Refactor pool candidate scheduling

apps/aether-gateway/src/ai_serving/planner/specialized/video.rs

@@ -2,8 +2,10 @@ mod decision;
 mod request;
 mod support;
 
+use async_trait::async_trait;
 use tracing::warn;
 
+use crate::ai_serving::planner::candidate_materialization::LocalExecutionAttemptSource;
 use crate::ai_serving::planner::plan_builders::{
     build_passthrough_sync_plan_from_decision, AiSyncAttempt,
 };
@@ -17,9 +19,21 @@ use crate::{AiExecutionDecision, AppState, GatewayError};
 
 use self::decision::maybe_build_local_video_create_decision_payload_for_candidate;
 use self::support::{
-    list_local_video_create_candidate_attempts, resolve_local_video_create_decision_input,
+    build_local_video_create_candidate_attempt_source, list_local_video_create_candidate_attempts,
+    resolve_local_video_create_decision_input, LocalVideoCreateCandidateAttempt,
+    LocalVideoCreateCandidateAttemptSource, LocalVideoCreateDecisionInput,
 };
 
+pub(crate) struct LocalVideoCreateSyncAttemptSource<'a> {
+    state: &'a AppState,
+    parts: &'a http::request::Parts,
+    body_json: &'a serde_json::Value,
+    trace_id: &'a str,
+    input: LocalVideoCreateDecisionInput,
+    spec: LocalVideoCreateSpec,
+    candidates: LocalVideoCreateCandidateAttemptSource<'a>,
+}
+
 pub(crate) async fn build_local_video_sync_plan_and_reports_for_kind(
     state: &AppState,
     parts: &http::request::Parts,
@@ -35,6 +49,116 @@ pub(crate) async fn build_local_video_sync_plan_and_reports_for_kind(
     build_local_sync_plan_and_reports(state, parts, body_json, trace_id, decision, spec).await
 }
 
+pub(crate) async fn build_local_video_sync_attempt_source_for_kind<'a>(
+    state: &'a AppState,
+    parts: &'a http::request::Parts,
+    body_json: &'a serde_json::Value,
+    trace_id: &'a str,
+    decision: &'a GatewayControlDecision,
+    plan_kind: &str,
+) -> Result<Option<(LocalVideoCreateSyncAttemptSource<'a>, usize)>, GatewayError> {
+    let Some(spec) = resolve_sync_spec(plan_kind) else {
+        return Ok(None);
+    };
+    let spec_metadata = local_video_create_spec_metadata(spec);
+
+    let Some(input) = resolve_local_video_create_decision_input(
+        state, parts, trace_id, decision, body_json, spec,
+    )
+    .await
+    else {
+        return Ok(None);
+    };
+
+    let Some((candidates, candidate_count)) = build_local_video_create_candidate_attempt_source(
+        state,
+        trace_id,
+        &input,
+        body_json,
+        spec_metadata.api_format,
+        spec_metadata.decision_kind,
+    )
+    .await?
+    else {
+        return Ok(None);
+    };
+
+    if candidate_count == 0 {
+        return Ok(None);
+    }
+
+    Ok(Some((
+        LocalVideoCreateSyncAttemptSource {
+            state,
+            parts,
+            body_json,
+            trace_id,
+            input,
+            spec,
+            candidates,
+        },
+        candidate_count,
+    )))
+}
+
+#[async_trait]
+impl LocalExecutionAttemptSource<AiSyncAttempt> for LocalVideoCreateSyncAttemptSource<'_> {
+    async fn next_execution_attempt(&mut self) -> Result<Option<AiSyncAttempt>, GatewayError> {
+        while let Some(attempt) = self.candidates.next_attempt().await {
+            match self.build_sync_attempt(attempt).await? {
+                Some(attempt) => return Ok(Some(attempt)),
+                None => continue,
+            }
+        }
+        Ok(None)
+    }
+
+    async fn drain_execution_attempts(&mut self) -> Result<Vec<AiSyncAttempt>, GatewayError> {
+        let mut drained = Vec::new();
+        for attempt in self.candidates.drain_static_attempts() {
+            if let Some(attempt) = self.build_sync_attempt(attempt).await? {
+                drained.push(attempt);
+            }
+        }
+        Ok(drained)
+    }
+}
+
+impl LocalVideoCreateSyncAttemptSource<'_> {
+    async fn build_sync_attempt(
+        &self,
+        attempt: LocalVideoCreateCandidateAttempt,
+    ) -> Result<Option<AiSyncAttempt>, GatewayError> {
+        let spec_metadata = local_video_create_spec_metadata(self.spec);
+        let Some(payload) = maybe_build_local_video_create_decision_payload_for_candidate(
+            self.state,
+            self.parts,
+            self.body_json,
+            self.trace_id,
+            &self.input,
+            attempt,
+            self.spec,
+        )
+        .await
+        else {
+            return Ok(None);
+        };
+
+        match build_passthrough_sync_plan_from_decision(self.parts, payload) {
+            Ok(value) => Ok(value),
+            Err(err) => {
+                warn!(
+                    trace_id = %self.trace_id,
+                    decision_kind = spec_metadata.decision_kind,
+                    error = ?err,
+                    "gateway local video sync decision plan build failed"
+                );
+                Ok(None)
+            }
+        }
+    }
+}
+
 pub(crate) async fn maybe_build_sync_local_video_decision_payload(
     state: &AppState,
     parts: &http::request::Parts,