using System;
using System.IO;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Controls.Primitives;
using System.Windows;
using Txt2Bib.Records;
using System.ComponentModel.DataAnnotations;

namespace Txt2Bib
{
    internal class Text2Bib
    {
        private readonly Dictionary<string, string> _citTypes = new()
        {
            { "J" , "article" },
            { "B", "book" },
            { "P", "conference" },
            { "C" , "inbook" }
        };
        /// <summary>
        /// Generate single .bib file from input text files
        /// </summary>
        /// <param name="filenames"></param>
        /// <returns></returns>
        public string Generate(string filenames)
        {
            var paths = filenames.Trim().Split('\n');
            string result = "";
            string output = "";

            foreach (var path in paths)
            {
                var reader = File.OpenText(path);
                byte[] contentBytes = File.ReadAllBytes(path);

                result += Encoding.Latin1.GetString(contentBytes);
            }

            var entries = result.Split('%').ToList<string>().Select(entry =>
            {
                return Process(entry);
            });

            foreach (var entry in entries)
            {
                output += entry;
            }

            return output;
        }

        private string Process(string entryFromTxt)
        {
            var lines = entryFromTxt.Trim().Replace("\r", string.Empty).Split("\n");
            var type = lines.First();

            System.Diagnostics.Debug.WriteLine($"Entry: {entryFromTxt}; Prima riga: {type}");

            string citation = type switch
            {
                "J" => ConvertArticle(lines),
                //"B" => new BookBib(),
                //"C" => new ChapterBib(),
                //"P" => new ConferenceBib(),
                _ => ConvertArticle(lines),
            };

            return citation;
        }

        private static string ConvertArticle(string[] entryLines)
        {
            var temp = entryLines[1].Split(',');
            var rearrange = (string a) =>
            {
                a = a.Trim();
                var s = a.Split(' ');
                return $"{s[1]} {s[0]}";
            }; 
            var authors = temp.Select(a => rearrange(a)).ToArray();
            var article = new ArticleBib
            {
                Author = authors,
                Year = ushort.Parse(entryLines[2]),
                Title = entryLines[3],
                Journal = entryLines[4],
                // TODO split with ',' for issue
                Volume = entryLines[5].Split(',').Length == 2 ?
                   byte.Parse(entryLines[5].Split(',')[0]) :
                   byte.Parse(entryLines[5]), 
                Issue = entryLines[5].Split(',').Length == 2 ?
                   byte.Parse(entryLines[5].Split(',')[1]) : null, 
                FirstPage = ushort.Parse(entryLines[6].Split('-')[0]),
                LastPage = ushort.Parse(entryLines[6].Split('-')[1]),
                Doi = entryLines.Length > 7 ? entryLines[7] : "",
            };

            return article.ToString();
        }

        /// <summary>
        /// TODO: How to determine correct encoding of text file??
        /// </summary>
        /// <param name="reader">The stream reader for the file</param>
        /// <returns></returns>
        private Encoding GuessEncoding(StreamReader reader)
        {
            var cp = "UTF-8";
            return Encoding.GetEncoding(cp);

        }
    }
}