using MesETL.App.Options;
using Microsoft.Extensions.Logging;

namespace MesETL.App.Services.ETL;

/// <summary>
/// 截取提供ZST文件中的第一行，然后复制成指定数量的数据
/// </summary>
public class ZstMockReader : ZstReader
{
    private long _currentCount;
    private readonly long _mockCount;
    private DataRecord? _template;
    private readonly bool _deepCopy;
    private readonly string[]? _autoIncrementColumn;
    
    static readonly IReadOnlyList<int> Range = [500, 1500, 2500];
    
    public ZstMockReader(TableMockConfig mockConfig, string filePath, string tableName, string[] headers, string delimiter = ",", char quoteChar = '\"', ILogger? logger = null) : base(filePath, tableName, headers, delimiter, quoteChar, logger)
    {
        _mockCount = mockConfig.MockCount;
        _deepCopy = mockConfig.UseDeepCopy;
        _autoIncrementColumn = mockConfig.AutoIncrementColumn;
    }

    public ZstMockReader(TableMockConfig mockConfig, Stream stream, string tableName, string[] headers, string delimiter = ",", char quoteChar = '\"', ILogger? logger = null) : base(stream, tableName, headers, delimiter, quoteChar, logger)
    {
        _mockCount = mockConfig.MockCount;
        _deepCopy = mockConfig.UseDeepCopy;
        _autoIncrementColumn = mockConfig.AutoIncrementColumn;
    }

    public override async ValueTask<bool> ReadAsync()
    {
        if (_template is null)
        {
            if (!await base.ReadAsync())
                throw new InvalidOperationException("所提供的ZST源为空，无法生成模板数据");
            _template = Current.Clone() as DataRecord;
            if (_template is null)
                throw new ApplicationException("记录拷贝失败");
            _currentCount++;
            return true;
        }

        if (_deepCopy)
        {
            Current = _template.Clone() as DataRecord ?? throw new ApplicationException("记录拷贝失败");
            if(_autoIncrementColumn is not null)
            {
                foreach (var column in _autoIncrementColumn)
                {
                    Current[column] = (Convert.ToInt64(Current[column]) + 1).ToString();
                    _template = Current;
                }
            }

            Current["CompanyID"] = Range[Random.Shared.Next(0, Range.Count)].ToString();//随机CompanyID
        }
        else Current = _template;
        _currentCount++;
        return _currentCount < _mockCount;
    }
}