// Charter Standard Library - XTZH 黄金储备模块
// Issue #61/#62: 黄金永续合约储备系统
// 版本: 1.0

/// 交易所信息
public struct ExchangeInfo {
    name: string,
    weight: uint64,       // 权重，定点数 1e4（10000 = 100%）
    max_exposure: uint64, // 最大敞口，定点数 1e4
    is_active: bool
}

/// 储备状态快照
public struct ReserveSnapshot {
    timestamp: uint64,
    total_notional: uint64,   // 合约名义总价值（XTZH 单位）
    xtzh_supply: uint64,      // XTZH 流通量
    coverage_ratio: uint64,   // 覆盖率，定点数 1e4（12500 = 125%）
    gold_price_usd: uint64,   // 黄金价格，定点数 1e2
    buffer_l1: uint64,        // L1 缓冲池余额
    buffer_l2: uint64         // L2 缓冲池余额
}

/// 赎回队列条目
public struct RedemptionEntry {
    requester: address,
    amount: uint64,
    request_epoch: uint64,
    max_wait_epoch: uint64    // 最长等待 30 天 = 30 纪元
}

/// 黄金储备法典核心合约
/// 宪法级约束：铸造必须同步建立 125% 黄金合约储备
contract XTZHGoldReserve {
    // 宪法级常量（不可通过治理修改，仅宪法修正案可变更）
    const MIN_COVERAGE_RATIO: uint64 = 12500;  // 125.00%
    const MAX_SINGLE_EXCHANGE: uint64 = 3000;  // 30.00%
    const REBALANCE_THRESHOLD: uint64 = 200;   // 2.00% 偏离触发再平衡
    const EMERGENCY_THRESHOLD: uint64 = 11000; // 110.00% 触发紧急补仓
    const MAX_REDEMPTION_WAIT: uint64 = 30;    // 最长等待 30 纪元（天）
    const BUFFER_L1_TARGET: uint64 = 500;      // L1 缓冲目标 5.00%
    const BUFFER_L2_TARGET: uint64 = 1000;     // L2 缓冲目标 10.00%

    // 状态变量
    state reserve: ReserveSnapshot;
    state exchanges: [ExchangeInfo; 10];
    state exchange_count: uint64;
    state is_frozen: bool;
    state redemption_queue: [RedemptionEntry; 1000];
    state queue_head: uint64;
    state queue_tail: uint64;

    /// 查询当前储备状态
    @view
    pub fn get_reserve() -> ReserveSnapshot {
        return self.reserve;
    }

    /// 查询覆盖率是否满足宪法要求
    @view
    pub fn is_compliant() -> bool {
        return self.reserve.coverage_ratio >= MIN_COVERAGE_RATIO;
    }

    /// 查询赎回队列长度
    @view
    pub fn queue_length() -> uint64 {
        return self.queue_tail - self.queue_head;
    }

    /// 铸造 XTZH（必须同步建立 125% 黄金合约储备）
    @payable
    pub fn mint(amount: uint64, cr: ConstitutionalReceipt) {
        require(xtzh::verify_rate_receipt(cr), "无效的宪法收据");
        require(!self.is_frozen, "储备系统已冻结");
        require(amount > 0, "铸造量必须大于 0");

        // 获取当前汇率
        let rate = xtzh::get_rate();

        // 验证储备充足（铸造后覆盖率仍需 >= 125%）
        let new_supply = self.reserve.xtzh_supply + amount;
        let required_notional = new_supply * MIN_COVERAGE_RATIO / 10000;
        require(
            self.reserve.total_notional >= required_notional,
            "储备不足：黄金合约覆盖率低于 125%"
        );

        // 更新状态
        self.reserve.xtzh_supply = new_supply;
        self.reserve.coverage_ratio =
            self.reserve.total_notional * 10000 / new_supply;
        self.reserve.timestamp = rate.timestamp;

        emit XTZHRateUpdated {
            epoch: rate.epoch,
            rate_sdr: rate.rate_sdr,
            rate_usd: rate.rate_usd,
            updater: msg.sender
        };
    }

    /// 提交赎回请求（最长等待 30 天，每日公示队列）
    pub fn request_redeem(amount: uint64, cr: ConstitutionalReceipt) {
        require(xtzh::verify_rate_receipt(cr), "无效的宪法收据");
        require(!self.is_frozen, "储备系统已冻结");
        require(amount > 0, "赎回量必须大于 0");
        require(amount <= self.reserve.xtzh_supply, "赎回量超过流通量");

        let rate = xtzh::get_rate();

        // 加入赎回队列
        self.redemption_queue[self.queue_tail] = RedemptionEntry {
            requester: msg.sender,
            amount: amount,
            request_epoch: rate.epoch,
            max_wait_epoch: rate.epoch + MAX_REDEMPTION_WAIT
        };
        self.queue_tail = self.queue_tail + 1;
    }

    /// 执行赎回（系统自动调用，每纪元处理队列）
    @system
    pub fn process_redemptions(cr: ConstitutionalReceipt) {
        require(xtzh::verify_rate_receipt(cr), "无效的宪法收据");
        let rate = xtzh::get_rate();

        // 处理到期赎回请求
        while self.queue_head < self.queue_tail {
            let entry = self.redemption_queue[self.queue_head];
            if entry.request_epoch + MAX_REDEMPTION_WAIT <= rate.epoch {
                // 强制执行（超时不可拒绝）
                self.reserve.xtzh_supply = self.reserve.xtzh_supply - entry.amount;
                if self.reserve.xtzh_supply > 0 {
                    self.reserve.coverage_ratio =
                        self.reserve.total_notional * 10000 / self.reserve.xtzh_supply;
                }
                self.queue_head = self.queue_head + 1;
            } else {
                break;
            }
        }
    }

    /// 触发再平衡（当单交易所敞口超过 30%）
    @system
    pub fn rebalance(cr: ConstitutionalReceipt) {
        require(xtzh::verify_rate_receipt(cr), "无效的宪法收据");
        require(!self.is_frozen, "储备系统已冻结");
        // 再平衡逻辑由 NVM 系统调用执行
        // 检查每个交易所的敞口比例
        let i: uint64 = 0;
        while i < self.exchange_count {
            let exchange = self.exchanges[i];
            if exchange.is_active && exchange.weight > MAX_SINGLE_EXCHANGE {
                // 触发再平衡信号（NVM 系统处理实际转移）
                emit XTZHRateDeviation {
                    epoch: 0,
                    deviation_bps: exchange.weight - MAX_SINGLE_EXCHANGE,
                    direction: "exchange_overweight"
                };
            }
            i = i + 1;
        }
    }

    /// 紧急冻结（需宪法法院 7/9 签署）
    @system
    pub fn emergency_freeze(cr: ConstitutionalReceipt) {
        require(xtzh::verify_rate_receipt(cr), "无效的宪法收据");
        self.is_frozen = true;
        let _ = xtzh::emergency_freeze(cr);
    }

    /// 缓冲池补充（当缓冲池低于目标 50% 时触发）
    @system
    pub fn replenish_buffer(cr: ConstitutionalReceipt) {
        require(xtzh::verify_rate_receipt(cr), "无效的宪法收据");
        let target_l1 = self.reserve.xtzh_supply * BUFFER_L1_TARGET / 10000;
        let target_l2 = self.reserve.xtzh_supply * BUFFER_L2_TARGET / 10000;

        // 当缓冲池低于目标 50% 时，将铸造费的 30% 注入
        if self.reserve.buffer_l1 < target_l1 / 2 {
            // NVM 系统自动将铸造费 30% 注入 L1 缓冲
        }
        if self.reserve.buffer_l2 < target_l2 / 2 {
            // NVM 系统自动将铸造费 30% 注入 L2 缓冲
        }
    }
}