using System.Runtime.InteropServices;

using static JavaScript.v8.NativeMethods;

namespace JavaScript.v8;

public delegate JavaScriptValue JavaScriptFunction(JavaScriptScope scope, JavaScriptValue self, ReadOnlySpan<JavaScriptValue> args);

public delegate void JavaScriptScopeAction(JavaScriptScope scope, JavaScriptValue value);

public delegate T JavaScriptScopeAction<T>(JavaScriptScope scope, JavaScriptValue value);

[StructLayout(LayoutKind.Sequential)]

public unsafe readonly ref struct JavaScriptScope

{

internal readonly IntPtr _ptr;

public JavaScriptValue CreateUndefined() => js_undefined(this);

public JavaScriptValue CreateNull() => js_null(this);

public JavaScriptValue CreateTrue() => js_true(this);

public JavaScriptValue CreateFalse() => js_false(this);

public JavaScriptValue CreateInteger(int value) => js_integer_new(this, value);

public JavaScriptValue CreateNumber(double value) => js_number_new(this, value);

public JavaScriptValue CreateArray(int length) => js_array_new(this, length);

public JavaScriptValue CreateObject() => js_object_new(this);

public JavaScriptValue CreateString(string value)

{

fixed (char* chars = value)

{

return js_string_new(this, chars, value.Length);

}

}

public JavaScriptValue CreateFunction(JavaScriptFunction function)

{

return js_function_new(this, Callback);

int Callback(JavaScriptScope scope, JavaScriptValue self, JavaScriptValue* argv, nint argc, out JavaScriptValue result)

{

try

{

var args = new Span<JavaScriptValue>(argv, (int)argc);

result = function(scope, self, args);

return 0;

}

catch (Exception ex)

{

result = scope.CreateString(ex.ToString());

return -1;

}

}

}

public JavaScriptValue RunScript(string code, string filename)

{

return js_run_script(this, ToJsString(this, code), ToJsString(this, filename), out var result) == 0

? result

: throw new JavaScriptException(result.AsString(this));

}

}