ConfigurableScriptBase.cs

using System.Reflection;
using Chaos.Common.Abstractions;

namespace Chaos.Scripting.Abstractions;

/// <summary>
///     Defines the basic functionality of a script that can have variables loaded into it
/// </summary>
/// <remarks>
///     This kind of script accepts variables through it's <see cref="Chaos.Common.Abstractions.IScriptVars" /> parameter.
///     It then scans the inheritance chain and populates all non-public, writable, instanced properties automatically with
///     values from the <see cref="Chaos.Common.Abstractions.IScriptVars" />
/// </remarks>
/// <typeparam name="T">
///     The <see cref="Chaos.Scripting.Abstractions.IScripted" /> object this script is attached to
/// </typeparam>
public abstract class ConfigurableScriptBase<T> : SubjectiveScriptBase<T> where T: IScripted
{
    /// <summary>
    ///     The variables that will be loaded into the script
    /// </summary>
    protected IScriptVars ScriptVars { get; }

    /// <summary>
    ///     Initializes a new instance of the <see cref="ConfigurableScriptBase{T}" /> class.
    /// </summary>
    /// <param name="subject">
    ///     The subject of this script. The object the script is attached to
    /// </param>
    /// <param name="scriptVars">
    ///     The configurable variables the script will use to execute
    /// </param>
    protected ConfigurableScriptBase(T subject, IScriptVars scriptVars)
        : base(subject)
    {
        ScriptVars = scriptVars;

        PopulateVars();
    }

    /// <summary>
    ///     Initializes a new instance of the <see cref="ConfigurableScriptBase{T}" /> class.
    /// </summary>
    /// <param name="subject">
    ///     The subject of this script. The object the script is attached to
    /// </param>
    /// <param name="scriptVarsFactory">
    ///     A function that produces the variables that this script will use to execute
    /// </param>
    /// <exception cref="NullReferenceException">
    ///     Thrown when the factory produces a null value
    /// </exception>
    protected ConfigurableScriptBase(T subject, Func<string, IScriptVars> scriptVarsFactory)
        : base(subject)
    {
        try
        {
            ScriptVars = scriptVarsFactory(ScriptKey);
        } catch
        {
            //ignored
        }

        if (ScriptVars == null)
            throw new NullReferenceException(
                $"ScriptVars for script \"{GetType().FullName}\" were not found, and are required. If this script has no configurable variables, do not use a ConfigurableScript.");

        PopulateVars();
    }

    /// <summary>
    ///     Populates the script's properties with values from <see cref="ScriptVars" />
    /// </summary>
    private void PopulateVars()
    {
        var props = GetType()
                    .GetProperties(BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic)
                    .Where(prop => prop.CanWrite);

        foreach (var prop in props)
        {
            var type = prop.PropertyType;
            var value = ScriptVars.Get(type, prop.Name);

            if (value != null)
                prop.SetValue(this, value);
        }
    }
}