//! 宪法收据模块

use serde::{Deserialize, Serialize};
use sha3::{Digest, Sha3_384};

/// 宪法收据
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct ConstitutionalReceipt {
    /// 交易哈希 (SHA3-384)
    pub transaction_hash: [u8; 48],
    /// 宾法哈希 (SHA3-384)
    pub constitutional_hash: [u8; 48],
    /// 条款掩码
    pub clause_mask: u64,
    /// 执行结果哈希 (SHA3-384)
    pub execution_result_hash: [u8; 48],
    /// 时间戳
    pub timestamp: u64,
    /// 有效期窗口
    pub validity_window: u64,
    /// CEE节点签名列表
    pub signatures: Vec<Vec<u8>>,
    /// 收据ID (SHA3-384)
    pub receipt_id: [u8; 48],
}

impl ConstitutionalReceipt {
    /// 创建新的宪法收据
    pub fn new(
        transaction_hash: [u8; 48],
        constitutional_hash: [u8; 48],
        clause_mask: u64,
    ) -> Self {
        let receipt_id = Self::generate_receipt_id(&transaction_hash);
        
        Self {
            transaction_hash,
            constitutional_hash,
            clause_mask,
            execution_result_hash: [0u8; 48],
            timestamp: 0,
            validity_window: 300,
            signatures: Vec::new(),
            receipt_id,
        }
    }

    fn generate_receipt_id(transaction_hash: &[u8; 48]) -> [u8; 48] {
        let mut hasher = Sha3_384::new();
        hasher.update(transaction_hash);
        hasher.update(b"NAC_CR");
        let result = hasher.finalize();
        
        let mut id = [0u8; 48];
        id.copy_from_slice(&result);
        id
    }

    /// 添加CEE签名
    pub fn add_signature(&mut self, signature: Vec<u8>) {
        self.signatures.push(signature);
    }

    /// 验证收据
    pub fn verify(&self) -> bool {
        let expected_id = Self::generate_receipt_id(&self.transaction_hash);
        if self.receipt_id != expected_id {
            return false;
        }
        !self.signatures.is_empty()
    }

    /// 检查收据是否在有效期内
    pub fn is_valid(&self) -> bool {
        true // TODO: 实现时间检查
    }
}

/// CEE请求数据
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct CEERequest {
    /// 交易哈希
    pub transaction_hash: String,
    /// 交易载荷（Base64编码，可选）
    pub transaction_payload: Option<String>,
}

impl CEERequest {
    /// 创建新的CEE请求
    pub fn new(transaction_hash: [u8; 48]) -> Self {
        Self {
            transaction_hash: format!("{:?}", transaction_hash),
            transaction_payload: None,
        }
    }
}

/// CEE响应数据
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct CEEResponse {
    /// 宪法收据
    pub receipt: ConstitutionalReceipt,
    /// CEE节点签名
    pub signature: String,
}