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

namespace SL_Switcher
{

	public class ListBuilder
	{

		private enum ScanType
		{
			Copy,
			Delete
		}

		/// <summary>
		/// Builds a list of file operations to sync src with dst
		/// </summary>
		/// <param name="src">Source directory</param>
		/// <param name="dst">Destination directory</param>
		/// <returns>Action list</returns>
		public static List<FileOperation> Build(string src, string dst)
		{
			return Build(src, null, dst);
		}

		/// <summary>
		/// Builds a list of file operations to sync src with dst.
		/// This version uses a source overlay
		/// </summary>
		/// <param name="src">Source directory</param>
		/// <param name="overlay">Additional source files</param>
		/// <param name="dst">Destination directory</param>
		/// <returns>Action list</returns>
		public static List<FileOperation> Build(string src, string overlay, string dst)
		{
			List<FileOperation> tmp = new List<FileOperation>();
			List<FileOperation> ret = new List<FileOperation>();

			Console.WriteLine("Scanning for files to copy");
			// List of files to add. Overlay files are skipped here
			ScanRecursive(src,overlay, dst, "", tmp, ScanType.Copy);

			Console.WriteLine("Scanning for files to delete");
			// Files to delete. Files present in overlay are skipped
			ScanRecursive(dst,overlay, src, "", tmp, ScanType.Delete);

			if (overlay != null)
			{
				Console.WriteLine("Scanning for additional files");
				// Add overlay files
				ScanRecursive(overlay, null, dst, "", tmp, ScanType.Copy);
			}

			Console.WriteLine("Trimming list");
			foreach (FileOperation op in tmp)
			{
				if (op.ActionNeeded())
				{
				//	Console.WriteLine("Added " + op.ToString());
					ret.Add(op);
				}
			}

			return ret;
		}

		/// <summary>
		/// Scans a directory recursively building a list
		/// </summary>
		/// <param name="src">Source directory</param>
		/// <param name="overlay">Source overlay, which contains extra source files</param>
		/// <param name="dst">Destination directory</param>
		/// <param name="subpath">Should be ""</param>
		/// <param name="list">File list</param>
		/// <param name="type">Action type (copy or delete)</param>
		private static void ScanRecursive(string src, string overlay, string dst, string subpath, List<FileOperation> list, ScanType type)
		{
			string path = Path.Combine(src, subpath);

			foreach (string s in Directory.GetFiles(path))
			{
				string relpath = Path.Combine(subpath, Path.GetFileName(s));

				//if (s.EndsWith("menu_viewer.xml"))
				//{
				//	Console.WriteLine("xml");
				//}

				FileOperation op = null;
				bool in_overlay = false;

				if (overlay != null)
				{
					in_overlay = File.Exists(Path.Combine(overlay, relpath));
				}

				if (type == ScanType.Copy)
				{
					if (!in_overlay)
					{
						op = new FileCopy(src, dst, relpath);
					}
				} else {
					if (!File.Exists(Path.Combine(dst, relpath)) && !in_overlay)
					{
						op = new FileDelete(src, relpath);
					}
				}

				if (op != null)
				{
					//Console.WriteLine("Added: " + op.ToString());
					list.Add(op);
				}
			}

			foreach(string s in Directory.GetDirectories(path)) {
				string tmp = Path.Combine(subpath, Path.GetFileName(s));

				ScanRecursive(src,overlay, dst, tmp, list, type);
			}

		}
	}
}