Advent of code day 1 part 2 rust

aoc-2023-day01-part2.rs

use tracing;
use std::fs;
use miette::Result;
use crate::aoc_error;

pub fn main() {
    let contents = fs::read_to_string("2023-day-01-part2")
        .expect("Should have been able to read the file");
    let result = calculate(contents); //55172
    match result {
        Ok(v) => println!("Result is: {v:?}"),
        Err(e) => println!("Error!: {e:?}")
    }
}

#[tracing::instrument]
fn calculate(input : String) -> Result<u32, aoc_error::AoCError> {

    let mut sum = 0;
    let lines = input.lines();
    for line in lines {
        let mut first = 10;
        let mut last = 10;
        let length = line.len();
        let chars: Vec<char> = line.chars().collect();
        for first_index in 0..chars.len() {
            if first == 10 {
                let first_char = chars[first_index];
                let first_digit = first_char.to_digit(10);
                match first_digit {
                    None => {
                        if first_char == 'o' && chars[first_index + 1] == 'n' && chars[first_index + 2] == 'e' {
                            first = 1;
                        }
                        else if first_char == 't' && chars[first_index + 1] == 'w' && chars[first_index + 2] == 'o' {
                            first = 2;
                        }
                        else if first_char == 't' && chars[first_index + 1] == 'h' && chars[first_index + 2] == 'r'  && chars[first_index + 3] == 'e'  && chars[first_index + 4] == 'e' {
                            first = 3;
                        }
                        else if first_char == 'f' && chars[first_index + 1] == 'o' && chars[first_index + 2] == 'u'  && chars[first_index + 3] == 'r' {
                            first = 4;
                        }
                        else if first_char == 'f' && chars[first_index + 1] == 'i' && chars[first_index + 2] == 'v'  && chars[first_index + 3] == 'e' {
                            first = 5;
                        }
                        else if first_char == 's' && chars[first_index + 1] == 'i' && chars[first_index + 2] == 'x' {
                            first = 6;
                        }
                        else if first_char == 's' && chars[first_index + 1] == 'e' && chars[first_index + 2] == 'v'  && chars[first_index + 3] == 'e'  && chars[first_index + 4] == 'n' {
                            first = 7;
                        }
                        else if first_char == 'e' && chars[first_index + 1] == 'i' && chars[first_index + 2] == 'g'  && chars[first_index + 3] == 'h'  && chars[first_index + 4] == 't' {
                            first = 8;
                        }
                        else if first_char == 'n' && chars[first_index + 1] == 'i' && chars[first_index + 2] == 'n'  && chars[first_index + 3] == 'e' {
                            first = 9;
                        }
                    }
                    Some(value) => {
                        first = value;
                    }
                }
            }
            if last == 10 {
                let last_index = (length - 1) - first_index;
                let last_char = chars[last_index];
                let last_digit = last_char.to_digit(10);
                match last_digit {
                    None => {
                        if last_char == 'e' && chars[last_index - 1] == 'n' && chars[last_index - 2] == 'o' {
                            last = 1;
                        }
                        else if last_char == 'o' && chars[last_index - 1] == 'w' && chars[last_index - 2] == 't' {
                            last = 2;
                        }
                        else if last_char == 'e' && chars[last_index - 1] == 'e' && chars[last_index - 2] == 'r'  && chars[last_index - 3] == 'h'  && chars[last_index - 4] == 't' {
                            last = 3;
                        }
                        else if last_char == 'r' && chars[last_index - 1] == 'u' && chars[last_index - 2] == 'o'  && chars[last_index - 3] == 'f' {
                            last = 4;
                        }
                        else  if last_char == 'e' && chars[last_index - 1] == 'v' && chars[last_index - 2] == 'i'  && chars[last_index - 3] == 'f' {
                            last = 5;
                        }
                        else if last_char == 'x' && chars[last_index - 1] == 'i' && chars[last_index - 2] == 's' {
                            last = 6;
                        }
                        else if last_char == 'n' && chars[last_index - 1] == 'e' && chars[last_index - 2] == 'v'  && chars[last_index - 3] == 'e'  && chars[last_index - 4] == 's' {
                            last = 7;
                        }
                        else if last_char == 't' && chars[last_index - 1] == 'h' && chars[last_index - 2] == 'g'  && chars[last_index - 3] == 'i'  && chars[last_index - 4] == 'e' {
                            last = 8;
                        }
                        else if last_char == 'e' && chars[last_index - 1] == 'n' && chars[last_index - 2] == 'i'  && chars[last_index - 3] == 'n' {
                            last = 9;
                        }
                    }
                    Some(value) => {
                        last = value;
                    }
                }
            }
        }
        let number = first * 10 + last;
        sum += number;
    }

    return Result::<u32, aoc_error::AoCError>::Ok(sum);
}

#[test]
fn it_works() -> Result<()> {
    let input = "two1nine //29
eightwothree //83
abcone2threexyz //13
xtwone3four //24
4nineeightseven2 //42
zoneight234 //14
7pqrstsixteen"; //76
    assert_eq!(281, calculate(input.to_string())?);
    Ok(())
}