%% 系統架構圖 — 離線 AI Agent 系統
graph TB
    subgraph CLIENT["🖥️ Client 端（繪圖筆電）"]
        direction TB
        UI["🌐 Desktop UI<br/>(Electron / Tauri / Web UI)<br/>RAM ≤ 500MB"]
        AgentClient["🤖 Agent Client<br/>(Python)"]
        LocalCache["💾 Local Cache<br/>(SQLite)"]
        LocalSkills["🔧 Local Skills / MCP<br/>(離線可用工具)"]
        LocalLLM["🧠 Local LLM (可選)<br/>(llama.cpp quantized)<br/>RAM ≤ 2GB"]

        UI --> AgentClient
        AgentClient --> LocalCache
        AgentClient --> LocalSkills
        AgentClient -.-> LocalLLM
    end

    subgraph NETWORK["🔒 內部網路 (TLS + API Token)"]
        direction LR
        REST["RESTful API<br/>HTTPS :443"]
    end

    subgraph SERVER["🏢 Server 端（整合部 Host）"]
        direction TB

        subgraph API_LAYER["API Gateway Layer"]
            Gateway["⚡ FastAPI Gateway<br/>(認證/路由/Rate Limit)"]
            AuthSvc["🔑 Auth Service<br/>(JWT / API Key)"]
            Middleware["📋 Middleware<br/>(Logging / CORS)"]
        end

        subgraph SERVICE_LAYER["Service Layer"]
            RAGPipeline["🔄 RAG Pipeline"]
            InferenceSvc["🧠 Inference Service"]
            RetrievalSvc["🔍 Retrieval Service"]
            EmbeddingSvc["🧮 Embedding Service"]
            DocProcessor["📄 Document Processor"]
            ContextMgr["📏 Context Manager"]
            SkillEngine["🔧 Skill Engine"]
            Reranker["📊 Reranker<br/>(Cross-Encoder)"]
        end

        subgraph INFERENCE_LAYER["Inference Adapters"]
            direction LR
            LlamaCpp["🥇 llama.cpp<br/>(首選)"]
            Foundry["🥈 Foundry Local<br/>(次選)"]
            Ollama["🔄 Ollama<br/>(備援)"]
        end

        subgraph PROCESSING["Document Processing Pipeline"]
            direction LR
            PDFParser["📝 PDF Parser<br/>(PyMuPDF)"]
            OCR["🔠 OCR<br/>(Tesseract)"]
            Chunker["✂️ Chunking<br/>(語意/固定長度)"]
        end

        subgraph DATA_LAYER["Data Layer"]
            PG["🐘 PostgreSQL"]
            PGVector["📊 pgvector<br/>(向量索引)"]
            FileStore["📁 File Storage<br/>(原始檔案)"]
        end

        %% API Layer 內部連結
        Gateway --> AuthSvc
        Gateway --> Middleware

        %% Gateway to Services
        Gateway --> RAGPipeline
        Gateway --> DocProcessor

        %% RAG Pipeline 連結
        RAGPipeline --> RetrievalSvc
        RAGPipeline --> InferenceSvc
        RAGPipeline --> ContextMgr
        RAGPipeline --> SkillEngine
        RAGPipeline --> EmbeddingSvc

        %% Retrieval 連結
        RetrievalSvc --> Reranker
        RetrievalSvc --> PGVector

        %% Inference Adapters
        InferenceSvc --> LlamaCpp
        InferenceSvc -.-> Foundry
        InferenceSvc -.-> Ollama

        %% Document Processing
        DocProcessor --> PDFParser
        DocProcessor --> OCR
        DocProcessor --> Chunker
        DocProcessor --> EmbeddingSvc
        PDFParser -.-> OCR

        %% Data Layer
        EmbeddingSvc --> PGVector
        DocProcessor --> FileStore
        Gateway --> PG
        PG --- PGVector
    end

    subgraph KM["📚 KM 系統"]
        KMSystem["文件存放系統"]
    end

    %% 跨區連結
    AgentClient <-->|"REST API<br/>(HTTPS)"| REST
    REST <--> Gateway
    KMSystem -->|"批次匯出/匯入"| DocProcessor

    %% 樣式
    classDef clientStyle fill:#E8F5E9,stroke:#4CAF50,stroke-width:2px
    classDef serverStyle fill:#E3F2FD,stroke:#2196F3,stroke-width:2px
    classDef dataStyle fill:#FFF3E0,stroke:#FF9800,stroke-width:2px
    classDef inferenceStyle fill:#F3E5F5,stroke:#9C27B0,stroke-width:2px
    classDef networkStyle fill:#ECEFF1,stroke:#607D8B,stroke-width:2px

    class UI,AgentClient,LocalCache,LocalSkills,LocalLLM clientStyle
    class Gateway,AuthSvc,Middleware,RAGPipeline,InferenceSvc,RetrievalSvc,EmbeddingSvc,DocProcessor,ContextMgr,SkillEngine,Reranker serverStyle
    class PG,PGVector,FileStore dataStyle
    class LlamaCpp,Foundry,Ollama inferenceStyle
    class REST networkStyle