using ConsoleApp2.Helpers;
using Microsoft.Extensions.Logging;
using System.IO;
using System.Text.RegularExpressions;
using ZstdSharp;
namespace ConsoleApp2.Services
{
    public class ZstSource : CsvSource
    {
        public ZstSource(string inputDir, string tableName, string delimiter = ",", char quoteChar = '"',
        ILogger? logger = null) : base(inputDir, tableName, delimiter = ",", quoteChar = '"', logger = null)
        {
            //throw new Exception("aaa");
            string pattern = $"^.*\\.{tableName}\\..*\\.sql.zst$";
             _sqlFilePath = Directory.GetFiles(_inputDir).FirstOrDefault(s => Regex.Match(s, pattern).Success);

        }
        private async Task<string> DecompressFile(string filePath)
        {
            using (var input = File.OpenRead(filePath))
            {
                using (var decopress = new DecompressionStream(input))
                {

                    var ms = new MemoryStream();
                    decopress.CopyTo(ms);
                    ms.Seek(0, SeekOrigin.Begin);
                    StreamReader reader = new StreamReader(ms);
                    var text = await reader.ReadToEndAsync();
                    return text;

                }
            }
        }
        public override async Task GetHeaderAndCsvFiles()
        {
            var text = await DecompressFile(_sqlFilePath);
            headers=await DumpDataHelper.GetCsvHeadersFromSqlFileAsync(text);
            csvFiles=await DumpDataHelper.GetCsvFileNamesFromSqlFileAsync(text, new Regex(@"'.+\.dat.zst'"));

        }
        public override async Task DoEnqueue(Action<DataRecord> action)
        {
           await GetHeaderAndCsvFiles();
            foreach (var file in csvFiles)
            {
                var filePath = Path.Combine(_inputDir, file);
                using (var input = File.OpenRead(filePath))
                {
                    using (var decopress = new DecompressionStream(input)) 
                    {
                        using( var reader = new StreamReader(decopress))
                        {
                            while (!reader.EndOfStream)
                            {
                                var line = await reader.ReadLineAsync();
                                var fields = ParseRow2(line, QuoteChar, Delimiter);
                                var record = new DataRecord(fields, _tableName, headers);
                                action?.Invoke(record);
                            }
                        }
                    }
                }

            }
        }
        public override async Task<DataRecord?> GetTestRecord()
        {
            await GetHeaderAndCsvFiles();
            var file = csvFiles.FirstOrDefault();
            if (file != null)
            {
                var filePath = Path.Combine(_inputDir, file);
                using (var input = File.OpenRead(filePath))
                {
                    using (var decopress = new DecompressionStream(input))
                    {
                        using (var reader = new StreamReader(decopress))
                        {
                            var line = await reader.ReadLineAsync();
                            var fields = ParseRow2(line, QuoteChar, Delimiter);
                            var record = new DataRecord(fields, _tableName, headers);
                            return record;
                        }

                    }
                }
            }
            return null;
        }
        public void Dispose()
        {
            //_reader.Dispose();
        }
    }
}