/// XTZH黄金永续合约储备法典 v1.0
/// Issue #62 | NAC公链宪法级合约
/// 法典编号: XTZH-CODEX-001
/// 生效纪元: 创世纪元

module xtzh_gold_reserve_codex
  version "1.0.0"
  description "XTZH黄金永续合约储备法典 - 宪法级约束"

/// ============================================================
/// 第一章：储备资产定义
/// ============================================================

/// 黄金储备单位（1 GoldUnit = 1 克纯金，精度 1e6）
const GOLD_UNIT_PRECISION: u64 = 1_000_000
const GOLD_PURITY_STANDARD: u64 = 9999  /// 9999 = 99.99% 纯度
const MIN_RESERVE_RATIO: u64 = 4000     /// 40.00% 最低储备率（定点数 1e4）
const MAX_SINGLE_REDEMPTION: u64 = 1_000_000_000  /// 单次最大赎回量（XTZH）

/// 储备资产类别
asset GoldReserveAsset {
  gnacs: "GOLD-RESERVE-V1"
  
  /// 黄金储备总量（克，精度 1e6）
  total_gold_grams: u64
  /// XTZH 流通总量
  total_xtzh_supply: u64
  /// 当前储备率（定点数 1e4）
  current_reserve_ratio: u64
  /// 黄金保管机构列表（最多 7 家，分散风险）
  custodians: Vec<Address>
  /// 最后审计时间戳
  last_audit_timestamp: u64
  /// 审计机构签名哈希（SHA3-384）
  audit_signature: Hash
  
  requires current_reserve_ratio >= MIN_RESERVE_RATIO
    "储备率不得低于40%"
  requires custodians.len() >= 3
    "至少需要3家独立保管机构"
  requires custodians.len() <= 7
    "保管机构不得超过7家"
}

/// ============================================================
/// 第二章：SDR锚定机制
/// ============================================================

/// SDR 货币篮子权重（定点数 1e6，合计 1_000_000）
const SDR_USD_WEIGHT: u64 = 437_000   /// 43.70% 美元
const SDR_EUR_WEIGHT: u64 = 289_000   /// 28.90% 欧元
const SDR_CNY_WEIGHT: u64 = 108_000   /// 10.80% 人民币
const SDR_JPY_WEIGHT: u64 = 77_000    /// 7.70% 日元
const SDR_GBP_WEIGHT: u64 = 89_000    /// 8.90% 英镑

/// SDR 汇率状态（由 XTZH 汇率预言机更新）
asset SdrRateState {
  gnacs: "SDR-RATE-V1"
  
  /// 各货币兑 XTZH 汇率（定点数 1e8）
  usd_rate: u64
  eur_rate: u64
  cny_rate: u64
  jpy_rate: u64
  gbp_rate: u64
  /// 综合 SDR 汇率（定点数 1e8）
  composite_sdr_rate: u64
  /// 汇率更新时间戳
  updated_at: u64
  /// 预言机签名
  oracle_signature: Hash
  
  requires updated_at > 0 "汇率必须已初始化"
}

/// 计算综合 SDR 汇率
fn calculate_sdr_rate(
  usd_rate: u64,
  eur_rate: u64,
  cny_rate: u64,
  jpy_rate: u64,
  gbp_rate: u64
) -> u64
  requires usd_rate > 0 "USD汇率不能为零"
  requires eur_rate > 0 "EUR汇率不能为零"
  ensures result > 0 "SDR汇率必须为正"
{
  let weighted_sum: u64 = 
    (usd_rate * SDR_USD_WEIGHT / 1_000_000) +
    (eur_rate * SDR_EUR_WEIGHT / 1_000_000) +
    (cny_rate * SDR_CNY_WEIGHT / 1_000_000) +
    (jpy_rate * SDR_JPY_WEIGHT / 1_000_000) +
    (gbp_rate * SDR_GBP_WEIGHT / 1_000_000)
  return weighted_sum
}

/// ============================================================
/// 第三章：铸造与销毁
/// ============================================================

/// XTZH 铸造申请（需宪法收据）
fn mint_xtzh(
  gold_grams: u64,
  recipient: Address,
  custodian: Address,
  audit_proof: Hash
) -> u64
  require_cr "XTZH-MINT-AUTH"
  requires gold_grams > 0 "铸造黄金量不能为零"
  requires custodian != Address::zero() "保管机构地址不能为空"
  ensures result > 0 "铸造量必须为正"
{
  /// 根据黄金量和当前 SDR 汇率计算 XTZH 铸造量
  let xtzh_amount: u64 = gold_grams * GOLD_UNIT_PRECISION
  emit MintEvent {
    gold_grams: gold_grams,
    xtzh_amount: xtzh_amount,
    recipient: recipient,
    custodian: custodian,
    audit_proof: audit_proof
  }
  return xtzh_amount
}

/// XTZH 销毁（赎回黄金）
fn burn_xtzh(
  xtzh_amount: u64,
  redeemer: Address,
  preferred_custodian: Address
) -> u64
  require_cr "XTZH-BURN-AUTH"
  requires xtzh_amount > 0 "销毁量不能为零"
  requires xtzh_amount <= MAX_SINGLE_REDEMPTION "单次赎回超过上限"
  ensures result > 0 "赎回黄金量必须为正"
{
  let gold_grams: u64 = xtzh_amount / GOLD_UNIT_PRECISION
  emit BurnEvent {
    xtzh_amount: xtzh_amount,
    gold_grams: gold_grams,
    redeemer: redeemer,
    custodian: preferred_custodian
  }
  return gold_grams
}

/// ============================================================
/// 第四章：储备审计
/// ============================================================

/// 储备审计记录
asset AuditRecord {
  gnacs: "AUDIT-RECORD-V1"
  
  audit_id: Hash
  auditor: Address
  /// 审计时间戳
  timestamp: u64
  /// 实际黄金储量（克）
  actual_gold_grams: u64
  /// XTZH 流通量
  xtzh_supply: u64
  /// 储备率（定点数 1e4）
  reserve_ratio: u64
  /// 审计结论：true=合格
  is_compliant: bool
  /// 审计签名
  signature: Hash
  
  requires reserve_ratio >= MIN_RESERVE_RATIO
    "审计储备率不得低于40%"
}

/// 提交审计结果
fn submit_audit(
  actual_gold_grams: u64,
  xtzh_supply: u64,
  auditor: Address,
  signature: Hash
) -> bool
  require_cr "AUDIT-SUBMIT-AUTH"
  requires actual_gold_grams > 0 "黄金储量不能为零"
  requires xtzh_supply > 0 "XTZH流通量不能为零"
{
  let reserve_ratio: u64 = actual_gold_grams * 10000 / xtzh_supply
  let is_compliant: bool = reserve_ratio >= MIN_RESERVE_RATIO
  
  if !is_compliant {
    emit ReserveAlertEvent {
      actual_ratio: reserve_ratio,
      required_ratio: MIN_RESERVE_RATIO,
      deficit: MIN_RESERVE_RATIO - reserve_ratio
    }
  }
  
  emit AuditCompletedEvent {
    auditor: auditor,
    actual_gold_grams: actual_gold_grams,
    xtzh_supply: xtzh_supply,
    reserve_ratio: reserve_ratio,
    is_compliant: is_compliant
  }
  
  return is_compliant
}

/// ============================================================
/// 第五章：紧急条款
/// ============================================================

/// 储备危机处理（储备率低于 30% 时触发）
const EMERGENCY_THRESHOLD: u64 = 3000  /// 30.00%

fn emergency_freeze(
  current_ratio: u64,
  authority: Address
) -> bool
  require_cr "EMERGENCY-AUTHORITY"
  requires current_ratio < EMERGENCY_THRESHOLD
    "储备率未达到紧急阈值，不能触发冻结"
{
  emit EmergencyFreezeEvent {
    triggered_by: authority,
    current_ratio: current_ratio,
    threshold: EMERGENCY_THRESHOLD
  }
  return true
}

/// ============================================================
/// 事件定义
/// ============================================================

event MintEvent {
  gold_grams: u64
  xtzh_amount: u64
  recipient: Address
  custodian: Address
  audit_proof: Hash
}

event BurnEvent {
  xtzh_amount: u64
  gold_grams: u64
  redeemer: Address
  custodian: Address
}

event AuditCompletedEvent {
  auditor: Address
  actual_gold_grams: u64
  xtzh_supply: u64
  reserve_ratio: u64
  is_compliant: bool
}

event ReserveAlertEvent {
  actual_ratio: u64
  required_ratio: u64
  deficit: u64
}

event EmergencyFreezeEvent {
  triggered_by: Address
  current_ratio: u64
  threshold: u64
}