minigrep-zyven 0.1.0

//! # minigrep-zyven
//!
//! `minigrep-zyven` is a minimal implementation of `grep` in Unix-like system which
//! will find given query in specified file. Author by [Zyven](https://github.com/Nonsensersunny)

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

pub struct Config {
    pub query: String,
    pub filename: String,
    pub case_sensitive: bool,
}

impl Config {
    pub fn new(mut args: std::env::Args) -> Result<Config, &'static str> {
        args.next();

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

        Ok(Config {
            query,
            filename,
            case_sensitive: match env::var("case_sensitive") {
                Ok(i) => i == "true",
                Err(_) => false,
            }
        })
    }
}

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

    let result = if config.case_sensitive {
        search(&*config.query, &*contents)
    } else {
        search_case_insensitive(&*config.query, &*contents)
    };

    for i in result {
        println!("{}", i);
    }

    Ok(())
}

/// Search query from contents
///
/// # Example
/// ```
/// use minigrep::search;
/// let query = "duct";
/// let contents = "\
/// Rust:
/// safe, fast, productive.
/// Pick three.
/// Duct tape.";
/// assert_eq!(
///   vec!["safe, fast, productive."],
///   search(query, contents)
/// );
/// ```
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> {
    contents.lines()
        .filter(|line| line.to_lowercase().contains(&query.to_lowercase()))
        .collect()
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn one_result() {
        let query = "duct";
        let contents = "\
Rust:
safe, fast, productive.
Pick three.";
        assert_eq!(vec!["safe, fast, productive."],
                   search(query, contents));
    }

    #[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)
        );
    }
}