using System.IO;

namespace RhSolutions.Services;

public class GuessReader : IReader
{
    private readonly Application _application;
    private ProgressBar _progressBar;

    public GuessReader(Application application)
    {
        _application = application;
    }

    public Dictionary<Product, double> ReadProducts(Range range)
    {
        _progressBar = new("Поиск возможных пар артикул-количество...", range.Columns.Count);
        int? productColumnIndex = null;
        List<int> amountColumnIndeces = new();

        for (int column = 1; column < range.Columns.Count + 1; column++)
        {
            _progressBar.Update();
            if (productColumnIndex == null && IsProductColumn(range.Columns[column]))
            {
                productColumnIndex = column;
            }
            else if (IsAmountColumn(range.Columns[column]))
            {
                amountColumnIndeces.Add(column);
            }
        }

        if (productColumnIndex == null)
        {
            throw new ArgumentException("Колонка с артикулом не определена");
        }

        if (amountColumnIndeces.Count == 0)
        {
            throw new ArgumentException("Колонка с количеством не определена");
        }

        else if (amountColumnIndeces.Count == 1)
        {
            return GetDictionaryFromColumns(range.Columns[productColumnIndex],
                range.Columns[amountColumnIndeces.First()]);
        }

        else
        {
            int amountColumnIndex = amountColumnIndeces
                .Where(i => i > productColumnIndex)
                .FirstOrDefault();

            if (amountColumnIndex == 0)
            {
                amountColumnIndex = amountColumnIndeces 
                    .OrderBy(i => i)
                    .Where(i => i < productColumnIndex)
                    .LastOrDefault();
            }

            if (amountColumnIndex == 0)
            {
                throw new ArgumentException("Колонка с количеством не определена");
            }

            return GetDictionaryFromColumns(range.Columns[productColumnIndex],
                range.Columns[amountColumnIndex]);
        }
    }

    private bool IsProductColumn(Range column)
    {
        int successCounter = 0;
        var cells = column.Value2;

        if (cells == null)
        {
            return false;
        }

        for (int row = 1; row < column.Rows.Count + 1; row++)
        {            
            object currentCell = column.Rows.Count == 1 ? cells : cells[row, 1];
            if (currentCell == null)
            {
                continue;
            }

            if (ProductSku.TryParse(currentCell.ToString(), out IEnumerable<ProductSku> skus))
            {
                successCounter++;
            }

            if (successCounter > 2)
            {
                return true;
            }
        }

        return successCounter > 0;
    }

    private bool IsAmountColumn(Range column)
    {
        int successCounter = 0;
        var cells = column.Value2;

        if (cells == null)
        {
            return false;
        }

        for (int row = 1; row < column.Rows.Count + 1; row++)
        {
            object currentCell = column.Rows.Count == 1 ? cells : cells[row, 1];
            if (currentCell == null)
            {
                continue;
            }

            double value = 0.0;

            if (currentCell.GetType() == typeof(double))
            {
                value = (double)currentCell;
            }

            else if (currentCell.GetType() == typeof(string))
            {
                double.TryParse((string)currentCell, out value);
            }

            if (value == 0)
            {
                continue;
            }

            if (value > 30000)
            {
                return false;
            }
            
            successCounter++;

            if (successCounter > 5)
            {
                return true;
            }
        }

        return successCounter > 0;
    }

    private Dictionary<Product, double> GetDictionaryFromColumns(Range productColumn, Range amountColumn)
    {
        Dictionary<Product, double> result = new();
        _progressBar = new("Заполняю словарь значений...", productColumn.Rows.Count);

        for (int row = 1; row < productColumn.Rows.Count + 1; row++)
        {
            _progressBar.Update();
            var amountCells = amountColumn.Value2;
            object currentAmountCell = productColumn.Rows.Count == 1 ? amountCells : amountCells[row, 1];

            var productCells = productColumn.Value2;
            object currentProductCell = productColumn.Rows.Count == 1 ? productCells : productCells[row, 1];

            double amountValue = 0.0;

            if (currentAmountCell == null || currentProductCell == null)
            {
                continue;
            }

            if (ProductSku.TryParse(currentProductCell.ToString(), out IEnumerable<ProductSku> skus))
            {
                Product p = new(skus.First())
                {
                    Name = "Распознанный артикул"
                };
                if (currentAmountCell.GetType() == typeof(double))
                {
                    amountValue = (double)currentAmountCell;
                }
                else if (currentAmountCell.GetType() == typeof(string))
                {
                    double.TryParse((string)currentAmountCell, out amountValue);
                }
                if (result.ContainsKey(p))
                {
                    result[p] += amountValue;
                }
                else
                {
                    result.Add(p, amountValue);
                }
            }
        }
        return result;
    }

    public List<(string, Dictionary<Product, double>)> ReadProducts(IEnumerable<Worksheet> worksheets)
    {
        List<(string, Dictionary<Product, double>)> result = new();
        foreach (Worksheet worksheet in worksheets)
        {
            string wbName = Path.GetFileNameWithoutExtension(
                worksheet.Parent.Name);
            Range range = worksheet.UsedRange;
            var productsDict = ReadProducts(range);
            result.Add((wbName, productsDict));
        }
        return result;
    }

    public List<(string, Dictionary<Product, double>)> ReadProducts(string[] files)
    {
        _progressBar = new("Открываю исходные файлы...", files.Length);
        List<Worksheet> worksheets = new();

        _application.ScreenUpdating = false;
        foreach (string file in files)
        {
            Workbook wb = _application.Workbooks.Open(file);
            worksheets.Add(wb.ActiveSheet);
            _progressBar.Update();
        }
        _application.ScreenUpdating = true;
        var result = ReadProducts(worksheets);
        foreach (var ws in worksheets)
        {
            ws.Parent.Close();
        }
        return result;
    }

    public void Dispose()
    {
        _progressBar?.Dispose();
    }
}