look at the following code:

function test(){
    console.log(this === window);
    show();
    window.show();
    function show(){
        console.log(this === window, "fn");
    }
}
function show(){
    console.log(this === window, "local");
}
test();

:
true
true "fn"
true "local"

my understanding is:
1 who calls the function where this is located, this represents who
2 when a function and object is not called by an object, the default is window object
3 when using a variable or function, priority is given to variables and functions in the current scope
first question: do I understand correctly?

but (second question, divided into three small questions)
1 when show () is called in the test () function, is the window object called by default?
2 if the above is true, why is the result different from the explicit window call below?
3 do local variables and local functions belong to window objects?

Thank you all