using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.InteropServices;
using System.Text;
using System.Threading.Tasks;

namespace WebDoorCreator.Core
{
    public class IniFile
    {
        public string FileName;

        /// <summary>
        /// Constructor
        /// </summary>
        /// <PARAM name="INIPath"></PARAM>
        public IniFile(string INIPath)
        {
            FileName = INIPath;
        }

        /// <summary>
        /// Read data from the Ini file
        /// </summary>
        /// <PARAM name="Section"></PARAM>
        /// <PARAM name="Key"></PARAM>
        /// <returns></returns>
        public string ReadString(string Section, string Key)
        {
            StringBuilder temp = new StringBuilder(255);
            int i = GetPrivateProfileString(Section, Key, "", temp, 255, FileName);
            return temp.ToString();
        }

        /// <summary>
        /// Read a string. If not found use default value
        /// </summary>
        /// <param name="Section"></param>
        /// <param name="Key"></param>
        /// <param name="DefaultVal"></param>
        /// <returns></returns>
        public string ReadString(string Section, string Key, string DefaultVal)
        {
            string temp = ReadString(Section, Key);
            if (temp == "") temp = DefaultVal;
            return temp;
        }

        /// <summary>
        /// GetPrivateProfileString: import windows dll functions
        /// </summary>
        /// <param name="section"></param>
        /// <param name="key"></param>
        /// <param name="def"></param>
        /// <param name="retVal"></param>
        /// <param name="size"></param>
        /// <param name="filePath"></param>
        /// <returns></returns>
        [DllImport("kernel32")]
        private static extern int GetPrivateProfileString(string section, string key, string def, StringBuilder retVal, int size, string filePath);

        /// <summary>
        /// GetPrivateProfileSection: import windows dll functions
        /// </summary>
        /// <param name="section"></param>
        /// <param name="retVal"></param>
        /// <param name="size"></param>
        /// <param name="filePath"></param>
        /// <returns></returns>
        [DllImport("kernel32")]
        private static extern int GetPrivateProfileSection(string section, IntPtr retVal, uint size, string filePath);

        /// <summary>
        /// Read a complete section (keys=values)
        /// </summary>
        /// <param name="Section"></param>
        /// Section name
        /// <returns>
        /// restituisce delle stringhe keys=values da suddividere appunto come key/val successivamente
        /// </returns>
        public string[] ReadSection(string Section)
        {
            const int bufferSize = 2048; // max is 32767

            StringBuilder returnedString = new StringBuilder();

            IntPtr pReturnedString = Marshal.AllocCoTaskMem(bufferSize);
            try
            {
                int bytesReturned = GetPrivateProfileSection(Section, pReturnedString, bufferSize, FileName);
                if (bytesReturned > 0)
                {
                    //bytesReturned -1 to remove trailing \0
                    for (int i = 0; i < bytesReturned - 1; i++)
                    {
                        var currPointer = IntPtr.Add(pReturnedString, i);
                        var currChar = (char)Marshal.ReadByte(currPointer);
                        returnedString.Append(currChar);
                    }
                }
            }
            finally
            {
                Marshal.FreeCoTaskMem(pReturnedString);
            }

            string sectionData = returnedString.ToString();
            return sectionData.Split('\0');
        }
    }
}