use std::collections::HashMap;

use serde_derive::Serialize;

use crate::post::Post;

#[derive(Serialize, Debug)]
pub struct Tag {
    pub slug: String,
    pub absolute_path: String,
    pub posts: Vec<String>,
}

pub fn get_tags<'a>(posts: impl IntoIterator<Item=&'a Post>) -> HashMap<String,Tag> {
    let mut tags: HashMap<String,Tag> = HashMap::new();

    for post in posts.into_iter() {
        for key in &post.tags {
            if let Some(tag) = tags.get_mut(key) {
                tag.posts.push(post.slug.clone());
            }
            else {
                tags.insert(key.clone(), Tag {
                    slug: key.clone(),
                    absolute_path: format!("/tags/{key}/"),
                    posts: vec![post.slug.clone()]
                });
            }
        }
    }

    tags
}