restrict client from trying to set starting entropy before valid bloc…

…k hash is available

contracts/game/src/game/constants.cairo

@@ -35,6 +35,7 @@ mod messages {
     const STARTING_ENTROPY_ZERO: felt252 = 'block hash should not be zero';
     const GAME_ALREADY_STARTED: felt252 = 'game already started';
     const STARTING_ENTROPY_IS_VALID: felt252 = 'starting entropy is valid';
+    const VALID_BLOCK_HASH_UNAVAILABLE: felt252 = 'valid hash not yet available';
 }
 
 // TODO: Update for mainnet

contracts/game/src/lib.cairo

@@ -234,6 +234,9 @@ mod Game {
             // player can only call this before starting game (defeating starter beast)
             assert(_load_adventurer(@self, adventurer_id).xp == 0, messages::GAME_ALREADY_STARTED);
 
+            // prevent client from trying to set start entropy prior to valid block hash being available
+            _assert_valid_block_hash_available(@self, adventurer_id);
+
             // verify the block_hash is not zero
             assert(block_hash != 0, messages::STARTING_ENTROPY_ZERO);
 
@@ -728,7 +731,9 @@ mod Game {
         ) -> felt252 {
             self._starting_entropy.read(adventurer_id)
         }
-        fn get_contract_calculated_entropy(self: @ContractState, adventurer_id: felt252) -> felt252 {
+        fn get_contract_calculated_entropy(
+            self: @ContractState, adventurer_id: felt252
+        ) -> felt252 {
             _get_starting_block_hash(self, adventurer_id)
         }
         fn get_adventurer_entropy(self: @ContractState, adventurer_id: felt252) -> felt252 {
@@ -1322,15 +1327,27 @@ mod Game {
         );
     }
 
+    // @title Assert Valid Block Hash Availability
+    // @notice This function asserts that a valid block hash is available for the given adventurer.
+    // @dev If this function is called prior to 2 blocks from the start of the game for the given adventurer, an exception will be thrown.
+    // @param adventurer_id The ID of the adventurer for which to check the block hash availability.
+    fn _assert_valid_block_hash_available(self: @ContractState, adventurer_id: felt252) {
+        let current_block = starknet::get_block_info().unbox().block_number;
+        let adventurer_start_block = _load_adventurer_metadata(self, adventurer_id).start_block;
+        let block_hash_available = adventurer_start_block + 2;
+        assert(current_block >= block_hash_available, messages::VALID_BLOCK_HASH_UNAVAILABLE);
+    }
+
+    // @title Check if starting entropy is valid
+    // @notice This function checks if the starting entropy provided to the contract is equal to the entropy generated by the contract based on the block hash of the block after the player committed to playing the game.
+    // @dev If no manual starting entropy was provided, the starting entropy is considered valid. If a starting entropy was manually provided, it is compared with the block hash of the block after the player committed to playing the game.
+    // @param adventurer_id The ID of the adventurer for which to check the starting entropy.
+    // @return Returns true if the starting entropy is valid, false otherwise.
     fn _is_starting_entropy_valid(self: @ContractState, adventurer_id: felt252) -> bool {
-        // get starting entropy manually provided to the contract
         let starting_entropy = self._starting_entropy.read(adventurer_id);
         if starting_entropy == 0 {
-            // if no manual starting entropy was provided, the starting entropy is valid
             true
         } else {
-            // if a starting entropy was manually provided
-            // compare it with the block hash of the block after the player committed to playing the game
             starting_entropy == _get_starting_block_hash(self, adventurer_id)
         }
     }

contracts/game/src/tests/test_game.cairo

@@ -289,6 +289,7 @@ mod tests {
         let mut game = new_adventurer(starting_block, starting_time);
 
         if (starting_entropy != 0) {
+            testing::set_block_number(starting_block + 2);
             game.set_starting_entropy(ADVENTURER_ID, starting_entropy);
         }
 
@@ -2324,6 +2325,7 @@ mod tests {
     #[should_panic(expected: ('Not authorized to act', 'ENTRYPOINT_FAILED'))]
     fn test_set_starting_entropy_not_owner() {
         let mut game = new_adventurer(1000, 1696201757);
+        testing::set_block_number(1002);
         // change to different caller
         testing::set_contract_address(contract_address_const::<50>());
         // try to set starting entropy, should revert
@@ -2334,16 +2336,27 @@ mod tests {
     #[should_panic(expected: ('game already started', 'ENTRYPOINT_FAILED'))]
     fn test_set_starting_entropy_game_started() {
         let mut game = new_adventurer(1000, 1696201757);
+        testing::set_block_number(1002);
         // defeat starter beast
         game.attack(ADVENTURER_ID, true);
         // then attempt to set starting entropy, should revert
         game.set_starting_entropy(ADVENTURER_ID, 1);
     }
 
+
+    #[test]
+    #[should_panic(expected: ('valid hash not yet available', 'ENTRYPOINT_FAILED'))]
+    fn test_set_starting_entropy_before_hash_available() {
+        let mut game = new_adventurer(1000, 1696201757);
+        // attempt to set starting entropy before hash is available, should revert
+        game.set_starting_entropy(ADVENTURER_ID, 1);
+    }
+
     #[test]
     #[should_panic(expected: ('block hash should not be zero', 'ENTRYPOINT_FAILED'))]
     fn test_set_starting_entropy_zero_hash() {
         let mut game = new_adventurer(1000, 1696201757);
+        testing::set_block_number(1002);
         // attempt to pass in 0 for starting entropy hash, should revert
         game.set_starting_entropy(ADVENTURER_ID, 0);
     }
@@ -2352,6 +2365,7 @@ mod tests {
     #[should_panic(expected: ('starting entropy already set', 'ENTRYPOINT_FAILED'))]
     fn test_set_starting_entropy_double_call() {
         let mut game = new_adventurer(1000, 1696201757);
+        testing::set_block_number(1002);
         // attempt to set starting entropy twice, should revert
         game.set_starting_entropy(ADVENTURER_ID, 1);
         game.set_starting_entropy(ADVENTURER_ID, 1);
@@ -2360,6 +2374,7 @@ mod tests {
     #[test]
     fn test_set_starting_entropy_basic() {
         let mut game = new_adventurer(1000, 1696201757);
+        testing::set_block_number(1002);
         game.set_starting_entropy(ADVENTURER_ID, 123);
         // verify starting entropy was set
         assert(
@@ -2373,6 +2388,7 @@ mod tests {
     fn test_set_starting_entropy_wrong_hash() {
         let wrong_starting_entropy = 12345678910112;
         let mut game = new_adventurer_lvl3(1000, 1696201757, wrong_starting_entropy);
+        testing::set_block_number(1002);
 
         // go out exploring till beast
         game.explore(ADVENTURER_ID, true);