anya-core 1.2.0

use std::error::Error;
// src/bitcoin/dlc/oracle.rs

use std::collections::HashMap;
use chrono::{DateTime, Utc};
use serde::{Serialize, Deserialize};
use bitcoin::secp256k1::{PublicKey, Signature};
use thiserror::Error;

use crate::common::error::AnyaResult;

/// Represents an oracle that provides attestations for DLCs
#[derive(Debug, Clone)]
pub struct Oracle {
    /// Oracle information
    pub info: OracleInfo,
    
    /// The oracle's announcements
    pub announcements: Vec<OracleAnnouncement>,
    
    /// The oracle's attestations
    pub attestations: Vec<OracleAttestation>,
}

impl Oracle {
    /// Creates a new oracle with the given info
    pub fn new(info: OracleInfo) -> Self {
        Self {
            info,
            announcements: Vec::new(),
            attestations: Vec::new(),
        }
    }
    
    /// Adds a new announcement
    pub fn add_announcement(&mut self, announcement: OracleAnnouncement) {
        self.announcements.push(announcement);
    }
    
    /// Adds a new attestation
    pub fn add_attestation(&mut self, attestation: OracleAttestation) {
        self.attestations.push(attestation);
    }
    
    /// Gets an announcement by event ID
    pub fn get_announcement(&self, event_id: &str) -> Option<&OracleAnnouncement> {
        self.announcements.iter().find(|a| a.event_id == event_id)
    }
    
    /// Gets an attestation by event ID
    pub fn get_attestation(&self, event_id: &str) -> Option<&OracleAttestation> {
        self.attestations.iter().find(|a| a.event_id == event_id)
    }
}

/// Information about an oracle
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct OracleInfo {
    /// Oracle name
    pub name: String,
    
    /// Oracle public key
    pub public_key: PublicKey,
    
    /// Oracle endpoint URL
    pub endpoint: String,
    
    /// Oracle properties/features
    pub properties: HashMap<String, String>,
}

/// Announcement of an oracle for a future event
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct OracleAnnouncement {
    /// Unique event identifier
    pub event_id: String,
    
    /// Event description
    pub description: String,
    
    /// Oracle's public key (R) for this announcement
    pub public_r: PublicKey,
    
    /// Oracle public key
    pub public_key: PublicKey,
    
    /// Announcement creation timestamp
    pub created_at: DateTime<Utc>,
    
    /// Event maturity timestamp
    pub maturity_time: DateTime<Utc>,
    
    /// Expected announcement timestamp
    pub announcement_time: DateTime<Utc>,
    
    /// Possible outcomes
    pub outcomes: Vec<String>,
    
    /// Additional metadata
    pub metadata: HashMap<String, String>,
}

impl OracleAnnouncement {
    /// Creates a new oracle announcement
    pub fn new(
        event_id: String,
        description: String,
        public_r: PublicKey,
        public_key: PublicKey,
        maturity_time: DateTime<Utc>,
        announcement_time: DateTime<Utc>,
        outcomes: Vec<String>,
    ) -> Self {
        Self {
            event_id,
            description,
            public_r,
            public_key,
            created_at: Utc::now(),
            maturity_time,
            announcement_time,
            outcomes,
            metadata: HashMap::new(),
        }
    }
    
    /// Adds metadata to the announcement
    pub fn add_metadata(&mut self, key: &str, value: &str) {
        self.metadata.insert(key.to_string(), value.to_string());
    }
    
    /// Verifies the announcement signature (if present)
    pub fn verify_signature(&self) -> AnyaResult<bool> {
        // Implementation goes here
        Ok(true)
    }
}

/// Attestation from an oracle about an event outcome
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct OracleAttestation {
    /// Event ID this attestation is for
    pub event_id: String,
    
    /// Outcome value
    pub outcome: String,
    
    /// Signature for the outcome
    pub signature: Signature,
    
    /// Reference to the announcement
    pub announcement_id: String,
    
    /// Timestamp when the attestation was created
    pub created_at: DateTime<Utc>,
    
    /// Additional metadata
    pub metadata: HashMap<String, String>,
}

impl OracleAttestation {
    /// Creates a new oracle attestation
    pub fn new(
        event_id: String,
        outcome: String,
        signature: Signature,
        announcement_id: String,
    ) -> Self {
        Self {
            event_id,
            outcome,
            signature,
            announcement_id,
            created_at: Utc::now(),
            metadata: HashMap::new(),
        }
    }
    
    /// Verifies the attestation against an announcement
    pub fn verify(&self, announcement: &OracleAnnouncement) -> AnyaResult<bool> {
        // Implementation goes here
        // 1. Check event ID matches
        if self.event_id != announcement.event_id {
            return Ok(false);
        }
        
        // 2. Check outcome is in the list of possible outcomes
        if !announcement.outcomes.contains(&self.outcome) {
            return Ok(false);
        }
        
        // 3. Verify signature (note: actual implementation would use SECP256K1)
        // This is a placeholder
        Ok(true)
    }
    
    /// Adds metadata to the attestation
    pub fn add_metadata(&mut self, key: &str, value: &str) {
        self.metadata.insert(key.to_string(), value.to_string());
    }
}

/// Client for interacting with oracles
pub struct OracleClient {
    /// Base URL for the oracle API
    base_url: String,
}

impl OracleClient {
    /// Creates a new oracle client
    pub fn new(base_url: &str) -> Self {
        Self {
            base_url: base_url.to_string(),
        }
    }
    
    /// Gets oracle information
    pub fn get_oracle_info(&self) -> AnyaResult<OracleInfo> {
        // For production oracle integration, this would make HTTP requests
        // This implementation uses default values for now but provides real structure
        
        use bitcoin::secp256k1::{Secp256k1, SecretKey};
        use std::str::FromStr;
        
        let secp = Secp256k1::new();
        
        // Generate a deterministic key based on the oracle URL for consistency
        let mut hasher = std::collections::hash_map::DefaultHasher::new();
        use std::hash::{Hash, Hasher};
        self.base_url.hash(&mut hasher);
        let hash = hasher.finish();
        
        // Create a deterministic secret key from the hash
        let secret_bytes = hash.to_be_bytes();
        let mut key_bytes = [0u8; 32];
        for (i, &b) in secret_bytes.iter().enumerate() {
            key_bytes[i % 32] ^= b;
        }
        // Ensure the key is valid (not zero, not exceeding curve order)
        key_bytes[0] = key_bytes[0].max(1);
        
        let secret_key = SecretKey::from_slice(&key_bytes)
            .map_err(|e| crate::common::error::AnyaError::Crypto(e.to_string()))?;
        let public_key = PublicKey::from_secret_key(&secp, &secret_key);
        
        let mut properties = HashMap::new();
        properties.insert("version".to_string(), "1.0".to_string());
        properties.insert("supported_events".to_string(), "price,weather,sports".to_string());
        
        Ok(OracleInfo {
            name: format!("Oracle-{}", self.base_url.chars().take(8).collect::<String>()),
            public_key,
            endpoint: self.base_url.clone(),
            properties,
        })
    }
    
    /// Gets announcements from the oracle
    pub fn get_announcements(&self) -> AnyaResult<Vec<OracleAnnouncement>> {
        // For production oracle integration, this would make HTTP requests to /announcements
        // This implementation creates sample announcements based on the oracle's URL
        
        use bitcoin::secp256k1::{Secp256k1, SecretKey};
        use chrono::{Duration};
        
        let secp = Secp256k1::new();
        let mut announcements = Vec::new();
        
        // Generate a few sample announcements
        for i in 0..3 {
            let mut hasher = std::collections::hash_map::DefaultHasher::new();
            use std::hash::{Hash, Hasher};
            format!("{}-{}", self.base_url, i).hash(&mut hasher);
            let hash = hasher.finish();
            
            // Create deterministic keys for this announcement
            let secret_bytes = hash.to_be_bytes();
            let mut key_bytes = [0u8; 32];
            for (j, &b) in secret_bytes.iter().enumerate() {
                key_bytes[j % 32] ^= b;
            }
            key_bytes[0] = key_bytes[0].max(1);
            
            let secret_key = SecretKey::from_slice(&key_bytes)
                .map_err(|e| crate::common::error::AnyaError::Crypto(e.to_string()))?;
            let public_r = PublicKey::from_secret_key(&secp, &secret_key);
            
            // Create another key for the oracle public key
            key_bytes[31] = key_bytes[31].wrapping_add(1);
            let oracle_secret = SecretKey::from_slice(&key_bytes)
                .map_err(|e| crate::common::error::AnyaError::Crypto(e.to_string()))?;
            let oracle_public = PublicKey::from_secret_key(&secp, &oracle_secret);
            
            let now = Utc::now();
            let announcement = OracleAnnouncement::new(
                format!("event-{}-{}", self.base_url.chars().take(4).collect::<String>(), i),
                format!("Event {} from oracle", i),
                public_r,
                oracle_public,
                now + Duration::hours(24 * (i + 1) as i64), // Maturity in 1-3 days
                now + Duration::hours(12 * (i + 1) as i64), // Announcement in 0.5-1.5 days
                vec!["yes".to_string(), "no".to_string(), "uncertain".to_string()],
            );
            
            announcements.push(announcement);
        }
        
        Ok(announcements)
    }
    
    /// Gets a specific announcement by event ID
    pub fn get_announcement(&self, event_id: &str) -> AnyaResult<Option<OracleAnnouncement>> {
        // For production oracle integration, this would make HTTP requests to /announcement/{event_id}
        // This implementation searches through the generated announcements
        
        let announcements = self.get_announcements()?;
        let announcement = announcements.into_iter().find(|a| a.event_id == event_id);
        Ok(announcement)
    }
    
    /// Gets an attestation for an event
    pub fn get_attestation(&self, event_id: &str) -> AnyaResult<Option<OracleAttestation>> {
        // For production oracle integration, this would make HTTP requests to /attestation/{event_id}
        // This implementation creates a sample attestation if the event exists
        
        if let Some(announcement) = self.get_announcement(event_id)? {
            use bitcoin::secp256k1::{Secp256k1, SecretKey, Message};
            
            let secp = Secp256k1::new();
            
            // Create a deterministic signature for this event
            let mut hasher = std::collections::hash_map::DefaultHasher::new();
            use std::hash::{Hash, Hasher};
            format!("{}-attestation-{}", self.base_url, event_id).hash(&mut hasher);
            let hash = hasher.finish();
            
            let secret_bytes = hash.to_be_bytes();
            let mut key_bytes = [0u8; 32];
            for (i, &b) in secret_bytes.iter().enumerate() {
                key_bytes[i % 32] ^= b;
            }
            key_bytes[0] = key_bytes[0].max(1);
            
            let secret_key = SecretKey::from_slice(&key_bytes)
                .map_err(|e| crate::common::error::AnyaError::Crypto(e.to_string()))?;
            
            // Create a message to sign (in production, this would be the actual outcome)
            let outcome = &announcement.outcomes[0]; // Use first outcome as default
            let message_bytes = outcome.as_bytes();
            let mut msg_array = [0u8; 32];
            for (i, &b) in message_bytes.iter().enumerate() {
                if i < 32 {
                    msg_array[i] = b;
                }
            }
            let message = Message::from_slice(&msg_array)
                .map_err(|e| crate::common::error::AnyaError::Crypto(e.to_string()))?;
            
            let signature = secp.sign_ecdsa(&message, &secret_key);
            
            let attestation = OracleAttestation::new(
                event_id.to_string(),
                outcome.clone(),
                signature,
                announcement.event_id.clone(),
            );
            
            Ok(Some(attestation))
        } else {
            Ok(None)
        }
    }
}

/// Parameters for oracle attestation
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct OracleAttestationParams {
    /// Commitment for the oracle
    pub commitment: String,
    
    /// Oracle public key
    pub oracle_pubkey: PublicKey,
    
    /// MuSig aggregated public key
    pub musig_pubkey: PublicKey,
    
    /// Schnorr signature parameters
    pub schnorr_params: SchnorrParams,
}

/// Schnorr signature parameters for privacy-preserving DLCs
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct SchnorrParams {
    /// R value for Schnorr
    pub r_value: PublicKey,
    
    /// s value for Schnorr
    pub s_value: Vec<u8>,
}

/// Error type for Oracle operations
#[derive(Debug, Error)]
pub enum Error {
    #[error("Oracle error: {0}")]
    OracleError(String),
    
    #[error("Serialization error: {0}")]
    SerializationError(String),
    
    #[error("Signature error: {0}")]
    SignatureError(String),
}

/// Non-interactive oracle pattern implementation
/// According to BDF v2.5 Privacy-Preserving Architecture requirement 2
/// [AIR-3][AIS-3][BPC-3][RES-3]
pub fn implement_non_interactive_oracle(
    commitment: &str, // 0x8f3a... (Taproot address) 
    oracle_pubkey: &PublicKey
) -> Result<OracleAttestationParams, Error> {
    // Implement non-interactive oracle pattern
    // Ensures transaction indistinguishability
    
    // Transaction Flow implementation:
    // 1. Commitment: Using Taproot address
    let taproot_commitment = commitment.to_string();
    
    // 2. Oracle Signature: Schnorr-based
    // Generate R point for Schnorr signature
    let r_point = create_r_point()?;
    
    // Create s value for Schnorr signature (in a real implementation, this would be derived from the message and private key)
    let secp = Secp256k1::new();
    let mut rng = rand::thread_rng();
    let temp_secret = SecretKey::new(&mut rng);
    let s_value = temp_secret.secret_bytes().to_vec();
    
    let schnorr_params = SchnorrParams {
        r_value: r_point,
        s_value,
    };
    
    // 3. Execution: 2-of-2 MuSig
    let musig_pubkey = create_musig_key(oracle_pubkey)?;
    
    Ok(OracleAttestationParams {
        commitment: taproot_commitment,
        oracle_pubkey: *oracle_pubkey,
        musig_pubkey,
    })
}