proof of wager

program/src/payout.rs

@@ -0,0 +1,62 @@
+use std::mem::size_of;
+
+use ore_api::prelude::*;
+use solana_program::{keccak::hashv, slot_hashes::SlotHash};
+use steel::*;
+
+pub fn process_payout(accounts: &[AccountInfo<'_>], _data: &[u8]) -> ProgramResult {
+    // Load accounts.
+    let clock = Clock::get()?;
+    let [signer_info, block_info, wager_info, recipient_info, treasury_info, treasury_tokens_info, system_program, token_program, slot_hashes_sysvar] =
+        accounts
+    else {
+        return Err(ProgramError::NotEnoughAccountKeys);
+    };
+    signer_info.is_signer()?;
+    let block = block_info
+        .as_account_mut::<Block>(&ore_api::ID)?
+        .assert_mut(|b| b.ends_at < clock.slot)?
+        .assert_mut(|b| b.payed_out == 0)?;
+    let wager = wager_info.as_account::<Wager>(&ore_api::ID)?;
+    recipient_info.as_associated_token_account(&wager.authority, &MINT_ADDRESS)?;
+    treasury_info.has_address(&TREASURY_ADDRESS)?;
+    treasury_tokens_info
+        .has_address(&TREASURY_TOKENS_ADDRESS)?
+        .is_writable()?;
+    system_program.is_program(&system_program::ID)?;
+    token_program.is_program(&spl_token::ID)?;
+    slot_hashes_sysvar.is_sysvar(&sysvar::slot_hashes::ID)?;
+
+    // Select the slothash from the slot at when the round ended.
+    // The represents the server seed for the provably fair random number.
+    let offset = clock.slot - block.ends_at;
+    let size = size_of::<SlotHash>();
+    let i = offset as usize * size;
+    let slot_hash = &slot_hashes_sysvar.data.borrow()[i..i + size];
+    block.noise = hashv(&[&block.noise, slot_hash]).to_bytes();
+
+    // Calculate the random number.
+    let x = u64::from_le_bytes(block.noise[0..8].try_into().unwrap());
+    let y = u64::from_le_bytes(block.noise[8..16].try_into().unwrap());
+    let z = u64::from_le_bytes(block.noise[16..24].try_into().unwrap());
+    let w = u64::from_le_bytes(block.noise[24..32].try_into().unwrap());
+    let roll = (x ^ y ^ z ^ w) % block.total_bets;
+
+    // Assert that the wager account passed in is the winner.
+    assert!(roll >= wager.cumulative_bets && roll < wager.cumulative_bets + wager.amount);
+
+    // Mark the block as paid out.
+    block.payed_out = 1;
+
+    // Transfer the winnings to the recipient.
+    transfer_signed(
+        &treasury_info,
+        &treasury_tokens_info,
+        &recipient_info,
+        &token_program,
+        ONE_ORE / 2,
+        &[TREASURY],
+    )?;
+
+    Ok(())
+}