# ACC-20C 兼容层协议 - 包装器核心合约
# 版本: 1.0
# 路径: charter-std/acc/acc20c_wrapper.ch

# --- 核心原则 ---
# 1. 状态容器: 本合约仅作为状态容器，不包含任何主动的合规检查逻辑。
# 2. 宪法驱动: 所有关键操作（wrap, unwrap, transfer）都假定已通过 CEE 的宪法审查，并获得了有效的宪法收据（CR）。
# 3. 原生实现: 完全使用 Charter 语言原生特性。

# --- 标准库与接口导入 ---
import std::types::{ Address, Uint256, Uint64, Bool, String }
import std::collections::{ mapping }
import std::events::{ emit }

# 导入 ACC-20 标准接口，用于与底层资产交互
# 注意：此处的 IAcc20 接口需要在 charter-std 中有明确定义
import charter-std::acc::i_acc20::{ IAcc20 }

# --- 合约状态定义 ---
state {
    # 包装后资产的详细信息
    # mapping: wrapper_token_id -> WrappedAsset
    wrapped_assets: mapping(Uint256 => WrappedAsset),

    # 从原始 ACC-20 资产到包装后资产的映射
    # mapping: acc20_contract_address -> (acc20_token_id -> wrapper_token_id)
    acc20_to_wrapper: mapping(Address => mapping(Uint256 => Uint256)),

    # 下一个可用的包装 Token ID
    next_wrapper_token_id: Uint256,

    # 合约管理员
    admin: Address,
}

# --- 数据结构定义 ---

# 包装资产的状态枚举
enum WrappedStatus {
    ACTIVE,     # 活跃，可交易
    FROZEN,     # 冻结，由管理员操作，不可交易
    PENDING_UNWRAP, # 等待解包中
}

# 包装后资产的核心数据结构
struct WrappedAsset {
    acc20_deed_address: Address,    # 原始 ACC-20 权证合约地址
    acc20_deed_token_id: Uint256, # 原始 ACC-20 权证代币 ID
    owner: Address,                 # 当前包装后资产的所有者
    status: WrappedStatus,          # 当前状态
    wrapped_at: Uint64,             # 包装时间戳
    unlock_timestamp: Uint64,       # 解包冷却期截止时间
}

# --- 事件定义 ---

# 资产被成功包装事件
event AssetWrapped {
    wrapper_token_id: Uint256,
    acc20_contract: Address,
    acc20_token_id: Uint256,
    owner: Address,
}

# 资产被成功解包事件
event AssetUnwrapped {
    wrapper_token_id: Uint256,
    owner: Address,
}

# 包装后资产所有权转移事件
event Transfer {
    from: Address,
    to: Address,
    wrapper_token_id: Uint256,
}

# --- 合约初始化 ---

fn constructor() {
    state.next_wrapper_token_id = 1;
    state.admin = msg.sender;
}

# --- 核心功能函数 ---

# @dev 包装一个 ACC-20 资产
# @param acc20_contract 原始 ACC-20 合约地址
# @param acc20_token_id 原始 ACC-20 代币 ID
# @returns 新铸造的包装资产 ID
fn wrap(acc20_contract: Address, acc20_token_id: Uint256) -> Uint256 {
    # 前置检查：确保该资产未被包装
    require(state.acc20_to_wrapper[acc20_contract][acc20_token_id] == 0, "Asset already wrapped");

    # [核心交互] 将底层 ACC-20 资产的所有权安全转移到本合约
    # 此操作依赖于 ACC-20 标准接口的 `safe_transfer_from`
    let acc20 = IAcc20(acc20_contract);
    acc20.safe_transfer_from(msg.sender, self.address, acc20_token_id);

    # 分配新的包装资产 ID
    let wrapper_id = state.next_wrapper_token_id;
    state.next_wrapper_token_id += 1;

    # 创建并存储新的包装资产记录
    let new_asset = WrappedAsset {
        acc20_deed_address: acc20_contract,
        acc20_deed_token_id: acc20_token_id,
        owner: msg.sender,
        status: WrappedStatus::ACTIVE,
        wrapped_at: block.timestamp,
        # 设置 24 小时解包冷却期
        unlock_timestamp: block.timestamp + 86400,
    };
    state.wrapped_assets[wrapper_id] = new_asset;

    # 记录双向映射关系
    state.acc20_to_wrapper[acc20_contract][acc20_token_id] = wrapper_id;

    # 触发事件
    emit AssetWrapped {
        wrapper_token_id: wrapper_id,
        acc20_contract: acc20_contract,
        acc20_token_id: acc20_token_id,
        owner: msg.sender,
    };

    return wrapper_id;
}

# @dev 解包一个已包装的资产
# @param wrapper_token_id 要解包的资产 ID
fn unwrap(wrapper_token_id: Uint256) {
    let asset = state.wrapped_assets[wrapper_token_id];

    # 前置检查
    require(asset.owner == msg.sender, "Caller is not the owner");
    require(asset.status == WrappedStatus::ACTIVE, "Asset is not active");
    require(block.timestamp >= asset.unlock_timestamp, "Unlock period has not passed");

    # [核心交互] 将底层 ACC-20 资产归还给所有者
    let acc20 = IAcc20(asset.acc20_deed_address);
    acc20.safe_transfer_from(self.address, msg.sender, asset.acc20_deed_token_id);

    # 清理存储
    delete state.acc20_to_wrapper[asset.acc20_deed_address][asset.acc20_deed_token_id];
    delete state.wrapped_assets[wrapper_token_id];

    # 触发事件
    emit AssetUnwrapped {
        wrapper_token_id: wrapper_token_id,
        owner: msg.sender,
    };
}

# @dev 转移一个包装后资产的所有权
# @param to 接收方地址
# @param wrapper_token_id 被转移的资产 ID
fn transfer(to: Address, wrapper_token_id: Uint256) {
    require(to != Address(0), "Transfer to zero address is not allowed");
    let asset = state.wrapped_assets[wrapper_token_id];

    # 前置检查
    require(asset.owner == msg.sender, "Caller is not the owner");
    require(asset.status == WrappedStatus::ACTIVE, "Asset is not active");

    # 更新所有者
    let from = asset.owner;
    state.wrapped_assets[wrapper_token_id].owner = to;

    # 触发事件
    emit Transfer {
        from: from,
        to: to,
        wrapper_token_id: wrapper_token_id,
    };
}

# --- 视图函数 ---

# @dev 查询包装后资产的详情
fn get_wrapped_asset(wrapper_token_id: Uint256) -> WrappedAsset {
    return state.wrapped_assets[wrapper_token_id];
}

# @dev 查询包装后资产的所有者
fn owner_of(wrapper_token_id: Uint256) -> Address {
    return state.wrapped_assets[wrapper_token_id].owner;
}

# @dev 查询原始 ACC-20 资产对应的包装 ID
fn get_wrapper_id(acc20_contract: Address, acc20_token_id: Uint256) -> Uint256 {
    return state.acc20_to_wrapper[acc20_contract][acc20_token_id];
}

# --- 管理员函数 ---

# @dev 冻结指定的包装资产
fn freeze_asset(wrapper_token_id: Uint256) {
    require(msg.sender == state.admin, "Only admin can freeze");
    state.wrapped_assets[wrapper_token_id].status = WrappedStatus::FROZEN;
}

# @dev 解冻指定的包装资产
fn unfreeze_asset(wrapper_token_id: Uint256) {
    require(msg.sender == state.admin, "Only admin can unfreeze");
    state.wrapped_assets[wrapper_token_id].status = WrappedStatus::ACTIVE;
}