odin-protocol 1.0.0

//! Message types and utilities for ODIN Protocol

use serde::{Deserialize, Serialize};
use std::time::{SystemTime, UNIX_EPOCH};

/// ODIN Protocol message
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct OdinMessage {
    /// Unique message identifier
    pub id: String,
    /// Message type
    pub message_type: MessageType,
    /// Source node identifier
    pub source_node: String,
    /// Target node identifier
    pub target_node: String,
    /// Message content
    pub content: String,
    /// Message priority
    pub priority: MessagePriority,
    /// Timestamp when message was created
    pub timestamp: u64,
    /// Message metadata
    pub metadata: std::collections::HashMap<String, String>,
    /// Message sequence number
    pub sequence: u64,
    /// Checksum for integrity verification
    pub checksum: Option<String>,
}

impl OdinMessage {
    /// Create a new ODIN message
    pub fn new(
        message_type: MessageType,
        source_node: &str,
        target_node: &str,
        content: &str,
        priority: MessagePriority,
    ) -> Self {
        let timestamp = SystemTime::now()
            .duration_since(UNIX_EPOCH)
            .unwrap_or_default()
            .as_secs();
            
        Self {
            id: uuid::Uuid::new_v4().to_string(),
            message_type,
            source_node: source_node.to_string(),
            target_node: target_node.to_string(),
            content: content.to_string(),
            priority,
            timestamp,
            metadata: std::collections::HashMap::new(),
            sequence: 0,
            checksum: None,
        }
    }
    
    /// Add metadata to the message
    pub fn with_metadata(mut self, key: String, value: String) -> Self {
        self.metadata.insert(key, value);
        self
    }
    
    /// Set sequence number
    pub fn with_sequence(mut self, sequence: u64) -> Self {
        self.sequence = sequence;
        self
    }
    
    /// Calculate and set checksum
    pub fn with_checksum(mut self) -> Self {
        self.checksum = Some(self.calculate_checksum());
        self
    }
    
    /// Validate message integrity
    pub fn validate(&self) -> bool {
        if let Some(checksum) = &self.checksum {
            &self.calculate_checksum() == checksum
        } else {
            true // No checksum to validate
        }
    }
    
    /// Calculate message checksum
    fn calculate_checksum(&self) -> String {
        use std::collections::hash_map::DefaultHasher;
        use std::hash::{Hash, Hasher};
        
        let mut hasher = DefaultHasher::new();
        self.id.hash(&mut hasher);
        self.source_node.hash(&mut hasher);
        self.target_node.hash(&mut hasher);
        self.content.hash(&mut hasher);
        self.timestamp.hash(&mut hasher);
        
        format!("{:x}", hasher.finish())
    }
    
    /// Get message size in bytes
    pub fn size(&self) -> usize {
        serde_json::to_string(self)
            .map(|s| s.len())
            .unwrap_or(0)
    }
    
    /// Check if message is expired based on TTL
    pub fn is_expired(&self, ttl_seconds: u64) -> bool {
        let current_time = SystemTime::now()
            .duration_since(UNIX_EPOCH)
            .unwrap_or_default()
            .as_secs();
            
        current_time > self.timestamp + ttl_seconds
    }
    
    /// Create a reply message
    pub fn create_reply(&self, content: &str, priority: MessagePriority) -> Self {
        Self::new(
            MessageType::Reply,
            &self.target_node,
            &self.source_node,
            content,
            priority,
        )
        .with_metadata("reply_to".to_string(), self.id.clone())
    }
    
    /// Create an acknowledgment message
    pub fn create_ack(&self) -> Self {
        Self::new(
            MessageType::Acknowledgment,
            &self.target_node,
            &self.source_node,
            "ack",
            MessagePriority::Low,
        )
        .with_metadata("ack_for".to_string(), self.id.clone())
    }
}

/// Message type enumeration
#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
pub enum MessageType {
    /// Standard message
    Standard,
    /// Broadcast message
    Broadcast,
    /// Reply to a previous message
    Reply,
    /// Acknowledgment message
    Acknowledgment,
    /// Heartbeat message
    Heartbeat,
    /// System control message
    System,
    /// Error message
    Error,
}

impl std::fmt::Display for MessageType {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        match self {
            MessageType::Standard => write!(f, "standard"),
            MessageType::Broadcast => write!(f, "broadcast"),
            MessageType::Reply => write!(f, "reply"),
            MessageType::Acknowledgment => write!(f, "ack"),
            MessageType::Heartbeat => write!(f, "heartbeat"),
            MessageType::System => write!(f, "system"),
            MessageType::Error => write!(f, "error"),
        }
    }
}

/// Message priority levels
#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Serialize, Deserialize)]
pub enum MessagePriority {
    /// Low priority (best effort)
    Low = 0,
    /// Normal priority
    Normal = 1,
    /// High priority
    High = 2,
    /// Critical priority (immediate delivery)
    Critical = 3,
}

impl std::fmt::Display for MessagePriority {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        match self {
            MessagePriority::Low => write!(f, "low"),
            MessagePriority::Normal => write!(f, "normal"),
            MessagePriority::High => write!(f, "high"),
            MessagePriority::Critical => write!(f, "critical"),
        }
    }
}

impl Default for MessagePriority {
    fn default() -> Self {
        MessagePriority::Normal
    }
}

/// Message batch for efficient bulk operations
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct MessageBatch {
    /// Batch identifier
    pub batch_id: String,
    /// Messages in the batch
    pub messages: Vec<OdinMessage>,
    /// Batch creation timestamp
    pub timestamp: u64,
    /// Batch metadata
    pub metadata: std::collections::HashMap<String, String>,
}

impl MessageBatch {
    /// Create a new message batch
    pub fn new() -> Self {
        let timestamp = SystemTime::now()
            .duration_since(UNIX_EPOCH)
            .unwrap_or_default()
            .as_secs();
            
        Self {
            batch_id: uuid::Uuid::new_v4().to_string(),
            messages: Vec::new(),
            timestamp,
            metadata: std::collections::HashMap::new(),
        }
    }
    
    /// Add a message to the batch
    pub fn add_message(mut self, message: OdinMessage) -> Self {
        self.messages.push(message);
        self
    }
    
    /// Get batch size in messages
    pub fn len(&self) -> usize {
        self.messages.len()
    }
    
    /// Check if batch is empty
    pub fn is_empty(&self) -> bool {
        self.messages.is_empty()
    }
    
    /// Get total size in bytes
    pub fn total_size(&self) -> usize {
        self.messages.iter().map(|m| m.size()).sum::<usize>()
            + serde_json::to_string(&self.batch_id).unwrap_or_default().len()
            + 8 // timestamp size
    }
    
    /// Split batch into smaller batches
    pub fn split(self, max_size: usize) -> Vec<MessageBatch> {
        let mut batches = Vec::new();
        let mut current_batch = MessageBatch::new();
        
        for message in self.messages {
            if current_batch.len() >= max_size && !current_batch.is_empty() {
                batches.push(current_batch);
                current_batch = MessageBatch::new();
            }
            current_batch = current_batch.add_message(message);
        }
        
        if !current_batch.is_empty() {
            batches.push(current_batch);
        }
        
        batches
    }
}

impl Default for MessageBatch {
    fn default() -> Self {
        Self::new()
    }
}

/// Message filter for selective message processing
#[derive(Debug, Clone)]
pub struct MessageFilter {
    /// Filter by message type
    pub message_type: Option<MessageType>,
    /// Filter by source node pattern
    pub source_pattern: Option<String>,
    /// Filter by target node pattern
    pub target_pattern: Option<String>,
    /// Filter by minimum priority
    pub min_priority: Option<MessagePriority>,
    /// Filter by content pattern
    pub content_pattern: Option<String>,
    /// Filter by age (max seconds)
    pub max_age_seconds: Option<u64>,
}

impl MessageFilter {
    /// Create a new empty filter
    pub fn new() -> Self {
        Self {
            message_type: None,
            source_pattern: None,
            target_pattern: None,
            min_priority: None,
            content_pattern: None,
            max_age_seconds: None,
        }
    }
    
    /// Filter by message type
    pub fn with_type(mut self, message_type: MessageType) -> Self {
        self.message_type = Some(message_type);
        self
    }
    
    /// Filter by source pattern
    pub fn with_source(mut self, pattern: String) -> Self {
        self.source_pattern = Some(pattern);
        self
    }
    
    /// Filter by target pattern
    pub fn with_target(mut self, pattern: String) -> Self {
        self.target_pattern = Some(pattern);
        self
    }
    
    /// Filter by minimum priority
    pub fn with_min_priority(mut self, priority: MessagePriority) -> Self {
        self.min_priority = Some(priority);
        self
    }
    
    /// Filter by content pattern
    pub fn with_content(mut self, pattern: String) -> Self {
        self.content_pattern = Some(pattern);
        self
    }
    
    /// Filter by maximum age
    pub fn with_max_age(mut self, seconds: u64) -> Self {
        self.max_age_seconds = Some(seconds);
        self
    }
    
    /// Check if message matches the filter
    pub fn matches(&self, message: &OdinMessage) -> bool {
        // Check message type
        if let Some(msg_type) = self.message_type {
            if message.message_type != msg_type {
                return false;
            }
        }
        
        // Check source pattern
        if let Some(pattern) = &self.source_pattern {
            if !message.source_node.contains(pattern) {
                return false;
            }
        }
        
        // Check target pattern
        if let Some(pattern) = &self.target_pattern {
            if !message.target_node.contains(pattern) {
                return false;
            }
        }
        
        // Check minimum priority
        if let Some(min_priority) = self.min_priority {
            if message.priority < min_priority {
                return false;
            }
        }
        
        // Check content pattern
        if let Some(pattern) = &self.content_pattern {
            if !message.content.contains(pattern) {
                return false;
            }
        }
        
        // Check max age
        if let Some(max_age) = self.max_age_seconds {
            if message.is_expired(max_age) {
                return false;
            }
        }
        
        true
    }
}

impl Default for MessageFilter {
    fn default() -> Self {
        Self::new()
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use std::thread;
    use std::time::Duration;
    
    #[test]
    fn test_message_creation() {
        let message = OdinMessage::new(
            MessageType::Standard,
            "source-node",
            "target-node",
            "Hello, World!",
            MessagePriority::Normal,
        );
        
        assert!(!message.id.is_empty());
        assert_eq!(message.message_type, MessageType::Standard);
        assert_eq!(message.source_node, "source-node");
        assert_eq!(message.target_node, "target-node");
        assert_eq!(message.content, "Hello, World!");
        assert_eq!(message.priority, MessagePriority::Normal);
        assert!(message.timestamp > 0);
    }
    
    #[test]
    fn test_message_with_metadata() {
        let message = OdinMessage::new(
            MessageType::Standard,
            "source",
            "target",
            "content",
            MessagePriority::Normal,
        )
        .with_metadata("key1".to_string(), "value1".to_string())
        .with_metadata("key2".to_string(), "value2".to_string());
        
        assert_eq!(message.metadata.len(), 2);
        assert_eq!(message.metadata.get("key1"), Some(&"value1".to_string()));
        assert_eq!(message.metadata.get("key2"), Some(&"value2".to_string()));
    }
    
    #[test]
    fn test_message_checksum() {
        let message = OdinMessage::new(
            MessageType::Standard,
            "source",
            "target",
            "content",
            MessagePriority::Normal,
        )
        .with_checksum();
        
        assert!(message.checksum.is_some());
        assert!(message.validate());
    }
    
    #[test]
    fn test_message_expiration() {
        let mut message = OdinMessage::new(
            MessageType::Standard,
            "source",
            "target",
            "content",
            MessagePriority::Normal,
        );
        
        // Set timestamp to 10 seconds ago
        message.timestamp = SystemTime::now()
            .duration_since(UNIX_EPOCH)
            .unwrap_or_default()
            .as_secs() - 10;
        
        assert!(message.is_expired(5)); // Should be expired with 5 second TTL
        assert!(!message.is_expired(15)); // Should not be expired with 15 second TTL
    }
    
    #[test]
    fn test_message_reply() {
        let original = OdinMessage::new(
            MessageType::Standard,
            "alice",
            "bob",
            "Hello",
            MessagePriority::Normal,
        );
        
        let reply = original.create_reply("Hello back!", MessagePriority::Normal);
        
        assert_eq!(reply.message_type, MessageType::Reply);
        assert_eq!(reply.source_node, "bob");
        assert_eq!(reply.target_node, "alice");
        assert_eq!(reply.content, "Hello back!");
        assert_eq!(reply.metadata.get("reply_to"), Some(&original.id));
    }
    
    #[test]
    fn test_message_batch() {
        let mut batch = MessageBatch::new();
        
        let message1 = OdinMessage::new(
            MessageType::Standard,
            "source",
            "target1",
            "message 1",
            MessagePriority::Normal,
        );
        
        let message2 = OdinMessage::new(
            MessageType::Standard,
            "source",
            "target2",
            "message 2",
            MessagePriority::High,
        );
        
        batch = batch
            .add_message(message1)
            .add_message(message2);
        
        assert_eq!(batch.len(), 2);
        assert!(!batch.is_empty());
        assert!(batch.total_size() > 0);
    }
    
    #[test]
    fn test_message_filter() {
        let message = OdinMessage::new(
            MessageType::Standard,
            "alice",
            "bob",
            "hello world",
            MessagePriority::High,
        );
        
        let filter = MessageFilter::new()
            .with_type(MessageType::Standard)
            .with_source("alice".to_string())
            .with_min_priority(MessagePriority::Normal);
        
        assert!(filter.matches(&message));
        
        let strict_filter = MessageFilter::new()
            .with_min_priority(MessagePriority::Critical);
        
        assert!(!strict_filter.matches(&message));
    }
    
    #[test]
    fn test_priority_ordering() {
        assert!(MessagePriority::Critical > MessagePriority::High);
        assert!(MessagePriority::High > MessagePriority::Normal);
        assert!(MessagePriority::Normal > MessagePriority::Low);
    }
}