namespace Cef3
{
    using System;
    using System.Collections.Generic;
    using System.Diagnostics;
    using System.Runtime.InteropServices;
    using Cef3.Interop;

    /// <summary>
    /// Interface that should be implemented to handle V8 function calls. The methods
    /// of this class will always be called on the render process main thread.
    /// </summary>
    public abstract unsafe partial class CefV8Handler
    {
        private static readonly CefV8Value[] emtpyArgs = new CefV8Value[0];

        private int execute(cef_v8handler_t* self, cef_string_t* name, cef_v8value_t* @object, UIntPtr argumentsCount, cef_v8value_t** arguments, cef_v8value_t** retval, cef_string_t* exception)
        {
            CheckSelf(self);

            var m_name = cef_string_t.ToString(name);
            var m_obj = CefV8Value.FromNative(@object);
            var argc = (int)argumentsCount;
            CefV8Value[] m_arguments;
            if (argc == 0) { m_arguments = emtpyArgs; }
            else
            {
                m_arguments = new CefV8Value[argc];
                for (var i = 0; i < argc; i++)
                {
                    m_arguments[i] = CefV8Value.FromNative(arguments[i]);
                }
            }

            CefV8Value m_returnValue;
            string m_exception;

            var handled = Execute(m_name, m_obj, m_arguments, out m_returnValue, out m_exception);

            if (handled)
            {
                if (m_exception != null)
                {
                    cef_string_t.Copy(m_exception, exception);
                }
                else if (m_returnValue != null)
                {
                    *retval = m_returnValue.ToNative();
                }
            }

            return handled ? 1 : 0;
        }

        /// <summary>
        /// Handle execution of the function identified by |name|. |object| is the
        /// receiver ('this' object) of the function. |arguments| is the list of
        /// arguments passed to the function. If execution succeeds set |retval| to the
        /// function return value. If execution fails set |exception| to the exception
        /// that will be thrown. Return true if execution was handled.
        /// </summary>
        protected abstract bool Execute(string name, CefV8Value obj, CefV8Value[] arguments, out CefV8Value returnValue, out string exception);
    }
}