use std::fmt::Display;

struct Pair<T> {
    x: T,
    y: T,
}

impl<T> Pair<T> {
    fn new(x: T, y: T) -> Self {
        Self {
            x,
            y,
        }
    }
}

impl<T: Display + PartialOrd> Pair<T> {
    fn cmp_display(&self) {
        if self.x >= self.y {
            println!("{}", self.x);
        }
        else {
            println!("{}", self.y);
        }
    }
}

pub trait Summary {
    fn summarize(&self) -> String {
        format!("(read more from {}...)", self.summarize_author())
    }

    fn summarize_author(&self) -> String;
}

pub struct NewsArticle {
    pub headline: String,
    pub location: String,
    pub author: String,
    pub content: String,
}

impl Summary for NewsArticle {
//    fn summarize(&self) -> String {
//        format!("{}, by {} ({})", self.headline, self.author, self.location)
//    }

    fn summarize_author(&self) -> String {
        format!("{}", self.author)
    }

}

pub struct Tweet {
    pub username: String,
    pub content: String,
    pub reply: bool,
    pub retweet: bool,
}

impl Summary for Tweet {
//    fn summarize(&self) -> String {
//        format!("{}: {}", self.username, self.content)
//    }

    fn summarize_author(&self) -> String {
        format!("@{}", self.username)
    }
}

pub fn notify(item: impl Summary) {
    println!("breaking news: {}", item.summarize());
}

fn returns_summarizable() -> impl Summary {

    NewsArticle {
        headline: String::from("Penguins win the stanley cup championship!"),
        location: String::from("Pittsburgh, PA, USA"),
        author: String::from("Iceburgh"),
        content: String::from("The pittsburgh penguins are winners I guess."),
    }
//    Tweet {
//        username: String::from("horse_ebooks"),
//        content: String::from("of course blargh"),
//        reply: false,
//        retweet: false,
//    }
}

fn main() {
    
    let tweet = Tweet {
        username: String::from("horse_ebooks"),
        content: String::from("of course, as you probably already know, people"),
        reply: false,
        retweet: false,
    };

    //dbg!(tweet.summarize());

    let article = NewsArticle {
        headline: String::from("Penguins win the stanley cup championship!"),
        location: String::from("Pittsburgh, PA, USA"),
        author: String::from("Iceburgh"),
        content: String::from("The pittsburgh penguins are winners I guess."),
    };

    //dbg!(article.summarize());

    //notify(tweet);

    returns_summarizable();
}