using System;
using System.Collections.Generic;
using System.IO;
using System.Text;
using Server.ContextMenus;
using Server.Gumps;
using Server.Multis;
using Server.Network;

namespace Server.Items
{
  public class BookPageInfo
  {
    public BookPageInfo() => Lines = new string[0];

    public BookPageInfo(params string[] lines) => Lines = lines;

    public BookPageInfo(GenericReader reader)
    {
      int length = reader.ReadInt();

      Lines = new string[length];

      for (int i = 0; i < Lines.Length; ++i)
        Lines[i] = Utility.Intern(reader.ReadString());
    }

    public string[] Lines{ get; set; }

    public void Serialize(GenericWriter writer)
    {
      writer.Write(Lines.Length);

      for (int i = 0; i < Lines.Length; ++i)
        writer.Write(Lines[i]);
    }
  }

  public class BaseBook : Item, ISecurable
  {
    private string m_Author;
    private string m_Title;

    [Constructible]
    public BaseBook(int itemID, int pageCount = 20, bool writable = true) : this(itemID, null, null, pageCount, writable)
    {
    }

    [Constructible]
    public BaseBook(int itemID, string title, string author, int pageCount, bool writable) : base(itemID)
    {
      BookContent content = DefaultContent;

      m_Title = title ?? content?.Title;
      m_Author = author ?? content?.Author;
      Writable = writable;

      if (content == null)
      {
        Pages = new BookPageInfo[Math.Min(pageCount, 255)];

        for (int i = 0; i < Pages.Length; ++i)
          Pages[i] = new BookPageInfo();
      }
      else
        Pages = content.Copy();
    }

    // Intended for defined books only
    public BaseBook(int itemID, bool writable) : this(itemID, 0, writable)
    {
    }

    public BaseBook(Serial serial) : base(serial)
    {
    }

    [CommandProperty(AccessLevel.GameMaster)]
    public string Title
    {
      get => m_Title;
      set
      {
        m_Title = value;
        InvalidateProperties();
      }
    }

    [CommandProperty(AccessLevel.GameMaster)]
    public string Author
    {
      get => m_Author;
      set
      {
        m_Author = value;
        InvalidateProperties();
      }
    }

    [CommandProperty(AccessLevel.GameMaster)]
    public bool Writable{ get; set; }

    [CommandProperty(AccessLevel.GameMaster)]
    public int PagesCount => Pages.Length;

    public BookPageInfo[] Pages{ get; private set; }

    public virtual BookContent DefaultContent => null;

    public string ContentAsString
    {
      get
      {
        StringBuilder sb = new StringBuilder();

        foreach (BookPageInfo bpi in Pages)
        foreach (string line in bpi.Lines)
          sb.AppendLine(line);

        return sb.ToString();
      }
    }

    public string[] ContentAsStringArray
    {
      get
      {
        List<string> lines = new List<string>();

        foreach (BookPageInfo bpi in Pages) lines.AddRange(bpi.Lines);

        return lines.ToArray();
      }
    }

    #region ISecurable Members

    [CommandProperty(AccessLevel.GameMaster)]
    public SecureLevel Level{ get; set; }

    #endregion

    public override void GetContextMenuEntries(Mobile from, List<ContextMenuEntry> list)
    {
      base.GetContextMenuEntries(from, list);
      SetSecureLevelEntry.AddTo(from, this, list);
    }

    public override void Serialize(GenericWriter writer)
    {
      base.Serialize(writer);

      BookContent content = DefaultContent;

      SaveFlags flags = SaveFlags.None;

      if (m_Title != content?.Title)
        flags |= SaveFlags.Title;

      if (m_Author != content?.Author)
        flags |= SaveFlags.Author;

      if (Writable)
        flags |= SaveFlags.Writable;

      if (content?.IsMatch(Pages) != true)
        flags |= SaveFlags.Content;


      writer.Write(4); // version

      writer.Write((int)Level);

      writer.Write((byte)flags);

      if ((flags & SaveFlags.Title) != 0)
        writer.Write(m_Title);

      if ((flags & SaveFlags.Author) != 0)
        writer.Write(m_Author);

      if ((flags & SaveFlags.Content) != 0)
      {
        writer.WriteEncodedInt(Pages.Length);

        for (int i = 0; i < Pages.Length; ++i)
          Pages[i].Serialize(writer);
      }
    }

    public override void Deserialize(GenericReader reader)
    {
      base.Deserialize(reader);

      int version = reader.ReadInt();

      switch (version)
      {
        case 4:
        {
          Level = (SecureLevel)reader.ReadInt();
          goto case 3;
        }
        case 3:
        case 2:
        {
          BookContent content = DefaultContent;

          SaveFlags flags = (SaveFlags)reader.ReadByte();

          if ((flags & SaveFlags.Title) != 0)
            m_Title = Utility.Intern(reader.ReadString());
          else if (content != null)
            m_Title = content.Title;

          if ((flags & SaveFlags.Author) != 0)
            m_Author = reader.ReadString();
          else if (content != null)
            m_Author = content.Author;

          Writable = (flags & SaveFlags.Writable) != 0;

          if ((flags & SaveFlags.Content) != 0)
          {
            Pages = new BookPageInfo[reader.ReadEncodedInt()];

            for (int i = 0; i < Pages.Length; ++i)
              Pages[i] = new BookPageInfo(reader);
          }
          else
            Pages = content?.Copy() ?? new BookPageInfo[0];

          break;
        }
        case 1:
        case 0:
        {
          m_Title = reader.ReadString();
          m_Author = reader.ReadString();
          Writable = reader.ReadBool();

          if (version == 0 || reader.ReadBool())
          {
            Pages = new BookPageInfo[reader.ReadInt()];

            for (int i = 0; i < Pages.Length; ++i)
              Pages[i] = new BookPageInfo(reader);
          }
          else
            Pages = DefaultContent?.Copy() ?? new BookPageInfo[0];

          break;
        }
      }

      if (version < 3 && (Weight == 1 || Weight == 2))
        Weight = -1;
    }

    public override void AddNameProperty(ObjectPropertyList list)
    {
      if (!string.IsNullOrEmpty(m_Title))
        list.Add(m_Title);
      else
        base.AddNameProperty(list);
    }

    /*public override void GetProperties( ObjectPropertyList list )
    {
      base.GetProperties( list );

      if ( m_Title?.Length > 0 )
        list.Add( 1060658, "Title\t{0}", m_Title ); // ~1_val~: ~2_val~

      if ( m_Author?.Length > 0 )
        list.Add( 1060659, "Author\t{0}", m_Author ); // ~1_val~: ~2_val~

      if ( m_Pages?.Length > 0 )
        list.Add( 1060660, "Pages\t{0}", m_Pages.Length ); // ~1_val~: ~2_val~
    }*/

    public override void OnSingleClick(Mobile from)
    {
      LabelTo(from, "{0} by {1}", m_Title, m_Author);
      LabelTo(from, "[{0} pages]", Pages.Length);
    }

    public override void OnDoubleClick(Mobile from)
    {
      if (m_Title == null && m_Author == null && Writable)
      {
        Title = "a book";
        Author = from.Name;
      }

      BookPackets.SendBookHeader(from.NetState, from, this);
      BookPackets.SendBookPageDetails(from.NetState, this);
    }

    public static void Initialize()
    {
      PacketHandlers.Register(0xD4, 0, true, HeaderChange);
      PacketHandlers.Register(0x66, 0, true, ContentChange);
      PacketHandlers.Register(0x93, 99, true, OldHeaderChange);
    }

    public static void OldHeaderChange(NetState state, PacketReader pvSrc)
    {
      Mobile from = state.Mobile;

      if (!(World.FindItem(pvSrc.ReadUInt32()) is BaseBook book) || !book.Writable ||
          !from.InRange(book.GetWorldLocation(), 1) || !book.IsAccessibleTo(from))
        return;

      pvSrc.Seek(4, SeekOrigin.Current); // Skip flags and page count

      string title = pvSrc.ReadStringSafe(60);
      string author = pvSrc.ReadStringSafe(30);

      book.Title = Utility.FixHtml(title);
      book.Author = Utility.FixHtml(author);
    }

    public static void HeaderChange(NetState state, PacketReader pvSrc)
    {
      Mobile from = state.Mobile;

      if (!(World.FindItem(pvSrc.ReadUInt32()) is BaseBook book) || !book.Writable ||
          !from.InRange(book.GetWorldLocation(), 1) || !book.IsAccessibleTo(from))
        return;

      pvSrc.Seek(4, SeekOrigin.Current); // Skip flags and page count

      int titleLength = pvSrc.ReadUInt16();

      if (titleLength > 60)
        return;

      string title = pvSrc.ReadStringSafe(titleLength);

      int authorLength = pvSrc.ReadUInt16();

      if (authorLength > 30)
        return;

      string author = pvSrc.ReadStringSafe(authorLength);

      book.Title = Utility.FixHtml(title);
      book.Author = Utility.FixHtml(author);
    }

    public static void ContentChange(NetState state, PacketReader pvSrc)
    {
      Mobile from = state.Mobile;

      if (!(World.FindItem(pvSrc.ReadUInt32()) is BaseBook book) || !book.Writable ||
          !from.InRange(book.GetWorldLocation(), 1) || !book.IsAccessibleTo(from))
        return;

      int pageCount = pvSrc.ReadUInt16();

      if (pageCount > book.PagesCount)
        return;

      for (int i = 0; i < pageCount; ++i)
      {
        int index = pvSrc.ReadUInt16();

        if (index < 1 || index > book.PagesCount)
          return;

        --index;

        int lineCount = pvSrc.ReadUInt16();

        if (lineCount > 8)
          return;

        string[] lines = new string[lineCount];

        for (int j = 0; j < lineCount; ++j)
          if ((lines[j] = pvSrc.ReadUTF8StringSafe()).Length >= 80)
            return;

        book.Pages[index].Lines = lines;
      }
    }

    [Flags]
    private enum SaveFlags
    {
      None = 0x00,
      Title = 0x01,
      Author = 0x02,
      Writable = 0x04,
      Content = 0x08
    }
  }
}