//
//  Class:			ExcelReader
//	Current CLR:	4.0.30319.34209
//	System:			Microsoft Visual Studio 10.0
//	Author:			dani
// 	Created:		6/15/2015 10:03:40 PM
//
//	Copyright (c) 2015 Informatikbüro Daniel Schick. All rights reserved.

using System;
using System.Collections.Generic;
using System.Data;
using System.Globalization;
using System.IO;

using log4net;
using Microsoft.Office.Interop.Excel;

namespace bsmd.ExcelReadService
{
    public class ExcelReader : IDisposable
    {        
        private ILog _log = LogManager.GetLogger(typeof(ExcelReader));
        private Workbooks _excelWorkbooks;
        private Application _excelApp;
        private Dictionary<string, Name> _nameDict;

        public ExcelReader(string filePath)
        {
            this._excelApp = new Application();
            this._excelWorkbooks = _excelApp.Workbooks;
            Workbook portcall = _excelWorkbooks.Open(filePath, 0, true, 5, "", "", false, XlPlatform.xlWindows, "", false, false, 0, false, false, false);
            _nameDict = new Dictionary<string, Name>();
            foreach(Name name in portcall.Names)
            {
                _nameDict[name.Name] = name;
            }
        }

        public string ReadText(string lookup)
        {
            if (!_nameDict.ContainsKey(lookup)) return null;
            var val = _nameDict[lookup].RefersToRange.Value;
            var val2 = _nameDict[lookup].RefersToRange.Value2;
            if(val != null)
                return val.ToString();
            if (val2 != null)
                return val2.ToString();
            return null;
        }
        

        public void Dispose()
        {
            if (this._excelWorkbooks != null)
                this._excelWorkbooks.Close();
            if (this._excelApp != null)
                this._excelApp.Quit();
        }

        internal DateTime? ReadDate(string lookup)
        {
            try
            {
                var val = _nameDict[lookup].RefersToRange.Value;
                if (val is DateTime) return val;
                if (val is double)
                    return DateTime.FromOADate(val);
                DateTime date;
                if (DateTime.TryParse(val, out date))
                    return date;
                // TODO: weitere varianten ausprobieren

                return null;
            }
            catch (Exception)
            {
                _log.WarnFormat("error parsing datetime for lookup {0}", lookup);
                return null;
            }            
        }

        internal DateTime? ReadTime(string lookup)
        {            
            try
            {
                var val = _nameDict[lookup].RefersToRange.Value;
                if (val is DateTime) return val;
                if (val is double)
                    return DateTime.FromOADate(val);
                DateTime date;
                if (DateTime.TryParseExact(val, "HH:mm:ss", CultureInfo.InvariantCulture, DateTimeStyles.NoCurrentDateDefault, out date))
                    return date;
                if (DateTime.TryParseExact(val, "HH:mm", CultureInfo.InvariantCulture, DateTimeStyles.NoCurrentDateDefault, out date))
                    return date;
                return null;
            }
            catch (Exception)
            {
                _log.WarnFormat("error reading time for lookup {0}", lookup);
                return null;
            }
        }

        internal double? ReadNumber(string lookup)
        {
            double result;
            try
            {
                var val = _nameDict[lookup].RefersToRange.Value;
                if (val is double) return val;
                if (val is string)
                {
                    if (double.TryParse(val, NumberStyles.None, CultureInfo.InvariantCulture, out result))
                        return result;
                    if (double.TryParse(val, out result))
                        return result;
                }
                return null;
            }
            catch (Exception)
            {
                _log.WarnFormat("error reading number for lookup {0}", lookup);
                return null;
            }
        }
       
    }
}