mod dna;
mod match_replace;

use std::env;
use std::fs;
use std::fs::File;
use std::io::Write;

fn main() {
    let args: Vec<String> = env::args().collect();
    if args.len() < 4 {
        println!("Usage: {} <prefix file> <dna file> <rna file>", args[0]);
        return;
    }

    let Ok(prefix) = fs::read_to_string(&args[1]) else {
        println!("Failed to read prefix file at {}", &args[1]);
        return;
    };
    let Ok(dna) = fs::read_to_string(&args[2]) else {
        println!("Failed to read dna file at {}", &args[2]);
        return;
    };

    let mut dna = dna::DnaRef::from_string(&prefix) + dna::DnaRef::from_string(&dna);
    let Ok(mut rna_file) = File::create(&args[3]) else {
        println!("Failed to create rna output file at {}", &args[3]);
        return;
    };
    let mut rna = Vec::new();
    loop {
        if let Some(new_dna) = match_replace::match_replace(dna, &mut rna) {
            dna = new_dna;
        } else {
            break;
        }

        for r in rna.iter() {
            let rna_str: String = r.iter().map(|b| b.to_char()).collect();
            // Just tolerate a write error.
            let _ = rna_file.write(rna_str.as_bytes());
            let _ = rna_file.write(b"\n");
        }

        rna.clear();
    }

    return;
}