app/services/optimizer.py

from copy import deepcopy

from app.models.workflow import (
    OptimizationResponse,
    OptimizationSuggestion,
    WorkflowDocument,
)


class WorkflowOptimizer:
    def optimize(self, workflow: WorkflowDocument) -> OptimizationResponse:
        optimized = deepcopy(workflow)
        suggestions: list[OptimizationSuggestion] = []

        http_nodes = [
            node for node in optimized.nodes if node.data.type == "n8n-nodes-base.httpRequest"
        ]
        for node in http_nodes:
            options = node.data.parameters.setdefault("options", {})
            if isinstance(options, dict) and "retry" not in options:
                options.update({"retry": {"maxTries": 3, "waitBetweenTries": 1000}})
                suggestions.append(
                    OptimizationSuggestion(
                        title="Add API retries",
                        description=f"Added bounded retry behavior to {node.data.label}.",
                        impact="high",
                        nodeIds=[node.id],
                    )
                )

        if not optimized.settings.get("saveExecutionProgress"):
            optimized.settings["saveExecutionProgress"] = True
            suggestions.append(
                OptimizationSuggestion(
                    title="Enable execution recovery",
                    description="Save execution progress so long-running workflows can recover.",
                    impact="medium",
                )
            )

        linear_pairs = []
        for edge in optimized.edges:
            source = next((node for node in optimized.nodes if node.id == edge.source), None)
            target = next((node for node in optimized.nodes if node.id == edge.target), None)
            if source and target and source.data.type == target.data.type == "n8n-nodes-base.set":
                linear_pairs.append((source, target))
        if linear_pairs:
            suggestions.append(
                OptimizationSuggestion(
                    title="Combine adjacent Edit Fields nodes",
                    description="Adjacent field transformations can be handled by one node.",
                    impact="medium",
                    nodeIds=[node.id for pair in linear_pairs for node in pair],
                )
            )

        branches = {}
        for edge in optimized.edges:
            branches[edge.source] = branches.get(edge.source, 0) + 1
        parallel = [node_id for node_id, count in branches.items() if count > 1]
        if parallel:
            suggestions.append(
                OptimizationSuggestion(
                    title="Review parallel branches",
                    description="Independent branches can execute concurrently; merge only when required.",
                    impact="medium",
                    nodeIds=parallel,
                )
            )

        if not suggestions:
            suggestions.append(
                OptimizationSuggestion(
                    title="Workflow is already compact",
                    description="No deterministic optimization could be applied safely.",
                    impact="low",
                )
            )

        return OptimizationResponse(workflow=optimized, suggestions=suggestions)


optimizer = WorkflowOptimizer()