In Progress Add Mock

contracts/FundMe.sol

@@ -1,86 +1,110 @@
 // SPDX-License-Identifier: MIT
-pragma solidity ^0.8.8;
+/*
+    Get funds from users
+    Withdraw funds
+    Set a minimum funding value in USD
+*/
+pragma solidity ^0.8.0;
 
-import "@chainlink/contracts/src/v0.8/shared/interfaces/AggregatorV3Interface.sol";
 import "./PriceConverter.sol";
+// Save Gas - constant, immutable
 
 error NotOwner();
 
+// 816914
 contract FundMe {
+    /*
+        Transaction Fields
+            Nonce
+            Gas Price
+            Gas Limit - Max Gas that this TX can use
+            To - Address
+            Value - Amount of wei to send
+            Data - What to send to the Address (Can Empty)
+            v, r, s - components of TX signature
+    */
+
     using PriceConverter for uint256;
+    uint256 public constant MINIMUM_USD = 50 * 1e18;
 
-    mapping(address => uint256) public addressToAmountFunded;
     address[] public funders;
+    mapping(address => uint256) public addressToAmountFunded;
 
-    // Could we make this constant?  /* hint: no! We should make it immutable! */
-    address public /* immutable */ i_owner;
-    uint256 public constant MINIMUM_USD = 50 * 10 ** 18;
-    
-    constructor() {
+    // immutable only can declare 1 time at contructor
+    address public immutable i_owner;
+
+    AggregatorV3Interface public priceFeed;
+
+    constructor(address priceFeedAddress) {
         i_owner = msg.sender;
+        priceFeed = AggregatorV3Interface(priceFeedAddress);
     }
 
     function fund() public payable {
-        require(msg.value.getConversionRate() >= MINIMUM_USD, "You need to spend more ETH!");
-        // require(PriceConverter.getConversionRate(msg.value) >= MINIMUM_USD, "You need to spend more ETH!");
-        addressToAmountFunded[msg.sender] += msg.value;
+        /*
+            Want to be able to set a minimum fund amount in USD
+            1. How do we send ETH to this contract
+        */
+        //require (msg.value >= 1e18, "Didn't send enough"); // 1e18 = 1 * 10 * 18 = 1000000000000000000
+        require(
+            msg.value.getConversionRate(priceFeed) >= MINIMUM_USD,
+            "Didn't send enough"
+        );
         funders.push(msg.sender);
+        addressToAmountFunded[msg.sender] = msg.value;
     }
-    
-    function getVersion() public view returns (uint256){
-        // ETH/USD price feed address of Sepolia Network.
-        AggregatorV3Interface priceFeed = AggregatorV3Interface(0x694AA1769357215DE4FAC081bf1f309aDC325306);
-        return priceFeed.version();
-    }
-    
-    modifier onlyOwner {
-        // require(msg.sender == owner);
-        if (msg.sender != i_owner) revert NotOwner();
-        _;
-    }
-    
+
+    // Owner of this contract only can withdraw
     function withdraw() public onlyOwner {
-        for (uint256 funderIndex=0; funderIndex < funders.length; funderIndex++){
+        // Can use modifier to replace
+        // require(msg.sender == owner, "Sender is not owner");
+
+        /* starting index, eding index, step amount */
+        for (
+            uint256 funderIndex = 0;
+            funderIndex < funders.length;
+            funderIndex++
+        ) {
             address funder = funders[funderIndex];
             addressToAmountFunded[funder] = 0;
         }
+        // reset the array
         funders = new address[](0);
-        // // transfer
-        // payable(msg.sender).transfer(address(this).balance);
-        // // send
-        // bool sendSuccess = payable(msg.sender).send(address(this).balance);
-        // require(sendSuccess, "Send failed");
-        // call
-        (bool callSuccess, ) = payable(msg.sender).call{value: address(this).balance}("");
+
+        /*
+        // transfer - over 2300 gas will cause exception
+        payable(msg.sender).transfer(address(this).balance);
+        // send - over 2300 gas will not cause exception, only will return true or false
+        bool sendSuccess = payable(msg.sender).send(address(this).balance);
+        require(sendSuccess, "Send failed");
+        */
+
+        // call - lower level
+        (bool callSuccess, ) = payable(msg.sender).call{
+            value: address(this).balance
+        }("");
         require(callSuccess, "Call failed");
     }
-    // Explainer from: https://solidity-by-example.org/fallback/
-    // Ether is sent to contract
-    //      is msg.data empty?
-    //          /   \ 
-    //         yes  no
-    //         /     \
-    //    receive()?  fallback() 
-    //     /   \ 
-    //   yes   no
-    //  /        \
-    //receive()  fallback()
 
-    fallback() external payable {
-        fund();
+    modifier onlyOwner() {
+        // require(msg.sender == i_owner, "Sender is not owner!");
+        if (msg.sender != i_owner) {
+            revert NotOwner();
+        }
+
+        _; // doing the rest of the code
     }
 
+    // What happens if someone send this contract ETH without calling the fund fucntion
+    /*
+        receive - people send money / empty money into this contract
+        fallback - cannot identify which function to run
+    */
     receive() external payable {
         fund();
     }
 
+    fallback() external payable {
+        fund();
+    }
 }
-
-// Concepts we didn't cover yet (will cover in later sections)
-// 1. Enum
-// 2. Events
-// 3. Try / Catch
-// 4. Function Selector
-// 5. abi.encode / decode
-// 6. Hash with keccak256
-// 7. Yul / Assembly