tinygrep 0.1.0

use std::env;
use std::error::Error;
use std::fs;

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

impl Config {
    pub fn build(mut args: impl ExactSizeIterator<Item = String>) -> Result<Config, &'static str> {
        // skip first arg as it is binary filepath
        args.next();
        if args.len() < 2 {
            return Err("Not enough arguments");
        }

        let ignore_case: bool;
        if args.len() > 2 {
            // argument overrides envar
            ignore_case = match args.next() {
                Some(arg) => arg.contains("IGNORE_CASE"),
                None => false,
            };
        } else {
            ignore_case = env::var("IGNORE_CASE").is_ok();
        }

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

        Ok(Config {
            query,
            file_path,
            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> {
    // only handles basic unicode
    contents
        .lines()
        .filter(|line| line.to_lowercase().contains(&query.to_lowercase()))
        .collect()
}

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

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

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

    Ok(())
}

// TODO: add integration tests for cli testing
#[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)
        )
    }
}