classDiagram
    direction LR

    class ConfigChangeLog {
        +String id
        +String config_key
        +Text old_value
        +Text new_value
        +String changed_by
        +DateTime changed_at
    }
    class AuditLog {
        +String id
        +String employee_id
        +String action
        +String resource
        +String resource_id
        +JSON details
        +String result
        +String ip_address
        +Text user_agent
        +DateTime created_at
    }
    class RuntimeLogEntry {
        +String timestamp
        +String level
        +String logger
        +String message
        +String module
        +String function
        +int line
        +String request_id
        +String user_id
    }
    class ConfigHistoryItem {
        +String id
        +String config_key
        +String old_value
        +String new_value
        +String changed_by
        +String changed_by_name
        +DateTime changed_at
    }

    class AdminApi {
        +GET /system-logs
    }
    class AuditApi {
        +GET /audit-logs
    }
    class RuntimeApi {
        +GET /runtime-logs
    }
    class AdminService {
        +get_system_logs(db, config_key, changed_by, from, to, page, page_size)
    }
    class AuditLogService {
        +list_audit_logs(db, employee_id, action, resource, from, to, page, page_size)
    }
    class RuntimeLogService {
        +read_runtime_logs(dir, level, from, to, keyword, page, page_size)
        +build_runtime_log_stream(dir, level, from, to, keyword)
    }
    class RuntimeLogStore {
        <<filesystem>>
        +RUNTIME_LOG_DIR/*.log
    }

    AdminApi ..> AdminService : 调用
    AuditApi ..> AuditLogService : 调用
    RuntimeApi ..> RuntimeLogService : 调用

    AdminService ..> ConfigChangeLog : SELECT
    AuditLogService ..> AuditLog : SELECT
    RuntimeLogService ..> RuntimeLogStore : 读文件

    ConfigHistoryItem <|.. ConfigChangeLog : 映射
    RuntimeLogEntry <|.. RuntimeLogStore : 逐行解析