using System;
using System.Collections.Generic;
using System.Text;

using SabreTools.Library.Data;
using SabreTools.Library.DatItems;
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 hashfile such as an SFV, MD5, or SHA-1 file
	/// </summary>
	internal class Hashfile : DatFile
	{
		// Private instance variables specific to Hashfile DATs
		Hash _hash;

		/// <summary>
		/// Constructor designed for casting a base DatFile
		/// </summary>
		/// <param name="datFile">Parent DatFile to copy from</param>
		/// <param name="hash">Type of hash that is associated with this DAT</param> 
		public Hashfile(DatFile datFile, Hash hash)
			: base(datFile, cloneHeader: false)
		{
			_hash = hash;
		}

		/// <summary>
		/// Parse a hashfile or SFV 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="keep">True if full pathnames are to be kept, false otherwise (default)</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 override void ParseFile(
			// Standard Dat parsing
			string filename,
			int sysid,
			int srcid,

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

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

				// Split the line and get the name and hash
				string[] split = line.Split(' ');
				string name = "";
				string hash = "";

				// If we have CRC, then it's an SFV file and the name is first are
				if ((_hash & Hash.CRC) != 0)
				{
					name = split[0].Replace("*", String.Empty);
					hash = split[1];
				}
				// Otherwise, the name is second
				else
				{
					name = split[1].Replace("*", String.Empty);
					hash = split[0];
				}

				Rom rom = new Rom
				{
					Name = name,
					Size = -1,
					CRC = ((_hash & Hash.CRC) != 0 ? Utilities.CleanHashData(hash, Constants.CRCLength) : null),
					MD5 = ((_hash & Hash.MD5) != 0 ? Utilities.CleanHashData(hash, Constants.MD5Length) : null),
					SHA1 = ((_hash & Hash.SHA1) != 0 ? Utilities.CleanHashData(hash, Constants.SHA1Length) : null),
					SHA256 = ((_hash & Hash.SHA256) != 0 ? Utilities.CleanHashData(hash, Constants.SHA256Length) : null),
					SHA384 = ((_hash & Hash.SHA384) != 0 ? Utilities.CleanHashData(hash, Constants.SHA384Length) : null),
					SHA512 = ((_hash & Hash.SHA512) != 0 ? Utilities.CleanHashData(hash, Constants.SHA512Length) : null),
					ItemStatus = ItemStatus.None,

					MachineName = Path.GetFileNameWithoutExtension(filename),

					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 override bool WriteToFile(string outfile, bool ignoreblanks = false)
		{
			try
			{
				Globals.Logger.User("Opening file for writing: {0}", outfile);
				FileStream fs = Utilities.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(false));

				// Get a properly sorted set of keys
				List<string> keys = Keys;
				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);
						}

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

				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 DatItem using the supplied StreamWriter
		/// </summary>
		/// <param name="sw">StreamWriter to output to</param>
		/// <param name="rom">DatItem 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 WriteDatItem(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 = "";

				// Pre-process the item name
				ProcessItemName(rom, true);

				switch (_hash)
				{
					case Hash.MD5:
						if (rom.Type == ItemType.Rom)
						{
							state += ((Rom)rom).MD5 + " *" + (GameName ? rom.MachineName + Path.DirectorySeparatorChar : "") + rom.Name + "\n";
						}
						else if (rom.Type == ItemType.Disk)
						{
							state += ((Disk)rom).MD5 + " *" + (GameName ? rom.MachineName + Path.DirectorySeparatorChar : "") + rom.Name + "\n";
						}
						break;
					case Hash.CRC:
						if (rom.Type == ItemType.Rom)
						{
							state += (GameName ? rom.MachineName + Path.DirectorySeparatorChar : "") + rom.Name + " " + ((Rom)rom).CRC + "\n";
						}
						break;
					case Hash.SHA1:
						if (rom.Type == ItemType.Rom)
						{
							state += ((Rom)rom).SHA1 + " *" + (GameName ? rom.MachineName + Path.DirectorySeparatorChar : "") + rom.Name + "\n";
						}
						else if (rom.Type == ItemType.Disk)
						{
							state += ((Disk)rom).SHA1 + " *" + (GameName ? rom.MachineName + Path.DirectorySeparatorChar : "") + rom.Name + "\n";
						}
						break;
					case Hash.SHA256:
						if (rom.Type == ItemType.Rom)
						{
							state += ((Rom)rom).SHA256 + " *" + (GameName ? rom.MachineName + Path.DirectorySeparatorChar : "") + rom.Name + "\n";
						}
						else if (rom.Type == ItemType.Disk)
						{
							state += ((Disk)rom).SHA256 + " *" + (GameName ? rom.MachineName + Path.DirectorySeparatorChar : "") + rom.Name + "\n";
						}
						break;
					case Hash.SHA384:
						if (rom.Type == ItemType.Rom)
						{
							state += ((Rom)rom).SHA384 + " *" + (GameName ? rom.MachineName + Path.DirectorySeparatorChar : "") + rom.Name + "\n";
						}
						else if (rom.Type == ItemType.Disk)
						{
							state += ((Disk)rom).SHA384 + " *" + (GameName ? rom.MachineName + Path.DirectorySeparatorChar : "") + rom.Name + "\n";
						}
						break;
					case Hash.SHA512:
						if (rom.Type == ItemType.Rom)
						{
							state += ((Rom)rom).SHA512 + " *" + (GameName ? rom.MachineName + Path.DirectorySeparatorChar : "") + rom.Name + "\n";
						}
						else if (rom.Type == ItemType.Disk)
						{
							state += ((Disk)rom).SHA512 + " *" + (GameName ? rom.MachineName + Path.DirectorySeparatorChar : "") + rom.Name + "\n";
						}
						break;
				}

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

			return true;
		}
	}
}