loop-agent-sdk 0.1.0

//! Loop Agent SDK - Push Notifications
//! 
//! Lightweight notification layer that:
//! 1. Checks DynamoDB for cached push_token (<5ms)
//! 2. Falls back to Supabase if not cached
//! 3. Caches token in DynamoDB for future use
//! 4. Calls Supabase send-push Edge Function
//! 
//! This keeps 99% of notifications under 100ms.

use serde::{Deserialize, Serialize};
use std::time::{SystemTime, UNIX_EPOCH};
use tracing::{info, warn, error, instrument};

// ============================================================================
// CONFIGURATION
// ============================================================================

/// Notification service configuration
#[derive(Debug, Clone)]
pub struct NotificationConfig {
    /// Supabase project URL
    pub supabase_url: String,
    /// Supabase service role key (for calling edge functions)
    pub supabase_service_key: String,
    /// DynamoDB table name
    pub dynamo_table: String,
    /// Cache TTL for push tokens (seconds)
    pub token_cache_ttl: i64,
}

impl NotificationConfig {
    /// Load from environment variables
    pub fn from_env() -> Result<Self, NotificationError> {
        Ok(Self {
            supabase_url: std::env::var("SUPABASE_URL")
                .map_err(|_| NotificationError::MissingConfig("SUPABASE_URL".into()))?,
            supabase_service_key: std::env::var("SUPABASE_SERVICE_ROLE_KEY")
                .map_err(|_| NotificationError::MissingConfig("SUPABASE_SERVICE_ROLE_KEY".into()))?,
            dynamo_table: std::env::var("DYNAMO_TABLE")
                .unwrap_or_else(|_| "loop-agent-state".into()),
            token_cache_ttl: 86400 * 7, // 7 days
        })
    }
}

// ============================================================================
// NOTIFICATION SERVICE
// ============================================================================

/// Push notification service with DynamoDB caching
pub struct NotificationService {
    config: NotificationConfig,
    http_client: reqwest::Client,
    dynamo_client: aws_sdk_dynamodb::Client,
}

impl NotificationService {
    /// Create new notification service
    pub async fn new(config: NotificationConfig) -> Result<Self, NotificationError> {
        let aws_config = aws_config::load_defaults(aws_config::BehaviorVersion::latest()).await;
        let dynamo_client = aws_sdk_dynamodb::Client::new(&aws_config);
        
        let http_client = reqwest::Client::builder()
            .timeout(std::time::Duration::from_secs(10))
            .build()
            .map_err(|e| NotificationError::InitError(e.to_string()))?;
        
        Ok(Self {
            config,
            http_client,
            dynamo_client,
        })
    }
    
    /// Send push notification to user
    /// 
    /// Flow:
    /// 1. Check DynamoDB cache for push_token
    /// 2. If miss, query Supabase profiles table
    /// 3. Cache token in DynamoDB
    /// 4. Call Supabase send-push edge function
    #[instrument(skip(self))]
    pub async fn send(
        &self,
        user_pubkey: &str,
        notification: &PushNotification,
    ) -> Result<NotificationResult, NotificationError> {
        // Step 1: Try to get push token from DynamoDB cache
        let push_token = match self.get_cached_token(user_pubkey).await? {
            Some(token) => {
                info!(user = %user_pubkey, "Push token found in cache");
                token
            }
            None => {
                // Step 2: Query Supabase for token
                info!(user = %user_pubkey, "Cache miss, querying Supabase");
                let token = self.fetch_token_from_supabase(user_pubkey).await?;
                
                // Step 3: Cache it for next time
                if let Some(ref t) = token {
                    self.cache_token(user_pubkey, t).await?;
                }
                
                token.ok_or(NotificationError::NoToken)?
            }
        };
        
        // Step 4: Send via Supabase edge function
        self.send_via_supabase(&push_token, user_pubkey, notification).await
    }
    
    /// Send capture notification (convenience method)
    pub async fn send_capture_notification(
        &self,
        user_pubkey: &str,
        cred_amount: f64,
        merchant_name: &str,
    ) -> Result<NotificationResult, NotificationError> {
        let notification = PushNotification {
            title: "Cred Captured! 🎉".into(),
            body: format!(
                "You earned {:.2} Cred at {}. Tap to see it grow.",
                cred_amount,
                merchant_name
            ),
            data: Some(NotificationData {
                notification_type: "capture".into(),
                cred_amount: Some(cred_amount),
                merchant_name: Some(merchant_name.into()),
                ..Default::default()
            }),
            sound: Some("default".into()),
            priority: NotificationPriority::High,
            badge: None,
        };
        
        self.send(user_pubkey, &notification).await
    }
    
    /// Send auto-stake notification
    pub async fn send_stake_notification(
        &self,
        user_pubkey: &str,
        cred_amount: f64,
        duration_days: u16,
        apy: f64,
    ) -> Result<NotificationResult, NotificationError> {
        let notification = PushNotification {
            title: "Auto-Staked 📈".into(),
            body: format!(
                "{:.2} Cred staked for {} days at {:.1}% APY",
                cred_amount, duration_days, apy
            ),
            data: Some(NotificationData {
                notification_type: "stake".into(),
                cred_amount: Some(cred_amount),
                ..Default::default()
            }),
            sound: None, // Silent for auto-actions
            priority: NotificationPriority::Normal,
            badge: None,
        };
        
        self.send(user_pubkey, &notification).await
    }
    
    /// Send unlock reminder
    pub async fn send_unlock_notification(
        &self,
        user_pubkey: &str,
        cred_amount: f64,
        yield_amount: f64,
        hours_until: u16,
    ) -> Result<NotificationResult, NotificationError> {
        let notification = PushNotification {
            title: "Position Unlocking Soon ⏰".into(),
            body: format!(
                "Your {:.2} Cred stake unlocks in {} hours with {:.2} Cred yield!",
                cred_amount, hours_until, yield_amount
            ),
            data: Some(NotificationData {
                notification_type: "unlock".into(),
                cred_amount: Some(cred_amount),
                ..Default::default()
            }),
            sound: Some("default".into()),
            priority: NotificationPriority::High,
            badge: None,
        };
        
        self.send(user_pubkey, &notification).await
    }
    
    // ========================================================================
    // INTERNAL METHODS
    // ========================================================================
    
    /// Get cached push token from DynamoDB
    async fn get_cached_token(&self, user_pubkey: &str) -> Result<Option<String>, NotificationError> {
        use aws_sdk_dynamodb::types::AttributeValue;
        
        let result = self.dynamo_client
            .get_item()
            .table_name(&self.config.dynamo_table)
            .key("pk", AttributeValue::S(format!("USER#{}", user_pubkey)))
            .key("sk", AttributeValue::S("PUSH_TOKEN".into()))
            .send()
            .await
            .map_err(|e| NotificationError::DynamoError(e.to_string()))?;
        
        if let Some(item) = result.item {
            // Check TTL
            if let Some(AttributeValue::N(ttl_str)) = item.get("ttl") {
                let ttl: i64 = ttl_str.parse().unwrap_or(0);
                let now = SystemTime::now()
                    .duration_since(UNIX_EPOCH)
                    .unwrap()
                    .as_secs() as i64;
                
                if ttl < now {
                    // Token expired
                    return Ok(None);
                }
            }
            
            if let Some(AttributeValue::S(token)) = item.get("push_token") {
                return Ok(Some(token.clone()));
            }
        }
        
        Ok(None)
    }
    
    /// Cache push token in DynamoDB
    async fn cache_token(&self, user_pubkey: &str, token: &str) -> Result<(), NotificationError> {
        use aws_sdk_dynamodb::types::AttributeValue;
        
        let now = SystemTime::now()
            .duration_since(UNIX_EPOCH)
            .unwrap()
            .as_secs() as i64;
        let ttl = now + self.config.token_cache_ttl;
        
        self.dynamo_client
            .put_item()
            .table_name(&self.config.dynamo_table)
            .item("pk", AttributeValue::S(format!("USER#{}", user_pubkey)))
            .item("sk", AttributeValue::S("PUSH_TOKEN".into()))
            .item("push_token", AttributeValue::S(token.into()))
            .item("cached_at", AttributeValue::N(now.to_string()))
            .item("ttl", AttributeValue::N(ttl.to_string()))
            .send()
            .await
            .map_err(|e| NotificationError::DynamoError(e.to_string()))?;
        
        info!(user = %user_pubkey, "Push token cached in DynamoDB");
        Ok(())
    }
    
    /// Fetch push token from Supabase profiles table
    async fn fetch_token_from_supabase(&self, user_pubkey: &str) -> Result<Option<String>, NotificationError> {
        // Query profiles table by wallet_address
        let url = format!(
            "{}/rest/v1/profiles?select=push_token&wallet_address=eq.{}",
            self.config.supabase_url,
            user_pubkey
        );
        
        let response = self.http_client
            .get(&url)
            .header("apikey", &self.config.supabase_service_key)
            .header("Authorization", format!("Bearer {}", self.config.supabase_service_key))
            .send()
            .await
            .map_err(|e| NotificationError::SupabaseError(e.to_string()))?;
        
        if !response.status().is_success() {
            let status = response.status();
            let body = response.text().await.unwrap_or_default();
            error!(status = %status, body = %body, "Supabase query failed");
            return Err(NotificationError::SupabaseError(format!("HTTP {}: {}", status, body)));
        }
        
        #[derive(Deserialize)]
        struct ProfileRow {
            push_token: Option<String>,
        }
        
        let profiles: Vec<ProfileRow> = response.json().await
            .map_err(|e| NotificationError::SupabaseError(e.to_string()))?;
        
        Ok(profiles.first().and_then(|p| p.push_token.clone()))
    }
    
    /// Send notification via Supabase send-push edge function
    async fn send_via_supabase(
        &self,
        push_token: &str,
        user_pubkey: &str,
        notification: &PushNotification,
    ) -> Result<NotificationResult, NotificationError> {
        let url = format!("{}/functions/v1/send-push", self.config.supabase_url);
        
        let payload = SendPushPayload {
            push_token: push_token.into(),
            user_id: None, // We use pubkey, not Supabase user_id
            title: Some(notification.title.clone()),
            body: Some(notification.body.clone()),
            data: notification.data.clone(),
            sound: notification.sound.clone(),
            priority: match notification.priority {
                NotificationPriority::High => "high",
                NotificationPriority::Normal => "normal",
            }.into(),
            badge: notification.badge,
        };
        
        let response = self.http_client
            .post(&url)
            .header("Authorization", format!("Bearer {}", self.config.supabase_service_key))
            .header("Content-Type", "application/json")
            .json(&payload)
            .send()
            .await
            .map_err(|e| NotificationError::SupabaseError(e.to_string()))?;
        
        let status = response.status();
        let body: SendPushResponse = response.json().await
            .map_err(|e| NotificationError::SupabaseError(e.to_string()))?;
        
        if body.sent {
            info!(
                user = %user_pubkey,
                ticket_id = ?body.ticket_id,
                "Push notification sent"
            );
            Ok(NotificationResult {
                sent: true,
                ticket_id: body.ticket_id,
                error: None,
            })
        } else {
            warn!(
                user = %user_pubkey,
                error = ?body.error,
                "Push notification failed"
            );
            
            // If token is invalid, clear the cache
            if body.error.as_deref() == Some("DeviceNotRegistered") {
                self.clear_cached_token(user_pubkey).await.ok();
            }
            
            Ok(NotificationResult {
                sent: false,
                ticket_id: None,
                error: body.error,
            })
        }
    }
    
    /// Clear cached push token (e.g., if it's invalid)
    async fn clear_cached_token(&self, user_pubkey: &str) -> Result<(), NotificationError> {
        use aws_sdk_dynamodb::types::AttributeValue;
        
        self.dynamo_client
            .delete_item()
            .table_name(&self.config.dynamo_table)
            .key("pk", AttributeValue::S(format!("USER#{}", user_pubkey)))
            .key("sk", AttributeValue::S("PUSH_TOKEN".into()))
            .send()
            .await
            .map_err(|e| NotificationError::DynamoError(e.to_string()))?;
        
        info!(user = %user_pubkey, "Cleared invalid push token from cache");
        Ok(())
    }
}

// ============================================================================
// DATA TYPES
// ============================================================================

/// Push notification to send
#[derive(Debug, Clone, Serialize)]
pub struct PushNotification {
    pub title: String,
    pub body: String,
    pub data: Option<NotificationData>,
    pub sound: Option<String>,
    pub priority: NotificationPriority,
    pub badge: Option<u32>,
}

#[derive(Debug, Clone, Copy, Serialize)]
pub enum NotificationPriority {
    High,
    Normal,
}

/// Additional data payload
#[derive(Debug, Clone, Default, Serialize, Deserialize)]
pub struct NotificationData {
    #[serde(rename = "type")]
    pub notification_type: String,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub cred_amount: Option<f64>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub merchant_name: Option<String>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub position_id: Option<String>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub transaction_id: Option<String>,
}

/// Result of sending a notification
#[derive(Debug, Clone)]
pub struct NotificationResult {
    pub sent: bool,
    pub ticket_id: Option<String>,
    pub error: Option<String>,
}

/// Payload for Supabase send-push function
#[derive(Debug, Serialize)]
struct SendPushPayload {
    push_token: String,
    #[serde(skip_serializing_if = "Option::is_none")]
    user_id: Option<String>,
    #[serde(skip_serializing_if = "Option::is_none")]
    title: Option<String>,
    #[serde(skip_serializing_if = "Option::is_none")]
    body: Option<String>,
    #[serde(skip_serializing_if = "Option::is_none")]
    data: Option<NotificationData>,
    #[serde(skip_serializing_if = "Option::is_none")]
    sound: Option<String>,
    priority: String,
    #[serde(skip_serializing_if = "Option::is_none")]
    badge: Option<u32>,
}

/// Response from Supabase send-push function
#[derive(Debug, Deserialize)]
struct SendPushResponse {
    sent: bool,
    ticket_id: Option<String>,
    error: Option<String>,
}

// ============================================================================
// ERRORS
// ============================================================================

#[derive(Debug, Clone)]
pub enum NotificationError {
    /// Missing required configuration
    MissingConfig(String),
    /// Initialization failed
    InitError(String),
    /// DynamoDB error
    DynamoError(String),
    /// Supabase error
    SupabaseError(String),
    /// User has no push token
    NoToken,
}

impl std::fmt::Display for NotificationError {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        match self {
            Self::MissingConfig(key) => write!(f, "Missing config: {}", key),
            Self::InitError(msg) => write!(f, "Init error: {}", msg),
            Self::DynamoError(msg) => write!(f, "DynamoDB error: {}", msg),
            Self::SupabaseError(msg) => write!(f, "Supabase error: {}", msg),
            Self::NoToken => write!(f, "User has no push token"),
        }
    }
}

impl std::error::Error for NotificationError {}

#[cfg(test)]
mod tests {
    use super::*;
    
    #[test]
    fn notification_data_serializes() {
        let data = NotificationData {
            notification_type: "capture".into(),
            cred_amount: Some(4.95),
            merchant_name: Some("Miami Coffee".into()),
            ..Default::default()
        };
        
        let json = serde_json::to_string(&data).unwrap();
        assert!(json.contains("capture"));
        assert!(json.contains("4.95"));
        assert!(json.contains("Miami Coffee"));
    }
}