mini__grep 0.1.0

use std::error::Error;
use std::fs;
use std::env;

pub struct Config {
    query: String,
    path: String,
    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(q) => q,
            None => Err("Didn't get a query string")?
        };

        let path = match  args.next() {
            Some(p) => p,
            None => Err("Didn't get a path string")?
        };

        let ignore_case = env::var("IGNORE_CASE").is_ok();
        Ok(Config{query, path, ignore_case})
    }
}


/// Prints the lines in file at config.path that contain config.query.
/// 
/// Example:
/// ```
///     minigrep::run(minigrep::Config{query:"the", path: "poem.txt".to_string()});
/// ```
/// 
/// 
pub fn run(config: Config) -> Result<(), Box<dyn Error>> {
    let contents = fs::read_to_string(config.path)?;
    
    let func = if config.ignore_case {search_case_insensitive} else {search};
    func(&config.query, &contents).iter()
        .for_each(|line| println!("{line}"));

    Ok(())
}

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

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