minigrep_testing_crates 0.1.0

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

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

impl Config {
    pub fn build(mut args: impl Iterator<Item = String>) -> Result<Config, &'static str> {
        args.next();
        let query = match args.next() {
            Some(x) => x,
            None => {
                return Err("No query string");
            }
        };
        let filepath = match args.next() {
            Some(x) => x,
            None => {
                return Err("No filepath");
            }
        };
        let ignore_case = env::var("IGNORE_CASE").is_ok();
        Ok(Config { query, filepath, ignore_case })
    }
}

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) {
            results.push(line);
        }
    }
    results
}

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

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

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

#[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_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));
    }
}