using System;
using System.Collections.Concurrent;
using System.Collections.Generic;
using Newtonsoft.Json;

namespace LibSearchBox
{
	public class SearchBoxException : Exception { public SearchBoxException(string message) : base(message) {  } }

	[JsonObject(MemberSerialization.OptIn)]
	public class SearchBox
	{
		private IdMap idMap = new IdMap();

		[JsonProperty("ids")]
		public Dictionary<int, string> IdMap {
			get {
				Dictionary<int, string> result = idMap.MapOut;
				if (result.Count == 0) return null;
				return result;
			}
			set {
				if (value == null) return;
				idMap.Import(value);
			}
		}

		[JsonProperty]
		public ConcurrentDictionary<int, DocumentMeta> metaTable = new ConcurrentDictionary<int, DocumentMeta>();
		[JsonProperty]
		public InvertedIndex index = new InvertedIndex();

		public SearchBox()
		{

		}

		public void AddDocument(string title, IEnumerable<string> tags, string content)
		{
			DocumentMeta info = new DocumentMeta(title, tags);
			int id = idMap.GetId(info.Title);
			metaTable.AddOrUpdate(id, info, (key, oldValue) => info);
			Index upsideIndex = new Index(content);
			index.AddIndex(id, upsideIndex);
		}

		public void UpdateDocument(string title, IEnumerable<string> newTags, string oldContent, string newContent)
		{
			int id = idMap.GetId(title);
			DocumentMeta info = metaTable[id];
			info.ReplaceTags(newTags);

			Index oldIndex = new Index(oldContent), newIndex = new Index(newContent);
			if (!index.ReplaceIndex(id, oldIndex, newIndex))
				throw new SearchBoxException($"Error: Failed to replace index for document with title {title}.");
		}

		public void RemoveDocument(string title)
		{
			int id = idMap.DeletePageName(title);
			metaTable.TryRemove(id, out DocumentMeta noop);
			if (!index.RemoveById(id))
				throw new SearchBoxException($"Failed to remove page with title '{title}' from inverted index.");
			
		}
	}
}