using System.Diagnostics;

namespace StardewModdingAPI.Framework.Deprecations
{
    /// <summary>An immutable stack trace that caches its values.</summary>
    internal class ImmutableStackTrace
    {
        /*********
        ** Fields
        *********/
        /// <summary>The underlying stack trace.</summary>
        private readonly StackTrace StackTrace;

        /// <summary>The individual method calls in the stack trace.</summary>
        private StackFrame[]? Frames;

        /// <summary>The string representation of the stack trace.</summary>
        private string? StringForm;


        /*********
        ** Public methods
        *********/
        /// <summary>Construct an instance.</summary>
        /// <param name="stackTrace">The underlying stack trace.</param>
        public ImmutableStackTrace(StackTrace stackTrace)
        {
            this.StackTrace = stackTrace;
        }

        /// <summary>Get the underlying frames.</summary>
        /// <remarks>This is a reference to the underlying stack frames, so this array should not be edited.</remarks>
        public StackFrame[] GetFrames()
        {
            return this.Frames ??= this.StackTrace.GetFrames();
        }

        /// <inheritdoc />
        public override string ToString()
        {
            return this.StringForm ??= this.StackTrace.ToString();
        }

        /// <summary>Get the current stack trace.</summary>
        /// <param name="skipFrames">The number of frames up the stack from which to start the trace.</param>
        public static ImmutableStackTrace Get(int skipFrames = 0)
        {
            return new ImmutableStackTrace(
                new StackTrace(skipFrames: skipFrames + 1) // also skip this method
            );
        }
    }
}