#pragma warning disable IDE0073
// Copyright 2019 The MediaPipe Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

using System;
using System.Text.RegularExpressions;

namespace Mediapipe
{
  /// <summary>
  ///   translated version of mediapipe/framework/tool/validate_name.cc
  /// <summary/>

  internal static partial class Internal
  {
    public const int MaxCollectionItemId = 10000;
  }

  public static partial class Tool
  {
    private const string _NameRegex = "[a-z_][a-z0-9_]*";
    private const string _NumberRegex = "(0|[1-9][0-9]*)";
    private const string _TagRegex = "[A-Z_][A-Z0-9_]*";
    private static readonly string _TagAndNameRegex = $"({_TagRegex}:)?{_NameRegex}";
    private static readonly string _TagIndexNameRegex = $"({_TagRegex}:({_NumberRegex}:)?)?{_NameRegex}";
    private static readonly string _TagIndexRegex = $"({_TagRegex})?(:{_NumberRegex})?";

    public static void ValidateName(string name)
    {
      if (name.Length > 0 && new Regex($"^{_NameRegex}$").IsMatch(name))
      {
        return;
      }
      throw new ArgumentException($"Name \"{name}\" does not match \"{_NameRegex}\".");
    }

    public static void ValidateNumber(string number)
    {
      if (number.Length > 0 && new Regex($"^{_NumberRegex}$").IsMatch(number))
      {
        return;
      }
      throw new ArgumentException($"Number \"{number}\" does not match \"{_NumberRegex}\".");
    }

    public static void ValidateTag(string tag)
    {
      if (tag.Length > 0 && new Regex($"^{_TagRegex}$").IsMatch(tag))
      {
        return;
      }
      throw new ArgumentException($"Tag \"{tag}\" does not match \"{_TagRegex}\".");
    }

    public static void ParseTagAndName(string tagAndName, out string tag, out string name)
    {
      var nameIndex = -1;
      var v = tagAndName.Split(':');

      try
      {
        if (v.Length == 1)
        {
          ValidateName(v[0]);
          nameIndex = 0;
        }
        else if (v.Length == 2)
        {
          ValidateTag(v[0]);
          ValidateName(v[1]);
          nameIndex = 1;
        }

        if (nameIndex == -1)
        {
          throw new ArgumentException();
        }
      }
      catch (ArgumentException)
      {
        throw new ArgumentException($"\"tag and name\" is invalid, \"{tagAndName}\" does not match \"{_TagAndNameRegex}\" (examples: \"TAG:name\", \"longer_name\").");
      }

      tag = nameIndex == 1 ? v[0] : "";
      name = v[nameIndex];
    }

    public static void ParseTagIndexName(string tagIndexName, out string tag, out int index, out string name)
    {
      var nameIndex = -1;
      var theIndex = 0;
      var v = tagIndexName.Split(':');

      try
      {
        if (v.Length == 1)
        {
          ValidateName(v[0]);
          theIndex = -1;
          nameIndex = 0;
        }
        else if (v.Length == 2)
        {
          ValidateTag(v[0]);
          ValidateName(v[1]);
          nameIndex = 1;
        }
        else if (v.Length == 3)
        {
          ValidateTag(v[0]);
          ValidateNumber(v[1]);

          theIndex = int.TryParse(v[1], out var result) && result <= Internal.MaxCollectionItemId ? result : throw new ArgumentException();
          ValidateName(v[2]);
          nameIndex = 2;
        }

        if (nameIndex == -1)
        {
          throw new ArgumentException();
        }
      }
      catch (ArgumentException)
      {
        throw new ArgumentException($"TAG:index:name is invalid, \"{tagIndexName}\" does not match \"{_TagIndexNameRegex}\" (examples: \"TAG:name\", \"VIDEO:2:name_b\", \"longer_name\").");
      }

      tag = nameIndex != 0 ? v[0] : "";
      index = theIndex;
      name = v[nameIndex];
    }

    public static void ParseTagIndex(string tagIndex, out string tag, out int index)
    {
      var theIndex = -1;
      var v = tagIndex.Split(':');

      try
      {
        if (v.Length == 1)
        {
          if (v[0].Length != 0)
          {
            ValidateTag(v[0]);
          }
          theIndex = 0;
        }
        else if (v.Length == 2)
        {
          if (v[0].Length != 0)
          {
            ValidateTag(v[0]);
          }
          ValidateNumber(v[1]);

          theIndex = int.TryParse(v[1], out var result) && result <= Internal.MaxCollectionItemId ? result : throw new ArgumentException();
        }

        if (theIndex == -1)
        {
          throw new ArgumentException();
        }
      }
      catch (ArgumentException)
      {
        throw new ArgumentException($"TAG:index is invalid, \"{tagIndex}\" does not match \"{_TagIndexRegex}\" (examples: \"TAG\", \"VIDEO:2\").");
      }

      tag = v[0];
      index = theIndex;
    }
  }
}
#pragma warning restore IDE0073