reifydb-sub-server 0.4.13

// SPDX-License-Identifier: Apache-2.0
// Copyright (c) 2025 ReifyDB

use std::fmt;

#[cfg(not(reifydb_single_threaded))]
use reifydb_core::error::diagnostic::internal::internal;
use reifydb_core::interface::catalog::id::SubscriptionId;
use reifydb_engine::engine::StandardEngine;
#[cfg(not(reifydb_single_threaded))]
use reifydb_type::error::Error;
#[cfg(not(reifydb_single_threaded))]
use reifydb_type::value::frame::column::FrameColumn;
use reifydb_type::{
	Result as TypeResult,
	params::Params,
	value::{Value, frame::frame::Frame, identity::IdentityId},
};
#[cfg(not(reifydb_single_threaded))]
use tracing::debug;
#[allow(unused_imports)]
use tracing::error;

/// Error type for subscription creation.
pub enum CreateSubscriptionError {
	Execute(ExecuteError),
	ExtractionFailed,
}

impl fmt::Display for CreateSubscriptionError {
	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
		match self {
			CreateSubscriptionError::Execute(e) => write!(f, "{}", e),
			CreateSubscriptionError::ExtractionFailed => write!(f, "Failed to extract subscription ID"),
		}
	}
}

impl fmt::Debug for CreateSubscriptionError {
	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
		match self {
			CreateSubscriptionError::Execute(e) => f.debug_tuple("Execute").field(e).finish(),
			CreateSubscriptionError::ExtractionFailed => write!(f, "ExtractionFailed"),
		}
	}
}

impl From<ExecuteError> for CreateSubscriptionError {
	fn from(err: ExecuteError) -> Self {
		CreateSubscriptionError::Execute(err)
	}
}

/// Result of creating a subscription: either local or remote.
pub enum CreateSubscriptionResult {
	Local(SubscriptionId),
	Remote {
		address: String,
		rql: String,
		token: Option<String>,
	},
}

#[cfg(not(reifydb_single_threaded))]
use reifydb_core::actors::server::Operation;
#[cfg(not(reifydb_single_threaded))]
use tokio::task::spawn_blocking;

use crate::execute::ExecuteError;
#[cfg(not(reifydb_single_threaded))]
use crate::{
	dispatch::dispatch_subscribe,
	interceptor::{RequestContext, RequestMetadata},
	state::AppState,
};

/// Execute `CREATE SUBSCRIPTION AS { query }` and extract the subscription ID from the result.
#[cfg(not(reifydb_single_threaded))]
pub async fn create_subscription(
	state: &AppState,
	identity: IdentityId,
	rql: &str,
	metadata: RequestMetadata,
) -> Result<CreateSubscriptionResult, CreateSubscriptionError> {
	let subscription_rql = format!("CREATE SUBSCRIPTION AS {{ {} }}", rql);
	debug!("Subscription rql: {}", subscription_rql);

	let ctx = RequestContext {
		identity,
		operation: Operation::Subscribe,
		rql: subscription_rql,
		params: Params::None,
		metadata,
	};
	let (frames, _metrics) = dispatch_subscribe(state, ctx).await?;
	let frame = frames.first().ok_or(CreateSubscriptionError::ExtractionFailed)?;

	if let Some(remote) = extract_remote_result(frame)? {
		return Ok(remote);
	}
	extract_local_result(frame)
}

#[cfg(not(reifydb_single_threaded))]
fn extract_remote_result(frame: &Frame) -> Result<Option<CreateSubscriptionResult>, CreateSubscriptionError> {
	let Some(addr_col) = frame.columns.iter().find(|c| c.name == "remote_address") else {
		return Ok(None);
	};
	let address = match first_utf8_value(addr_col) {
		Some(s) => s,
		None => return Err(CreateSubscriptionError::ExtractionFailed),
	};
	let rql = frame
		.columns
		.iter()
		.find(|c| c.name == "remote_rql")
		.and_then(first_utf8_value)
		.ok_or(CreateSubscriptionError::ExtractionFailed)?;
	let token = frame.columns.iter().find(|c| c.name == "remote_token").and_then(first_utf8_value);
	Ok(Some(CreateSubscriptionResult::Remote {
		address,
		rql,
		token,
	}))
}

#[cfg(not(reifydb_single_threaded))]
fn extract_local_result(frame: &Frame) -> Result<CreateSubscriptionResult, CreateSubscriptionError> {
	frame.columns
		.iter()
		.find(|c| c.name == "subscription_id")
		.and_then(|col| {
			if col.data.is_empty() {
				None
			} else {
				Some(col.data.get_value(0))
			}
		})
		.and_then(|value| match value {
			Value::Uint8(id) => Some(SubscriptionId(id)),
			other => {
				error!("subscription_id column has wrong type: {:?}", other);
				None
			}
		})
		.map(CreateSubscriptionResult::Local)
		.ok_or(CreateSubscriptionError::ExtractionFailed)
}

#[cfg(not(reifydb_single_threaded))]
#[inline]
fn first_utf8_value(col: &FrameColumn) -> Option<String> {
	if col.data.is_empty() {
		return None;
	}
	match col.data.get_value(0) {
		Value::Utf8(s) => Some(s),
		_ => None,
	}
}

/// Extract the subscription ID from frames returned by `engine.subscribe_as`.
///
/// The engine returns a single-row frame with a `subscription_id` column
/// containing a `Value::Uint8(id)`.
pub fn extract_subscription_id(frames: &[Frame]) -> Option<SubscriptionId> {
	let frame = frames.first()?;
	frame.columns
		.iter()
		.find(|c| c.name == "subscription_id")
		.and_then(|col| {
			if !col.data.is_empty() {
				Some(col.data.get_value(0))
			} else {
				None
			}
		})
		.and_then(|value| match value {
			Value::Uint8(id) => Some(SubscriptionId(id)),
			_ => None,
		})
}

/// Synchronous cleanup: drop subscription via DDL.
pub fn cleanup_subscription_sync(engine: &StandardEngine, subscription_id: SubscriptionId) -> TypeResult<()> {
	let rql = format!("drop subscription if exists subscription_{};", subscription_id.0);
	engine.admin_as(IdentityId::system(), &rql, Params::None).check()?;
	Ok(())
}

/// Async cleanup via a blocking task.
#[cfg(not(reifydb_single_threaded))]
pub async fn cleanup_subscription(state: &AppState, subscription_id: SubscriptionId) -> TypeResult<()> {
	let engine = state.engine_clone();

	spawn_blocking(move || cleanup_subscription_sync(&engine, subscription_id))
		.await
		.map_err(|e| Error(Box::new(internal(format!("Blocking task error: {:?}", e)))))?
}