All tokens go to heaven

Simple Summary

Make wallets and shops created from certified contracts make erc20 tokens easy to use for commerce.

wallet

Abstract

The mutual trust between the wallet and the shop created by the authenticated contract allows you to pay for and purchase items at a simple process.

Motivation

New standards with improvements have been released, but the majority of tokens currently being developed are erc20 tokens. So I felt I needed a proposal to use old tokens in commerce. To use various erc20 tokens for trading, you need a custom contract. However, a single wallet with a variety of tokens, and a mutually trusted store, can make transactions that are simple and efficient. The erc20 token is traded through two calls, approve (address _spender, uint256 _value) and transferFrom (address _from, address _to, uint256 _value), but when using the wallet contract, paySafe (address _shop, uint256 _item)will be traded only in one call. And if you only reuse the store interface, you can also trade using payUnsafe (address _shop, uint256 _item).

Specification

workflow

WalletCenter

Methods

createWallet

Create wallet contract and add to list. Returns the address of new wallet.

function createWallet() public returns (address _wallet)

isWallet

Returns true or false value for test this address is a created by createWallet.

function isWallet(address _wallet) public constant returns (bool)

createShop

Create Shop contract and add to list. Returns the address of new Shop with erc20 token address.

function createShop(address _erc20) public returns (address _shop)

isShop

Returns true or false value for test this address is a created by createWallet.

function isShop(address _shop) public constant returns (bool)

Events

Wallet

Search for my wallet.

event Wallet(address indexed _owner, address indexed _wallet)

Shop

Search for my shop.

event Shop(address indexed _owner, address indexed _shop, address indexed _erc20)

Wallet

Wallet must be created by wallet center.

Methods

balanceOf

Returns the account balance of Wallet.

function balanceOf(address _erc20) public constant returns (uint256 balance)

withdrawal

withdrawal _value amount of _erc20 token to _owner.

function withdrawal(address _erc20, uint256 _value) onlyOwner public returns (bool success)

paySafe

Pay for safe shop (created by contract) item with item index _item.

function paySafe(address _shop, uint256 _item) onlyOwner onlyShop(_shop) public payable returns (bool success)

payUnsafe

Pay for unsafe shop (did not created by contract) item with item index _item.

function payUnsafe(address _shop, uint256 _item) onlyOwner public payable returns (bool success)

payCancel

Cancel pay and refund. (only weekly model)

function payCancel(address _shop, uint256 _item) onlyOwner public returns (bool success)

refund

Refund from shop with item index _item.

function refund(uint256 _item, uint256 _value) public payable returns (bool success)

Events

Pay

event Pay(address indexed _shop, uint256 indexed _item, uint256 indexed _value)

Refund

event Refund(address indexed _shop, uint256 indexed _item, uint256 indexed _value)

Shop

Shop is created by wallet center or not. but Shop that created by wallet center is called safe shop.

Methods

balanceOf

Returns the account balance of Shop.

function balanceOf(address _erc20) public constant returns (uint256 balance)

withdrawal

withdrawal _value amount of _erc20 token to _owner.

function withdrawal(address _erc20, uint256 _value) onlyOwner public returns (bool success)

pay

Pay from buyer with item index _item.

function pay(uint256 _item) onlyWallet(msg.sender) public payable returns (bool success)

refund

refund token to _to.

function refund(address _buyer, uint256 _item, uint256 _value) onlyWallet(_buyer) onlyOwner public payable returns (bool success)

resister

Listing item for sell.

function resister(uint8 _category, uint256 _price, uint256 _stock) onlyOwner public returns (uint256 _itemId)

update

Update item state for sell. (change item _price or add item _stock)

function update(uint256 _item, uint256 _price, uint256 _stock) onlyOwner public

price

Get token address and price from buyer with item index _item.

function price(uint256 _item) public constant returns (address _erc20, uint256 _value)

canBuy

_who can Buy _item.

function canBuy(address _who, uint256 _item) public constant returns (bool _canBuy)

isBuyer

_who is buyer of _item.

function isBuyer(address _who, uint256 _item) public constant returns (bool _buyer)

info

Set shop information bytes.

function info(bytes _msgPack)

upVote

Up vote for this shop.

function upVote()

dnVote

Down vote for this shop.

function dnVote()

about

Get shop token, up vote and down vote.

function about() view returns (address _erc20, uint256 _up, uint256 _down)

infoItem

Set item information bytes.

function infoItem(uint256 _item, bytes _msgPack)

upVoteItem

Up vote for this item.

function upVoteItem(uint256 _item)

dnVoteItem

Down vote for this item.

function dnVoteItem(uint256 _item)

aboutItem

Get Item price, up vote and down vote.

function aboutItem(uint256 _item) view returns (uint256 _price, uint256 _up, uint256 _down)

Events

Pay

event Pay(address indexed _buyer, uint256 indexed _item, uint256 indexed _value)

Refund

event Refund(address indexed _to, uint256 indexed _item, uint256 indexed _value)

Item

event Item(uint256 indexed _item, uint256 _price)

Info

event Info(bytes _msgPack)

InfoItem

event InfoItem(uint256 indexed _item, bytes _msgPack)

Implementation

Sample token contract address is 0x393dd70ce2ae7b30501aec94727968c517f90d52

WalletCenter contract address is 0x1fe0862a4a8287d6c23904d61f02507b5044ea31

WalletCenter create shop contract address is 0x59117730D02Ca3796121b7975796d479A5Fe54B0

WalletCenter create wallet contract address is 0x39da7111844df424e1d0a0226183533dd07bc5c6

Appendix

pragma solidity ^0.4.24;

contract ERC20Interface {
    function totalSupply() public constant returns (uint);
    function balanceOf(address tokenOwner) public constant returns (uint balance);
    function allowance(address tokenOwner, address spender) public constant returns (uint remaining);
    function transfer(address to, uint tokens) public returns (bool success);
    function approve(address spender, uint tokens) public returns (bool success);
    function transferFrom(address from, address to, uint tokens) public returns (bool success);

    event Transfer(address indexed from, address indexed to, uint tokens);
    event Approval(address indexed tokenOwner, address indexed spender, uint tokens);
}

contract SafeMath {
    function safeAdd(uint a, uint b) public pure returns (uint c) {
        c = a + b;
        require(c >= a);
    }
    function safeSub(uint a, uint b) public pure returns (uint c) {
        require(b <= a);
        c = a - b;
    }
    function safeMul(uint a, uint b) public pure returns (uint c) {
        c = a * b;
        require(a == 0 || c / a == b);
    }
    function safeDiv(uint a, uint b) public pure returns (uint c) {
        require(b > 0);
        c = a / b;
    }
}

contract _Base {
    address internal owner;
    address internal walletCenter;
    
    modifier onlyOwner {
        require(owner == msg.sender);
        _;
    }
    modifier onlyWallet(address _addr) {
        require(WalletCenter(walletCenter).isWallet(_addr));
        _;
    }
    modifier onlyShop(address _addr) {
        require(WalletCenter(walletCenter).isShop(_addr));
        _;
    }

    function balanceOf(address _erc20) public constant returns (uint256 balance) {
        if(_erc20==address(0))
            return address(this).balance;
        return ERC20Interface(_erc20).balanceOf(this);
    }

    function transfer(address _to, address _erc20, uint256 _value) internal returns (bool success) {
        require((_erc20==address(0)?address(this).balance:ERC20Interface(_erc20).balanceOf(this))>=_value);
        if(_erc20==address(0))
            _to.transfer(_value);
        else
            ERC20Interface(_erc20).approve(_to,_value);
        return true;
    }
    
    function withdrawal(address _erc20, uint256 _value) public returns (bool success);
    
    event Pay(address indexed _who, uint256 indexed _item, uint256 indexed _value);
    event Refund(address indexed _who, uint256 indexed _item, uint256 indexed _value);
    event Prize(address indexed _who, uint256 indexed _item, uint256 indexed _value);
}

contract _Wallet is _Base {
    constructor(address _who) public {
        owner           = _who;
        walletCenter    = msg.sender;
    }
    
    function pay(address _shop, uint256 _item) private {
        require(_Shop(_shop).canBuy(this,_item));

        address _erc20;
        uint256 _value;
        (_erc20,_value) = _Shop(_shop).price(_item);
        
        transfer(_shop,_erc20,_value);
        _Shop(_shop).pay(_item);
        emit Pay(_shop,_item,_value);
    }
    
    function paySafe(address _shop, uint256 _item) onlyOwner onlyShop(_shop) public payable returns (bool success) {
        pay(_shop,_item);
        return true;
    }
    function payUnsafe(address _shop, uint256 _item) onlyOwner public payable returns (bool success) {
        pay(_shop,_item);
        return true;
    }
    function payCancel(address _shop, uint256 _item) onlyOwner public returns (bool success) {
        _Shop(_shop).payCancel(_item);
        return true;
    }

    function refund(address _erc20, uint256 _item, uint256 _value) public payable returns (bool success) {
        require((_erc20==address(0)?msg.value:ERC20Interface(_erc20).allowance(msg.sender,this))==_value);
        if(_erc20!=address(0))
            ERC20Interface(_erc20).transferFrom(msg.sender,this,_value);
        emit Refund(msg.sender,_item,_value);
        return true;
    }
    function prize(address _erc20, uint256 _item, uint256 _value) public payable returns (bool success) {
        require((_erc20==address(0)?msg.value:ERC20Interface(_erc20).allowance(msg.sender,this))==_value);
        if(_erc20!=address(0))
            ERC20Interface(_erc20).transferFrom(msg.sender,this,_value);
        emit Prize(msg.sender,_item,_value);
        return true;
    }
    
    function withdrawal(address _erc20, uint256 _value) onlyOwner public returns (bool success) {
        require((_erc20==address(0)?address(this).balance:ERC20Interface(_erc20).balanceOf(this))>=_value);
        if(_erc20==address(0))
            owner.transfer(_value);
        else
            ERC20Interface(_erc20).transfer(owner,_value);
        return true;
    }
}

contract _Shop is _Base, SafeMath{
    address erc20;
    constructor(address _who, address _erc20) public {
        owner           = _who;
        walletCenter    = msg.sender;
        erc20           = _erc20;
    }
    
    struct item {
        uint8                       category;   // 0 = disable, 1 = non Stock, non Expire, 2 = can Expire (after 1 week), 3 = stackable
        uint256                     price;
        uint256                     stockCount;

        mapping(address=>uint256)   customer;
    }

    uint                    index;
    mapping(uint256=>item)  items;
    
    function pay(uint256 _item) onlyWallet(msg.sender) public payable returns (bool success) {
        require(canBuy(msg.sender, _item));
        require((erc20==address(0)?msg.value:ERC20Interface(erc20).allowance(msg.sender,this))==items[_item].price);
        
        if(erc20!=address(0))
            ERC20Interface(erc20).transferFrom(msg.sender,this,items[_item].price);
        
        if(items[_item].category==1 || items[_item].category==2 && now > safeAdd(items[_item].customer[msg.sender], 1 weeks))
            items[_item].customer[msg.sender]   = now;
        else if(items[_item].category==2 && now < safeAdd(items[_item].customer[msg.sender], 1 weeks) )
            items[_item].customer[msg.sender]   = safeAdd(items[_item].customer[msg.sender], 1 weeks);
        else if(items[_item].category==3) {
            items[_item].customer[msg.sender]   = safeAdd(items[_item].customer[msg.sender],1);
            items[_item].stockCount             = safeSub(items[_item].stockCount,1);
        }

        emit Pay(msg.sender,_item,items[_item].customer[msg.sender]);
        return true;
    }
    
    function payCancel(uint256 _item) onlyWallet(msg.sender) public returns (bool success) {
        require (items[_item].category==2&&safeAdd(items[_item].customer[msg.sender],2 weeks)>now&&balanceOf(erc20)>=items[_item].price);

        items[_item].customer[msg.sender]  = safeSub(items[_item].customer[msg.sender],1 weeks);
        transfer(msg.sender, erc20, items[_item].price);
        _Wallet(msg.sender).refund(erc20,_item,items[_item].price);
        emit Refund(msg.sender,_item,items[_item].price);

        return true;
    }
    function refund(address _to, uint256 _item) onlyWallet(_to) onlyOwner public payable returns (bool success) {
        require(isBuyer(_to,_item)&&items[_item].category>0&&(items[_item].customer[_to]>0||(items[_item].category==2&&safeAdd(items[_item].customer[_to],2 weeks)>now)));
        require((erc20==address(0)?address(this).balance:ERC20Interface(erc20).balanceOf(this))>=items[_item].price);

        if(items[_item].category==1)
            items[_item].customer[_to]  = 0;
        else if(items[_item].category==2)
            items[_item].customer[_to]  = safeSub(items[_item].customer[_to],1 weeks);
        else
            items[_item].customer[_to]  = safeSub(items[_item].customer[_to],1);
            
        transfer(_to, erc20, items[_item].price);
        _Wallet(_to).refund(erc20,_item,items[_item].price);
        emit Refund(_to,_item,items[_item].price);

        return true;
    }
    
    event Item(uint256 indexed _item, uint256 _price);
    function resister(uint8 _category, uint256 _price, uint256 _stock) onlyOwner public returns (uint256 _itemId) {
        require(_category>0&&_category<4);
        require(_price>0);
        items[index]    = item(_category,_price,_stock);
        index = safeAdd(index,1);
        emit Item(index,_price);
        return safeSub(index,1);
    }
    function update(uint256 _item, uint256 _price, uint256 _stock) onlyOwner public {
        require(items[_item].category>0);
        require(_price>0);
        uint256 temp = items[_item].price;
        items[_item].price      = _price;
        items[_item].stockCount = safeAdd(items[_item].stockCount,_stock);
        
        if(temp!=items[_item].price)
            emit Item(index,items[_item].price);
    }
    
    function price(uint256 _item) public constant returns (address _erc20, uint256 _value) {
        return (erc20,items[_item].price);
    }
    
    function canBuy(address _who, uint256 _item) public constant returns (bool _canBuy) {
        return  (items[_item].category>0) &&
                !(items[_item].category==1&&items[_item].customer[_who]>0) &&
                (items[_item].stockCount>0);
    }
    
    function isBuyer(address _who, uint256 _item) public constant returns (bool _buyer) {
        return (items[_item].category==1&&items[_item].customer[_who]>0)||(items[_item].category==2&&safeAdd(items[_item].customer[_who],1 weeks)>now)||(items[_item].category==3&&items[_item].customer[_who]>0);
    }
    
    uint lastWithdrawal;
    function withdrawal(address _erc20, uint256 _value) onlyOwner public returns (bool success) {
        require(safeAdd(lastWithdrawal,1 weeks)<=now);
        require((_erc20==address(0)?address(this).balance:ERC20Interface(_erc20).balanceOf(this))>=_value);
        if(_erc20==address(0))
            owner.transfer(_value);
        else
            ERC20Interface(_erc20).transfer(owner,_value);
        lastWithdrawal = now;
        return true;
    }
}

contract WalletCenter {
    mapping(address=>bool) public     wallet;
    event Wallet(address indexed _owner, address indexed _wallet);
    function createWallet() public returns (address _wallet) {
        _wallet = new _Wallet(msg.sender);
        wallet[_wallet] = true;
        emit Wallet(msg.sender,_wallet);
        return _wallet;
    }
    function isWallet(address _wallet) public constant returns (bool) {
        return wallet[_wallet];
    }
    mapping(address=>bool) public     shop;
    event Shop(address indexed _owner, address indexed _shop, address indexed _erc20);
    function createShop(address _erc20) public returns (address _shop) {
        _shop   = new _Shop(msg.sender,_erc20);
        shop[_shop] = true;
        emit Shop(msg.sender,_shop,_erc20);
        return _shop;
    }
    function isShop(address _shop) public constant returns (bool) {
        return shop[_shop];
    }
}

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