fn solve_1(input: &str) -> u32 {
    input
        .lines()
        .map(|l| {
            // Digits are 0-9, so we know that if they
            // are still 10 they haven't been changed
            let mut first = 10;
            let mut last = 10;

            for c in l.chars() {
                if let Some(digit) = c.to_digit(10) {
                    if first == 10 {
                        first = digit;
                    }
                    last = digit;
                }
            }

            first * 10 + last
        })
        .sum()
}

fn digitify(chars: &str) -> u32 {
    let mut chars_left = &chars[..];

    while chars_left.len() > 0 {
        if chars_left.len() >= 3 {
            if let Some(digit) = chars_left.chars().next().unwrap().to_digit(10) {
                return digit;
            } else if &chars_left[0..3] == "one" {
                return 1;
            } else if &chars_left[0..3] == "two" {
                return 2;
            } else if &chars_left[0..3] == "six" {
                return 6;
            } else if chars_left.len() >= 4 {
                if &chars_left[0..4] == "four" {
                    return 4;
                } else if &chars_left[0..4] == "five" {
                    return 5;
                } else if &chars_left[0..4] == "nine" {
                    return 9;
                } else if chars_left.len() >= 5 {
                    if &chars_left[0..5] == "three" {
                        return 3;
                    } else if &chars_left[0..5] == "seven" {
                        return 7;
                    } else if &chars_left[0..5] == "eight" {
                        return 8;
                    } else {
                        chars_left = &chars_left[1..];
                    }
                } else {
                    chars_left = &chars_left[1..];
                }
            } else {
                chars_left = &chars_left[1..];
            }
        } else if let Some(digit) = chars_left.chars().next().unwrap().to_digit(10) {
            return digit;
        } else {
            chars_left = &chars_left[1..];
        }
    }

    return 0;
}

fn digitify_backwards(line: &str) -> u32 {
    let chars_left = line.chars().rev().collect::<String>();
    let mut chars_left = chars_left.as_str();

    while chars_left.len() > 0 {
        if chars_left.len() >= 3 {
            if let Some(digit) = chars_left.chars().next().unwrap().to_digit(10) {
                return digit;
            } else if &chars_left[0..3] == "eno" {
                return 1;
            } else if &chars_left[0..3] == "owt" {
                return 2;
            } else if &chars_left[0..3] == "xis" {
                return 6;
            } else if chars_left.len() >= 4 {
                if &chars_left[0..4] == "ruof" {
                    return 4;
                } else if &chars_left[0..4] == "evif" {
                    return 5;
                } else if &chars_left[0..4] == "enin" {
                    return 9;
                } else if chars_left.len() >= 5 {
                    if &chars_left[0..5] == "eerht" {
                        return 3;
                    } else if &chars_left[0..5] == "neves" {
                        return 7;
                    } else if &chars_left[0..5] == "thgie" {
                        return 8;
                    } else {
                        chars_left = &chars_left[1..];
                    }
                } else {
                    chars_left = &chars_left[1..];
                }
            } else {
                chars_left = &chars_left[1..];
            }
        } else if let Some(digit) = chars_left.chars().next().unwrap().to_digit(10) {
            return digit;
        } else {
            chars_left = &chars_left[1..];
        }
    }

    return 0;
}

fn solve_2(input: &str) -> u32 {
    input
        .lines()
        .map(|l| {
            let first = digitify(&l[..]);
            let last = digitify_backwards(&l[..]);

            first * 10 + last
        })
        .sum()
}

fn main() {
    println!("Hello, this is Patrick!");

    let input_txt = include_str!("../input.txt");

    let result_1 = solve_1(input_txt);

    println!("The sum of all calibration values is {}", result_1);

    let result_2 = solve_2(input_txt);

    println!("The sum of all improved calibration values is {}", result_2);
}

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

    #[test]
    fn test_1() {
        let test_input = include_str!("../test.txt");

        assert_eq!(solve_1(test_input), 142);
    }

    #[test]
    fn test_2() {
        let test_input = include_str!("../test2.txt");

        assert_eq!(solve_2(test_input), 281);
    }
}