using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Web;

using SabreTools.Library.Data;
using SabreTools.Library.Items;
using SabreTools.Library.Tools;

#if MONO
using System.IO;
#else
using Alphaleonis.Win32.Filesystem;

using FileStream = System.IO.FileStream;
using StreamReader = System.IO.StreamReader;
using StreamWriter = System.IO.StreamWriter;
#endif
using NaturalSort;

namespace SabreTools.Library.DatFiles
{
	/// <summary>
	/// Represents parsing and writing of a RomCenter DAT
	/// </summary>
	public class RomCenter : DatFile
	{
		/// <summary>
		/// Constructor designed for casting a base DatFile
		/// </summary>
		/// <param name="datFile">Parent DatFile to copy from</param>
		public RomCenter(DatFile datFile)
		{
			this._datHeader = datFile._datHeader;
			this._items = datFile._items;
			this._sortedBy = datFile._sortedBy;
			this._datStats = datFile._datStats;
		}

		/// <summary>
		/// Parse a RomCenter DAT and return all found games and roms within
		/// </summary>
		/// <param name="filename">Name of the file to be parsed</param>
		/// <param name="sysid">System ID for the DAT</param>
		/// <param name="srcid">Source ID for the DAT</param>
		/// <param name="clean">True if game names are sanitized, false otherwise (default)</param>
		/// <param name="remUnicode">True if we should remove non-ASCII characters from output, false otherwise (default)</param>
		public void Parse(
			// Standard Dat parsing
			string filename,
			int sysid,
			int srcid,

			// Miscellaneous
			bool clean,
			bool remUnicode)
		{
			// Open a file reader
			Encoding enc = Style.GetEncoding(filename);
			StreamReader sr = new StreamReader(FileTools.TryOpenRead(filename), enc);

			string blocktype = "";
			while (!sr.EndOfStream)
			{
				string line = sr.ReadLine();

				// If the line is the start of the credits section
				if (line.ToLowerInvariant().StartsWith("[credits]"))
				{
					blocktype = "credits";
				}
				// If the line is the start of the dat section
				else if (line.ToLowerInvariant().StartsWith("[dat]"))
				{
					blocktype = "dat";
				}
				// If the line is the start of the emulator section
				else if (line.ToLowerInvariant().StartsWith("[emulator]"))
				{
					blocktype = "emulator";
				}
				// If the line is the start of the game section
				else if (line.ToLowerInvariant().StartsWith("[games]"))
				{
					blocktype = "games";
				}
				// Otherwise, it's not a section and it's data, so get out all data
				else
				{
					// If we have an author
					if (line.ToLowerInvariant().StartsWith("author="))
					{
						Author = (String.IsNullOrEmpty(Author) ? line.Split('=')[1] : Author);
					}
					// If we have one of the three version tags
					else if (line.ToLowerInvariant().StartsWith("version="))
					{
						switch (blocktype)
						{
							case "credits":
								Version = (String.IsNullOrEmpty(Version) ? line.Split('=')[1] : Version);
								break;
							case "emulator":
								Description = (String.IsNullOrEmpty(Description) ? line.Split('=')[1] : Description);
								break;
						}
					}
					// If we have a URL
					else if (line.ToLowerInvariant().StartsWith("url="))
					{
						Url = (String.IsNullOrEmpty(Url) ? line.Split('=')[1] : Url);
					}
					// If we have a comment
					else if (line.ToLowerInvariant().StartsWith("comment="))
					{
						Comment = (String.IsNullOrEmpty(Comment) ? line.Split('=')[1] : Comment);
					}
					// If we have the split flag
					else if (line.ToLowerInvariant().StartsWith("split="))
					{
						if (Int32.TryParse(line.Split('=')[1], out int split))
						{
							if (split == 1 && ForceMerging == ForceMerging.None)
							{
								ForceMerging = ForceMerging.Split;
							}
						}
					}
					// If we have the merge tag
					else if (line.ToLowerInvariant().StartsWith("merge="))
					{
						if (Int32.TryParse(line.Split('=')[1], out int merge))
						{
							if (merge == 1 && ForceMerging == ForceMerging.None)
							{
								ForceMerging = ForceMerging.Full;
							}
						}
					}
					// If we have the refname tag
					else if (line.ToLowerInvariant().StartsWith("refname="))
					{
						Name = (String.IsNullOrEmpty(Name) ? line.Split('=')[1] : Name);
					}
					// If we have a rom
					else if (line.StartsWith("¬"))
					{
						// Some old RC DATs have this behavior
						if (line.Contains("¬N¬O"))
						{
							line = line.Replace("¬N¬O", "") + "¬¬";
						}

						/*
						The rominfo order is as follows:
						1 - parent name
						2 - parent description
						3 - game name
						4 - game description
						5 - rom name
						6 - rom crc
						7 - rom size
						8 - romof name
						9 - merge name
						*/
						string[] rominfo = line.Split('¬');

						// Try getting the size separately
						if (!Int64.TryParse(rominfo[7], out long size))
						{
							size = 0;
						}

						Rom rom = new Rom
						{
							Name = rominfo[5],
							Size = size,
							CRC = rominfo[6],
							ItemStatus = ItemStatus.None,

							MachineName = rominfo[3],
							MachineDescription = rominfo[4],
							CloneOf = rominfo[1],
							RomOf = rominfo[8],

							SystemID = sysid,
							SourceID = srcid,
						};

						// Now process and add the rom
						ParseAddHelper(rom, clean, remUnicode);
					}
				}
			}

			sr.Dispose();
		}

		/// <summary>
		/// Create and open an output file for writing direct from a dictionary
		/// </summary>
		/// <param name="outfile">Name of the file to write to</param>
		/// <param name="ignoreblanks">True if blank roms should be skipped on output, false otherwise (default)</param>
		/// <returns>True if the DAT was written correctly, false otherwise</returns>
		public bool WriteToFile(string outfile, bool ignoreblanks = false)
		{
			try
			{
				Globals.Logger.User("Opening file for writing: {0}", outfile);
				FileStream fs = FileTools.TryCreate(outfile);

				// If we get back null for some reason, just log and return
				if (fs == null)
				{
					Globals.Logger.Warning("File '{0}' could not be created for writing! Please check to see if the file is writable", outfile);
					return false;
				}

				StreamWriter sw = new StreamWriter(fs, new UTF8Encoding(true));

				// Write out the header
				WriteHeader(sw);

				// Write out each of the machines and roms
				string lastgame = null;
				List<string> splitpath = new List<string>();

				// Get a properly sorted set of keys
				List<string> keys = Keys.ToList();
				keys.Sort(new NaturalComparer());

				foreach (string key in keys)
				{
					List<DatItem> roms = this[key];

					// Resolve the names in the block
					roms = DatItem.ResolveNames(roms);

					for (int index = 0; index < roms.Count; index++)
					{
						DatItem rom = roms[index];

						// There are apparently times when a null rom can skip by, skip them
						if (rom.Name == null || rom.MachineName == null)
						{
							Globals.Logger.Warning("Null rom found!");
							continue;
						}

						// If we have a "null" game (created by DATFromDir or something similar), log it to file
						if (rom.Type == ItemType.Rom
							&& ((Rom)rom).Size == -1
							&& ((Rom)rom).CRC == "null")
						{
							Globals.Logger.Verbose("Empty folder found: {0}", rom.MachineName);

							rom.Name = (rom.Name == "null" ? "-" : rom.Name);
							((Rom)rom).Size = Constants.SizeZero;
							((Rom)rom).CRC = ((Rom)rom).CRC == "null" ? Constants.CRCZero : null;
							((Rom)rom).MD5 = ((Rom)rom).MD5 == "null" ? Constants.MD5Zero : null;
							((Rom)rom).SHA1 = ((Rom)rom).SHA1 == "null" ? Constants.SHA1Zero : null;
							((Rom)rom).SHA256 = ((Rom)rom).SHA256 == "null" ? Constants.SHA256Zero : null;
							((Rom)rom).SHA384 = ((Rom)rom).SHA384 == "null" ? Constants.SHA384Zero : null;
							((Rom)rom).SHA512 = ((Rom)rom).SHA512 == "null" ? Constants.SHA512Zero : null;
						}

						// Now, output the rom data
						WriteRomData(sw, rom, ignoreblanks);

						// Set the new data to compare against
						lastgame = rom.MachineName;
					}
				}

				Globals.Logger.Verbose("File written!" + Environment.NewLine);
				sw.Dispose();
				fs.Dispose();
			}
			catch (Exception ex)
			{
				Globals.Logger.Error(ex.ToString());
				return false;
			}

			return true;
		}

		/// <summary>
		/// Write out DAT header using the supplied StreamWriter
		/// </summary>
		/// <param name="sw">StreamWriter to output to</param>
		/// <returns>True if the data was written, false on error</returns>
		private bool WriteHeader(StreamWriter sw)
		{
			try
			{
				string header = header = "[CREDITS]\n" +
							"author=" + Author + "\n" +
							"version=" + Version + "\n" +
							"comment=" + Comment + "\n" +
							"[DAT]\n" +
							"version=2.50\n" +
							"split=" + (ForceMerging == ForceMerging.Split ? "1" : "0") + "\n" +
							"merge=" + (ForceMerging == ForceMerging.Full || ForceMerging == ForceMerging.Merged ? "1" : "0") + "\n" +
							"[EMULATOR]\n" +
							"refname=" + Name + "\n" +
							"version=" + Description + "\n" +
							"[GAMES]\n";

				// Write the header out
				sw.Write(header);
				sw.Flush();
			}
			catch (Exception ex)
			{
				Globals.Logger.Error(ex.ToString());
				return false;
			}

			return true;
		}

		/// <summary>
		/// Write out RomData using the supplied StreamWriter
		/// </summary>
		/// <param name="sw">StreamWriter to output to</param>
		/// <param name="rom">RomData object to be output</param>
		/// <param name="ignoreblanks">True if blank roms should be skipped on output, false otherwise (default)</param>
		/// <returns>True if the data was written, false on error</returns>
		private bool WriteRomData(StreamWriter sw, DatItem rom, bool ignoreblanks = false)
		{
			// If we are in ignore blanks mode AND we have a blank (0-size) rom, skip
			if (ignoreblanks
				&& (rom.Type == ItemType.Rom
				&& (((Rom)rom).Size == 0 || ((Rom)rom).Size == -1)))
			{
				return true;
			}

			try
			{
				string state = "";
				if (rom.Type == ItemType.Rom)
				{
					state += "¬" + (String.IsNullOrEmpty(rom.CloneOf) ? "" : HttpUtility.HtmlEncode(rom.CloneOf)) +
					"¬" + (String.IsNullOrEmpty(rom.CloneOf) ? "" : HttpUtility.HtmlEncode(rom.CloneOf)) +
					"¬" + HttpUtility.HtmlEncode(rom.MachineName) +
					"¬" + HttpUtility.HtmlEncode((String.IsNullOrEmpty(rom.MachineDescription) ? rom.MachineName : rom.MachineDescription)) +
					"¬" + HttpUtility.HtmlEncode(rom.Name) +
					"¬" + ((Rom)rom).CRC.ToLowerInvariant() +
					"¬" + (((Rom)rom).Size != -1 ? ((Rom)rom).Size.ToString() : "") + "¬¬¬\n";
				}
				else if (rom.Type == ItemType.Disk)
				{
					state += "¬" + (String.IsNullOrEmpty(rom.CloneOf) ? "" : HttpUtility.HtmlEncode(rom.CloneOf)) +
					"¬" + (String.IsNullOrEmpty(rom.CloneOf) ? "" : HttpUtility.HtmlEncode(rom.CloneOf)) +
					"¬" + HttpUtility.HtmlEncode(rom.MachineName) +
					"¬" + HttpUtility.HtmlEncode((String.IsNullOrEmpty(rom.MachineDescription) ? rom.MachineName : rom.MachineDescription)) +
					"¬" + HttpUtility.HtmlEncode(rom.Name) +
					"¬¬¬¬¬\n";
				}

				sw.Write(state);
				sw.Flush();
			}
			catch (Exception ex)
			{
				Globals.Logger.Error(ex.ToString());
				return false;
			}

			return true;
		}
	}
}