// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
 
using System.Collections.Generic;
using System.Collections.Immutable;
using Microsoft.AspNetCore.Razor.PooledObjects;
 
namespace Microsoft.CodeAnalysis.Razor.Completion;
 
internal static class VSInternalCompletionItemExtensions
{
    public const string ResultIdKey = "_resultId";
 
    private static readonly Dictionary<RazorCommitCharacter, VSInternalCommitCharacter> s_commitCharacterCache = [];
 
    public static bool TryGetCompletionListResultIds(this VSInternalCompletionItem completion, out ImmutableArray<int> resultIds)
    {
        if (!CompletionListMerger.TrySplit(completion.Data, out var splitData))
        {
            resultIds = default;
            return false;
        }
 
        using var ids = new PooledArrayBuilder<int>();
        for (var i = 0; i < splitData.Length; i++)
        {
            var data = splitData[i];
            if (data.TryGetProperty(ResultIdKey, out var resultIdElement) &&
                resultIdElement.TryGetInt32(out var resultId))
            {
                ids.Add(resultId);
            }
        }
 
        if (ids.Count > 0)
        {
            resultIds = ids.ToImmutable();
            return true;
        }
 
        resultIds = default;
        return false;
    }
 
    public static void UseCommitCharactersFrom(
        this VSInternalCompletionItem completionItem,
        RazorCompletionItem razorCompletionItem,
        VSInternalClientCapabilities clientCapabilities)
    {
        var razorCommitCharacters = razorCompletionItem.CommitCharacters;
        if (razorCommitCharacters.IsEmpty)
        {
            return;
        }
 
        var supportsVSExtensions = clientCapabilities?.SupportsVisualStudioExtensions ?? false;
        if (supportsVSExtensions)
        {
            using var builder = new PooledArrayBuilder<VSInternalCommitCharacter>(capacity: razorCommitCharacters.Length);
 
            lock (s_commitCharacterCache)
            {
                foreach (var c in razorCommitCharacters)
                {
                    if (!s_commitCharacterCache.TryGetValue(c, out var commitCharacter))
                    {
                        commitCharacter = new() { Character = c.Character, Insert = c.Insert };
                        s_commitCharacterCache.Add(c, commitCharacter);
                    }
 
                    builder.Add(commitCharacter);
                }
            }
 
            completionItem.VsCommitCharacters = builder.ToArray();
        }
        else
        {
            using var builder = new PooledArrayBuilder<string>(capacity: razorCommitCharacters.Length);
 
            foreach (var c in razorCommitCharacters)
            {
                builder.Add(c.Character);
            }
 
            completionItem.CommitCharacters = builder.ToArray();
        }
    }
}