tepwgrep 0.1.0

prototype grep from TepWacha
Documentation
use std::fs;
use std::error::Error;
use std::env;

pub fn run(config : Config) -> Result<(), Box<dyn Error>>{
    let contents  = fs::read_to_string(config.file_path)?;
    let result = if config.ignore_case {
        search_case_insensitive(&config.query, &contents)
    } else {
        search(&config.query, &contents)
    };
    for line in result {
        println!("{line}");
    }
    Ok(())
}

pub struct Config {
    pub query : String,
    pub file_path : String,
    pub ignore_case : bool,
}

impl Config {
    pub fn build(mut args : impl Iterator<Item = String>) -> Result<Config, &'static str> {
        args.next();
        let query = match args.next() {
            Some(s) => s,
            None => return Err("Didn't get a query string")
        };
        let file_path = match args.next() {
            Some(s) => s,
            None => return Err("Didn't get a file path")
        };
        let ignore_case = env::var("IGNORE_CASE").is_ok();
        Ok(Config {query, file_path, ignore_case})
    }
}

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

pub fn search_case_insensitive<'a>(query : &str, contents : &'a str) -> Vec<&'a str> {
    let query = query.to_lowercase();
    contents.lines().filter(|line| line.to_lowercase().contains(&query)).collect()
}

#[cfg(test)]
mod tests {
    use super::*;
    #[test]
    fn case_sensitive() {
        let query = "duct";
        let contents = "\
Rust:
safe, fast, productive.
Pick three.";
        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));
    }
}