fix: Update land id logic.

land_registry/src/land_register.cairo

@@ -68,6 +68,7 @@ pub mod LandRegistryContract {
         price_update_count: Map::<u256, u256>, // listing_id -> number of price updates
         active_listings: Map::<u256, u256>, // index -> listing_id
         active_listing_count: u256,
+        id_exists: Map::<u256, bool>,
     }
 
     #[event]
@@ -130,9 +131,21 @@ pub mod LandRegistryContract {
             let caller = get_caller_address();
 
             let timestamp = get_block_timestamp();
-            // Generate unique land ID based on owner, timestamp and location
-            let land_id = create_land_id(caller, timestamp, location);
+            // Generate unique land ID based on owner, timestamp, location, and a counter
+            // This counter increases for each registration to re-ensure uniqueness.
+            let mut counter = self.land_count.read();
+            let mut land_id = create_land_id(caller, timestamp, location, counter);
+
+            while self.id_exists.read(land_id) {
+                // This is highly impossible, but not impossible. re-iterate.
+                counter += 1;
+                land_id = create_land_id(caller, timestamp, location, counter);
+            };
+
             let transaction_count = self.land_transaction_count.read(land_id);
+
+            // id is available, now make it unavailable.
+            self.id_exists.write(land_id, true);
 
             // Create new land record
             let new_land = Land {

land_registry/src/utils.cairo

@@ -4,16 +4,21 @@ pub mod utils {
     use core::hash::{HashStateTrait, HashStateExTrait};
     use land_registry::interface::land_register::{Location, LandUse};
 
+    pub const MODULO_BASE: u256 = 100000000000000000000000000000000;    // reduce the id to 32 digits
 
-    pub fn create_land_id(caller: ContractAddress, timestamp: u64, location: Location) -> u256 {
+    pub fn create_land_id(
+        caller: ContractAddress, timestamp: u64, location: Location, counter: u256
+    ) -> u256 {
         let caller_hash = PoseidonTrait::new().update_with(caller).finalize();
         let timestamp_hash = PoseidonTrait::new().update_with(timestamp).finalize();
         let location_hash = PoseidonTrait::new()
             .update_with(location.latitude + location.longitude)
+            .update_with(counter * 255_u256)
             .finalize();
 
         let felt_land_id = caller_hash + timestamp_hash + location_hash;
-        let land_id: u256 = felt_land_id.into();
+        let mut land_id: u256 = felt_land_id.into();
+        land_id = land_id % MODULO_BASE;
         land_id
     }
 

land_registry/tests/test_land_register.cairo

@@ -7,6 +7,7 @@ use land_registry::interface::land_register::{
     ILandRegistryDispatcher, ILandRegistryDispatcherTrait, LandUse, Location, LandStatus,
     ListingStatus
 };
+use land_registry::utils::utils::MODULO_BASE;
 use starknet::ContractAddress;
 use core::array::ArrayTrait;
 use core::traits::TryInto;
@@ -54,6 +55,7 @@ fn test_can_register_land() {
 
     // Register the land
     let land_id = land_register_dispatcher.register_land(location, area, land_use);
+    assert_le!(land_id, MODULO_BASE - 1); // ensure the id is within the 32-digit range.
 
     // Get the registered land
     let registered_land = land_register_dispatcher.get_land(land_id);
@@ -89,10 +91,7 @@ fn test_can_create_land_id() {
     start_cheat_block_timestamp(contract_address, 10);
 
     let id_1 = land_register_dispatcher.register_land(location1, area, land_use);
-    assert(
-        id_1 == 689216240506425664519995665376830138699152617179386928383439581252423035401,
-        'land_id is not as expected (1)'
-    );
+    assert(id_1 == 76145004285422410213294800731643, 'land_id is not as expected (1)');
 
     stop_cheat_caller_address(contract_address);
     stop_cheat_block_timestamp(contract_address);
@@ -102,10 +101,7 @@ fn test_can_create_land_id() {
     start_cheat_block_timestamp(contract_address, 20);
 
     let id_2 = land_register_dispatcher.register_land(location2, area, land_use);
-    assert(
-        id_2 == 14747943344839073547474207539210781044163306897453701102442319167742800565,
-        'land_id is not as expected (2)'
-    );
+    assert(id_2 == 4946593347159045342371278487724, 'land_id is not as expected (2)');
 
     stop_cheat_caller_address(contract_address);
     stop_cheat_block_timestamp(contract_address);
@@ -115,11 +111,8 @@ fn test_can_create_land_id() {
     start_cheat_block_timestamp(contract_address, 30);
 
     let id_3 = land_register_dispatcher.register_land(location3, area, land_use);
-    assert(
-        id_3 == 864555402638950626684962868225518693284860492943333490893906025290030385222,
-        'land_id is not as expected (3)'
-    );
-
+    assert(id_3 == 83119874197453254617171158536104, 'land_id is not as expected (3)');
+    println!("id 3: {}", id_3);
     stop_cheat_caller_address(contract_address);
     stop_cheat_block_timestamp(contract_address);
 }