }
                                cmd.ExecuteNonQuery();
                            }
                            tran.Commit();
                        }
                        catch (Exception) { tran.Rollback(); throw; }
                    }
                }
            }
        }

        /// <summary>
        /// 执行查询语句，并返回第一个结果。
        /// </summary>
        /// <param name="sql">查询语句。</param>
        /// <returns>查询结果。</returns>
        /// <exception cref="Exception"></exception>
        public static object ExecuteScalar(string sql, params SQLiteParameter[] parameters)
        {
            using (SQLiteConnection conn = new SQLiteConnection(connectionString))
            {
                using (SQLiteCommand cmd = new SQLiteCommand(conn))
                {
                    try
                    {
                        conn.Open();
                        cmd.CommandText = sql;
                        if (parameters.Length != 0)
                        {
                            cmd.Parameters.AddRange(parameters);
                        }
                        return cmd.ExecuteScalar();
                    }
                    catch (Exception) { throw; }
                }
            }
        }

        /// <summary> 
        /// 执行一个查询语句，返回一个包含查询结果的DataTable。 
        /// </summary> 
        /// <param name="sql">要执行的查询语句。</param> 
        /// <param name="parameters">执行SQL查询语句所需要的参数，参数必须以它们在SQL语句中的顺序为准。</param> 
        /// <returns></returns> 
        /// <exception cref="Exception"></exception>
        public static DataTable ExecuteQuery(string sql, params SQLiteParameter[] parameters)
        {
            using (SQLiteConnection connection = new SQLiteConnection(connectionString))
            {
                using (SQLiteCommand command = new SQLiteCommand(sql, connection))
                {
                    if (parameters.Length != 0)
                    {
                        command.Parameters.AddRange(parameters);
                    }
                    SQLiteDataAdapter adapter = new SQLiteDataAdapter(command);
                    DataTable data = new DataTable();
                    try { adapter.Fill(data); }
                    catch (Exception) { throw; }
                    return data;
                }
            }
        }

        /// <summary> 
        /// 执行一个查询语句，返回一个关联的SQLiteDataReader实例。 
        /// </summary> 
        /// <param name="sql">要执行的查询语句。</param> 
        /// <param name="parameters">执行SQL查询语句所需要的参数，参数必须以它们在SQL语句中的顺序为准。</param> 
        /// <returns></returns> 
        /// <exception cref="Exception"></exception>
        public static SQLiteDataReader ExecuteReader(string sql, params SQLiteParameter[] parameters)
        {
            SQLiteConnection connection = new SQLiteConnection(connectionString);
            SQLiteCommand command = new SQLiteCommand(sql, connection);
            try
            {
                if (parameters.Length != 0)
                {
                    command.Parameters.AddRange(parameters);
                }
                connection.Open();
                return command.ExecuteReader(CommandBehavior.CloseConnection);
            }
            catch (Exception) { throw; }
        }

        /// <summary> 
        /// 查询数据库中的所有数据类型信息。
        /// </summary> 
        /// <returns></returns> 
        /// <exception cref="Exception"></exception>
        public static DataTable GetSchema()
        {
            using (SQLiteConnection connection = new SQLiteConnection(connectionString))
            {
                try
                {
                    connection.Open();
                    return connection.GetSchema("TABLES");
                }
                catch (Exception) { throw; }
            }
        }



        /// <summary>
        /// 读取Excel第一个工作表的内容
        /// </summary>
        /// <param name="strPath"></param>
        /// <returns></returns>
        public static Dictionary<string, DataTable> ReadSQLiteTables()
        {
            Dictionary<string, DataTable> dictTables = new Dictionary<string, DataTable>();
            try
            {
                string sql = "";
                DataTable TablesName = ExecuteQuery("select * from sqlite_master;", new SQLiteParameter[] { });//得到所有表
                foreach (DataRow dr in TablesName.Rows)
                {
                    string strTableName = dr[1].ToString();

                    sql = string.Format("SELECT * FROM [{0}]", strTableName); //查询字符串
                    

                    dictTables.Add(strTableName, ExecuteQuery(sql, new SQLiteParameter[] { }));
                }
            }
            catch (Exception ex)
            {
                //发生异常，写入日志
                log.Error(ex.Message);
            }
            return dictTables;
        }
    }
}
