FirstAXAXAXAXAXAXAXAXXAXA 0.1.0

use std::collections::HashMap;
use std::env;
use std::error::Error;
use std::fs;
use std::hash::Hash;

pub fn run(config: Config) -> Result<(), Box<dyn Error>> {
    let contents = fs::read_to_string(&config.filename)?;

    let results = if config.case_sensitive {
        search(&config.query, &contents)
    } else {
        search_case_insensitive(&config.query, &contents)
    };

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

    Ok(())
}

pub fn search<'a>(query: &'a str, content: &'a str) -> Vec<&'a str> {
    content
        .lines()
        .filter(|line| line.contains(query))
        .collect()
}

pub fn search_case_insensitive<'a>(query: &'a str, content: &'a str) -> Vec<&'a str> {
    let query = query.to_lowercase();

    content.lines()
        .filter(|line| line.to_lowercase().contains(&query))
        .collect()
}

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

impl Config {
    pub fn new(mut args: env::Args) -> Result<Config, &'static str> {
        args.next();

        let query = match args.next() {
            Some(x) => x,
            None => return Err("Didn't get a query string"),
        };

        let filename = match args.next() {
            Some(x) => x,
            None => return Err("Didn't get a file name"),
        };

        let case_sensitive = env::var("CASE_INSENSITIVE").is_err();

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

struct Cacher<T, Arg, Res>
where
    T: Fn(Arg) -> Res,
    Arg: PartialEq + Eq + Hash + ToOwned,
{
    calculation: T,
    values: HashMap<Arg, Res>,
}

impl<T, Arg, Res> Cacher<T, Arg, Res>
where
    T: Fn(Arg) -> Res,
    Arg: Hash + PartialEq + Eq + ToOwned<Owned = Arg>,
{
    fn new(calculation: T) -> Cacher<T, Arg, Res> {
        let values: HashMap<Arg, Res> = HashMap::new();

        Cacher {
            calculation,
            values,
        }
    }

    fn value(&mut self, arg: Arg) -> &Res {
        self.values
            .entry(arg.to_owned())
            .or_insert((self.calculation)(arg))
    }
}

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

    #[test]
    fn case_sensitive() {
        let query = "duct";
        let contents = "\
Rust:
safe, fast, productive.
Pick three.
Duct tape.";

        assert_eq!(vec!["safe, fast, productive."], search(query, contents));
    }

    #[test]
    fn case_insensitive() {
        let query = "rUsT";
        let contents = "\
Rust:
safe, fast, productive.
Pick three.
Trust me.";
        assert_eq!(
            vec!["Rust:", "Trust me."],
            search_case_insensitive(query, contents)
        );
    }

    #[test]
    fn cacher_test() {
        let calculation = |arg: String| -> String { arg + "_New" };

        let mut cacher = Cacher::new(calculation);
        let ans1 = cacher.value(String::from("AAA"));
        assert_eq!(*ans1, String::from("AAA_New"));
        assert_eq!(ans1.as_ptr(), cacher.value(String::from("AAA")).as_ptr());

        let calculation = |arg: &String| -> String { format!("{}_New", arg) };

        let mut cacher = Cacher::new(calculation);
        let aaa = String::from("AAA");
        let ans1 = cacher.value(&aaa);
        assert_eq!(*ans1, String::from("AAA_New"));
        assert_eq!(ans1.as_ptr(), cacher.value(&aaa).as_ptr());
    }
}