sequenceDiagram
    participant TemplateCard
    participant WorkflowPreview
    participant WorkflowPreviewBlock
    participant SubflowContainer
    participant BlockConfig
    
    TemplateCard->>WorkflowPreview: render(workflowState, lightweight=true)
    WorkflowPreview->>WorkflowPreview: Build containerChildIndex (O(n) parent-child mapping)
    WorkflowPreview->>WorkflowPreview: Calculate nodes from workflowState.blocks
    
    loop For each block
        alt Block is loop/parallel
            WorkflowPreview->>WorkflowPreview: Get childBlocks from containerChildIndex (O(1))
            WorkflowPreview->>WorkflowPreview: calculateContainerDimensions(childBlocks)
            WorkflowPreview->>WorkflowPreviewBlock: render(isSubflow=true, subflowKind, width, height)
            WorkflowPreviewBlock->>SubflowContainer: render(name, width, height, kind)
            SubflowContainer-->>WorkflowPreviewBlock: Container with handles (target, start-source, end-source)
        else Block is regular
            WorkflowPreview->>WorkflowPreviewBlock: render(type, name, isTrigger, subBlockValues, lightweight)
            WorkflowPreviewBlock->>BlockConfig: getBlock(type)
            
            alt lightweight=false
                WorkflowPreviewBlock->>WorkflowPreviewBlock: buildCanonicalIndex(subBlocks)
                WorkflowPreviewBlock->>WorkflowPreviewBlock: Calculate visibleSubBlocks with trigger mode logic
                
                alt effectiveTrigger=true AND isPureTriggerBlock=true
                    WorkflowPreviewBlock->>WorkflowPreviewBlock: Show subblocks with mode=trigger OR no mode
                else effectiveTrigger=true AND isPureTriggerBlock=false
                    WorkflowPreviewBlock->>WorkflowPreviewBlock: Show only subblocks with mode=trigger
                else effectiveTrigger=false
                    WorkflowPreviewBlock->>WorkflowPreviewBlock: Hide all subblocks with mode=trigger
                end
                
                alt Block is condition
                    WorkflowPreviewBlock->>WorkflowPreviewBlock: Calculate condition rows from rawValues
                    WorkflowPreviewBlock->>WorkflowPreviewBlock: Render handles for each condition branch + error handle
                else Block is router_v2
                    WorkflowPreviewBlock->>WorkflowPreviewBlock: Calculate router rows from rawValues
                    WorkflowPreviewBlock->>WorkflowPreviewBlock: Render handles for each route + error handle
                else Block is standard
                    WorkflowPreviewBlock->>WorkflowPreviewBlock: Render source handle + error handle (if not trigger)
                end
            else lightweight=true
                WorkflowPreviewBlock->>WorkflowPreviewBlock: Skip expensive computations (empty canonicalIndex, rawValues, visibleSubBlocks)
            end
        end
    end
    
    WorkflowPreview->>WorkflowPreview: Calculate edges with execution status
    WorkflowPreview-->>TemplateCard: ReactFlow with consolidated rendering