minigrep_nc 0.1.0

use std::{error::Error, fs, env};

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(); //First arg is program path -> throw away.

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

        let file_path = match args.next(){
            Some(arg) => arg,
            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 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_case_sensitive(&config.query, &contents)
    };


    for line in result{
        println!("{line}");
    }
    Ok(())
}

pub fn search_case_sensitive<'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_lower = query.to_lowercase();
    contents
        .lines()
        .filter(|line| line.to_lowercase().contains(&query_lower))
        .collect()

}

#[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_case_sensitive(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)
        );
    }
}