// NAC 香港辖区宪法规则验证插件（HK_PLUGIN）
// 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
// 此插件由CEE加载，对每笔交易独立出具宪法收据（CR）
// 参与即是共识：HK辖区节点加载此插件参与出块，即代表对香港辖区宪法规则的背书

use serde::{Deserialize, Serialize};

/// 香港辖区交易上下文
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct HKTxContext {
    pub from: [u8; 32],
    pub to: [u8; 32],
    pub amount: u128,
    pub asset_type: String,
    pub kyc_level: KycLevel,
    pub aml_cleared: bool,
    pub regulatory_approved: 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,
}

/// 宪法收据（CR）— 参与即是共识，节点出具CR即代表对规则的背书
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct ConstitutionalReceipt {
    pub jurisdiction: String,
    pub tx_hash: Vec<u8>,
    pub rules_passed: Vec<String>,
    pub timestamp: u64,
    pub plugin_version: String,
}

/// 宪法规则违反错误
#[derive(Debug, Clone)]
pub struct ConstitutionalViolation {
    pub rule_id: String,
    pub reason: String,
}

/// 香港辖区宪法规则验证器
pub struct HKConstitutionalValidator;

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

    /// 验证交易是否符合香港辖区宪法规则
    /// CBPP：参与即是共识，节点调用此函数即代表对规则的背书
    pub fn validate(&self, ctx: &HKTxContext) -> Result<ConstitutionalReceipt, ConstitutionalViolation> {
        let mut rules_passed = Vec::new();

        // 继承GLOBAL规则验证
        self.validate_global_aml(ctx, &mut rules_passed)?;
        self.validate_global_kyc(ctx, &mut rules_passed)?;
        self.validate_global_sanctions(ctx, &mut rules_passed)?;

        // 香港辖区特定规则验证
        self.validate_hk_hk_sfo_001(ctx, &mut rules_passed)?;
        self.validate_hk_hk_vasp_001(ctx, &mut rules_passed)?;

        Ok(ConstitutionalReceipt {
            jurisdiction: "HK".to_string(),
            tx_hash: vec![],
            rules_passed,
            timestamp: 0,
            plugin_version: "v1.0".to_string(),
        })
    }

    fn validate_global_aml(&self, ctx: &HKTxContext, passed: &mut Vec<String>)
        -> Result<(), ConstitutionalViolation> {
        if !ctx.aml_cleared {
            return Err(ConstitutionalViolation {
                rule_id: "GLOBAL_AML_001".to_string(),
                reason: "AML检查未通过".to_string(),
            });
        }
        passed.push("GLOBAL_AML_001".to_string());
        Ok(())
    }

    fn validate_global_kyc(&self, ctx: &HKTxContext, passed: &mut Vec<String>)
        -> Result<(), ConstitutionalViolation> {
        if ctx.kyc_level == KycLevel::None {
            return Err(ConstitutionalViolation {
                rule_id: "GLOBAL_KYC_001".to_string(),
                reason: "未完成KYC验证".to_string(),
            });
        }
        passed.push("GLOBAL_KYC_001".to_string());
        Ok(())
    }

    fn validate_global_sanctions(&self, ctx: &HKTxContext, passed: &mut Vec<String>)
        -> Result<(), ConstitutionalViolation> {
        if !ctx.sanctions_cleared {
            return Err(ConstitutionalViolation {
                rule_id: "GLOBAL_SANCTIONS".to_string(),
                reason: "制裁名单检查未通过".to_string(),
            });
        }
        passed.push("GLOBAL_SANCTIONS".to_string());
        Ok(())
    }

    fn validate_hk_hk_sfo_001(&self, ctx: &HKTxContext, passed: &mut Vec<String>)
        -> Result<(), ConstitutionalViolation> {
        if ctx.kyc_level == KycLevel::Basic {
            return Err(ConstitutionalViolation {
                rule_id: "HK_SFO_001".to_string(),
                reason: "香港SFO要求须为专业投资者（资产800万港元以上）".to_string(),
            });
        }
        passed.push("HK_SFO_001".to_string());
        Ok(())
    }

    fn validate_hk_hk_vasp_001(&self, ctx: &HKTxContext, passed: &mut Vec<String>)
        -> Result<(), ConstitutionalViolation> {
        if !ctx.regulatory_approved {
            return Err(ConstitutionalViolation {
                rule_id: "HK_VASP_001".to_string(),
                reason: "须持有SFC颁发的VASP牌照".to_string(),
            });
        }
        passed.push("HK_VASP_001".to_string());
        Ok(())
    }
}

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

    fn make_valid_ctx() -> HKTxContext {
        HKTxContext {
            from: [1u8; 32],
            to: [2u8; 32],
            amount: 1000,
            asset_type: "REAL_ESTATE".to_string(),
            kyc_level: KycLevel::Enhanced,
            aml_cleared: true,
            regulatory_approved: true,
            is_cross_border: false,
            sanctions_cleared: true,
        }
    }

    #[test]
    fn test_valid_transaction() {
        let validator = HKConstitutionalValidator::new();
        let ctx = make_valid_ctx();
        let result = validator.validate(&ctx);
        assert!(result.is_ok(), "合规交易应通过验证");
        let cr = result.unwrap();
        assert_eq!(cr.jurisdiction, "HK");
        assert!(!cr.rules_passed.is_empty());
    }

    #[test]
    fn test_aml_violation() {
        let validator = HKConstitutionalValidator::new();
        let mut ctx = make_valid_ctx();
        ctx.aml_cleared = false;
        let result = validator.validate(&ctx);
        assert!(result.is_err());
        assert_eq!(result.unwrap_err().rule_id, "GLOBAL_AML_001");
    }

    #[test]
    fn test_kyc_violation() {
        let validator = HKConstitutionalValidator::new();
        let mut ctx = make_valid_ctx();
        ctx.kyc_level = KycLevel::None;
        let result = validator.validate(&ctx);
        assert!(result.is_err());
        assert_eq!(result.unwrap_err().rule_id, "GLOBAL_KYC_001");
    }

    #[test]
    fn test_sanctions_violation() {
        let validator = HKConstitutionalValidator::new();
        let mut ctx = make_valid_ctx();
        ctx.sanctions_cleared = false;
        let result = validator.validate(&ctx);
        assert!(result.is_err());
        assert_eq!(result.unwrap_err().rule_id, "GLOBAL_SANCTIONS");
    }

    #[test]
    fn test_regulatory_approval_required() {
        let validator = HKConstitutionalValidator::new();
        let mut ctx = make_valid_ctx();
        ctx.regulatory_approved = false;
        let result = validator.validate(&ctx);
        // 大多数辖区要求监管批准，此处验证是否有对应规则拦截
        // 具体规则ID因辖区而异
        let _ = result; // 不同辖区可能有不同的第一个失败规则
    }
}