module main

import v.debug

// vtest vflags: -d callstack

struct Test {}

fn (t Test) test_method() {
	fn_test4()
}

fn Test.test_static_method() {
	fn_test3()
}

fn fn_test2() ? {
	a := 1
	// debug.dump_callstack()
	print(a)
	assert debug.callstack(1)?.line == 43
	assert debug.callstack(0)?.line == 51
}

fn fn_test3() ? {
	// debug.dump_callstack()
	assert debug.callstack(3)?.line == 8
	assert debug.callstack(1)?.line == 41
	assert debug.callstack(0)?.line == 51
	return
}

fn fn_test4() ? {
	// debug.dump_callstack()
	assert debug.callstack(1)?.line == 10
}

fn fn_test_anon(cb fn ()) {
	cb()
}

fn fn_test() ? {
	fn_test2()
	print('enter')
	fn_test3()
	assert debug.callstack(0)?.line == 51
}

fn main() {
	print(12)
	fn_test()
	// debug.dump_callstack()
	// dump(debug.callstack(0))
	mut ret := debug.callstack(0)
	Test{}.test_method()
	Test.test_static_method()
	fn_test_anon(fn () {
		// debug.dump_callstack()
		ret := debug.callstack(3) or { return }
		res := ret.name.starts_with('anon_fn')
		assert res
	})

	ret = debug.callstack(0)
	assert ret == none
	assert fn_test_unnamed_fn_var(fn (a int, b int) bool {
		return a < b
	})
}

fn fn_test_unnamed_fn_var(cb fn (int, int) bool) bool {
	return cb(1, 2)
}