using System;
using System.Collections.Generic;
using System.Data;
using System.Data.OleDb;
using System.IO;
using System.Linq;
using System.Runtime.Remoting.Contexts;
using System.Text;
using System.Threading.Tasks;

using NCalc;

namespace ConsoleApp
{
    internal class Mdb
    {
        static void Main(string[] args)
        {
            //var expr = new Expression("1 + 2");
            //Func<int> f = expr.ToLambda<int>();
            //Console.WriteLine(f()); // will print 3

            //var expr = new Expression("([Param1] + 2)* [Param2]");
            //Func<ExpressionContext, double> f = expr.ToLambda<ExpressionContext, double>();

            //var context = new ExpressionContext { Param1 = 33.4, Param2 = 40.48 };
            //Console.WriteLine(f(context)); // will print True
            Dictionary<string, object> parameters = new Dictionary<string, object>() {
                {"Param1", 413.5 },
                {"Param3", 40.48}
            };

            var formula = "([Param1] + 2)* [Param2]";
            var result = EvaluateFormula(formula, parameters);
            Console.WriteLine(result);
        }

        public static double EvaluateFormula(string formula, Dictionary<string, object> parameters)
        {
            Expression e = new Expression(formula);
            e.Parameters = parameters;
            return Convert.ToDouble(e.Evaluate());
        }

        private static bool TestMBD()
        {
            Console.WriteLine("请输入MDB文件完整路径（例如：C:\\cs.mdb）：");
            string mdbPath = Console.ReadLine();
            mdbPath = @"D:\其他\地质\附件\和平站.mdb";
            if (!File.Exists(mdbPath))
            {
                Console.WriteLine("文件不存在！");
                return false;
            }

            // 检查是否为Access95 或Access97 MDB（旧格式）
            // 如果太旧，Jet或ACE也无法打开，需要转换
            if (IsOldAccessDatabase(mdbPath))
            {
                Console.WriteLine("检测到此MDB文件为非常老的Access版本 (如Access 95/97)，OLEDB 不支持直接读取。建议使用 Access 打开并另存为 2000/2003 格式。或者使用专门的MDB转换工具。");
                Console.ReadKey();
                return false;
            }

            string[] providers = new[]
            {
                "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + mdbPath + ";",
                "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" + mdbPath + ";Persist Security Info=False;"
            };

            foreach (var provider in providers)
            {
                Console.WriteLine($"尝试使用提供程序: {provider}");
                try
                {
                    ExportWithProvider(mdbPath, provider);
                    Console.WriteLine($"使用 {provider} 导出完成！\n===============================\n");
                }
                catch (Exception ex)
                {
                    Console.WriteLine($"使用 {provider} 出错: {ex.Message}\n===============================\n");
                }
            }

            Console.WriteLine("所有尝试完成！如果依然失败，请确认MDB文件格式是否过于陈旧。\n按任意键退出。");
            Console.ReadKey();
            return true;
        }

        static void ExportWithProvider(string mdbPath, string provider)
        {
            using (var conn = new OleDbConnection(provider))
            {
                conn.Open();
                DataTable tables = conn.GetOleDbSchemaTable(OleDbSchemaGuid.Tables, new object[] { null, null, null, "TABLE" });
                string outputDir = Path.Combine(Path.GetDirectoryName(mdbPath), "ExportedCSVs_" + (provider.Contains("Jet") ? "JET" : "ACE"));
                Directory.CreateDirectory(outputDir);

                foreach (DataRow row in tables.Rows)
                {
                    string tableName = row["TABLE_NAME"].ToString();
                    Console.WriteLine($"导出表: {tableName}");

                    var cmd = new OleDbCommand($"SELECT * FROM [{tableName}]", conn);
                    var adapter = new OleDbDataAdapter(cmd);
                    var dt = new DataTable();
                    adapter.Fill(dt);

                    string csvFilePath = Path.Combine(outputDir, tableName + ".csv");
                    using (var writer = new StreamWriter(csvFilePath, false, System.Text.Encoding.UTF8))
                    {
                        writer.WriteLine(string.Join(",", dt.Columns.Cast<DataColumn>().Select(c => $"\"{c.ColumnName}\"")));

                        foreach (DataRow dr in dt.Rows)
                        {
                            var fields = dr.ItemArray.Select(field => $"\"{field?.ToString()?.Replace("\"", "\"\"") ?? ""}\"");
                            writer.WriteLine(string.Join(",", fields));
                        }
                    }
                    Console.WriteLine($"已导出: {csvFilePath}");
                }
            }
        }

        static bool IsOldAccessDatabase(string path)
        {
            // 检查文件头字节，老MDB的文件头通常以0x00 0x01 0x00 0x00 开头
            // 或者标识0x00 0x01 0x00 0x00 0x00 0x00
            byte[] header = new byte[4];
            using (var fs = new FileStream(path, FileMode.Open, FileAccess.Read))
            {
                fs.Read(header, 0, 4);
            }

            return header[0] == 0x00 && header[1] == 0x01;
        }
    }
}