const (
    unsorted    = [2, 30, 10, 20, 1]
    sorted_asc  = [1, 2, 10, 20, 30]
    sorted_desc = [30, 20, 10, 2, 1]
)

fn test_sorting_simple() {
    mut a := unsorted.clone()
    a.sort()
    println(' a: ${a}')
    assert a == sorted_asc
}

fn test_sorting_with_condition_expression() {
    mut a := unsorted.clone()
    a.sort(a > b)
    println(' a: ${a}')
    assert a == sorted_desc
}

fn test_sorting_primitives_with_condition_expression() {
    mut x := ['9', '87', '3210', '654']
    x.sort(a.len < b.len)
    assert x == ['9', '87', '654', '3210']
}

// fn get_score(word string) int {
//     mut total := 0
//     for letter in word {
//         total += int(letter) - 97
//     }
//     return total
// }

// fn test_sorting_with_fn_call_in_condition_expression() {
//     mut words := ['aaaa', 'a', 'b', 'foo', 'bar']
//     words.sort(get_score(a) < get_score(b))
// }

fn mysort(mut a []int) {
    a.sort()
}

fn test_sorting_by_passing_a_mut_array_to_a_function() {
    mut a := unsorted.clone()
    mysort(mut a)
    println(' a: ${a}')
    assert a == sorted_asc
}

/*
fn test_sorting_by_passing_an_anonymous_sorting_function() {
    mut a := unsorted
    a.sort(fn(a &int, b &int) int {    return *b - *a })
    println(' a: $a')
    assert a == sort_desc
}
*/
fn test_sorting_u64s() {
    mut a := [u64(3), 2, 1, 9, 0, 8]
    a.sort()
    println(' a: ${a}')
    assert a == [u64(0), 1, 2, 3, 8, 9]
    a.sort(a > b)
    println(' a: ${a}')
    assert a == [u64(9), 8, 3, 2, 1, 0]
}

struct User {
    age  int
    name string
}

fn g(mut users []User) {
    users.sort(a.name > b.name)
}

fn f(mut users []User) {
    users.sort(a.name < b.name)
}

fn z(mut users []User) {
    users.sort(a.name < b.name)
}