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mod certs;
pub mod api {
    tonic::include_proto!("google.pubsub.v1");
}
use anyhow::Result;
use api::{
    subscriber_client::SubscriberClient, AcknowledgeRequest, PullRequest, ReceivedMessage,
    Subscription,
};
use google_auth::DefaultCredentials;
use log::debug;
use std::collections::HashMap;
use tonic::{
    metadata::MetadataValue,
    transport::{Certificate, Channel, ClientTlsConfig},
    Request,
};
const ENDPOINT: &str = "https://pubsub.googleapis.com";

pub struct Pubsub {
    project_id: String,
}

async fn create_subscriber_client() -> Result<SubscriberClient<Channel>> {
    let pem = certs::get_pem();
    let tls_config = ClientTlsConfig::new()
        .ca_certificate(Certificate::from_pem(&pem))
        .domain_name("pubsub.googleapis.com");
    let channel = Channel::from_static(ENDPOINT)
        .tls_config(tls_config)?
        .connect()
        .await?;

    let mut cred = DefaultCredentials::new();
    let token = cred.token().await?;
    let bearer_token = format!("Bearer {}", token.access_token);
    let header_value = MetadataValue::from_str(&bearer_token)?;
    let subscriber_client =
        SubscriberClient::with_interceptor(channel, move |mut req: Request<()>| {
            req.metadata_mut()
                .insert("authorization", header_value.clone());
            Ok(req)
        });
    Ok(subscriber_client)
}

impl Pubsub {
    pub fn new(project_id: &str) -> Self {
        Self {
            project_id: project_id.to_string(),
        }
    }
    pub async fn pull(&self, subscription_name: &str) -> Result<Vec<ReceivedMessage>> {
        let mut retry_counter: i32 = 0;
        let max_retry = 3;
        let mut subscriber_client = create_subscriber_client().await?;
        let response = loop {
            if retry_counter >= max_retry {
                debug!("retry exceed max_retry: {}", retry_counter);
                return Err(anyhow::anyhow!("gg"));
            }
            let result = subscriber_client
                .pull(PullRequest {
                    subscription: format!(
                        "projects/{}/subscriptions/{}",
                        &self.project_id, subscription_name
                    ),
                    return_immediately: true,
                    max_messages: 10,
                })
                .await;
            let res = match result {
                Ok(res) => res.into_inner(),
                Err(err) if err.code() == tonic::Code::Unauthenticated => {
                    subscriber_client = create_subscriber_client().await?;
                    debug!("unauthenticated: {}", err);
                    retry_counter += 1;
                    continue;
                }
                Err(err) => {
                    debug!("error: {}", err);
                    retry_counter += 1;
                    continue;
                }
            };
            break res;
        };
        Ok(response.received_messages)
    }
    pub async fn ack(&mut self, ack_ids: Vec<String>, subscription_name: &str) -> Result<()> {
        let mut subscriber_client = create_subscriber_client().await?;
        subscriber_client
            .acknowledge(AcknowledgeRequest {
                ack_ids,
                subscription: format!(
                    "projects/{}/subscriptions/{}",
                    &self.project_id, subscription_name
                ),
            })
            .await?
            .into_inner();
        Ok(())
    }
    pub async fn create_subscription(
        &mut self,
        topic_name: &str,
        subscription_name: &str,
    ) -> Result<()> {
        let mut subscriber_client = create_subscriber_client().await?;
        let subs = Subscription {
            name: format!(
                "projects/{}/subscriptions/{}",
                &self.project_id, subscription_name
            ),
            ack_deadline_seconds: 10,
            dead_letter_policy: None,
            detached: false,
            enable_message_ordering: true,
            expiration_policy: None,
            filter: "".to_string(),
            labels: HashMap::new(),
            message_retention_duration: None,
            push_config: None,
            retain_acked_messages: false,
            retry_policy: None,
            topic: format!("projects/{}/topics/{}", &self.project_id, topic_name),
        };
        let resp = subscriber_client.create_subscription(subs).await?;
        debug!("{:?}", resp);
        Ok(())
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    #[test]
    fn new_works() {
        let project_id = "test-123";
        Pubsub::new(project_id);
    }
}