// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.

using System;
using Microsoft.CodeAnalysis.Shared.Utilities;
using Roslyn.Utilities;

namespace Microsoft.CodeAnalysis.FindSymbols;

internal sealed partial class SyntaxTreeIndex
{
    private readonly struct IdentifierInfo(
        BloomFilter identifierFilter,
        BloomFilter escapedIdentifierFilter)
    {
        private readonly BloomFilter _identifierFilter = identifierFilter ?? throw new ArgumentNullException(nameof(identifierFilter));
        private readonly BloomFilter _escapedIdentifierFilter = escapedIdentifierFilter ?? throw new ArgumentNullException(nameof(escapedIdentifierFilter));

        /// <summary>
        /// Returns true when the identifier is probably (but not guaranteed) to be within the
        /// syntax tree.  Returns false when the identifier is guaranteed to not be within the
        /// syntax tree.
        /// </summary>
        public bool ProbablyContainsIdentifier(string identifier)
            => _identifierFilter.ProbablyContains(identifier);

        /// <summary>
        /// Returns true when the identifier is probably (but not guaranteed) escaped within the
        /// text of the syntax tree.  Returns false when the identifier is guaranteed to not be
        /// escaped within the text of the syntax tree.  An identifier that is not escaped within
        /// the text can be found by searching the text directly.  An identifier that is escaped can
        /// only be found by parsing the text and syntactically interpreting any escaping
        /// mechanisms found in the language ("\uXXXX" or "@XXXX" in C# or "[XXXX]" in Visual
        /// Basic).
        /// </summary>
        public bool ProbablyContainsEscapedIdentifier(string identifier)
            => _escapedIdentifierFilter.ProbablyContains(identifier);

        public void WriteTo(ObjectWriter writer)
        {
            _identifierFilter.WriteTo(writer);
            _escapedIdentifierFilter.WriteTo(writer);
        }

        public static IdentifierInfo? TryReadFrom(ObjectReader reader)
        {
            try
            {
                var identifierFilter = BloomFilter.ReadFrom(reader);
                var escapedIdentifierFilter = BloomFilter.ReadFrom(reader);

                return new IdentifierInfo(identifierFilter, escapedIdentifierFilter);
            }
            catch (Exception)
            {
            }

            return null;
        }
    }
}