Strike Training Solution

main.rs

// My solution to https://strikecommunity.azurewebsites.net/articles/8612/course-introduction-to-the-rust-programming-langua-1.html

use std::collections::HashMap;

fn main() -> Result<(), std::io::Error> {
    let mut arguments = std::env::args().skip(1);
    let k = arguments.next().unwrap();
    let v = arguments.next().unwrap();
    let mut db = Database::from_disk("kv.db")?;

    println!("Key: {} Value: {}", k, v);
    db.insert(k, v);
    db.insert("tuu".to_string(), "ni".to_string());
    db.flush()?;

    Ok(())
}

struct Database {
    path: String,
    hashmap: HashMap<String, String>,
}

impl Database {
    fn from_disk(path: &str) -> std::io::Result<Database> {
        let hashmap = std::fs::read_to_string(path)?
            .lines()
            .map(|line| {
                let mut chunks = line.split('\t');
                let k = chunks.next().unwrap().to_string();
                let v = chunks.next().unwrap().to_string();
                (k, v)
            })
            .into_iter()
            .collect();

        Ok(Database {
            path: path.to_string(),
            hashmap,
        })
    }

    fn insert(&mut self, k: String, v: String) {
        self.hashmap.insert(k, v);
    }

    fn flush(&self) -> std::io::Result<()> {
        let contents = self
            .hashmap
            .iter()
            .map(|(k, v)| format!("{}\t{}", k, v))
            .collect::<Vec<String>>()
            .join("\n");
        std::fs::write(&self.path, contents)
    }
}