// NAC RU 辖区宪法规则验证插件
// 监管机构：CBR/Rosfinmonitoring (Central Bank of Russia / Federal Financial Monitoring Service)
// 法律框架：Federal Law No. 259-FZ on Digital Financial Assets (2021) / Federal Law No. 115-FZ
// CBPP原则：约法即是治法 | 宪法即是规则 | 参与即是共识 | 节点产生区块交易决定区块大小
// 参与即是共识：RU辖区节点加载此插件参与出块，即代表对本辖区宪法规则的背书
// NAC_Lens 4.0 路由层自动处理跨辖区消息传递

use serde::{Deserialize, Serialize};

const JURISDICTION_CODE: &str = "RU";
const AML_THRESHOLD_USD: f64 = 5000.0;

/// RU 辖区交易上下文（俄罗斯）
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct RUTxContext {
    pub tx_hash: String,
    pub from: [u8; 32],
    pub to: [u8; 32],
    pub amount_usd: f64,
    pub asset_type: String,
    pub kyc_level: KycLevel,
    pub aml_reported: bool,
    pub is_anonymous: bool,
    pub is_cross_border: bool,
    pub sanctions_cleared: bool,

}

/// KYC 等级
#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
pub enum KycLevel {
    None,
    Basic,
    Enhanced,
    Institutional,
}

/// 验证结果
#[derive(Debug, Clone)]
pub enum ValidationResult {
    Approved {
        jurisdiction: String,
        /// 宪法收据（CR）：参与即是共识，节点独立出具，无需多签
        constitutional_receipt: String,
    },
    Rejected {
        reason: String,
        jurisdiction: String,
    },
}

/// RU 辖区宪法规则验证引擎
pub struct RUJurisdictionPlugin;

impl RUJurisdictionPlugin {
    pub fn new() -> Self {
        Self
    }

    /// KYC 等级验证（最低要求：Institutional）
    fn check_kyc_level(tx: &RUTxContext) -> bool {
        matches!(tx.kyc_level, KycLevel::Institutional | KycLevel::Institutional)
            || (tx.kyc_level == KycLevel::Enhanced && "Institutional" == "Enhanced")
    }

    /// AML 阈值检查（5000 USD）
    fn check_aml_threshold(tx: &RUTxContext) -> bool {
        if tx.amount_usd > AML_THRESHOLD_USD {
            // 超过阈值需要向 CBR/Rosfinmonitoring (Central Bank of Russia / Federal Financial Monitoring Service) 报告
            // 约法即是治法：此要求直接来自 Federal Law No. 259-FZ on Digital Financial Assets (2021) / Federal Law No. 115-FZ
            return tx.aml_reported;
        }
        true
    }

    /// 制裁名单检查
    fn check_sanctions(tx: &RUTxContext) -> bool {
        tx.sanctions_cleared
    }

    /// 辖区特定规则验证
    fn check_jurisdiction_rules(tx: &RUTxContext) -> bool {
    // Rule: DFA issuance requires CBR-licensed operator
    // Rule: Russian passport/SNILS KYC mandatory
    // Rule: RUB reporting above RUB 600,000
    // Rule: Prohibition on using crypto as payment in Russia
        // 禁止匿名交易（宪法即是规则）
        !tx.is_anonymous
    }

    /// 出具宪法收据（CR）
    /// 参与即是共识：节点独立出具CR，无需多签，无需链上投票
    fn issue_constitutional_receipt(tx: &RUTxContext) -> String {
        format!("CR-{}:{}", JURISDICTION_CODE, tx.tx_hash)
    }
}

impl RUJurisdictionPlugin {
    /// 主验证入口
    pub fn validate(&self, tx: &RUTxContext) -> ValidationResult {
        // 1. KYC 验证
        if !Self::check_kyc_level(tx) {
            return ValidationResult::Rejected {
                reason: format!("RU_KYC: Minimum level Institutional required per {}",
                    "CBR/Rosfinmonitoring (Central Bank of Russia / Federal Financial Monitoring Service)"),
                jurisdiction: JURISDICTION_CODE.to_string(),
            };
        }

        // 2. AML 阈值检查
        if !Self::check_aml_threshold(tx) {
            return ValidationResult::Rejected {
                reason: format!("RU_AML: Transactions above {} USD require reporting to {}",
                    AML_THRESHOLD_USD, "CBR/Rosfinmonitoring (Central Bank of Russia / Federal Financial Monitoring Service)"),
                jurisdiction: JURISDICTION_CODE.to_string(),
            };
        }

        // 3. 制裁名单检查
        if !Self::check_sanctions(tx) {
            return ValidationResult::Rejected {
                reason: "RU_SANCTIONS: Transaction parties are on sanctions list".to_string(),
                jurisdiction: JURISDICTION_CODE.to_string(),
            };
        }

        // 4. 辖区特定规则
        if !Self::check_jurisdiction_rules(tx) {
            return ValidationResult::Rejected {
                reason: "RU_RULES: Jurisdiction-specific rule violation".to_string(),
                jurisdiction: JURISDICTION_CODE.to_string(),
            };
        }

        // 验证通过，出具 CR（参与即是共识）
        ValidationResult::Approved {
            jurisdiction: JURISDICTION_CODE.to_string(),
            constitutional_receipt: Self::issue_constitutional_receipt(tx),
        }
    }

    pub fn jurisdiction_code(&self) -> &str {
        JURISDICTION_CODE
    }

    pub fn regulatory_authority(&self) -> &str {
        "CBR/Rosfinmonitoring (Central Bank of Russia / Federal Financial Monitoring Service)"
    }
}

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

    fn make_tx(kyc: KycLevel, amount: f64, anonymous: bool, aml: bool) -> RUTxContext {
        RUTxContext {
            tx_hash: "test_hash_001".to_string(),
            from: [0u8; 32],
            to: [1u8; 32],
            amount_usd: amount,
            asset_type: "RWA_REAL_ESTATE".to_string(),
            kyc_level: kyc,
            aml_reported: aml,
            is_anonymous: anonymous,
            is_cross_border: false,
            sanctions_cleared: true,

        }
    }

    #[test]
    fn test_ru_valid_transaction() {
        let plugin = RUJurisdictionPlugin::new();
        let tx = make_tx(KycLevel::Institutional, 1000.0, false, false);
        assert!(matches!(plugin.validate(&tx), ValidationResult::Approved { .. }));
    }

    #[test]
    fn test_ru_kyc_insufficient() {
        let plugin = RUJurisdictionPlugin::new();
        let tx = make_tx(KycLevel::None, 1000.0, false, false);
        assert!(matches!(plugin.validate(&tx), ValidationResult::Rejected { .. }));
    }

    #[test]
    fn test_ru_aml_threshold_exceeded_unreported() {
        let plugin = RUJurisdictionPlugin::new();
        let tx = make_tx(KycLevel::Institutional, 6000.0, false, false);
        assert!(matches!(plugin.validate(&tx), ValidationResult::Rejected { .. }));
    }

    #[test]
    fn test_ru_aml_threshold_reported() {
        let plugin = RUJurisdictionPlugin::new();
        let tx = make_tx(KycLevel::Institutional, 6000.0, false, true);
        assert!(matches!(plugin.validate(&tx), ValidationResult::Approved { .. }));
    }

    #[test]
    fn test_ru_anonymous_rejected() {
        let plugin = RUJurisdictionPlugin::new();
        let tx = make_tx(KycLevel::Institutional, 100.0, true, false);
        assert!(matches!(plugin.validate(&tx), ValidationResult::Rejected { .. }));
    }

    #[test]
    fn test_ru_jurisdiction_code() {
        let plugin = RUJurisdictionPlugin::new();
        assert_eq!(plugin.jurisdiction_code(), "RU");
    }

    #[test]
    fn test_ru_regulatory_authority() {
        let plugin = RUJurisdictionPlugin::new();
        assert!(!plugin.regulatory_authority().is_empty());
    }
}