use crate::error::RuntimeError;
use crate::eval::ContextMode;
use crate::eval::llm_args::LlmNodeArgs;
use crate::value::Value;
pub struct LlmContext {
pub messages: Vec<crate::message::Message>,
pub budget_text: String,
pub session_messages_len: usize,
}
pub fn build_llm_context(
args: &LlmNodeArgs,
context_mode: ContextMode,
_session: Option<&std::sync::Arc<crate::session::Session>>,
session_messages_handle: Option<
&std::sync::Arc<std::sync::Mutex<Vec<crate::message::Message>>>,
>,
turn_id: &crate::event::TurnId,
events: Option<&crate::event::EventSink>,
flow_run_id: Option<&crate::event::FlowRunId>,
) -> Result<LlmContext, Value> {
let (final_messages, prompt_for_budget) = if let Some(msgs) = args.messages_override.clone() {
let budget_text = msgs.last().map(|m| m.text_concat()).unwrap_or_default();
(msgs, budget_text)
} else if !matches!(context_mode, ContextMode::None)
&& let Some(handle) = session_messages_handle
{
let mut history = match context_mode {
ContextMode::Session => handle.lock().unwrap().clone(),
ContextMode::SessionRecent(n) => {
let all = handle.lock().unwrap().clone();
let start = all.len().saturating_sub(n);
all[start..].to_vec()
}
ContextMode::None => Vec::new(),
};
let budget_text = args.prompt.clone().unwrap_or_default();
if let Some(p) = args.prompt.clone()
&& !p.is_empty()
{
history.push(crate::message::Message::user_text(turn_id.clone(), p));
}
(history, budget_text)
} else {
let Some(mut prompt_text) = args.prompt.clone() else {
return Err(Value::Err(RuntimeError::MissingArg(
"llm node: either `prompt:` or `messages:` required".into(),
)));
};
if let Some(budget) = args.context_budget {
let (truncated, stat) = super::truncate_prompt_to_budget_tracked(prompt_text, budget);
prompt_text = truncated;
if let (Some(sink), Some(stat)) = (events, stat) {
sink.emit(crate::event::Event::ContextTruncated {
turn_id: Some(turn_id.clone()),
flow_run_id: flow_run_id.cloned(),
original_chars: stat.original_chars as u64,
result_chars: stat.result_chars as u64,
dropped_chars: stat.dropped_chars as u64,
budget_tokens: stat.budget_tokens,
});
}
}
let user_msg = crate::message::Message::user_text(turn_id.clone(), prompt_text.clone());
(vec![user_msg], prompt_text)
};
let session_messages_len = final_messages.len();
Ok(LlmContext {
messages: final_messages,
budget_text: prompt_for_budget,
session_messages_len,
})
}