// 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.Diagnostics.CodeAnalysis;
using Microsoft.CodeAnalysis.EmbeddedLanguages.StackFrame;
using Microsoft.CodeAnalysis.EmbeddedLanguages.VirtualChars;
using Microsoft.CodeAnalysis.Text;

namespace Microsoft.CodeAnalysis.StackTraceExplorer;

internal sealed class VSDebugCallstackParser : IStackFrameParser
{
    public bool TryParseLine(VirtualCharSequence line, [NotNullWhen(true)] out ParsedFrame? parsedFrame)
    {
        // Example line:
        // ConsoleApp4.dll!ConsoleApp4.MyClass.ThrowAtOne() Line 19	C#
        //                |--------------------------------|
        //                     Symbol data we care about
        parsedFrame = null;

        var startPoint = -1;
        for (var i = 0; i < line.Length; i++)
        {
            if (line[i] == '!')
            {
                // +1 here because we always want to skip the '!' character
                startPoint = i + 1;
                break;
            }
        }

        if (startPoint <= 0 || startPoint == line.Length)
        {
            return false;
        }

        var textToParse = line[startPoint..];
        var tree = StackFrameParser.TryParse(textToParse);

        if (tree is null)
        {
            return false;
        }

        parsedFrame = new ParsedStackFrame(tree);
        return true;
    }
}
