// Copyright (c) Six Labors.
// Licensed under the Six Labors Split License.

using System;
using System.Collections.Generic;
using System.Linq;

namespace SixLabors.Fonts {
  /// <summary>
  /// Exception for detailing missing font families.
  /// </summary>
  /// <seealso cref="FontException" />
  public class FontFamilyNotFoundException : FontException
  {
      /// <summary>
      /// Initializes a new instance of the <see cref="FontFamilyNotFoundException"/> class.
      /// </summary>
      /// <param name="family">The name of the missing font family.</param>
      public FontFamilyNotFoundException(string family)
          : this(family, Array.Empty<string>())
      {
      }

      /// <summary>
      /// Initializes a new instance of the <see cref="FontFamilyNotFoundException"/> class.
      /// </summary>
      /// <param name="family">The name of the missing font family.</param>
      /// <param name="searchDirectories">
      /// The collection of directories that were searched for the font family.
      /// Pass an empty collection if font families were not searched in directories.
      /// </param>
      public FontFamilyNotFoundException(string family, IReadOnlyCollection<string> searchDirectories)
          : base(GetMessage(family, searchDirectories))
      {
          this.FontFamily = family;
          this.SearchDirectories = searchDirectories;
      }

      /// <summary>
      /// Gets the name of the font family that was not found.
      /// </summary>
      public string FontFamily { get; }

      /// <summary>
      /// Gets the collection of directories that were unsuccessfully searched for the font family.
      /// </summary>
      /// <remarks>
      /// If the exception did not originate from the <see cref="SystemFonts.Collection"/> then this property will be empty.
      /// </remarks>
      public IReadOnlyCollection<string> SearchDirectories { get; }

      private static string GetMessage(string family, IReadOnlyCollection<string> searchDirectories)
      {
          if (searchDirectories.Count == 0)
          {
              return $"The \"{family}\" font family could not be found";
          }

          if (searchDirectories.Count == 1)
          {
              return $"The \"{family}\" font family could not be found in the following directory: {searchDirectories.First()}";
          }

          return $"The \"{family}\" font family could not be found in the following directories:{Environment.NewLine}{string.Join(Environment.NewLine, searchDirectories.Select(e => $" * {e}"))}";
      }
  }
}