use std::collections::HashMap;

use std::sync::Arc;

use axum::async_trait;

use churn_domain::{LogEvent, ServerEnrollReq};
use serde::{ser::SerializeStruct, Deserialize, Serialize};
use tokio::sync::{Mutex, RwLock};

use churn_capnp::CapnpPackExt;

use crate::db::Db;

#[derive(Clone)]
pub struct EventService(Arc<dyn EventServiceTrait + Send + Sync + 'static>);

impl EventService {
    pub fn new(db: Db) -> Self {
        Self(Arc::new(DefaultEventService::new(db)))
    }
}

impl std::ops::Deref for EventService {
    type Target = Arc<dyn EventServiceTrait + Send + Sync + 'static>;

    fn deref(&self) -> &Self::Target {
        &self.0
    }
}

impl Default for EventService {
    fn default() -> Self {
        Self(Arc::new(DefaultEventService::default()))
    }
}

#[derive(Default)]
struct DefaultEventService {
    db: Db,
}

impl DefaultEventService {
    pub fn new(db: Db) -> Self {
        Self { db }
    }
}

#[async_trait]
pub trait EventServiceTrait {
    async fn append(&self, req: LogEvent) -> anyhow::Result<()>;
    async fn get_from_cursor(&self, cursor: uuid::Uuid) -> anyhow::Result<Vec<LogEvent>>;
    async fn get_from_beginning(&self) -> anyhow::Result<Vec<LogEvent>>;
}

#[async_trait]
impl EventServiceTrait for DefaultEventService {
    async fn append(&self, req: LogEvent) -> anyhow::Result<()> {
        self.db
            .insert("events_log", &req.id.to_string(), &req.serialize_capnp())
            .await;

        Ok(())
    }
    async fn get_from_cursor(&self, cursor: uuid::Uuid) -> anyhow::Result<Vec<LogEvent>> {
        let events = self.db.get_all("events_log").await?;

        let events = events
            .iter()
            .map(|e| LogEvent::deserialize_capnp(e))
            .flatten()
            .skip_while(|item| item.id != cursor)
            .skip(1)
            .collect();

        Ok(events)
    }
    async fn get_from_beginning(&self) -> anyhow::Result<Vec<LogEvent>> {
        let events = self.db.get_all("events_log").await?;

        let events = events
            .iter()
            .map(|e| LogEvent::deserialize_capnp(e))
            .flatten()
            .collect();

        Ok(events)
    }
}