//! NAC UCA - 统一跨链审计器
//! Unified Cross-chain Auditor
//! 
//! 基于CSNP V2.0技术白皮书第5章"UCA"

use nac_udm::primitives::{Address, Hash};
use serde::{Deserialize, Serialize};
use std::collections::HashMap;
use thiserror::Error;

#[derive(Debug, Error)]
pub enum UcaError {
    #[error("Audit record not found: {0:?}")]
    RecordNotFound(Hash),
    
    #[error("Invalid proof")]
    InvalidProof,
    
    #[error("Violation detected: {0}")]
    ViolationDetected(String),
}

/// 跨链行为类型
#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
pub enum CrossChainAction {
    /// 资产转移
    AssetTransfer,
    /// 消息传递
    MessagePassing,
    /// 合约调用
    ContractCall,
    /// 状态同步
    StateSync,
}

/// 跨链审计记录
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct AuditRecord {
    /// 记录ID
    pub record_id: Hash,
    /// 源链ID
    pub source_chain_id: u64,
    /// 目标链ID
    pub target_chain_id: u64,
    /// 行为类型
    pub action: CrossChainAction,
    /// 发起者地址
    pub initiator: Address,
    /// 交易哈希
    pub tx_hash: Hash,
    /// 时间戳
    pub timestamp: u64,
    /// 行为数据
    pub data: Vec<u8>,
    /// 验证证明
    pub proof: Vec<u8>,
    /// 状态（pending/confirmed/violated）
    pub status: AuditStatus,
}

/// 审计状态
#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
pub enum AuditStatus {
    /// 待确认
    Pending,
    /// 已确认
    Confirmed,
    /// 违规
    Violated,
}

/// 违规记录
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct ViolationRecord {
    /// 违规ID
    pub violation_id: Hash,
    /// 相关审计记录ID
    pub audit_record_id: Hash,
    /// 违规类型
    pub violation_type: ViolationType,
    /// 违规描述
    pub description: String,
    /// 惩罚措施
    pub penalty: Penalty,
    /// 记录时间
    pub timestamp: u64,
}

/// 违规类型
#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
pub enum ViolationType {
    /// 双花攻击
    DoubleSpending,
    /// 未授权转移
    UnauthorizedTransfer,
    /// 数据不一致
    DataInconsistency,
    /// 超时未确认
    TimeoutUnconfirmed,
}

/// 惩罚措施
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct Penalty {
    /// 惩罚类型
    pub penalty_type: PenaltyType,
    /// 惩罚金额（如适用）
    pub amount: u64,
    /// 惩罚持续时间（秒）
    pub duration_secs: u64,
}

/// 惩罚类型
#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
pub enum PenaltyType {
    /// 警告
    Warning,
    /// 罚款
    Fine,
    /// 暂停服务
    Suspension,
    /// 永久封禁
    Ban,
}

/// UCA审计器
pub struct UnifiedCrossChainAuditor {
    /// 审计器ID
    auditor_id: String,
    /// 审计记录
    records: HashMap<Hash, AuditRecord>,
    /// 违规记录
    violations: HashMap<Hash, ViolationRecord>,
    /// 已审计交易数
    audited_count: u64,
    /// 检测到的违规数
    violation_count: u64,
}

impl UnifiedCrossChainAuditor {
    /// 创建新的UCA审计器
    pub fn new(auditor_id: String) -> Self {
        Self {
            auditor_id,
            records: HashMap::new(),
            violations: HashMap::new(),
            audited_count: 0,
            violation_count: 0,
        }
    }

    /// 记录跨链行为
    pub fn record_action(
        &mut self,
        source_chain_id: u64,
        target_chain_id: u64,
        action: CrossChainAction,
        initiator: Address,
        tx_hash: Hash,
        data: Vec<u8>,
        proof: Vec<u8>,
        timestamp: u64,
    ) -> Hash {
        // 生成记录ID
        let record_id = self.generate_record_id(&tx_hash, timestamp);

        let record = AuditRecord {
            record_id,
            source_chain_id,
            target_chain_id,
            action,
            initiator,
            tx_hash,
            timestamp,
            data,
            proof,
            status: AuditStatus::Pending,
        };

        self.records.insert(record_id, record);
        self.audited_count += 1;

        record_id
    }

    /// 验证跨链行为
    pub fn verify_action(&mut self, record_id: &Hash) -> Result<bool, UcaError> {
        // 先获取必要的数据
        let (is_valid, timestamp) = {
            let record = self.records
                .get(record_id)
                .ok_or(UcaError::RecordNotFound(*record_id))?;
            (!record.proof.is_empty(), record.timestamp)
        };

        // 更新状态
        if is_valid {
            if let Some(record) = self.records.get_mut(record_id) {
                record.status = AuditStatus::Confirmed;
            }
            Ok(true)
        } else {
            if let Some(record) = self.records.get_mut(record_id) {
                record.status = AuditStatus::Violated;
            }
            
            // 记录违规
            self.record_violation(
                *record_id,
                ViolationType::DataInconsistency,
                "Invalid proof".to_string(),
                Penalty {
                    penalty_type: PenaltyType::Warning,
                    amount: 0,
                    duration_secs: 0,
                },
                timestamp,
            );
            
            Ok(false)
        }
    }

    /// 记录违规
    pub fn record_violation(
        &mut self,
        audit_record_id: Hash,
        violation_type: ViolationType,
        description: String,
        penalty: Penalty,
        timestamp: u64,
    ) -> Hash {
        let violation_id = self.generate_violation_id(&audit_record_id, timestamp);

        let violation = ViolationRecord {
            violation_id,
            audit_record_id,
            violation_type,
            description,
            penalty,
            timestamp,
        };

        self.violations.insert(violation_id, violation);
        self.violation_count += 1;

        violation_id
    }

    /// 查询审计记录
    pub fn get_record(&self, record_id: &Hash) -> Option<&AuditRecord> {
        self.records.get(record_id)
    }

    /// 查询违规记录
    pub fn get_violation(&self, violation_id: &Hash) -> Option<&ViolationRecord> {
        self.violations.get(violation_id)
    }

    /// 获取统计信息
    pub fn get_stats(&self) -> UcaStats {
        UcaStats {
            auditor_id: self.auditor_id.clone(),
            total_audited: self.audited_count,
            total_violations: self.violation_count,
            pending_records: self.records.values()
                .filter(|r| r.status == AuditStatus::Pending)
                .count(),
        }
    }

    /// 生成记录ID
    fn generate_record_id(&self, tx_hash: &Hash, timestamp: u64) -> Hash {
        // 简化实现：使用tx_hash作为record_id
        *tx_hash
    }

    /// 生成违规ID
    fn generate_violation_id(&self, audit_record_id: &Hash, timestamp: u64) -> Hash {
        // 简化实现：使用audit_record_id作为violation_id
        *audit_record_id
    }

    /// 获取审计器ID
    pub fn auditor_id(&self) -> &str {
        &self.auditor_id
    }
}

/// UCA统计信息
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct UcaStats {
    pub auditor_id: String,
    pub total_audited: u64,
    pub total_violations: u64,
    pub pending_records: usize,
}

#[cfg(test)]
mod tests {
    use super::*;

    fn create_test_hash(id: u8) -> Hash {
        let mut bytes = [0u8; 48];
        bytes[47] = id;
        Hash::from_bytes(bytes)
    }

    fn create_test_address(id: u8) -> Address {
        let mut bytes = [0u8; 32];
        bytes[31] = id;
        Address::from_bytes(bytes)
    }

    #[test]
    fn test_record_and_verify() {
        let mut auditor = UnifiedCrossChainAuditor::new("uca1".to_string());
        
        let tx_hash = create_test_hash(1);
        let initiator = create_test_address(1);
        
        // 记录跨链行为
        let record_id = auditor.record_action(
            1,
            2,
            CrossChainAction::AssetTransfer,
            initiator,
            tx_hash,
            vec![1, 2, 3],
            vec![4, 5, 6], // 有效proof
            1000,
        );

        // 验证
        let is_valid = auditor.verify_action(&record_id).unwrap();
        assert!(is_valid);

        let record = auditor.get_record(&record_id).unwrap();
        assert_eq!(record.status, AuditStatus::Confirmed);
    }

    #[test]
    fn test_violation_detection() {
        let mut auditor = UnifiedCrossChainAuditor::new("uca1".to_string());
        
        let tx_hash = create_test_hash(1);
        let initiator = create_test_address(1);
        
        // 记录无效的跨链行为
        let record_id = auditor.record_action(
            1,
            2,
            CrossChainAction::AssetTransfer,
            initiator,
            tx_hash,
            vec![1, 2, 3],
            vec![], // 无效proof
            1000,
        );

        // 验证
        let is_valid = auditor.verify_action(&record_id).unwrap();
        assert!(!is_valid);

        let stats = auditor.get_stats();
        assert_eq!(stats.total_violations, 1);
    }
}