using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;
using Yaulw.Tools;
using Yaulw.Win32;
using System.Diagnostics;

namespace Yaulw.File
{
    /// <remarks>
    /// Responsible for Reading and Writing an INI File.
    /// Simply construct an INIFile Object passing in a File name and Path,
    /// as well as an enum that lists all the Categories and Keys.
    /// 
    /// An example *You can mix and match Categories and Keys as needed *:
    /// public enum INICatsNKeys
    /// {
    ///    App_Settings__Load_XML_At_StartUp,
    ///    App_Settings__Allow_Command_Line_to_override_INI,   
    ///    App_Settings__Default_User,
    ///    App_Settings__Default_Server,
    ///    Runtime_Debug__Error_Debug_Level,
    ///    Data_Access__Read_Only,
    ///    Settings__Program_Folder,
    ///    Settings__User1_Default,
    ///    Recent_File_List__File1,
    ///    Recent_File_List__File2,
    ///    Recent_File_List__File3,
    ///    Recent_File_List__File4,    
    /// }
    /// 
    /// The '__' Character signifies a category to Key change
    /// the '_' will be replaced by ' ', when actually writing to the Ini File.
    /// </remarks>
    public class INIFile
    {   
        #region Private Members

        private string _IniPathNFileName = String.Empty;
        private Type _IniKeysNCategories = null;

        #endregion

        #region Construction

        /// <summary>
        /// Initialize an INIFile object with a valid path and FileName to write/read from.
        /// Also pass in an Enum Type that contains Category and Key Information. This Enum will be used
        /// to read and write to the INIFile (to determine which Section/Key to read/write from/to)
        /// </summary>
        /// <param name="IniPathNFileName">Pass in the full file name and path to use * Creates Directory, if it does not exits *</param>
        /// <param name="IniKeysNCategories">Pass in an Enum that specifies the Categories and Keys</param>
        /// <exception cref="ArgumentException">Thrown if an invalid Enum is passed in via IniKeysNCategories</exception>
        public INIFile(string IniPathNFileName, Type IniKeysNCategories)
        {                        
            // Check and ensure Enum Accuracy
            if (IniKeysNCategories.IsEnum && EnumTool.EnumType_HasCategoryNKey(IniKeysNCategories))
            {
                _IniKeysNCategories = IniKeysNCategories;
            }
            else
                throw new ArgumentException("IniKeysNCategories is not an Enum or not all Enums contain Key and Category Information");

            // Ensure Directory Existence
            if (!Directory.Exists(Path.GetDirectoryName(IniPathNFileName)))
                Directory.CreateDirectory(Path.GetDirectoryName(IniPathNFileName));
            _IniPathNFileName = IniPathNFileName;
        }

        #endregion

        #region Public Properties
        
        /// <summary>
        /// Ini File Used by IniFile
        /// </summary>
        public string IniFile { get { return _IniPathNFileName; } }

        #endregion      

        #region Public Ini Key Reader / Writer Functions

        /// <summary>
        /// Use this to directly set a key to any string value
        /// </summary>
        /// <param name="cKey">Specify Key and category set Directly</param>
        /// <param name="Value">value to set</param>
        /// <exception cref="ArgumentException">If cKey is not a valid Category/Key Pair Enum</exception>
        public void SetKeyValue<T>(Enum cKey, T Value)
        {
            if (EnumTool.Enum_HasCategoryNKey(cKey))
            {
                string Category;
                string Key;
                EnumTool.Enum_ToCategoryNKey(cKey, out Category, out Key);
                string ValueStr = ObjTool.ConvertObjToString<T>(Value);
                SetKeyValueString(Category, Key, ValueStr);
            }
            else
            {
                throw new ArgumentException("cKey must have both Category and Key Information");
            }
        }

        /// <summary>
        /// Use this to directly retrieve a key
        /// </summary>
        /// <param name="cKey">Specify Key and category set Directly</param>
        /// <param name="defaultValue">default value to return, if not found</param>
        /// <returns>value retrieved or default value</returns>
        /// <exception cref="ArgumentException">If cKey is not a valid Category/Key Pair Enum</exception>        
        public T GetKeyValue<T>(Enum cKey, T defaultValue)
        {
            try
            {
                if (EnumTool.Enum_HasCategoryNKey(cKey))
                {
                    string Category;
                    string Key;
                    EnumTool.Enum_ToCategoryNKey(cKey, out Category, out Key);

                    // Get Key and verify that something was found
                    string defaultValueStr = ObjTool.ConvertObjToString<T>(defaultValue);
                    string KeyValue = GetKeyValueString(Category, Key, defaultValueStr);
                    bool bHasAValue = (KeyValue.Trim().Length != 0);

                    // always write the value back out to ini 
                    SetKeyValue(cKey, bHasAValue ? KeyValue : defaultValueStr);

                    // Return value
                    if (bHasAValue)
                    {
                        return ObjTool.ConvertStringToObj<T>(KeyValue);
                    }
                    else
                    {
                        return defaultValue;
                    }
                }
                else
                {
                    throw new ArgumentException("cKey must have both Category and Key Information");
                }
            }
            catch (Exception) { /* ignore */ }
            return defaultValue;
        }

        #endregion
                                 
        #region Private Generic Ini Key Reader / Writer Functions

        /// <summary>
        /// Set a value for the specified Key and for the specified category
        /// </summary>
        /// <param name="category">specify category</param>
        /// <param name="key">specify key</param>
        /// <param name="value">specify a value to set</param>
        private void SetKeyValueString(string category, string key, string value)
        {
            bool bSuccess = Kernel32.WritePrivateProfileString(category, key, value, IniFile);
            Debug.Assert(bSuccess);
        }

        /// <summary>
        /// Retrieve the value for a specified Key and for a specified category
        /// </summary>
        /// <param name="category">specify category</param>
        /// <param name="key">specify key</param>
        /// <param name="defaultValue">specify default value, returned when no value found</param>
        /// <returns>the value for the Key, or default value if no value found</returns>
        private string GetKeyValueString(string category, string key, string defaultValue)
        {
            StringBuilder returnString = new StringBuilder(1024); 
            Kernel32.GetPrivateProfileString(category, key, defaultValue, returnString, 1024, IniFile);
            return returnString.ToString().Split('\0')[0];
        }

        #endregion

        #region Private Generic Ini File Readers (Not Used)

        /// <summary>
        /// Use this to return all the categories in an INI File
        /// </summary>
        /// <returns>a list with Gategory Items, or 0 length list is none found</returns>
        private List<string> GetAllCategories()
        {
            StringBuilder returnString = new StringBuilder(65536);
            uint returnValue = Kernel32.GetPrivateProfileString(null, null, null, returnString, 65536, IniFile);
            List<string> result = new List<string>(returnString.ToString().Split('\0'));
            result.RemoveRange(result.Count - 2, 2);
            return result;
        }

        /// <summary>
        /// Use this to return the Keys from a category from an INI File
        /// </summary>
        /// <returns>a list with Key Items, or 0 length list is none found</returns>
        private List<string> GetAllKeysInCategory(string category)
        {
            StringBuilder returnString = new StringBuilder(32768);
            Kernel32.GetPrivateProfileString(category, null, null, returnString, 32768, IniFile);
            List<string> result = new List<string>(returnString.ToString().Split('\0'));
            result.RemoveRange(result.Count - 2, 2);
            return result;
        }

        #endregion
    }
}