contract TokenSellerFactory is Owned {

    event TradeListing(address indexed ownerAddress, address indexed tokenSellerAddress,
        address indexed asset, uint256 sellPrice, uint256 units, bool sellsTokens);
    event OwnerWithdrewERC20Token(address indexed tokenAddress, uint256 tokens);

    mapping(address => bool) _verify;

    // Anyone can call this method to verify the settings of a
    // TokenSeller contract. The parameters are:
    //   tradeContract  is the address of a TokenSeller contract
    //
    // Return values:
    //   valid        did this TokenTraderFactory create the TokenTrader contract?
    //   owner        is the owner of the TokenTrader contract
    //   asset        is the ERC20 asset address
    //   sellPrice    is the sell price in ethers per `units` of asset tokens
    //   units        is the number of units of asset tokens
    //   sellsTokens  is the TokenTrader contract selling tokens?
    //
    function verify(address tradeContract) constant returns (
        bool    valid,
        address owner,
        address asset,
        uint256 sellPrice,
        uint256 units,
        bool    sellsTokens
    ) {
        valid = _verify[tradeContract];
        if (valid) {
            TokenSeller t = TokenSeller(tradeContract);
            owner         = t.owner();
            asset         = t.asset();
            sellPrice     = t.sellPrice();
            units         = t.units();
            sellsTokens   = t.sellsTokens();
        }
    }

    // Maker can call this method to create a new TokenSeller contract
    // with the maker being the owner of this new contract
    //
    // Parameters:
    //   asset        is the ERC20 asset address
    //   sellPrice    is the sell price in ethers per `units` of asset tokens
    //   units        is the number of units of asset tokens
    //   sellsTokens  is the TokenSeller contract selling tokens?
    //
    // For example, listing a TokenSeller contract on the GNT Golem Network Token
    // where the contract will sell GNT tokens at a rate of 170/100000 = 0.0017 ETH
    // per GNT token:
    //   asset        0xa74476443119a942de498590fe1f2454d7d4ac0d
    //   sellPrice    170
    //   units        100000
    //   sellsTokens  true
    //
    // The TradeListing() event is logged with the following parameters
    //   ownerAddress        is the Maker's address
    //   tokenSellerAddress  is the address of the newly created TokenSeller contract
    //   asset               is the ERC20 asset address
    //   sellPrice           is the sell price in ethers per `units` of asset tokens
    //   unit                is the number of units of asset tokens
    //   sellsTokens         is the TokenSeller contract selling tokens?
    //
    // This method was called createTradeContract() in the old version
    //
    function createSaleContract(
        address asset,
        uint256 sellPrice,
        uint256 units,
        bool    sellsTokens
    ) returns (address seller) {
        // Cannot have invalid asset
        if (asset == 0x0) throw;
        // Cannot set zero or negative price
        if (sellPrice <= 0) throw;
        // Cannot sell zero or negative units
        if (units <= 0) throw;
        seller = new TokenSeller(
            asset,
            sellPrice,
            units,
            sellsTokens);
        // Record that this factory created the trader
        _verify[seller] = true;
        // Set the owner to whoever called the function
        TokenSeller(seller).transferOwnership(msg.sender);
        TradeListing(msg.sender, seller, asset, sellPrice, units, sellsTokens);
    }

    // Factory owner can withdraw any ERC20 asset tokens from this contract
    //
    // This method is included in the case where this contract receives
    // the wrong tokens
    //
    // The OwnerWithdrewERC20Token() event is logged with the following
    // parameter:
    //   tokenAddress  is the address of the tokens withdrawn by the maker
    //   tokens        is the number of tokens withdrawn by the maker
    function ownerWithdrawERC20Token(address tokenAddress, uint256 tokens) onlyOwner returns (bool ok) {
        OwnerWithdrewERC20Token(tokenAddress, tokens);
        return ERC20Partial(tokenAddress).transfer(owner, tokens);
    }

    // Prevents accidental sending of ether to the factory
    function () {
        throw;
    }
}
// This contract deploys TokenSeller contracts and logs the event
function ownerWithdrawERC20Token(address tokenAddress, uint256 tokens) onlyOwner returns (bool ok) {
    OwnerWithdrewERC20Token(tokenAddress, tokens);
    return ERC20Partial(tokenAddress).transfer(owner, tokens);
}

// Factory owner can withdraw any ERC20 asset tokens from this contract
//
// This method is included in the case where this contract receives
// the wrong tokens
//
// The OwnerWithdrewERC20Token() event is logged with the following
// parameter:
//   tokenAddress  is the address of the tokens withdrawn by the maker
//   tokens        is the number of tokens withdrawn by the maker