add lottery the first half course

.gitmodules

@@ -28,3 +28,9 @@
 [submodule "lottery/lib/forge-std"]
 	path = lottery/lib/forge-std
 	url = https://github.com/foundry-rs/forge-std
+[submodule "lottery/lib/chainlink"]
+	path = lottery/lib/chainlink
+	url = https://github.com/smartcontractkit/chainlink
+[submodule "lottery/lib/chainlink-brownie-contracts"]
+	path = lottery/lib/chainlink-brownie-contracts
+	url = https://github.com/smartcontractkit/chainlink-brownie-contracts

lottery/foundry.toml

@@ -2,5 +2,6 @@
 src = "src"
 out = "out"
 libs = ["lib"]
+remappings = ['@chainlink/contracts/=lib/chainlink-brownie-contracts/contracts/']
 
 # See more config options https://github.com/foundry-rs/foundry/blob/master/crates/config/README.md#all-options

lottery/lib/chainlink-brownie-contracts

@@ -0,0 +1 @@
+Subproject commit 12393bd475bd60c222ff12e75c0f68effe1bbaaf

lottery/src/Raffle.sol

@@ -22,26 +22,145 @@
 // SPDX-License-Identifier: SEE LICENSE IN LICENSE
 pragma solidity 0.8.19;
 
+import {VRFConsumerBaseV2Plus} from "@chainlink/contracts/src/v0.8/vrf/dev/VRFConsumerBaseV2Plus.sol";
+import {VRFV2PlusClient} from "@chainlink/contracts/src/v0.8/vrf/dev/libraries/VRFV2PlusClient.sol";
+
 /**
  * @title  A sample Raffle contract
  * @author hirugohan
  * @notice This contract is for creating a sample raffle
  * @dev    Implements Chainlink VRFv2.5
  */
-contract Raffle {
+contract Raffle is VRFConsumerBaseV2Plus {
+    /* Errors */
+    error Raffle__SendMoreToEnterRaffle();
+    error Raffle__TransferFailed();
+    error Raffle__RaffleNotOpen();
+	error Raffle__UpkeepNotNeeded(uint256 balance, uint256 playersLength, uint256 raffleState);
+
+    /* Type Declarations */
+    enum RaffleState {
+        OPEN, // 0
+        CALCULATING // 1
+
+    }
+
+    /* State Variables */
+    uint16 private constant REQUEST_CONFIRMATIONS = 3;
+    uint32 private constant NUM_WORDS = 1;
     uint256 private immutable i_entranceFee;
+    // @dev The duration of the lottery in seconds
+    uint256 private immutable i_interval;
+    bytes32 private immutable i_keyHash;
+    uint256 private immutable i_subscriptionId;
+    uint32 private immutable i_callbackGasLimit;
+    address payable[] private s_players;
+    uint256 private s_lastTimeStamp;
+    address private s_recentWinner;
+    RaffleState private s_raffleState;
 
-    constructor (uint256 entranceFee) {
+    /* Events */
+    event RaffleEntered(address indexed player);
+    event WinnerPicked(address indexed winner);
+
+    constructor(
+        uint256 entranceFee,
+        uint256 interval,
+        address vrfCoordinator,
+        bytes32 gasLane,
+        uint256 subscriptionId,
+        uint32 callbackGasLimit
+    ) VRFConsumerBaseV2Plus(vrfCoordinator) {
         i_entranceFee = entranceFee;
+        i_interval = interval;
+        i_keyHash = gasLane;
+        i_subscriptionId = subscriptionId;
+        i_callbackGasLimit = callbackGasLimit;
+
+        s_lastTimeStamp = block.timestamp;
+        s_raffleState = RaffleState.OPEN;
     }
 
-    function enterRaffle() public payable {
-        require(msg.value >= i_entranceFee, "Not enough ETH sent!");
+    function enterRaffle() external payable {
+        // require(msg.value >= i_entranceFee, "Not enough ETH sent!");
+        if (msg.value < i_entranceFee) {
+            revert Raffle__SendMoreToEnterRaffle();
+        }
+        if (s_raffleState != RaffleState.OPEN) {
+            revert Raffle__RaffleNotOpen();
         }
 
-    function pickWinner() public {}
+        // require(msg.value >= i_entranceFee, SendMoreToEnterRaffle());
+        s_players.push(payable(msg.sender));
+        emit RaffleEntered(msg.sender);
+    }
 
-    /** Getter Functions */
+    /**
+     * @dev This is a function that chainlink nodes will call to see
+     * if the lottery is ready to have a winner picked.
+     * The following should be true in order for upkeepNeeded to be true:
+     * 1. The time interval has passed between raffle runes
+     * 2. The lottery is open
+     * 3. The contract has ETH (has players)
+     * 4. Implicitly, your subscription has LINK
+     * @param - ignored
+     * @return upkeepNeeded - true if it's time to restart the lottery
+     * @return - ignored
+     */
+    function checkUpkeep(bytes memory /* checkData */ )
+        public
+        view
+        returns (bool upkeepNeeded, bytes memory /* performData */ )
+    {
+        bool timeHasPassed = ((block.timestamp - s_lastTimeStamp) >= i_interval); 
+		bool isOpen = s_raffleState == RaffleState.OPEN;
+		bool hasBalance = address(this).balance > 0;
+		bool hasPlayers = s_players.length > 0;
+		upkeepNeeded = timeHasPassed && isOpen && hasBalance && hasPlayers;
+		return (upkeepNeeded, "");
+    }
+
+    function performUpkeep(bytes calldata /* performData */) external {
+		(bool upkeepNeeded, ) = checkUpkeep("");
+		if (!upkeepNeeded) {
+			revert Raffle__UpkeepNotNeeded(address(this).balance, s_players.length, uint256(s_raffleState));
+		}
+        
+        s_raffleState = RaffleState.CALCULATING;
+        VRFV2PlusClient.RandomWordsRequest memory request = VRFV2PlusClient.RandomWordsRequest({
+            keyHash: i_keyHash,
+            subId: i_subscriptionId,
+            requestConfirmations: REQUEST_CONFIRMATIONS,
+            callbackGasLimit: i_callbackGasLimit,
+            numWords: NUM_WORDS,
+            extraArgs: VRFV2PlusClient._argsToBytes(VRFV2PlusClient.ExtraArgsV1({nativePayment: false}))
+        });
+        s_vrfCoordinator.requestRandomWords(request);
+    }
+
+    // CEI: Check, Effects, Interactions Pattern
+    function fulfillRandomWords(uint256 /* requestId */, uint256[] calldata randomWords) internal virtual override {
+        // Checks: check values before executing function
+
+        // Effect (Internal Contract State)
+        uint256 indexOfWinner = randomWords[0] % s_players.length;
+        address payable recentWinner = s_players[indexOfWinner];
+        s_recentWinner = recentWinner;
+        s_raffleState = RaffleState.OPEN;
+        s_players = new address payable[](0);
+        s_lastTimeStamp = block.timestamp;
+        emit WinnerPicked(s_recentWinner);
+
+        // Interactions (External Contract Interactions)
+        (bool success,) = recentWinner.call{value: address(this).balance}("");
+        if (!success) {
+            revert Raffle__TransferFailed();
+        }
+    }
+
+    /**
+     * Getter Functions
+     */
     function getEntranceFee() external view returns (uint256) {
         return i_entranceFee;
     }