minigrep_ao 1.0.0

//! # Minigrep
//! 
//! A grep utility written in Rust
    
use std::env;
use std::error::Error;
use std::fs;

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

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

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

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

impl Config {
    pub fn new(mut args: env::Args) -> 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_name = match args.next() {
            Some(arg) => arg,
            None => return Err("Didn't get a file name")
        };

        let case_sensitive = env::var("CASE_SENSITIVE")
            .map(|x| {
                return x == "true";
            })
            .unwrap_or(false);

        Ok(Config {
            query,
            file_name,
            case_sensitive,
        })
    }
}

/// Searching lines that match the query- Case sensitive
/// # Examples
/// 
/// ```
/// let query = "Hello";
/// 
/// let content = r#"Hello world!
/// hello to you!
/// Hello There"#;
/// let result = minigrep::search(&query, &content);
/// 
/// assert_eq!(vec!["Hello world!", "Hello There"], result);
/// ```
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> {
    let query = query.to_lowercase();
    let mut results = Vec::new();

    for line in contents.lines() {
        if line.to_lowercase().contains(&query.to_lowercase()) {
            results.push(line);
        }
    }
    results
}

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

    #[test]
    fn case_sensitive() {
        let query = "don't";
        let contents = "\
I don't know how to make songs like that
I don't know what words to use
Let me know when it occurs to you
While I'm rippin' any one of these verses
        ";

        assert_eq!(
            vec![
                "I don't know how to make songs like that",
                "I don't know what words to use"
            ],
            search(query, contents)
        );
    }

    #[test]
    fn case_insensitive() {
        let query = "dOn";
        let contents = "\
I don't know how to make songs like that
I doN't know what words to use
Let me know when it occurs to you
While I'm rippin' any one of these verses
        ";

        assert_eq!(
            vec![
                "I don't know how to make songs like that",
                "I doN't know what words to use"
            ],
            search_case_insensitive(query, contents)
        );
    }
}