extern crate regex;
use std::fs;
use std::error::Error;

pub struct Config {
    pub query: String,
    pub filename: String,
}

impl Config {
    pub fn new(args: &[String]) -> Result<Config, &'static str> {
        if args.len() < 3 { return Err("Not enough arguments"); }

        let query: String = args[1].clone().to_string(); // 0 == the current process. so we start at 1
        let filename: String = args[2].clone().to_string();

        Ok( Config { query: query, filename: filename } )
    }
}

pub fn run(config: Config) -> Result<(), Box<dyn Error>> {
    let contents: String = fs::read_to_string(config.filename)?;
    let mut matching = Vec::new();
    matching = search_regex(&config.query, &contents)?;

    if matching.len() == 0 {
        println!("[ WARNING ] No occurrences found");
        return Ok(());
    }

    println!("-----------------START---------------");

    for line in matching {
        println!("{}", line);
    }

    println!("-----------------END-----------------");
    Ok(())
}

fn search_regex(query: &str, contents: &str) -> Result<Vec<String>, Box<dyn Error>> {
    let mut results: Vec<String> = Vec::new();
    let re = regex::Regex::new(query)?;
    let mut current_line: i32 = 0;
    for line in contents.lines() {
        current_line += 1;
        let match_item = re.find(line);
        if match_item.is_some() {
            let unwrapped_result = match_item.unwrap();
            let data: String = format!("{}::{}:{} -> {}", current_line, unwrapped_result.start(), unwrapped_result.end(), &line[unwrapped_result.start()..unwrapped_result.end()]);
            results.push(data);
        }
    }
    Ok(results)
}