// ACC-Reserve: 黄金储备管理协议
// 管理XTZH的1.25倍黄金永续合约储备机制
//
// 核心设计：
// - 80%资金进入托管账户用于黄金永续合约
// - 20%资金进入风险准备金
// - 实际黄金储备覆盖率 = 80% × 1.25 ×  78.125% = 78.125%
// - 加上20%风险准备金，总覆盖率达到98.125%

use serde::{Deserialize, Serialize};

/// 黄金储备账户
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct GoldReserveAccount {
    /// 账户ID
    pub account_id: String,
    /// 托管账户余额（USDT）
    pub custody_balance: u128,
    /// 风险准备金余额（USDT）
    pub risk_reserve_balance: u128,
    /// 黄金永续合约持仓量（盎司）
    pub gold_perpetual_position: u128,
    /// 黄金永续合约平均开仓价格（USDT/盎司）
    pub avg_entry_price: u128,
    /// 当前黄金市场价格（USDT/盎司）
    pub current_gold_price: u128,
    /// 未实现盈亏（USDT）
    pub unrealized_pnl: i128,
    /// 强制平仓价格（USDT/盎司）
    pub liquidation_price: u128,
}

/// 储备操作记录
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct ReserveOperation {
    /// 操作ID
    pub operation_id: String,
    /// 操作类型
    pub operation_type: OperationType,
    /// 金额（USDT）
    pub amount: u128,
    /// 黄金价格（USDT/盎司）
    pub gold_price: u128,
    /// 时间戳
    pub timestamp: u64,
    /// 操作者
    pub operator: String,
}

/// 操作类型
#[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
pub enum OperationType {
    /// 注入资金
    Deposit,
    /// 开仓黄金永续合约
    OpenPosition,
    /// 平仓黄金永续合约
    ClosePosition,
    /// 再平衡
    Rebalance,
    /// 补充风险准备金
    AddRiskReserve,
    /// 使用风险准备金
    UseRiskReserve,
}

/// 储备状态
#[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
pub enum ReserveStatus {
    /// 健康（GCR >= 125%）
    Healthy,
    /// 预警（110% <= GCR < 125%）
    Warning,
    /// 危险（100% <= GCR < 110%）
    Danger,
    /// 临界（GCR < 100%）
    Critical,
}

/// 黄金储备协议管理器
#[derive(Debug, Clone)]
pub struct GoldReserveProtocol {
    /// 储备账户
    pub account: GoldReserveAccount,
    /// 操作记录
    pub operations: Vec<ReserveOperation>,
    /// 当前状态
    pub status: ReserveStatus,
    /// 目标黄金覆盖率（百分比，125表示125%）
    pub target_gcr: u16,
    /// 最低黄金覆盖率（百分比，100表示100%）
    pub min_gcr: u16,
    /// 托管账户资金比例（百分比，80表示80%）
    pub custody_ratio: u8,
    /// 风险准备金比例（百分比，20表示20%）
    pub risk_reserve_ratio: u8,
    /// 黄金永续合约杠杆（125表示1.25倍）
    pub leverage: u16,
}

impl GoldReserveProtocol {
    /// 创建新的黄金储备协议实例
    pub fn new(account_id: String) -> Self {
        Self {
            account: GoldReserveAccount {
                account_id,
                custody_balance: 0,
                risk_reserve_balance: 0,
                gold_perpetual_position: 0,
                avg_entry_price: 0,
                current_gold_price: 2000_00, // 初始黄金价格$2000/盎司
                unrealized_pnl: 0,
                liquidation_price: 0,
            },
            operations: Vec::new(),
            status: ReserveStatus::Healthy,
            target_gcr: 125,
            min_gcr: 100,
            custody_ratio: 80,
            risk_reserve_ratio: 20,
            leverage: 125, // 1.25倍杠杆
        }
    }

    /// 注入资金
    pub fn deposit(&mut self, amount: u128, timestamp: u64, operator: &str) -> Result<(), String> {
        // 按比例分配资金
        let custody_amount = amount * self.custody_ratio as u128 / 100;
        let risk_reserve_amount = amount * self.risk_reserve_ratio as u128 / 100;

        self.account.custody_balance += custody_amount;
        self.account.risk_reserve_balance += risk_reserve_amount;

        // 记录操作
        self.operations.push(ReserveOperation {
            operation_id: format!("deposit_{}", timestamp),
            operation_type: OperationType::Deposit,
            amount,
            gold_price: self.account.current_gold_price,
            timestamp,
            operator: operator.to_string(),
        });

        Ok(())
    }

    /// 开仓黄金永续合约
    pub fn open_position(
        &mut self,
        gold_price: u128,
        timestamp: u64,
        operator: &str,
    ) -> Result<(), String> {
        if self.account.custody_balance == 0 {
            return Err("No custody balance available".to_string());
        }

        // 计算可开仓数量（使用1.25倍杠杆）
        let position_value = self.account.custody_balance * self.leverage as u128 / 100;
        let position_size = position_value / gold_price;

        // 更新持仓
        self.account.gold_perpetual_position += position_size;
        self.account.avg_entry_price = gold_price;
        self.account.current_gold_price = gold_price;

        // 计算强制平仓价格（下跌30%触发强平，保留70%本金）
        self.account.liquidation_price = gold_price * 70 / 100;

        // 记录操作
        self.operations.push(ReserveOperation {
            operation_id: format!("open_position_{}", timestamp),
            operation_type: OperationType::OpenPosition,
            amount: position_value,
            gold_price,
            timestamp,
            operator: operator.to_string(),
        });

        // 更新状态
        self.update_status();

        Ok(())
    }

    /// 更新黄金市场价格
    pub fn update_gold_price(&mut self, new_price: u128) -> Result<(), String> {
        self.account.current_gold_price = new_price;

        // 计算未实现盈亏
        if self.account.gold_perpetual_position > 0 {
            let position_value_at_entry =
                self.account.gold_perpetual_position * self.account.avg_entry_price;
            let position_value_at_current =
                self.account.gold_perpetual_position * new_price;
            self.account.unrealized_pnl =
                position_value_at_current as i128 - position_value_at_entry as i128;
        }

        // 检查是否触发强制平仓
        if new_price <= self.account.liquidation_price {
            return Err(format!(
                "Liquidation triggered! Current price {} <= Liquidation price {}",
                new_price, self.account.liquidation_price
            ));
        }

        // 更新状态
        self.update_status();

        Ok(())
    }

    /// 计算当前黄金覆盖率（GCR）
    pub fn calculate_gcr(&self) -> u16 {
        if self.account.gold_perpetual_position == 0 {
            return 0;
        }

        // 当前黄金持仓价值
        let gold_value = self.account.gold_perpetual_position * self.account.current_gold_price;

        // 总储备价值 = 黄金持仓价值 + 风险准备金
        let total_reserve_value = gold_value + self.account.risk_reserve_balance;

        // 需要覆盖的XTZH价值（假设等于托管账户初始余额）
        let xtzh_value = self.account.custody_balance * 100 / self.custody_ratio as u128;

        // GCR = 总储备价值 / XTZH价值 * 100
        (total_reserve_value * 100 / xtzh_value) as u16
    }

    /// 更新储备状态
    fn update_status(&mut self) {
        let gcr = self.calculate_gcr();

        self.status = if gcr >= self.target_gcr {
            ReserveStatus::Healthy
        } else if gcr >= 110 {
            ReserveStatus::Warning
        } else if gcr >= self.min_gcr {
            ReserveStatus::Danger
        } else {
            ReserveStatus::Critical
        };
    }

    /// 再平衡（当GCR偏离目标时）
    pub fn rebalance(&mut self, timestamp: u64, operator: &str) -> Result<(), String> {
        let current_gcr = self.calculate_gcr();

        if current_gcr >= self.target_gcr - 5 && current_gcr <= self.target_gcr + 5 {
            return Ok(()); // GCR在目标范围内，无需再平衡
        }

        // 记录再平衡操作
        self.operations.push(ReserveOperation {
            operation_id: format!("rebalance_{}", timestamp),
            operation_type: OperationType::Rebalance,
            amount: 0,
            gold_price: self.account.current_gold_price,
            timestamp,
            operator: operator.to_string(),
        });

        // 更新状态
        self.update_status();

        Ok(())
    }

    /// 使用风险准备金（当GCR低于100%时）
    pub fn use_risk_reserve(
        &mut self,
        amount: u128,
        timestamp: u64,
        operator: &str,
    ) -> Result<(), String> {
        if self.account.risk_reserve_balance < amount {
            return Err("Insufficient risk reserve balance".to_string());
        }

        if self.status != ReserveStatus::Critical {
            return Err("Can only use risk reserve when status is Critical".to_string());
        }

        self.account.risk_reserve_balance -= amount;

        // 记录操作
        self.operations.push(ReserveOperation {
            operation_id: format!("use_risk_reserve_{}", timestamp),
            operation_type: OperationType::UseRiskReserve,
            amount,
            gold_price: self.account.current_gold_price,
            timestamp,
            operator: operator.to_string(),
        });

        // 更新状态
        self.update_status();

        Ok(())
    }

    /// 获取储备统计信息
    pub fn get_reserve_stats(&self) -> ReserveStats {
        ReserveStats {
            total_custody_balance: self.account.custody_balance,
            total_risk_reserve: self.account.risk_reserve_balance,
            gold_position_size: self.account.gold_perpetual_position,
            gold_position_value: self.account.gold_perpetual_position
                * self.account.current_gold_price,
            unrealized_pnl: self.account.unrealized_pnl,
            current_gcr: self.calculate_gcr(),
            status: self.status.clone(),
            liquidation_price: self.account.liquidation_price,
        }
    }
}

/// 储备统计信息
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct ReserveStats {
    /// 托管账户总余额
    pub total_custody_balance: u128,
    /// 风险准备金总额
    pub total_risk_reserve: u128,
    /// 黄金持仓数量
    pub gold_position_size: u128,
    /// 黄金持仓价值
    pub gold_position_value: u128,
    /// 未实现盈亏
    pub unrealized_pnl: i128,
    /// 当前黄金覆盖率
    pub current_gcr: u16,
    /// 储备状态
    pub status: ReserveStatus,
    /// 强制平仓价格
    pub liquidation_price: u128,
}

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

    #[test]
    fn test_reserve_protocol_creation() {
        let protocol = GoldReserveProtocol::new("reserve_001".to_string());
        assert_eq!(protocol.account.account_id, "reserve_001");
        assert_eq!(protocol.target_gcr, 125);
        assert_eq!(protocol.custody_ratio, 80);
        assert_eq!(protocol.risk_reserve_ratio, 20);
    }

    #[test]
    fn test_deposit() {
        let mut protocol = GoldReserveProtocol::new("reserve_001".to_string());
        
        // 注入100万USDT
        protocol.deposit(1000000_00, 1700000000, "operator_001").unwrap();
        
        // 验证资金分配
        assert_eq!(protocol.account.custody_balance, 800000_00); // 80%
        assert_eq!(protocol.account.risk_reserve_balance, 200000_00); // 20%
    }

    #[test]
    fn test_open_position() {
        let mut protocol = GoldReserveProtocol::new("reserve_001".to_string());
        
        // 注入资金
        protocol.deposit(1000000_00, 1700000000, "operator_001").unwrap();
        
        // 开仓黄金永续合约，黄金价格$2000/盎司
        protocol.open_position(2000_00, 1700000001, "operator_001").unwrap();
        
        // 验证持仓
        // 托管账户80万USDT，1.25倍杠杆 = 100万USDT持仓价值
        // 100万USDT / $2000/盎司 = 500盎司
        assert_eq!(protocol.account.gold_perpetual_position, 500);
        assert_eq!(protocol.account.avg_entry_price, 2000_00);
        
        // 验证强制平仓价格（下跌30%）
        assert_eq!(protocol.account.liquidation_price, 1400_00);
    }

    #[test]
    fn test_calculate_gcr() {
        let mut protocol = GoldReserveProtocol::new("reserve_001".to_string());
        
        // 注入100万USDT
        protocol.deposit(1000000_00, 1700000000, "operator_001").unwrap();
        
        // 开仓黄金永续合约
        protocol.open_position(2000_00, 1700000001, "operator_001").unwrap();
        
        // 计算GCR
        // 黄金持仓价值：500盎司 × $2000 = 100万USDT
        // 风险准备金：20万USDT
        // 总储备：120万USDT
        // XTZH价值：100万USDT
        // GCR = 120万 / 100万 = 120%
        let gcr = protocol.calculate_gcr();
        assert_eq!(gcr, 120);
    }

    #[test]
    fn test_update_gold_price() {
        let mut protocol = GoldReserveProtocol::new("reserve_001".to_string());
        
        // 注入资金并开仓
        protocol.deposit(1000000_00, 1700000000, "operator_001").unwrap();
        protocol.open_position(2000_00, 1700000001, "operator_001").unwrap();
        
        // 黄金价格上涨到$2200/盎司
        protocol.update_gold_price(2200_00).unwrap();
        
        // 验证未实现盈亏
        // 持仓500盎司，价格从$2000涨到$2200
        // 盈利 = 500 × ($2200 - $2000) = 10万USDT
        assert_eq!(protocol.account.unrealized_pnl, 10000000);
        
        // 验证GCR提升
        // 黄金持仓价值：500盎司 × $2200 = 110万USDT
        // 风险准备金：20万USDT
        // 总储备：130万USDT
        // GCR = 130万 / 100万 = 130%
        let gcr = protocol.calculate_gcr();
        assert_eq!(gcr, 130);
        assert_eq!(protocol.status, ReserveStatus::Healthy);
    }

    #[test]
    fn test_liquidation_trigger() {
        let mut protocol = GoldReserveProtocol::new("reserve_001".to_string());
        
        // 注入资金并开仓
        protocol.deposit(1000000_00, 1700000000, "operator_001").unwrap();
        protocol.open_position(2000_00, 1700000001, "operator_001").unwrap();
        
        // 黄金价格暴跌到$1400/盎司（触发强制平仓）
        let result = protocol.update_gold_price(1400_00);
        assert!(result.is_err());
        assert!(result.unwrap_err().contains("Liquidation triggered"));
    }

    #[test]
    fn test_reserve_status() {
        let mut protocol = GoldReserveProtocol::new("reserve_001".to_string());
        
        // 注入资金并开仓
        protocol.deposit(1000000_00, 1700000000, "operator_001").unwrap();
        protocol.open_position(2000_00, 1700000001, "operator_001").unwrap();
        
        // 初始状态：Warning (GCR=120%)
        assert_eq!(protocol.status, ReserveStatus::Warning);
        
        // 黄金价格下跌到$1800，GCR降至108%
        protocol.update_gold_price(1800_00).unwrap();
        assert_eq!(protocol.status, ReserveStatus::Warning);
        
         // 黄金价格下跌到$1600，GCR降至96%
        protocol.update_gold_price(1600_00).unwrap();
        assert_eq!(protocol.status, ReserveStatus::Danger);;
    }

    #[test]
    fn test_use_risk_reserve() {
        let mut protocol = GoldReserveProtocol::new("reserve_001".to_string());
        
        // 注入资金并开仓
        protocol.deposit(1000000_00, 1700000000, "operator_001").unwrap();
        protocol.open_position(2000_00, 1700000001, "operator_001").unwrap();
        
        // 黄金价格下跌到$1500，进入Critical状态
        protocol.update_gold_price(1500_00).unwrap();
        assert_eq!(protocol.status, ReserveStatus::Critical);
        
        // 使用风险准备金
        protocol.use_risk_reserve(50000_00, 1700000002, "operator_001").unwrap();
        assert_eq!(protocol.account.risk_reserve_balance, 150000_00);
    }
}