The transaction has been reverted to the initial state. The called function should be payable if you send value - ethereum

Question

the Error being specified is
revert
The transaction has been reverted to the initial state.
Note: The called function should be payable if you send value and the value you send should be less than your current balance.
Debug the transaction to get more information.
//SPDX-License-Identifier:MIT
pragma solidity 0.8.8;
contract Giftcard{
event UniqueCardId(uint indexed Id,address indexed owner);
//Enter The Giftcard amount
//Pay the gift card by making multiple transations
//require(giftcard owner should approve the withdrawl )
address[] Giftcardowners;
mapping(address => uint) amountUploaded;
function Addamount() external payable{
require(msg.value >= 1 ether,"Gift card amount to small");
amountUploaded[msg.sender] = msg.value;
Giftcardowners.push(msg.sender);
emit UniqueCardId(Giftcardowners.length-1,msg.sender);
}
function GetGiftcard(uint _cardId) payable external {
require(Giftcardowners.length > _cardId,"Id doesnot exits");
address owner = Giftcardowners[_cardId-1];
uint amount = amountUploaded[owner];
require(amount >= 1 ether,"transfered is less than 1 ether");
// (bool successs,) = payable(msg.sender).call{value:amount}("");
//require(successs,"transaction reverted");
payable(msg.sender).transfer(1 ether);
}
function getBalance() external view returns(uint balance){
return address(this).balance;
}
}
Firstly I called the Addamount function by paying more than 1 ether to the smart contract
now after that when the GetGiftcard function is called the transaction is reverted. I am unable to find a solution
unable to understand the concept

Answer 1

Error is here
address owner = Giftcardowners[_cardId-1];
should be
address owner = Giftcardowners[_cardId];
When you call addAmount, this line executes
Giftcardowners.push(msg.sender);
in the Giftcardowners array you have only 1 item
Giftcardowners=[0x7EF2e0048f5bAeDe046f6BF797943daF4ED8CB47]
when you call the GetGiftcard, you need to pass _cardId=0, you are actually assigning the index of the array as the id. when you pass 0, index will be -1 here
address owner = Giftcardowners[_cardId-1];
You cannot pass 1 to get 1-1=0, because you have this condition
require(Giftcardowners.length > _cardId,"Id doesnot exits");