use lazy_static::lazy_static;
use serde::Deserialize;
use serenity::{
    client::Context,
    model::channel::{Reaction, ReactionType},
};
use std::collections::HashMap;

lazy_static! {
    static ref ROLE_CONFIG: Vec<ReactableMessage> = {
        let c = serde_json::from_str(
            &std::fs::read_to_string("reaction_config.json").unwrap_or_else(|_| "[]".to_string()),
        )
        .expect("Could not read reaction config");
        eprintln!("Read reaction config: {:?}", c);
        c
    };
}

macro_rules! role_action {
    ($reaction: expr, $ctx: expr, $action: ident) => {
        if let ReactionType::Unicode(emoji) = &$reaction.emoji {
            if let Some(&role_id) = ROLE_CONFIG
                .iter()
                .find(|c| $reaction.message_id == c.message_id)
                .and_then(|rm| rm.roles.get(emoji))
            {
                $reaction
                    .guild_id
                    .expect("Configured message id is not in a guild")
                    .member(&$ctx, $reaction.user_id.unwrap())
                    .await?
                    .$action(&$ctx, role_id)
                    .await?
            }
        }
    };
}

pub(crate) async fn reaction_added(ctx: Context, reaction: Reaction) -> serenity::Result<()> {
    role_action!(reaction, ctx, add_role);
    Ok(())
}
pub(crate) async fn reaction_removed(ctx: Context, reaction: Reaction) -> serenity::Result<()> {
    role_action!(reaction, ctx, remove_role);
    Ok(())
}

#[derive(Debug, PartialEq, Deserialize)]
struct ReactableMessage {
    // I hate how this sounds like a Java interface name…
    message_id: u64,
    roles: HashMap<String, u64>,
}

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

    const TEST_JSON: &str = r#"
        [
          {
            "message_id": 12345,
            "roles": {
              "💤": 1,
              "🐑": 2
            }
          },
          {
            "message_id": 54321,
            "roles": {
              "💙": 3,
              "♻": 4
            }
          }
        ]"#;

    #[test]
    fn test_role_config_parsing() {
        assert_eq!(
            serde_json::from_str::<Vec<ReactableMessage>>(TEST_JSON).unwrap(),
            [
                ReactableMessage {
                    message_id: 12345,
                    roles: HashMap::from([("💤".to_string(), 1), ("🐑".to_string(), 2)]),
                },
                ReactableMessage {
                    message_id: 54321,
                    roles: HashMap::from([("💙".to_string(), 3), ("♻".to_string(), 4)]),
                },
            ],
        );
    }
}