fn main () {
        let data: String = std::fs::read_to_string("input").unwrap();
        let lines = data.lines();

        let sum: u32 = lines.map(|line| { get_calibration_values(line) }).sum();
        println!("the sum of all calibration values is {sum}!");
}

fn replace_numbers(line: &str) -> String {
        let numbers: [&str; 10] = ["zero", "one", "two", "three", "four", "five", "six", "seven", "eight", "nine"];
        let mut processed: String = String::from(line);
        loop {
                let mut clean = false;
                for i in 0..numbers.len() {
                        let old_line = processed.clone();
                        processed = processed.replace(numbers[i], i.to_string().as_str());
                        if processed == old_line {
                                clean = true;
                        }
                }
                if clean {
                        break;
                }
        }
        processed
}

fn get_calibration_values(raw_line: &str) -> u32 {
        let line: String = replace_numbers(raw_line);

        let first: u32 = line.chars().find_map(|ch| { ch.to_digit(10) }).unwrap();
        let last: u32 = line.chars().rev().find_map(|ch| { ch.to_digit(10) }).unwrap();

        let result = first * 10 + last;
        println!("{line} ({result})");

        // first * 10 + last
        result
}