using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Newtonsoft.Json;
using Stackoverflow.Utilities;

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

	public class IdMap
	{
		private int nextId = 0;
		public BiDictionary<int, string> map = new BiDictionary<int, string>();

		public Dictionary<int, string> MapOut {
			get {
				Dictionary<int, string> result = new Dictionary<int, string>();
				foreach (BiDictionary<int, string>.Pair pair in map)
					result.Add(pair.First, pair.Second);
				return result;
			}
		}

		public IdMap()
		{
		}


		public void Import(Dictionary<int, string> inMap, bool clearOld = true) {
			// Clear out the old map, if any
			if(clearOld) map.Clear();

			// Import the new records
			foreach (KeyValuePair<int, string> pair in inMap)
				map.Add(pair.Key, pair.Value);

			// Calculate the next id
			// FUTURE: Store & retrieve this via JSON
			nextId = map.Max((pair) => pair.First) + 1;
		}


		public int GetId(string pageName)
		{
			// Perform unicode normalization
			pageName = pageName.Normalize(System.Text.NormalizationForm.FormC);

			int result;
			if (!map.TryGetBySecond(pageName, out result)) {
				map.Add(result = nextId++, pageName);
			}
			return result;
		}

		public string GetPageName(int id)
		{
			string result;
			if (!map.TryGetByFirst(id, out result))
				throw new IdNotFoundException($"Error: Couldn't find {id} in the ID map.");
			return result;
		}

		public void MovePageName(string oldPageName, string newPageName)
		{
			int id = map.GetBySecond(oldPageName);
			map.RemoveBySecond(oldPageName);
			map.Add(id, newPageName);
		}

		public int DeletePageName(string pageName)
		{
			int id = GetId(pageName);
			map.RemoveBySecond(pageName);
			return id;
		}

		public override string ToString()
		{
			StringBuilder result = new StringBuilder("Id Map:\n");
			foreach (BiDictionary<int, string>.Pair pair in map)
				result.AppendLine($"\t{pair.First}: {pair.Second}");
			return result.ToString();
		}
	}
}