2.1 多簽錢包

address public owners:
uint public numConfirmationsRequired
event transactionsubmitted
event TransactionConfirmed
event transactionExecuted
constructor
for loop
function submitTransaction
function confirmTransaction
function executeTransaction
function isTransactionConfirmed
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.24;

contract MultiSig {
    address[] public owners; // the people who control this smart contract
    uint public numConfirmationsRequired; // how many people voted for this tx


    struct Transaction{
        address to; // the address of the person we care sending ether to
        uint value; // the amount of value we will be sending 
        bool executed; // whether the transaction is success or not
    }
    // neseted mapping
    mapping(uint=>mapping(address=>bool)) isConfirmed;
    Transaction[] public transactions;
    
    event TransactionSubmitted(uint transactionId,address sender, address receiver, uint amount);
    event TransactionConfirmed(uint transactionId);
    event TransactionExecuted(uint transactionId);
    constructor(address[] memory _owners,uint _numConfirmationsRequired){ // the person who sign this tx
        require(_owners.length>1, "Owners Required[Must Be Greater than 1"); // owners should be greater than 1 person
        require(_numConfirmationsRequired>0 && numConfirmationsRequired<=_owners.length,"Num of confirmation are not in sync with the number of owners"); // make sure the voted person qty is align with 

        for(uint i=0;i<_owners.length;i++){
            require(_owners[i]!=address(0), "Invalid Owner");
            owners.push(_owners[i]); 
        }
        numConfirmationsRequired=_numConfirmationsRequired;
 }

 function submitTransaction(address _to) public payable {
    require(_to!=address(0),"Invalid Receiver's Address");
    require(msg.value>0,"Transfer Amount Must Be Greater Than 0"); 
    uint transactionId = transactions.length;
    transactions.push(Transaction({to:_to,value:msg.value,executed:false}));
    emit TransactionSubmitted(transactionId,msg.sender,_to,msg.value);
  }

  function confirmTransaction(uint _transactionId) public{
    require(_transactionId<transactions.length, "Invalid Transaction Id");
    require(!isConfirmed[_transactionId][msg.sender], "Transaction Is Already Confirmed By The Owner");
    isConfirmed[_transactionId][msg.sender]=true;
    emit TransactionConfirmed(_transactionId);
    if(isTransactionConfirmed(_transactionId)){
        executeTransaction(_transactionId);
        }
    }

    function executeTransaction(uint _transactionId) public payable{
        require(_transactionId<transactions.length, "Invalid Transaction Id");
        require(!transactions[_transactionId].executed,"Transaction is already executed");
        // transaction[_transactionId].executed=true;
        (bool success,)=transactions[_transactionId].to.call{value: transactions[_transactionId].value}("")
        require(success,"Transaction Execution Failed");
        emit TransactionExecuted(_transactionId);
    }

    function isTransactionConfirmed(uint _transactionId) public view returns(bool){
        require(_transactionId<transactions.length, "Invalid Transaction Id");
        uint confirmationCount;//initially zero

        for(uint i=0; i<owners.length;i++){
            if(isConfirmed[_transactionId][owners[i]]){
             confirmationCount++;
            }
        } 
        return confirmationCount>=numConfirmationsRequired;
    }
}
[Reference]
