pub struct VolumeMetadata {
    creation_time: chrono::DateTime<chrono::Utc>,
    last_modified: chrono::DateTime<chrono::Utc>,
    status: VolumeStatus,
    labels: HashMap<String, String>, // For organization/selection
}

pub struct QoSConfig {
    iops_limit: Option<u32>,
    throughput_limit: Option<u64>, // bytes per second
    iops_guarantee: Option<u32>,
    throughput_guarantee: Option<u64>,
    burstable: Option<BurstConfig>,
}

pub struct BurstConfig {
    duration: chrono::Duration,
    iops_multiplier: f32,
    throughput_multiplier: f32,
}

pub struct SecurityConfig {
    encryption_enabled: bool,
    encryption_algorithm: Option<String>,
    key_management: Option<KeyManagementType>,
    access_policies: Vec<AccessPolicy>,
}

pub enum KeyManagementType {
    Internal,
    External { provider: String, config: HashMap<String, String> },
    CustomerManaged,
    HardwareSecurityModule { hsm_id: String },
}

pub struct AccessPolicy {
    allowed_users: Vec<String>,
    allowed_groups: Vec<String>,
    allowed_operations: Vec<VolumeOperation>,
}

pub enum VolumeOperation {
    Read,
    Write,
    Snapshot,
    Delete,
    Expand,
    Clone,
}

pub struct BackupPolicy {
    schedule: String, // cron format
    retention: RetentionPolicy,
    consistency_type: ConsistencyType,
    target_location: String,
}

pub enum ConsistencyType {
    Crash,
    Filesystem,
    Application { pre_backup_hook: String, post_backup_hook: String },
}

pub struct RetentionPolicy {
    daily: u32,
    weekly: u32,
    monthly: u32,
    yearly: u32,
}

pub enum Volume {
    /// Represents a temporary volume killed when the app instance is killed
    /// used for ephemeral storage within a single app instance.
    /// 
    /// In the event that multiple app instances are running on the same node,
    /// each instance will have its own version of the ephemeral volume, which
    /// is not shared with the other instances.
    /// 
    /// This allows for isolated storage for each app instance, ensuring that
    /// data is not inadvertently shared or corrupted between instances.
    /// This is useful for caching, temporary files, or any data that does not
    /// need to persist beyond the lifecycle of the app instance.
    Ephemeral(EphemeralVolume),
    /// Represents a persistent volume that can be shared across nodes in the cluster
    /// 
    /// This volume type is used for applications that require data to persist across
    /// app restarts or need to maintain state beyond the lifecycle of a single app
    /// instance. It is also used for applications that require data to be shared across
    /// multiple app instances running on different nodes in the cluster.
    /// 
    /// This volume type has a few different modes, each with its own characteristics:
    /// 
    /// Local Persistent Volumes are stored on worker node local disks but managed
    /// in a way that preserves the data even if the container using them is removed.
    /// These volumes offer excellent performance due to their local nature but are
    /// tied to a specific node. If that node fails, the volume becomes unavailable
    /// until the node recovers. This approach is suitable for workloads that
    /// prioritize performance over availability, or in clusters where node failures
    /// are rare.
    /// 
    /// Network-Attached Volumes are implemented via network storage protocols such
    /// as NFS, iSCSI, or specialized storage vendor APIs. These volumes can be
    /// accessed from any node in the cluster, allowing containers to be rescheduled
    /// freely without losing access to their data. The tradeoff is increased latency
    /// due to network communication, though modern networks and storage protocols can
    /// minimize this impact. Network-attached volumes are ideal for workloads that
    /// require flexibility in placement and moderate performance.
    /// 
    /// Distributed Volumes are spread across multiple physical nodes for redundancy
    /// and improved availability. Technologies like Ceph, GlusterFS, or Longhorn
    /// underpin these volumes, storing multiple copies of the data or using erasure
    /// coding to protect against node failures. Distributed volumes offer the best
    /// combination of availability and performance, though they typically require
    /// more resources due to the replication overhead. They're well-suited for
    /// mission-critical applications where both performance and reliability are
    /// important.
    Persistent(PersistentVolume),
    /// Represents a network-shared volume
    /// 
    /// This volume type is used for applications that require data to be shared
    /// across app instances running on different nodes in the cluster, and for applications
    // ... additional implementation
}

pub struct EphemeralVolume {
    id: Uuid,                // Unique identifier for the volume
    size: u64,               // Size in bytes
    name: String,            // Name of the volume
    metadata: VolumeMetadata, // Metadata for tracking volume status and details
    qos: Option<QoSConfig>,  // QoS settings for performance
    security: Option<SecurityConfig>, // Security settings
}

pub struct SharedVolume {
    id: Uuid,                // Unique identifier for the volume
    size: u64,               // Size in bytes
    name: String,            // Name of the volume
    status: String,          // Status of the volume (e.g., "available", "in-use")
    nodes: Vec<String>,      // List of nodes sharing this volume
    access_mode: AccessMode, // Access mode (RWO, ROX, RWX)
    metadata: VolumeMetadata, // Metadata for tracking volume status and details
    qos: Option<QoSConfig>,  // QoS settings for performance
    security: Option<SecurityConfig>, // Security settings
    backup_policy: Option<BackupPolicy>, // Backup settings
}

pub enum PersistentVolume {
    Local {
        id: Uuid,                // Unique identifier for the volume
        size: u64,               // Size in bytes
        name: String,            // Name of the volume
        status: String,          // Status of the volume (e.g., "available", "in-use")
        host_mount_path: String, // Path where the volume is mounted
        metadata: VolumeMetadata, // Metadata for tracking volume status and details
        qos: Option<QoSConfig>,  // QoS settings for performance
        security: Option<SecurityConfig>, // Security settings
        backup_policy: Option<BackupPolicy>, // Backup settings
    },
    NetworkAttached {
        id: Uuid,             // Unique identifier for the volume
        size: u64,            // Size in bytes
        name: String,         // Name of the volume
        status: String,       // Status of the volume (e.g., "available", "in-use")
        network_path: String, // Network path to the volume
        metadata: VolumeMetadata, // Metadata for tracking volume status and details
        qos: Option<QoSConfig>,  // QoS settings for performance
        security: Option<SecurityConfig>, // Security settings
        backup_policy: Option<BackupPolicy>, // Backup settings
    },
    Distributed {
        id: Uuid,           // Unique identifier for the volume
        size: u64,          // Size in bytes
        name: String,       // Name of the volume
        status: String,     // Status of the volume (e.g., "available", "in-use")
        nodes: Vec<String>, // List of nodes sharing this volume
        metadata: VolumeMetadata, // Metadata for tracking volume status and details
        qos: Option<QoSConfig>,  // QoS settings for performance
        security: Option<SecurityConfig>, // Security settings
        backup_policy: Option<BackupPolicy>, // Backup settings
    },
}

pub enum VolumeStatus {
    Available,
    InUse {
        node_id: Uuid, // ID of the node using the volume
    },
    Offline {
        last_seen: chrono::DateTime<chrono::Utc>, // Last time the volume was seen online
    },
    Blocked,
    Error,
}

pub enum AccessMode {
    ReadWriteOnce,
    ReadOnlyMany,
    ReadWriteMany,
}

pub struct VolumeSnapshot {
    id: Uuid,
    source_volume_id: Uuid,
    name: String,
    creation_time: chrono::DateTime<chrono::Utc>,
    size: u64,
    consistency_type: ConsistencyType,
}

pub enum VolumeError {
    NotFound,
    AlreadyExists,
    InsufficientCapacity,
    AccessDenied,
    InvalidState,
    ValidationFailed(String),
    DriverFailed(String),
    Timeout,
    Internal(String),
}

pub struct VolumeConfig {
    name: String,
    size: u64,
    volume_type: String,
    access_mode: Option<AccessMode>,
    qos: Option<QoSConfig>,
    security: Option<SecurityConfig>,
    backup_policy: Option<BackupPolicy>,
    labels: HashMap<String, String>,
}

    pub fn create(config: VolumeConfig) -> Result<Self, VolumeError> {
        // Implementation would go here
        unimplemented!("Volume creation not yet implemented")
    }

    /// Deletes this volume
    pub fn delete(&self) -> Result<(), VolumeError> {
    // ... function body
}

    pub fn delete(&self) -> Result<(), VolumeError> {
        // Implementation would go here
        unimplemented!("Volume deletion not yet implemented")
    }

    /// Attaches this volume to a specified node
    pub fn attach(&mut self, node_id: &str) -> Result<(), VolumeError> {
    // ... function body
}

    pub fn attach(&mut self, node_id: &str) -> Result<(), VolumeError> {
        // Implementation would go here
        unimplemented!("Volume attachment not yet implemented")
    }

    /// Detaches this volume from its current node
    pub fn detach(&mut self) -> Result<(), VolumeError> {
    // ... function body
}

    pub fn detach(&mut self) -> Result<(), VolumeError> {
        // Implementation would go here
        unimplemented!("Volume detachment not yet implemented")
    }

    /// Expands this volume to a new size
    pub fn expand(&mut self, new_size: u64) -> Result<(), VolumeError> {
    // ... function body
}

    pub fn expand(&mut self, new_size: u64) -> Result<(), VolumeError> {
        // Implementation would go here
        unimplemented!("Volume expansion not yet implemented")
    }

    /// Creates a snapshot of this volume
    pub fn snapshot(&self, name: &str) -> Result<VolumeSnapshot, VolumeError> {
    // ... function body
}

    pub fn snapshot(&self, name: &str) -> Result<VolumeSnapshot, VolumeError> {
        // Implementation would go here
        unimplemented!("Volume snapshot not yet implemented")
    }

    /// Restores this volume from a snapshot
    pub fn restore_from_snapshot(&mut self, snapshot: &VolumeSnapshot) -> Result<(), VolumeError> {
    // ... function body
}

    pub fn restore_from_snapshot(&mut self, snapshot: &VolumeSnapshot) -> Result<(), VolumeError> {
        // Implementation would go here
        unimplemented!("Volume restore not yet implemented")
    }

    /// Creates a clone of this volume
    pub fn clone(&self, name: &str) -> Result<Self, VolumeError> {
    // ... function body
}

    pub fn clone(&self, name: &str) -> Result<Self, VolumeError> {
        // Implementation would go here
        unimplemented!("Volume cloning not yet implemented")
    }

    /// Transforms this volume to a different type
    pub fn transform(&self, to_type: String) -> Result<Self, VolumeError> {
    // ... function body
}

    pub fn transform(&self, to_type: String) -> Result<Self, VolumeError> {
        // Implementation would go here
        unimplemented!("Volume transformation not yet implemented")
    }

    /// Checks the integrity of this volume
    pub fn check_integrity(&self) -> Result<bool, VolumeError> {
    // ... function body
}

    pub fn check_integrity(&self) -> Result<bool, VolumeError> {
        // Implementation would go here
        unimplemented!("Volume integrity checking not yet implemented")
    }

    /// Repairs this volume if possible
    pub fn repair(&mut self) -> Result<(), VolumeError> {
    // ... function body
}

    pub fn repair(&mut self) -> Result<(), VolumeError> {
        // Implementation would go here
        unimplemented!("Volume repair not yet implemented")
    }

    /// Updates the QoS configuration for this volume
    pub fn update_qos(&mut self, qos: QoSConfig) -> Result<(), VolumeError> {
    // ... function body
}

    pub fn update_qos(&mut self, qos: QoSConfig) -> Result<(), VolumeError> {
        // Implementation would go here
        unimplemented!("QoS update not yet implemented")
    }

    /// Updates the security configuration for this volume
    pub fn update_security(&mut self, security: SecurityConfig) -> Result<(), VolumeError> {
    // ... function body
}

    pub fn update_security(&mut self, security: SecurityConfig) -> Result<(), VolumeError> {
        // Implementation would go here
        unimplemented!("Security update not yet implemented")
    }

    /// Updates the backup policy for this volume
    pub fn update_backup_policy(&mut self, policy: BackupPolicy) -> Result<(), VolumeError> {
    // ... function body
}

    pub fn update_backup_policy(&mut self, policy: BackupPolicy) -> Result<(), VolumeError> {
        // Implementation would go here
        unimplemented!("Backup policy update not yet implemented")
    }
    // ... function body
}