//! # minigrep
//! minigrep is a command line tool which implements simple
//! features of grep.

pub mod structs;

use std::error::Error;
use std::fs;
use structs::config::Config;

/// run on the provided config.
/// #example
/// ```
/// use minigrep_xyp::structs::Config;
/// use minigrep_xyp::run;
/// let config = Config::new(
///     String::from("public"),
///     String::from("poem.txt"),
///     true
/// );
/// assert_eq!(run(config).unwrap(), "OK");
/// ```
pub fn run(config: Config) -> Result<&'static str, Box<dyn Error>> {
    let query = &config.query;
    let filename = &config.filename;

    let contents = fs::read_to_string(filename)?;

    let results = if config.case_sensitive {
        search(query, &contents)
    } else {
        search_case_insensitive(query, &contents)
    };
    for line in  results {
        println!("{}", line);
    }
    Ok("OK")
}

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



/// search a query in the contents,
/// and return the matched lines.
/// This function is case insensitive.
///
/// # example
/// ```
/// let query = "rUst";
/// let contents = "\
///rust, Python, Java,
///Rust, Ruby, Trust.
///Oops.
/// ";
/// assert_eq!(
///    minigrep_xyp::search_case_insensitive(query, contents),
///    vec!["rust, Python, Java,", "Rust, Ruby, Trust."]
///);
/// ```
pub 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.
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));
    }
}