statsai-sync 0.1.0

//! Sync sink interfaces for `statsai`.

use anyhow::{bail, Context, Result};
use statsai_core::{SyncAck, SyncBatch, SYNC_ACK_SCHEMA_VERSION};
use std::io::Write;
use std::path::PathBuf;
use std::time::Duration;

pub trait SyncSink {
    fn name(&self) -> &'static str;
    fn send(&self, batch: &SyncBatch) -> Result<()>;
}

pub struct StdoutSink;

impl SyncSink for StdoutSink {
    fn name(&self) -> &'static str {
        "stdout"
    }

    fn send(&self, batch: &SyncBatch) -> Result<()> {
        let stdout = std::io::stdout();
        let mut lock = stdout.lock();
        serde_json::to_writer_pretty(&mut lock, batch)?;
        writeln!(lock)?;
        Ok(())
    }
}

#[derive(Debug, Clone)]
pub struct HttpSink {
    endpoint: String,
    bearer_token: Option<String>,
    timeout: Duration,
}

impl HttpSink {
    /// Creates an HTTP sync sink.
    ///
    /// # Errors
    ///
    /// Returns an error when `endpoint` is not an `http://` or `https://` URL.
    pub fn new(endpoint: impl AsRef<str>, bearer_token: Option<String>) -> Result<Self> {
        let endpoint = endpoint.as_ref().trim();
        if !(endpoint.starts_with("http://") || endpoint.starts_with("https://")) {
            bail!("http sink supports http:// and https:// endpoints only");
        }
        Ok(Self {
            endpoint: endpoint.to_string(),
            bearer_token,
            timeout: Duration::from_secs(30),
        })
    }

    /// Sends a batch and returns the server acknowledgement.
    ///
    /// # Errors
    ///
    /// Returns an error if the endpoint rejects the batch, the connection fails,
    /// or the response is not a supported sync acknowledgement.
    pub fn send_with_ack(&self, batch: &SyncBatch) -> Result<SyncAck> {
        let request = ureq::post(&self.endpoint)
            .timeout(self.timeout)
            .set(
                "User-Agent",
                &format!("statsai/{}", env!("CARGO_PKG_VERSION")),
            )
            .set("Content-Type", "application/json")
            .set("Accept", "application/json");
        let request = if let Some(token) = self
            .bearer_token
            .as_deref()
            .filter(|token| !token.is_empty())
        {
            request.set("Authorization", &format!("Bearer {token}"))
        } else {
            request
        };
        let response = request.send_json(serde_json::to_value(batch)?);
        let response = match response {
            Ok(response) => response,
            Err(ureq::Error::Status(code, response)) => {
                let body = response.into_string().unwrap_or_default();
                bail!(
                    "sync endpoint returned HTTP {}: {}",
                    code,
                    body.trim().chars().take(200).collect::<String>()
                );
            }
            Err(error) => bail!("sync endpoint request failed: {}", error),
        };
        let ack: SyncAck = response.into_json().context("parse sync ack")?;
        if ack.schema_version != SYNC_ACK_SCHEMA_VERSION {
            bail!("unsupported sync ack schema {}", ack.schema_version);
        }
        Ok(ack)
    }
}

impl SyncSink for HttpSink {
    fn name(&self) -> &'static str {
        "http"
    }

    fn send(&self, batch: &SyncBatch) -> Result<()> {
        self.send_with_ack(batch)?;
        Ok(())
    }
}

#[derive(Debug, Clone)]
pub struct FileSink {
    path: PathBuf,
}

impl FileSink {
    #[must_use]
    pub fn new(path: PathBuf) -> Self {
        Self { path }
    }
}

impl SyncSink for FileSink {
    fn name(&self) -> &'static str {
        "file"
    }

    fn send(&self, batch: &SyncBatch) -> Result<()> {
        if let Some(parent) = self.path.parent() {
            std::fs::create_dir_all(parent)
                .with_context(|| format!("create {}", parent.display()))?;
        }
        let file = std::fs::File::create(&self.path)
            .with_context(|| format!("write {}", self.path.display()))?;
        serde_json::to_writer_pretty(file, batch)?;
        Ok(())
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use chrono::Utc;
    use statsai_core::SyncBatch;
    use std::sync::mpsc;
    use tiny_http::{Header, Method, Response, Server};

    fn empty_batch() -> SyncBatch {
        SyncBatch {
            schema_version: "sync_batch.v1".to_string(),
            batch_id: "batch_1".to_string(),
            device_id: "device".to_string(),
            sources: Vec::new(),
            accounts: Vec::new(),
            source_account_assignments: Vec::new(),
            subscriptions: Vec::new(),
            events: Vec::new(),
            summaries: Vec::new(),
            created_at: Utc::now(),
        }
    }

    #[test]
    fn file_sink_writes_json() {
        let dir = tempfile::tempdir().expect("tempdir");
        let path = dir.path().join("batch.json");
        let sink = FileSink::new(path.clone());
        sink.send(&empty_batch()).expect("write");

        let content = std::fs::read_to_string(&path).expect("read");
        assert!(content.contains("batch_1"));
        assert!(content.contains("device"));
    }

    #[test]
    fn http_sink_posts_sync_batch_with_bearer_token() {
        let server = Server::http("127.0.0.1:0").expect("server");
        let endpoint = format!("http://{}/v1/sync/batches", server.server_addr());
        let (tx, rx) = mpsc::channel();
        let handle = std::thread::spawn(move || {
            let mut request = server.recv().expect("request");
            assert_eq!(request.method(), &Method::Post);
            assert_eq!(request.url(), "/v1/sync/batches");
            let auth = request
                .headers()
                .iter()
                .find(|header| header.field.equiv("Authorization"))
                .map(|header| header.value.as_str().to_string());
            let content_type = request
                .headers()
                .iter()
                .find(|header| header.field.equiv("Content-Type"))
                .map(|header| header.value.as_str().to_string());
            let mut body = String::new();
            request.as_reader().read_to_string(&mut body).expect("body");
            tx.send((auth, content_type, body)).expect("send body");
            let response = Response::from_string(test_ack_json("batch_1"))
                .with_header(Header::from_bytes("content-type", "application/json").unwrap());
            request.respond(response).expect("respond");
        });

        let sink = HttpSink::new(endpoint, Some("token_123".to_string())).expect("sink");
        sink.send(&empty_batch()).expect("send");
        handle.join().expect("server thread");
        let (auth, content_type, body) = rx.recv().expect("request body");
        assert_eq!(auth.as_deref(), Some("Bearer token_123"));
        assert_eq!(content_type.as_deref(), Some("application/json"));
        assert!(body.contains("\"schema_version\":\"sync_batch.v1\""));
        assert!(body.contains("\"batch_id\":\"batch_1\""));
    }

    #[test]
    fn http_sink_rejects_non_success_status() {
        let server = Server::http("127.0.0.1:0").expect("server");
        let endpoint = format!("http://{}/v1/sync/batches", server.server_addr());
        let handle = std::thread::spawn(move || {
            let request = server.recv().expect("request");
            request
                .respond(Response::from_string("nope").with_status_code(500))
                .expect("respond");
        });

        let sink = HttpSink::new(endpoint, None).expect("sink");
        let error = sink.send(&empty_batch()).expect_err("500 should fail");
        handle.join().expect("server thread");
        assert!(error.to_string().contains("HTTP 500"));
    }

    #[test]
    fn http_sink_rejects_non_http_url() {
        let error =
            HttpSink::new("ftp://example.com/v1/sync/batches", None).expect_err("bad scheme");
        assert!(error.to_string().contains("http://"));
    }

    fn test_ack_json(batch_id: &str) -> String {
        format!(
            r#"{{
              "schema_version":"sync_ack.v1",
              "batch_id":"{batch_id}",
              "accepted":{{"sources":0,"accounts":0,"source_account_assignments":0,"subscriptions":0,"events":0,"summaries":0}},
              "duplicates":{{"sources":0,"accounts":0,"source_account_assignments":0,"subscriptions":0,"events":0,"summaries":0}},
              "rejected":[]
            }}"#
        )
    }
}