using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Xml.Linq;

namespace FastExcel
{
    /// <summary>
    /// Row that contains the Cells
    /// </summary>
    public class Row
    {
        /// <summary>
        /// The Row Number (Row numbers start at 1)
        /// </summary>
        public int RowNumber { get; set; }

        /// <summary>
        /// The collection of cells for this row
        /// </summary>
        public IEnumerable<Cell> Cells { get; set; }

        /// <summary>
        /// Create a new Row
        /// </summary>
        /// <param name="rowNumber">Row number starting with 1</param>
        /// <param name="cells">Cells on this row</param>
        public Row(int rowNumber, IEnumerable<Cell> cells)
        {
            if (rowNumber <= 0)
            {
                throw new Exception("Row numbers starting at 1");
            }
            RowNumber = rowNumber;
            Cells = cells;
        }

        /// <summary>
        /// Constructor
        /// </summary>
        public Row(XElement rowElement, Worksheet worksheet)
        {
            try
            {
                RowNumber = (from a in rowElement.Attributes("r")
                             select int.Parse(a.Value)).First();
            }
            catch (Exception ex)
            {
                throw new Exception("Row Number not found", ex);
            }
                        
            if (rowElement.HasElements)
            {
                Cells = GetCells(rowElement, worksheet);
            }
        }

        /// <summary>
        /// Retreive cell that is in column specified
        /// </summary>
        /// <param name="columnName">Column letter or defined name</param>
        /// <returns>Matching cell or null if not found</returns>
        public Cell GetCellByColumnName(string columnName)
        {
            return (from c in Cells where c.ColumnName == columnName select c).FirstOrDefault();
        }

        // <summary>
        // Get all cells in this row.
        // </summary>
        private IEnumerable<Cell> GetCells(XElement rowElement, Worksheet worksheet)
        {
            foreach (XElement cellElement in rowElement.Elements())
            {
                yield return new Cell(cellElement, worksheet);
            }
        }

        // <summary>
        // Output Row as an Xml element with cells nested
        // </summary>
        internal StringBuilder ToXmlString(SharedStrings sharedStrings)
        {
            var row = new StringBuilder();

            if (Cells != null && Cells.Any())
            {
                row.AppendFormat("<row r=\"{0}\">", RowNumber);
                try
                {
                    foreach (Cell cell in Cells)
                    {
                        row.Append(cell.ToXmlString(sharedStrings, RowNumber));
                    }
                }
                finally
                {
                    row.Append("</row>");
                }
            }

            return row;
        }

        /// <summary>
        /// Merge this row and the passed one togeather
        /// </summary>
        /// <param name="row">Row to be merged into this one</param>
        internal void Merge(Row row)
        {
            // Merge cells
            var outputList = new List<Cell>();
            foreach (var cell in Cells.Union(row.Cells).GroupBy(c => c.ColumnNumber))
            {
                int count = cell.Count();
                if (count == 1)
                {
                    outputList.Add(cell.First());
                }
                else
                {
                    cell.First().Merge(cell.Skip(1).First());

                    outputList.Add(cell.First());
                }
            }

            // Sort
            Cells = (from c in outputList
                          orderby c.ColumnNumber
                          select c);
        }
    }
}