qingwen_minigrep 0.1.0

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

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

impl Config {
    pub fn build(args: &Vec<String>) -> Result<Config, &'static str> {
        if args.len() < 3 {
            Err("no enough arguments!")
        } else {
            let ignore_case = env::var("IGNORE_CASE").is_ok();
            Ok(Config {
                query: args[1].clone(),
                file_path: args[2].clone(),
                ignore_case
            })
        }
    }
}

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(())
}

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

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
}

#[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)
        );
    }
}