graph TD
    subgraph UI_Layer["🖥️ Frontend UI Layer (Streamlit)"]
        UI["app.py (Streamlit Web Dashboard)"]
        CSS["Dynamic Glassmorphism Theme Engine"]
        Cache["@st.cache_data (5-Min Caching Layer)"]
    end

    subgraph MCP_Client_Layer["⚡ MCP Client IPC Layer"]
        ClientSession["mcp.Client (Stdio Client Session)"]
        ProcessParams["StdioServerParameters (sys.executable server.py)"]
    end

    subgraph MCP_Server_Layer["🔌 MCP Server Layer (server.py)"]
        MCPServer["mcp.server.MCPServer"]
        ToolWeather["@mcp.tool() weather"]
        ToolTime["@mcp.tool() time_info"]
        ToolGeocode["@mcp.tool() geocode"]
    end

    subgraph Backend_Services["⚙️ External Services & Logic Layer"]
        WeatherEngine["weather.py (Open-Meteo Integration)"]
        TimeEngine["time_service.py (TimeAPI.io & ZoneInfo)"]
    end

    subgraph External_APIs["🌐 External REST APIs"]
        OpenMeteo["Open-Meteo Forecast & Geocoding API"]
        TimeAPI["TimeAPI.io REST API Service"]
    end

    UI --> Cache
    Cache --> ClientSession
    ClientSession -->|JSON-RPC 2.0 via Stdio| ProcessParams
    ProcessParams --> MCPServer
    MCPServer --> ToolWeather
    MCPServer --> ToolTime
    MCPServer --> ToolGeocode

    ToolWeather --> WeatherEngine
    ToolTime --> TimeEngine

    WeatherEngine -->|Async HTTP GET| OpenMeteo
    TimeEngine -->|Async HTTP GET| TimeAPI

sequenceDiagram
    autonumber
    actor User
    participant Dashboard as Streamlit UI (app.py)
    participant Client as MCP Client Session
    participant Server as MCP Server (server.py)
    participant ExternalAPIs as External REST APIs (Open-Meteo & TimeAPI)

    User->>Dashboard: Search City (e.g. "Berlin")
    Dashboard->>Client: Request Weather & International Time
    Client->>Server: Call MCP Tools (weather & time_info)
    Server->>ExternalAPIs: Fetch Live Weather & Time Data
    ExternalAPIs-->>Server: Return Data Payloads
    Server-->>Client: Return Structured MCP Tool Response
    Client-->>Dashboard: Deliver Formatted Weather & Time Data
    Dashboard-->>User: Render Dynamic Glassmorphic UI Dashboard