agomesd_minigrep 0.1.0

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

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

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

    for line in results {
        println!("{line}")
    }
    Ok(())
}

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

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()
}

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

impl Config {
    pub fn build(mut args: impl Iterator<Item = String>) -> Result<Config, &'static str> {
        args.next();

        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})
    }
}

#[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)
    )
    }
}