#[cfg(feature = "opentelemetry")]
pub mod telemetry;

#[cfg(feature = "opentelemetry")]
pub use opentelemetry_sdk::trace::SdkTracerProvider;

#[cfg(feature = "tracing-loki")]
mod loki;

use tracing_subscriber::{
    EnvFilter, Layer, Registry, layer::SubscriberExt, util::SubscriberInitExt,
};

/// Telemetry handle
#[derive(bon::Builder)]
#[builder(finish_fn(vis = "", name = build_internal))]
pub struct Tracing {
    #[builder(field = vec![tracing_subscriber::fmt::layer().boxed()])]
    layers: Vec<Box<dyn Layer<Registry> + Sync + Send>>,
    #[cfg(feature = "tracing-loki")]
    #[builder(setters(vis = "", name = loki_internal))]
    pub loki_task: tracing_loki::BackgroundTask,
    #[cfg(feature = "opentelemetry")]
    #[builder(setters(vis = "", name = otel_internal))]
    pub otel_provider: opentelemetry_sdk::trace::SdkTracerProvider,
}

// Define a custom finishing function as a method on the `UserBuilder`.
// The builder's state must implement the `IsComplete` trait.
// See details about it in the tip below this example.
impl<S: tracing_builder::IsComplete> TracingBuilder<S> {
    pub fn build(self, config: &crate::Monitoring) -> Tracing {
        // Delegate to `build_internal()` to get the instance of user.
        let mut tracing = self.build_internal();

        let layers = std::mem::take(&mut tracing.layers);
        tracing_subscriber::registry()
            .with(layers)
            .with(
                EnvFilter::try_from_default_env()
                    .unwrap_or_else(|_| config.log_level.to_string().into()),
            )
            .try_init()
            .ok();
        tracing
    }
}

#[cfg(test)]
mod tests {
    use crate::{AppConfig, Environment, Monitoring};

    use super::*;

    #[tokio::test]
    async fn build() {
        let config = Monitoring {
            log_level: "error".to_string(),
            opentelemetry_endpoint: "http://localhost:4317".into(),
            loki_endpoint: "http://localhost:3100".into(),
        };

        let app_config = AppConfig {
            name: "test".into(),
            version: "1.0.0".into(),
            env: Environment::Development,
            port: 6969,
        };

        let tracing = Tracing::builder().opentelemetry(&app_config, &config);
        assert!(tracing.is_ok());

        let tracing = tracing.unwrap().loki(&app_config, &config);

        assert!(tracing.is_ok());
    }
}