using System;
using System.Collections.Generic;
using System.IO;
using System.Text.RegularExpressions;
using System.Xml;

namespace SabreTools.Helper
{
	public class RomManipulation
	{
		/// <summary>
		/// Parse a 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="logger">Logger object for console and/or file output</param>
		/// <returns>List of RomData objects representing the found data</returns>
		public static List<RomData> Parse(string filename, int sysid, int srcid, Logger logger)
		{
			List<RomData> roms = new List<RomData>();

			bool superdat = false;
			XmlDocument doc = new XmlDocument();
			try
			{
				doc.LoadXml(File.ReadAllText(filename));
			}
			catch (XmlException)
			{
				doc.LoadXml(Converters.RomVaultToXML(File.ReadAllLines(filename)).ToString());
			}

			// Experimental looping using only XML parsing
			XmlNode node = doc.FirstChild;
			if (node != null && node.Name == "xml")
			{
				// Skip over everything that's not an element
				while (node.NodeType != XmlNodeType.Element)
				{
					node = node.NextSibling;
				}
			}

			// Once we find the main body, enter it
			if (node != null && (node.Name == "datafile" || node.Name == "softwarelist"))
			{
				node = node.FirstChild;
			}

			// Skip the header if it exists
			if (node != null && node.Name == "header")
			{
				// Check for SuperDAT mode
				if (node.SelectSingleNode("name").InnerText.Contains(" - SuperDAT"))
				{
					superdat = true;
				}

				// Skip over anything that's not an element
				while (node.NodeType != XmlNodeType.Element)
				{
					node = node.NextSibling;
				}
			}

			// Loop over the document until the end
			while (node != null)
			{
				if (node.NodeType == XmlNodeType.Element && (node.Name == "machine" || node.Name == "game" || node.Name == "software"))
				{
					string tempname = "";
					if (node.Name == "software")
					{
						tempname = node.SelectSingleNode("description").InnerText;
					}
					else
					{
						// There are rare cases where a malformed XML will not have the required attributes. We can only skip them.
						if (node.Attributes.Count == 0)
						{
							logger.Error(@"A node with malformed XML has been found!
	For RV DATs, please make sure that all names and descriptions are quoted.
	For XML DATs, make sure that the DAT has all required information.");
							node = node.NextSibling;
							continue;
						}
						tempname = node.Attributes["name"].Value;
					}

					if (superdat)
					{
						tempname = Regex.Match(tempname, @".*?\\(.*)").Groups[1].Value;
					}

					// Get the roms from the machine
					if (node.HasChildNodes)
					{
						// If this node has children, traverse the children
						foreach (XmlNode child in node.ChildNodes)
						{
							// If we find a rom or disk, add it
							if (child.NodeType == XmlNodeType.Element && (child.Name == "rom" || child.Name == "disk"))
							{
								// Take care of hex-sized files
								long size = -1;
								if (child.Attributes["size"] != null && child.Attributes["size"].Value.Contains("0x"))
								{
									size = Convert.ToInt64(child.Attributes["size"].Value, 16);
								}
								else if (child.Attributes["size"] != null)
								{
									size = Int64.Parse(child.Attributes["size"].Value);
								}

								roms.Add(new RomData
								{
									Game = tempname,
									Name = child.Attributes["name"].Value,
									Type = child.Name,
									SystemID = sysid,
									SourceID = srcid,
									Size = size,
									CRC = (child.Attributes["crc"] != null ? child.Attributes["crc"].Value.ToLowerInvariant().Trim() : ""),
									MD5 = (child.Attributes["md5"] != null ? child.Attributes["md5"].Value.ToLowerInvariant().Trim() : ""),
									SHA1 = (child.Attributes["sha1"] != null ? child.Attributes["sha1"].Value.ToLowerInvariant().Trim() : ""),
								});
							}
							// If we find the signs of a software list, traverse the children
							else if (child.NodeType == XmlNodeType.Element && child.Name == "part" && child.HasChildNodes)
							{
								foreach (XmlNode part in child.ChildNodes)
								{
									// If we find a dataarea, traverse the children
									if (part.NodeType == XmlNodeType.Element && part.Name == "dataarea")
									{
										foreach (XmlNode data in part.ChildNodes)
										{
											// If we find a rom or disk, add it
											if (data.NodeType == XmlNodeType.Element && (data.Name == "rom" || data.Name == "disk") && data.Attributes["name"] != null)
											{
												// Take care of hex-sized files
												long size = -1;
												if (data.Attributes["size"] != null && data.Attributes["size"].Value.Contains("0x"))
												{
													size = Convert.ToInt64(data.Attributes["size"].Value, 16);
												}
												else if (data.Attributes["size"] != null)
												{
													size = Int64.Parse(data.Attributes["size"].Value);
												}

												roms.Add(new RomData
												{
													Game = tempname,
													Name = data.Attributes["name"].Value,
													Type = data.Name,
													SystemID = sysid,
													SourceID = srcid,
													Size = size,
													CRC = (data.Attributes["crc"] != null ? data.Attributes["crc"].Value.ToLowerInvariant().Trim() : ""),
													MD5 = (data.Attributes["md5"] != null ? data.Attributes["md5"].Value.ToLowerInvariant().Trim() : ""),
													SHA1 = (data.Attributes["sha1"] != null ? data.Attributes["sha1"].Value.ToLowerInvariant().Trim() : ""),
												});
											}
										}
									}
								}
							}
						}
					}
				}
				node = node.NextSibling;
			}

			return roms;
		}

		/// <summary>
		/// Merge an arbitrary set of ROMs based on the supplied information
		/// </summary>
		/// <param name="inroms">List of RomData objects representing the roms to be merged</param>
		/// <param name="presorted">True if the list should be considered pre-sorted (default false)</param>
		/// <returns>A List of RomData objects representing the merged roms</returns>
		public static List<RomData> Merge(List<RomData> inroms, bool presorted = false)
		{
			List<RomData> outroms = new List<RomData>();

			// First sort the roms by size, crc, sysid, srcid, md5, and sha1 (in order), if not sorted already
			if (!presorted)
			{
				inroms.Sort(delegate (RomData x, RomData y)
				{
					if (x.Size == y.Size)
					{
						if (x.CRC == y.CRC)
						{
							if (x.SystemID == y.SystemID)
							{
								if (x.SourceID == y.SourceID)
								{
									if (x.MD5 == y.MD5)
									{
										return String.Compare(x.SHA1, y.SHA1);
									}
									return String.Compare(x.MD5, y.MD5);
								}
								return x.SourceID - y.SourceID;
							}
							return x.SystemID - y.SystemID;
						}
						return String.Compare(x.CRC, y.CRC);
					}
					return (int)(x.Size - y.Size);
				});
			}

			// Then, deduplicate them by checking to see if data matches
			foreach (RomData rom in inroms)
			{
				// If it's the first rom in the list, don't touch it
				if (outroms.Count != 0)
				{
					// Check if the rom is a duplicate
					RomData last = outroms[outroms.Count - 1];

					bool shouldcont = false;
					if (rom.Type == "rom" && last.Type == "rom")
					{
						shouldcont = ((rom.Size != -1 && rom.Size == last.Size) && (
								(rom.CRC != "" && last.CRC != "" && rom.CRC == last.CRC) ||
								(rom.MD5 != "" && last.MD5 != "" && rom.MD5 == last.MD5) ||
								(rom.SHA1 != "" && last.SHA1 != "" && rom.SHA1 == last.SHA1)
								)
							);
					}
					else if (rom.Type == "disk" && last.Type == "disk")
					{
						shouldcont = ((rom.MD5 != "" && last.MD5 != "" && rom.MD5 == last.MD5) ||
								(rom.SHA1 != "" && last.SHA1 != "" && rom.SHA1 == last.SHA1)
							);
					}

					// If it's a duplicate, skip adding it to the output but add any missing information
					if (shouldcont)
					{
						last.CRC = (last.CRC == "" && rom.CRC != "" ? rom.CRC : last.CRC);
						last.MD5 = (last.MD5 == "" && rom.MD5 != "" ? rom.MD5 : last.MD5);
						last.SHA1 = (last.SHA1 == "" && rom.SHA1 != "" ? rom.SHA1 : last.SHA1);

						outroms.RemoveAt(outroms.Count - 1);
						outroms.Insert(outroms.Count, last);

						continue;
					}
					else
					{
						outroms.Add(rom);
					}
				}
				else
				{
					outroms.Add(rom);
				}
			}

			// Then return the result
			return outroms;
		}

		/// <summary>
		/// Sort a list of RomData objects by SystemID, SourceID, Game, and Name (in order)
		/// </summary>
		/// <param name="roms">List of RomData objects representing the roms to be sorted</param>
		/// <param name="norename">True if files are not renamed, false otherwise</param>
		public static void Sort(List<RomData> roms, bool norename)
		{
			roms.Sort(delegate (RomData x, RomData y)
			{
				if (x.SystemID == y.SystemID)
				{
					if (x.SourceID == y.SourceID)
					{
						if (x.Game == y.Game)
						{
							return String.Compare(x.Name, y.Name);
						}
						return String.Compare(x.Game, y.Game);
					}
					return (norename ? String.Compare(x.Game, y.Game) : x.SourceID - y.SourceID);
				}
				return (norename ? String.Compare(x.Game, y.Game) : x.SystemID - y.SystemID);
			});
		}
	}
}