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//! Agent streaming implementation.
use anyhow::Result;
use tokio::time::{Duration, sleep};
use crate::event::AgentEvent;
use crate::providers::{ChatRequest, ChatResponse, ContentBlock, StopReason, StreamEvent, Usage};
use super::types::Agent;
/// Wait for cancellation signal, checking periodically.
async fn wait_for_cancel_stream(token: &crate::cancel::CancellationToken) {
while !token.is_cancelled() {
sleep(Duration::from_millis(100)).await;
}
}
impl Agent {
/// Drain any pending input messages from the channel.
/// Called during streaming to collect real-time appended messages.
pub(crate) fn drain_pending_inputs(&mut self) {
let inputs = self.session.drain_pending_inputs();
for msg in inputs {
log::info!(
"Agent received pending input: {}",
msg.chars().take(50).collect::<String>()
);
self.state.add_pending_input(msg);
}
}
/// Check if there are pending inputs waiting to be processed.
pub fn has_pending_inputs(&self) -> bool {
self.state.has_pending_inputs()
}
/// Get and clear all pending inputs.
pub fn take_pending_inputs(&mut self) -> Vec<String> {
self.state.take_pending_inputs()
}
/// Call provider with streaming and emit events in real-time.
/// Also monitors pending_input_rx for real-time message appending.
pub(crate) async fn call_streaming(&mut self, request: &ChatRequest) -> Result<ChatResponse> {
const MAX_RETRIES: u32 = 5;
const RETRY_DELAY_MS: u64 = 1000;
let mut attempt = 0;
loop {
attempt += 1;
log::info!(
"Agent: API call attempt {} with {} messages",
attempt,
request.messages.len()
);
if self.session.is_cancelled() {
return Err(anyhow::anyhow!("Operation cancelled"));
}
log::info!("Agent: calling provider.chat_stream");
let rx_result = self.provider.chat_stream(request.clone()).await;
log::info!("Agent: provider.chat_stream returned");
match rx_result {
Ok(mut rx) => {
let mut response_content: Vec<ContentBlock> = Vec::new();
let mut current_text = String::new();
let mut current_thinking = String::new();
let mut usage = Usage {
input_tokens: 0,
output_tokens: 0,
cache_creation_input_tokens: 0,
cache_read_input_tokens: 0,
};
let mut should_retry = false;
loop {
// Use biased select! to prioritize stream events over pending input checks
// This prevents losing stream events when sleep completes first
let event = if let Some(token) = self.session.cancel_token() {
tokio::select! {
biased;
// Primary: receive stream event (highest priority)
event = rx.recv() => event,
// Cancellation signal (second priority)
_ = wait_for_cancel_stream(token) => {
return Err(anyhow::anyhow!("Operation cancelled"));
}
// Check for pending inputs periodically (lowest priority)
// Increased interval to reduce competition with stream events
_ = sleep(Duration::from_millis(200)) => {
self.drain_pending_inputs();
continue;
}
}
} else {
// No cancellation token, but still check pending inputs
tokio::select! {
biased;
// Primary: receive stream event (highest priority)
event = rx.recv() => event,
// Check for pending inputs periodically (lower priority)
_ = sleep(Duration::from_millis(200)) => {
self.drain_pending_inputs();
continue;
}
}
};
match event {
None => break,
Some(StreamEvent::FirstByte) => {}
Some(StreamEvent::ThinkingDelta(delta)) => {
// Check cancellation before emitting
if self.session.is_cancelled() {
return Err(anyhow::anyhow!("Operation cancelled"));
}
if current_thinking.is_empty() {
self.emit(AgentEvent::thinking_start())?;
}
current_thinking.push_str(&delta);
self.emit(AgentEvent::thinking_delta(delta, None))?;
}
Some(StreamEvent::TextDelta(delta)) => {
// Check cancellation before emitting
if self.session.is_cancelled() {
return Err(anyhow::anyhow!("Operation cancelled"));
}
if current_text.is_empty() {
self.emit(AgentEvent::text_start())?;
}
current_text.push_str(&delta);
self.emit(AgentEvent::text_delta(delta))?;
}
Some(StreamEvent::ToolUseStart { id, name }) => {
// Emit events for UI but don't push content blocks
// Content will be added from Done event's resp.content
if !current_thinking.is_empty() {
self.emit(AgentEvent::thinking_end())?;
current_thinking.clear();
}
if !current_text.is_empty() {
self.emit(AgentEvent::text_end())?;
current_text.clear();
}
self.emit(AgentEvent::tool_use_start(&id, &name, None))?;
}
Some(StreamEvent::ToolInputDelta { bytes_so_far: _ }) => {}
Some(StreamEvent::ToolInputComplete { id, name, input }) => {
self.state.mark_tool_input_previewed(id.clone());
self.emit(AgentEvent::tool_use_start(&id, &name, Some(input)))?;
}
Some(StreamEvent::Usage { output_tokens }) => {
self.emit(AgentEvent::usage_with_cache(
0,
output_tokens as u64,
0,
0,
))?;
usage.output_tokens = output_tokens;
}
Some(StreamEvent::Done(resp)) => {
// Check cancellation before processing final response
if self.session.is_cancelled() {
return Err(anyhow::anyhow!("Operation cancelled"));
}
// Final drain of pending inputs before completing
self.drain_pending_inputs();
// IMPORTANT: Add current_thinking/current_text to response_content FIRST
// before checking for duplicates from resp.content
// This ensures all streamed content is preserved
if !current_thinking.is_empty() {
self.emit(AgentEvent::thinking_end())?;
// Add to response_content with signature from resp if available
let signature = resp.content.iter()
.find_map(|b| {
if let ContentBlock::Thinking { thinking, signature } = b {
if thinking == ¤t_thinking {
signature.clone()
} else {
None
}
} else {
None
}
});
response_content.push(ContentBlock::Thinking {
thinking: current_thinking.clone(),
signature,
});
current_thinking.clear();
}
if !current_text.is_empty() {
self.emit(AgentEvent::text_end())?;
// Add to response_content
response_content.push(ContentBlock::Text {
text: current_text.clone(),
});
current_text.clear();
}
// Then add any additional blocks from final response that are NOT duplicates
for block in &resp.content {
// Smart deduplication: compare content, not entire block
let is_duplicate = response_content.iter().any(|b| {
match (b, block) {
// For Thinking blocks, compare thinking content only (signature may differ)
(
ContentBlock::Thinking { thinking: t1, .. },
ContentBlock::Thinking { thinking: t2, .. },
) => t1 == t2,
// For Text blocks, compare text content
(
ContentBlock::Text { text: t1 },
ContentBlock::Text { text: t2 },
) => t1 == t2,
// For ToolUse, compare id
(
ContentBlock::ToolUse { id: id1, .. },
ContentBlock::ToolUse { id: id2, .. },
) => id1 == id2,
// For ToolResult, compare tool_use_id
(
ContentBlock::ToolResult {
tool_use_id: id1, ..
},
ContentBlock::ToolResult {
tool_use_id: id2, ..
},
) => id1 == id2,
// Default: exact comparison
_ => b == block,
}
});
if !is_duplicate {
response_content.push(block.clone());
}
}
usage = resp.usage;
}
Some(StreamEvent::Error(msg)) => {
if attempt < MAX_RETRIES {
self.emit(AgentEvent::progress(
format!(
"⚠️ Stream error, retrying ({}/{}): {}",
attempt, MAX_RETRIES, &msg
),
None,
))?;
let delay = RETRY_DELAY_MS * (1 << (attempt - 1));
tokio::time::sleep(tokio::time::Duration::from_millis(delay))
.await;
should_retry = true;
break;
} else {
self.emit(AgentEvent::error(msg.clone(), None, None))?;
return Err(anyhow::anyhow!(
"Stream error after {} retries: {}",
MAX_RETRIES,
msg
));
}
}
}
}
if should_retry {
continue;
}
return Ok(ChatResponse {
content: response_content,
stop_reason: StopReason::EndTurn,
usage,
});
}
Err(e) => {
if attempt < MAX_RETRIES {
let error_msg = e.to_string();
self.emit(AgentEvent::progress(
format!(
"⚠️ API error, retrying ({}/{}): {}",
attempt, MAX_RETRIES, &error_msg
),
None,
))?;
let delay = RETRY_DELAY_MS * (1 << (attempt - 1));
tokio::time::sleep(tokio::time::Duration::from_millis(delay)).await;
} else {
return Err(anyhow::anyhow!(
"API error after {} retries: {}",
MAX_RETRIES,
e
));
}
}
}
}
}
}