use std::env;
use std::fs::File;
use std::io::prelude::*;
use std::error::Error;

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

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

pub fn run(config: Config) -> Result<(), Box<Error>> {
	let mut file = File::open(config.filename)?;
	let mut contents = String::new();
	file.read_to_string(&mut contents)?;
	let result = if config.case_sensitive {
		search(&config.query, &contents)
	} else {
		search_case_insensitive(&config.query, &contents)
	};

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

	Ok(())
}

pub fn search<'a>(query: &str, contents: &'a str) -> Vec<&'a str> {
	let mut result = Vec::new();
	for line in contents.lines() {
		if line.contains(query) {
			result.push(line);
		}
	}
	result
}

pub fn search_case_insensitive<'a>(query: &str, contents: &'a str) -> Vec<&'a str> {
	let mut result = Vec::new();
	let query = query.to_lowercase();
	for line in contents.lines() {
		if line.to_lowercase().contains(&query) {
			result.push(line);
		}
	}
	result
}

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

	#[test]
	fn searching() {
		let contents = "\
abc def to name,
998 ab To you
after de";
		let result = search("ou", contents);
		assert_eq!(vec!["998 ab To you"], result);
	}

	#[test]
	fn searching_case_insensitive() {
		let contents = "\
abc def to name,
998 ab To you
after de";
		let result = search_case_insensitive("TO", contents);
		assert_eq!(vec!["abc def to name,", "998 ab To you"], result);
	}

	#[test]
	fn new_config() {
		let args = vec!["app".to_string(), "pzs".to_string(), "zj".to_string()];

		let config = Config::new(args).unwrap();

		assert_eq!(String::from("pzs"), config.query);
		assert_eq!(String::from("zj"), config.filename);
		assert_eq!(true, config.case_sensitive);
	}



}