Select random investor

Fair-Squares · Oct 25, 2023 · bbdf4ea · bbdf4ea
1 parent b394bde
commit bbdf4ea
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Showing 5 changed files with 110 additions and 9 deletions.
diff --git a/Cargo.lock b/Cargo.lock
diff --git a/pallets/bidding/src/functions.rs b/pallets/bidding/src/functions.rs
@@ -1,6 +1,12 @@
 pub use super::*;
 pub use sp_runtime::{BoundedVec,Percent};
-pub use frame_support::pallet_prelude::ConstU32;
+pub use frame_support::{
+	dispatch::{DispatchResult, GetDispatchInfo},
+	ensure,
+	pallet_prelude::MaxEncodedLen,
+	traits::{Currency, ExistenceRequirement::KeepAlive, Get, Randomness, ReservableCurrency},
+	PalletId,
+};
 pub use Onboarding::Zero;
 pub use pallet_roles::vec;
 
@@ -36,6 +42,42 @@ impl<T: Config> Pallet<T> {
     }
 
 
+    /// Randomly choose an investor from among an investors list.
+	/// Returns `None` if there are no investors in the list.
+	fn choose_ticket(mut investors: Vec<AccountIdOf<T>>) -> (Option<AccountIdOf<T>>,usize) {
+        let total = investors.len() as u32;
+		if total == 0 {
+			return (None,0)
+		}
+		let mut random_number = Self::generate_random_number(0);
+
+		// Best effort attempt to remove bias from modulus operator.
+		for i in 1..T::MaxGenerateRandom::get() {
+			if random_number < u32::MAX - u32::MAX % total && ( 0..total-1).contains(&(random_number%total)) {
+				break
+			}
+
+			random_number = Self::generate_random_number(i);
+		}
+        let num = random_number % total; 
+        let inv = investors[num as usize].clone();
+		(Some(inv),num as usize)
+	}
+
+
+    	/// Generate a random number from a given seed.
+	/// Note that there is potential bias introduced by using modulus operator.
+	/// You should call this function with different seed values until the random
+	/// number lies within `u32::MAX - u32::MAX % n`.
+	/// TODO: deal with randomness freshness
+	/// https://github.com/paritytech/substrate/issues/8311
+	fn generate_random_number(seed: u32) -> u32 {
+		let (random_seed, _) = T::Randomness::random(&(T::PalletId::get(), seed).encode());
+		let random_number = <u32>::decode(&mut random_seed.as_ref())
+			.expect("secure hashes should always be bigger than u32; qed");
+		random_number
+	}
+
 
 }
 
diff --git a/pallets/bidding/src/lib.rs b/pallets/bidding/src/lib.rs
@@ -15,6 +15,8 @@ pub use pallet::*;
 //pub use weights::*;
 mod functions;
 mod types;
+pub use functions::*;
+pub use types::*;
 pub use pallet_onboarding as Onboarding;
 pub use pallet_roles as Roles;
 pub use pallet_housing_fund as Houses;
@@ -50,7 +52,10 @@ pub mod pallet {
 	+ Share::Config {
 		/// The overarching runtime event type.
 		type RuntimeEvent: From<Event<Self>> + IsType<<Self as frame_system::Config>::RuntimeEvent>;
-
+		/// Something that provides randomness in the runtime.
+		type Randomness: Randomness<Self::Hash, BlockNumberFor<Self>>;
+		#[pallet::constant]
+		type MaxGenerateRandom: Get<u32>;
 	}
 
 	/// A storage item for this pallet.

diff --git a/runtime/Cargo.toml b/runtime/Cargo.toml
@@ -51,6 +51,7 @@ pallet-assets = { git = "https://github.com/paritytech/polkadot-sdk",  tag = "po
 pallet-identity = { git = "https://github.com/paritytech/polkadot-sdk",  tag = "polkadot-v1.1.0", default-features = false }
 pallet-nfts = { git = "https://github.com/paritytech/polkadot-sdk",  tag = "polkadot-v1.1.0", default-features = false }
 pallet-nfts-runtime-api = { git = "https://github.com/paritytech/polkadot-sdk",  tag = "polkadot-v1.1.0", default-features = false }
+pallet-insecure-randomness-collective-flip = { git = "https://github.com/paritytech/polkadot-sdk",  tag = "polkadot-v1.1.0", default-features = false }
 sp-storage = { version = "13.0.0", default-features = false, git = "https://github.com/paritytech/polkadot-sdk",  tag = "polkadot-v1.1.0" }
 
 
@@ -124,7 +125,8 @@ std = [
 	"pallet-nfts/std",
 	"pallet-nfts-runtime-api/std",
 	"pallet-share_distributor/std",
-	"pallet-bidding/std"
+	"pallet-bidding/std",
+	"pallet-insecure-randomness-collective-flip/std",
 	### add new std
 ]
 runtime-benchmarks = [
@@ -152,7 +154,7 @@ runtime-benchmarks = [
 	"pallet-democracy/runtime-benchmarks",
 	"pallet-nfts/runtime-benchmarks",
 	"pallet-share_distributor/runtime-benchmarks",
-	"pallet-bidding/runtime-benchmarks"
+	"pallet-bidding/runtime-benchmarks",
 	### add new runtime-benchmarks
 ]
 try-runtime = [
@@ -179,7 +181,8 @@ try-runtime = [
 	"pallet-democracy/try-runtime",
 	"pallet-nfts/try-runtime",
 	"pallet-share_distributor/try-runtime",
-	"pallet-bidding/try-runtime"
+	"pallet-bidding/try-runtime",
+	"pallet-insecure-randomness-collective-flip/try-runtime",
 
 	### add new try-runtime
 ]
diff --git a/runtime/src/lib.rs b/runtime/src/lib.rs
@@ -289,15 +289,23 @@ impl pallet_roles::Config for Runtime {
 	//type WeightInfo = pallet_roles::weights::SubstrateWeight<Runtime>;
 }
 
+parameter_types!{
+	pub const MaxGenerateRandom:u32 =60;
+}
 impl pallet_bidding::Config for Runtime{
 	type RuntimeEvent = RuntimeEvent;
+	type MaxGenerateRandom = MaxGenerateRandom;
+	type Randomness = RandomnessCollectiveFlip;
+
 }
 
 impl pallet_finalizer::Config for Runtime{
 	type RuntimeEvent = RuntimeEvent;
 	//type WeightInfo = 
 }
 
+impl pallet_insecure_randomness_collective_flip::Config for Runtime {}
+
 impl pallet_council::Config for Runtime {
 	type RuntimeEvent = RuntimeEvent;
 	type RuntimeCall = RuntimeCall;
@@ -696,6 +704,7 @@ construct_runtime!(
 		FinalizerModule: pallet_finalizer,
 		ShareDistributorModule: pallet_share_distributor,
 		BiddingModule: pallet_bidding,
+		RandomnessCollectiveFlip: pallet_insecure_randomness_collective_flip,
 		// flag add pallet runtime
 	}
 );