// 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.
 
#nullable disable
 
using System.Collections.Immutable;
using Microsoft.CodeAnalysis.Diagnostics.Analyzers.NamingStyles;
using Microsoft.CodeAnalysis.NamingStyles;
using Microsoft.CodeAnalysis.PooledObjects;
using Microsoft.CodeAnalysis.Shared.Collections;
using Microsoft.CodeAnalysis.Shared.Utilities;
using Microsoft.CodeAnalysis.Text;
 
namespace Microsoft.CodeAnalysis.Shared.Naming
{
    internal readonly struct IdentifierNameParts
    {
        public readonly string BaseName;
        public readonly ImmutableArray<string> BaseNameParts;
 
        public IdentifierNameParts(string baseName, ImmutableArray<string> baseNameParts)
        {
            BaseName = baseName;
            BaseNameParts = baseNameParts;
        }
 
        public static IdentifierNameParts CreateIdentifierNameParts(ISymbol symbol, ImmutableArray<NamingRule> rules)
        {
            var baseName = RemovePrefixesAndSuffixes(symbol, rules, symbol.Name);
 
            using var parts = TemporaryArray<TextSpan>.Empty;
            StringBreaker.AddWordParts(baseName, ref parts.AsRef());
            var words = CreateWords(parts, baseName);
 
            return new IdentifierNameParts(baseName, words);
        }
 
        private static string RemovePrefixesAndSuffixes(ISymbol symbol, ImmutableArray<NamingRule> rules, string baseName)
        {
            var newBaseName = baseName;
 
            foreach (var rule in rules)
            {
                if (rule.SymbolSpecification.AppliesTo(symbol))
                {
                    // remove specified prefix
                    var prefix = rule.NamingStyle.Prefix;
                    newBaseName = newBaseName.StartsWith(prefix)
                        ? newBaseName[prefix.Length..]
                        : newBaseName;
 
                    // remove specified suffix
                    var suffix = rule.NamingStyle.Suffix;
                    newBaseName = newBaseName.EndsWith(suffix)
                        ? newBaseName[..^suffix.Length]
                        : newBaseName;
 
                    break;
                }
            }
 
            // remove any common prefixes
            newBaseName = NamingStyle.StripCommonPrefixes(newBaseName, out var _);
 
            // If no changes were made to the basename passed in, we're done
            if (newBaseName == baseName)
            {
                return baseName;
            }
 
            // otherwise, see if any other prefixes exist
            return RemovePrefixesAndSuffixes(symbol, rules, newBaseName);
        }
 
        private static ImmutableArray<string> CreateWords(in TemporaryArray<TextSpan> parts, string name)
        {
            using var words = TemporaryArray<string>.Empty;
            foreach (var part in parts)
                words.Add(name.Substring(part.Start, part.Length));
 
            return words.ToImmutableAndClear();
        }
    }
}