// Copyright (c) Ben A Adams. All rights reserved.
// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.

namespace DTLib.Ben.Demystifier;

public partial class EnhancedStackTrace : StackTrace, IEnumerable<EnhancedStackFrame>
{
    private readonly List<EnhancedStackFrame> _frames;

    /// <summary>
    ///     Initializes a new instance of the System.Diagnostics.StackTrace class using the
    ///     provided exception object
    /// </summary>
    public EnhancedStackTrace(Exception e)
    {
        _frames = GetFrames(new StackTrace(e, true));
    }

    public EnhancedStackTrace(StackTrace stackTrace)
    {
        _frames = GetFrames(stackTrace);
    }

    /// <returns>The number of frames in the stack trace.</returns>
    public override int FrameCount => _frames.Count;

    IEnumerator<EnhancedStackFrame> IEnumerable<EnhancedStackFrame>.GetEnumerator() => _frames.GetEnumerator();

    IEnumerator IEnumerable.GetEnumerator() => _frames.GetEnumerator();
    
    public static EnhancedStackTrace Current() 
        => new EnhancedStackTrace(new StackTrace(1 /* skip this one frame */, true));

    /// <param name="index">The index of the stack frame requested.</param>
    /// <returns>The specified stack frame.</returns>
    public override StackFrame GetFrame(int index) => _frames[index];

    /// <returns>a copy of all stack frames in the current stack trace. </returns>
    public override StackFrame[] GetFrames() => _frames.ToArray();

    /// <summary>
    ///     Builds a readable representation of the stack trace.
    /// </summary>
    public override string ToString()
    {
        if (_frames.Count == 0) return "";

        var sb = new StringBuilder();
        AppendTo(sb);
        return sb.ToString();
    }
    
    public void AppendTo(StringBuilder sb)
    {
        var count = _frames.Count;
        for (var i = 0; i < count; i++)
        {
            if (i > 0) sb.Append(Environment.NewLine);
            var frame = _frames[i];
            sb.Append("   at ");
            frame.MethodInfo.AppendTo(sb);

            var fileName = frame.GetFileName();
            if (!string.IsNullOrEmpty(fileName))
            {
                sb.Append(" in ");
                sb.Append(TryGetFullPath(fileName!));
            }

            var lineNo = frame.GetFileLineNumber();
            if (lineNo != 0)
            {
                sb.Append(":line ");
                sb.Append(lineNo);
            }
        }
    }

    /// <summary>
    ///     Tries to convert a given <paramref name="filePath" /> to a full path.
    ///     Returns original value if the conversion isn't possible or a given path is relative.
    /// </summary>
    public static string TryGetFullPath(string filePath)
    {
        if (Uri.TryCreate(filePath, UriKind.Absolute, out var uri) && uri.IsFile)
            return Uri.UnescapeDataString(uri.AbsolutePath);
        return filePath;
    }
}