using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Linq;
using xCommons.Extensions;
using xDataService.Models;

namespace xDataService.Extensions
{
    public static class XReferenceExtensions
    {
        /// <summary>
        /// Converts an XReference<T> to String Representation ...
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="source"></param>
        /// <param name="splitter"></param>
        /// <returns></returns>
        public static string ToXReferenceString<T>(
            this XReference<T> source,
            char? splitter = '_'
        )
        {
            //
            var result = string.Empty;

            //
            // Normalize Splitter ...
            if (!splitter.HasValue)
            {
                splitter = '_';
            }

            //
            if (!source.IsNullOrDefault() && source.Index >= 0 && !source.ReferencedTo.IsNull())
            {
                result = $"{source.ProvidedFor}{splitter.Value}{source.ReferencedTo}{splitter.Value}{source.Index}";
            }

            //
            return result;
        }

        /// <summary>
        /// Parse an String and Extract to XReference<T> if it's Described ...
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="source"></param>
        /// <param name="splitter"></param>
        /// <returns></returns>
        public static XReference<T> FromXReference<T>(
            this string source,
            char? splitter = '_'
        )
        {
            //
            XReference<T> result = null;

            //
            // Normalize Splitter ...
            if (!splitter.HasValue)
            {
                splitter = '_';
            }

            //
            if (!source.IsNullOrEmpty())
            {
                //
                var parts = source.Split(splitter.Value);
                if (parts.Count() >= 3)
                {
                    //
                    T referencedTo;
                    try
                    {
                        referencedTo = (T)Convert.ChangeType(parts[1], typeof(T));
                    } catch
                    {
                        referencedTo = (T)TypeDescriptor.GetConverter(typeof(T)).ConvertFrom(parts[1]);                        
                    }

                    //
                    // Parse String Parts ...
                    result = new XReference<T>
                    {
                        ReferencedTo = referencedTo,
                        Index = (int)Convert.ChangeType(parts[2], typeof(int)),
                        ProvidedFor = (string)Convert.ChangeType(parts[0], typeof(string)),
                    };
                }
            }

            //
            return result;
        }

        /// <summary>
        /// Converts a Collection of XReference<T> to it's String Representation ...
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="source"></param>
        /// <returns></returns>
        public static string ToXReferenceString<T>(this IEnumerable<XReference<T>> source)
        {
            //
            var result = string.Empty;

            //
            if (!source.IsNull() && source.HasChild())
            {
                //
                var stringList = new List<string>();
                foreach (var s in source)
                {
                    //
                    var sr = ToXReferenceString(s);
                    if (!sr.IsNullOrEmpty())
                    {
                        stringList.Add(sr);
                    }
                }

                //
                result = stringList.ToListString();
            }

            //
            return result;
        }
        public static string ToXReferenceString<T>(this ICollection<XReference<T>> source)
        {
            //
            var result = source
                .AsEnumerable()
                .ToXReferenceString();

            //
            return result;
        }
        public static string ToXReferenceString<T>(this IList<XReference<T>> source)
        {
            //
            var result = source
                .AsEnumerable()
                .ToXReferenceString();

            //
            return result;
        }

        /// <summary>
        /// Parse an string to XReference<T> Collection Representation ...
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="source"></param>
        /// <returns></returns>
        public static IList<XReference<T>> ParseXReferenceList<T>(this string source)
        {
            //
            var result = new List<XReference<T>>();

            //
            if (!source.IsNullOrEmpty())
            {
                //
                var stringList = source.ParseListString<string>();
                if (!stringList.IsNull() && stringList.HasChild())
                {
                    //
                    foreach (var s in stringList)
                    {
                        //
                        var sr = FromXReference<T>(s);
                        if (!sr.IsNullOrDefault())
                        {
                            result.Add(sr);
                        }
                    }
                }
            }

            //
            return result;
        }
    }
}