hs-rust-learn 0.1.0

//! # rust learn
//! Test test test...
//! 哇咔咔咔咔咔

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


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

impl Config {
    pub fn new(args: &[String]) -> Result<Config, &'static str> {
        if args.len() < 3{
            return Err("not enough arguments");
        }
        let str = &args[1];
        let file = &args[2];
        let case_sensitive = env::var("CASE_INSENSITIVE").is_err();
        println!("{} at {}", str, file);
    
        Ok(Config {
            query: str.to_string(),
            filename: file.to_string(),
            case_sensitive,
        })
    }
}


pub fn find_query_in_file(config: &Config) -> Result<(), Box<dyn Error>> {
    let contents = 
        fs::read_to_string(&config.filename)?;
    println!("With text:\n{}", contents);
    if config.case_sensitive {
        for line in search(&config.query, &contents) {
            println!("{}", line);
        }
    } else {
        for line in search_case_insensitive(&config.query, &contents) {
            println!("{}", line);
        }
    }
    
    Ok(())
}

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

/// 不区分大小写搜索
/// # Examples
/// 
/// ```
/// let query = "rUsT";
/// let contents = "\
/// Rust:
/// safe, fast, productive.
/// Pick three.
/// Trust me.";
/// assert_eq!(
///     vec!["Rust:", "Trust me."],
///     search_case_insensitive(query, contents)
/// );
/// ```
pub fn search_case_insensitive<'a>(query: &str, contents: &'a str) -> Vec<&'a str> {
    let lowercase_query = query.to_lowercase();
    contents.lines()
        .filter(|line| line.to_lowercase().contains(&lowercase_query))
        .collect()
}

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

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

    #[test]
    fn test_search_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)
        );
    }
}