sequenceDiagram
    participant Client
    participant BulkAPI as Bulk API Handler
    participant IngestFn as Unified Ingest Function
    participant Pipeline as Pipeline Processor
    participant WriteLog as Write Logs Function
    participant WAL as Write-Ahead Log

    Client->>BulkAPI: POST /_bulk (raw logs)
    
    Note over BulkAPI: Parse bulk format<br/>line-by-line
    
    loop For each data line
        BulkAPI->>BulkAPI: Parse stream name & doc_id
        BulkAPI->>BulkAPI: Validate timestamp
        BulkAPI->>BulkAPI: Check stream not blocked
        BulkAPI->>BulkAPI: Collect to HashMap<Stream, Vec<Value>>
    end
    
    Note over BulkAPI: Group by stream name
    
    loop For each stream
        BulkAPI->>IngestFn: ingest(IngestionRequest::JsonValues(Bulk, records))
        
        Note over IngestFn: Single unified ingestion path<br/>for all log APIs
        
        IngestFn->>IngestFn: Format stream name
        IngestFn->>IngestFn: Check ingestion allowed
        IngestFn->>IngestFn: Get pipeline & schema settings
        
        alt Has Pipeline
            loop For each record
                IngestFn->>IngestFn: Flatten JSON
                IngestFn->>IngestFn: Handle timestamp
                IngestFn->>Pipeline: Buffer for batch processing
            end
            IngestFn->>Pipeline: process_batch()
            Pipeline-->>IngestFn: Transformed records by destination stream
        else No Pipeline
            loop For each record
                IngestFn->>IngestFn: Flatten JSON
                IngestFn->>IngestFn: Handle timestamp
                IngestFn->>IngestFn: Apply user-defined schema
                IngestFn->>IngestFn: Add _original & _all_values if needed
                IngestFn->>IngestFn: Group by hour key
            end
        end
        
        IngestFn->>WriteLog: write_logs_by_stream()
        
        loop For each stream
            WriteLog->>WriteLog: Get stream schema & settings
            WriteLog->>WriteLog: Check for schema evolution
            WriteLog->>WriteLog: Cast types & validate records
            WriteLog->>WriteLog: Evaluate alerts
            WriteLog->>WriteLog: Collect distinct values
            WriteLog->>WAL: write_file()
            WAL-->>WriteLog: Request stats
            WriteLog->>WriteLog: Report usage statistics
        end
        
        WriteLog-->>IngestFn: Success
        IngestFn-->>BulkAPI: IngestionResponse with items
    end
    
    BulkAPI->>BulkAPI: Aggregate all responses
    BulkAPI-->>Client: BulkResponse with all items