use std::fs::File;
use std::io::{BufRead, BufReader, Result};
use std::collections::HashMap;
use std::env;
use std::fs;
use std::process;

fn apply_renames(filename: &String, renames: &HashMap<String, String>) -> Result<()> {
    let mut outputs = Vec::new();

    let pls_file = File::open(filename)?;
    for entry in BufReader::new(pls_file).lines() {
        let entry = entry?;
        let new = renames.get(&entry).unwrap_or(&entry).to_string();
        outputs.push(new);
    }
    let data = outputs.join("\n");
    fs::write(filename, data).expect("unable to write");
    Ok(())
}

fn main() -> Result<()> {
    let args: Vec<String> = env::args().collect();

    if args.len() < 3 {
        println!("At least two arguments are required");
        process::exit(1);
    }

    let rename_file = &args[1];

    let file = File::open(rename_file)?;
    let mut renames = HashMap::new();
    for line in BufReader::new(file).lines() {
        let line = line?;
        let split: Vec<&str> = line.split("\t\t").collect();
        renames.insert(split[0].to_string(), split[1].to_string());
    }
    for r in &args[2..] {
        try!(apply_renames(&r, &renames));
        /*
        match apply_renames(&r, &renames) {
            Ok(()) => println!("Successfully processed renames for {}", r)
        },
        _ => println!("Error processing {}", r);
        */
    }
    
   Ok(())
}