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mod gen_range;

mod combi;

pub struct RangeIterator {
    curr: i32,
    stop: i32,
    step: i32,
}

impl RangeIterator {
    pub fn new(start: i32, stop: i32, step: i32) -> Self {
        RangeIterator {
            curr: start,
            stop,
            step,
        }
    }
}

impl Iterator for RangeIterator {
    type Item = i32;

    // next - includes start, excludes stop end point
    fn next(&mut self) -> Option<Self::Item> {
        if self.curr >= self.stop {
            return None;
        }
        let res = self.curr;

        self.curr += self.step;
        Some(res)
    }


}




#[cfg(test)]
mod tests {
    use super::RangeIterator;

    use itertools::Itertools;



    #[test]
    fn it_works() {
        assert_eq!(2 + 2, 4);
    }

    #[test]
    fn iter_test() {
        let my_iter = RangeIterator::new(2, 12, 2);

        let mut sum = 0;
        for s in my_iter {
            println!("s, sum = {}, {}", s, sum);
            sum += s;
        }
        assert_eq!(sum, 30, "Test 1");
        
    }

    #[test]
    fn tup_test() {
        let mut v = Vec::new();
        for (a, b) in (1..5).tuples() {
            v.push((a, b));
        }
        assert_eq!(v, vec![(1, 2), (3, 4)]);
        
    
let mut it = (1..7).tuples();
assert_eq!(Some((1, 2, 3)), it.next());
assert_eq!(Some((4, 5, 6)), it.next());
assert_eq!(None, it.next());

// this requires a type hint
let it = (1..7).tuples::<(_, _, _)>();
itertools::assert_equal(it, vec![(1, 2, 3), (4, 5, 6)]);

// you can also specify the complete type
use itertools::Tuples;
use std::ops::Range;

let it: Tuples<Range<u32>, (u32, u32, u32)> = (1..7).tuples();
itertools::assert_equal(it, vec![(1, 2, 3), (4, 5, 6)]);
    }
}