graph TB
    subgraph "User Input Layer"
        A["Single Text Input Interface<br/>CustomTkinter Text Area<br/>Email Content or Natural Language Commands<br/>Placeholder: Paste email or enter your command..."]
    end
    
    subgraph "Local LLM Management Layer"
        B["Ollama Server Manager<br/>llm_manager.py"]
        B1["Qwen 2.5-14B Model Loading<br/>4-bit Quantization Q4_K_M<br/>Automatic Server Lifecycle"]
        B2["Health Monitoring<br/>API tags endpoint checking<br/>Model Cache Management"]
    end
    
    subgraph "Natural Language Processing Engine"
        C["Reasoning Engine<br/>reasoning_engine.py<br/>Chain of Thought Processing"]
        
        subgraph "Chain of Thought Streaming"
            C1["Real-time Stream Processing<br/>50ms Update Intervals<br/>Queue-based UI Updates"]
            C2["Reasoning Visualization<br/>Semantic Highlighting<br/>Step-by-step Analysis Display"]
        end
        
        subgraph "Core NLP Components"
            D["Intent Classifier<br/>intent_classifier.py<br/>VEHICLE_OPERATION MAINTENANCE_REQUEST<br/>RESERVATION_BOOKING PARKING_ASSIGNMENT"]
            E["Entity Extractor<br/>entity_extractor.py<br/>Vehicle IDs VINs Dates Locations<br/>Confidence Scoring 0-1.0"]
            F["Input Processor<br/>email_parser.py + command_processor.py<br/>Email Header Detection + Content Cleaning"]
        end
    end
    
    subgraph "Fleet Management Intelligence"
        G["Template Management System<br/>template_manager.py"]
        G1["Template Selection<br/>template_selector.py<br/>Intent-based Template Matching"]
        G2["JSON Generation<br/>json_generator.py<br/>Entity Population + Validation"]
        G3["Knowledge Base Integration<br/>knowledge directory<br/>API Docs Business Rules Prompts"]
    end
    
    subgraph "Human-in-the-Loop Approval"
        H["Approval Workflow Interface<br/>approval_workflow.py<br/>CustomTkinter Components"]
        H1["Request Preview<br/>Human-readable Summary<br/>Technical JSON Display<br/>Confidence Indicators"]
        H2["User Actions<br/>Approve | Edit & Approve<br/>Regenerate | Reject"]
        H3["Inline Editing<br/>JSON Editor with Validation<br/>Syntax Highlighting"]
    end
    
    subgraph "API Execution Layer"
        I["HTTP Client Manager<br/>client.py + authentication.py"]
        I1["Authentication Management<br/>Cookie Token Storage<br/>Windows Credential Manager"]
        I2["Request Execution<br/>Retry Logic + Error Handling<br/>TLS 1.3 + Certificate Validation"]
        I3["Response Processing<br/>Status Code Handling<br/>Success Error Reporting"]
    end
    
    subgraph "Data Persistence & Audit"
        J["SQLite Database<br/>connection_manager.py"]
        J1["Audit Logging<br/>audit_logger.py<br/>All User Actions + API Calls<br/>Tamper-evident Storage"]
        J2["Configuration Storage<br/>config_repository.py<br/>User Preferences + Settings"]
        J3["Performance Metrics<br/>Processing Time Success Rate<br/>Memory Usage Tracking"]
    end
    
    subgraph "Output & Results"
        K["API Response Display<br/>Success Error Status<br/>Response Details"]
        L["Audit Trail Export<br/>CSV JSON Format<br/>Compliance Reporting"]
        M["Session Management<br/>Request History<br/>User Preferences Persistence"]
    end
    
    %% Connections
    A --> B
    B --> B1
    B1 --> B2
    B2 --> C
    C --> C1
    C --> C2
    C --> D
    C --> E
    C --> F
    D --> G
    E --> G
    F --> G
    G --> G1
    G1 --> G2
    G2 --> G3
    G3 --> H
    H --> H1
    H1 --> H2
    H2 --> H3
    H3 --> I
    I --> I1
    I1 --> I2
    I2 --> I3
    I3 --> J
    J --> J1
    J1 --> J2
    J2 --> J3
    J3 --> K
    J3 --> L
    J3 --> M
    
    %% Styling
    classDef inputLayer fill:#e3f2fd
    classDef llmLayer fill:#f3e5f5
    classDef nlpLayer fill:#fff3e0
    classDef fleetLayer fill:#e8f5e8
    classDef approvalLayer fill:#ffecb3
    classDef apiLayer fill:#fce4ec
    classDef dataLayer fill:#f0f8ff
    classDef outputLayer fill:#e8f5e8
    
    class A inputLayer
    class B,B1,B2 llmLayer
    class C,C1,C2,D,E,F nlpLayer
    class G,G1,G2,G3 fleetLayer
    class H,H1,H2,H3 approvalLayer
    class I,I1,I2,I3 apiLayer
    class J,J1,J2,J3 dataLayer
    class K,L,M outputLayer