use std::{collections::HashMap, sync::Arc};
use crate::database::Database;
use tokio::sync::{broadcast, RwLock};

const CHANNEL_CAPACITY: usize = 256;

#[derive(Debug, Clone)]
pub struct NoteUpdate {
    pub content: String,
    pub revision_id: i64,
    pub updated_at: String,
    pub author: Option<String>,
    pub owner_map: String,
}

#[derive(Debug)]
pub struct AppState {
    pub db: Database,
    pub asset_version: String,
    pub files_dir: String,
    pub upload_max_size_bytes: usize,
    channels: RwLock<HashMap<String, broadcast::Sender<NoteUpdate>>>,
}

impl AppState {
    pub fn new(db: Database, asset_version: String, files_dir: String, upload_max_size_bytes: usize) -> Self {
        Self { db, asset_version, files_dir, upload_max_size_bytes, channels: RwLock::new(HashMap::new()) }
    }
    async fn channel_for_key(&self, key: String) -> broadcast::Sender<NoteUpdate> {
        if let Some(sender) = self.channels.read().await.get(&key) { return sender.clone(); }
        let mut channels = self.channels.write().await;
        channels.entry(key).or_insert_with(|| broadcast::channel(CHANNEL_CAPACITY).0).clone()
    }
    pub async fn note_channel(&self, workspace_slug: &str, note_slug: &str) -> broadcast::Sender<NoteUpdate> {
        self.channel_for_key(format!("workspace:{workspace_slug}/{note_slug}")).await
    }
    pub async fn pad_channel(&self, slug: &str) -> broadcast::Sender<NoteUpdate> {
        self.channel_for_key(format!("pad:{slug}")).await
    }
}

pub type SharedState = Arc<AppState>;