Add configurable fee with linear decay to bid wall

programs/bid_wall/src/error.rs

@@ -16,4 +16,6 @@ pub enum BidWallError {
     InvalidInputAmount,
     #[msg("Invalid crank address")]
     InvalidCrankAddress,
+    #[msg("Invalid fee decay duration. Must be greater than 0")]
+    InvalidFeeDecayDuration,
 }

programs/bid_wall/src/events.rs

@@ -30,6 +30,9 @@ pub struct BidWallInitializedEvent {
     pub base_mint: Pubkey,
     pub fee_recipient: Pubkey,
     pub duration_seconds: u32,
+    pub fee_decay_duration_seconds: u32,
+    pub max_fee_bps: u16,
+    pub min_fee_bps: u16,
     pub pda_bump: u8,
 }
 

programs/bid_wall/src/instructions/initialize_bid_wall.rs

@@ -5,6 +5,7 @@ use anchor_spl::{
 };
 
 use crate::{
+    error::BidWallError,
     events::{BidWallInitializedEvent, CommonFields},
     state::BidWall,
     usdc_mint,
@@ -16,6 +17,9 @@ pub struct InitializeBidWallArgs {
     pub nonce: u64,
     pub initial_amm_quote_reserves: u64,
     pub duration_seconds: u32,
+    pub fee_decay_duration_seconds: u32,
+    pub max_fee_bps: u16,
+    pub min_fee_bps: u16,
 }
 
 #[event_cpi]
@@ -63,7 +67,14 @@ pub struct InitializeBidWall<'info> {
 }
 
 impl InitializeBidWall<'_> {
-    pub fn validate(&self, _args: &InitializeBidWallArgs) -> Result<()> {
+    pub fn validate(&self, args: &InitializeBidWallArgs) -> Result<()> {
+        // Prevents division by zero in the sell_tokens instruction
+        require_gt!(
+            args.fee_decay_duration_seconds,
+            0,
+            BidWallError::InvalidFeeDecayDuration
+        );
+
         Ok(())
     }
 
@@ -101,6 +112,9 @@ impl InitializeBidWall<'_> {
             base_mint: ctx.accounts.base_mint.key(),
             fee_recipient: ctx.accounts.fee_recipient.key(),
             duration_seconds: args.duration_seconds,
+            fee_decay_duration_seconds: args.fee_decay_duration_seconds,
+            max_fee_bps: args.max_fee_bps,
+            min_fee_bps: args.min_fee_bps,
             pda_bump: ctx.bumps.bid_wall,
         });
 
@@ -116,6 +130,9 @@ impl InitializeBidWall<'_> {
             base_mint: ctx.accounts.base_mint.key(),
             fee_recipient: ctx.accounts.fee_recipient.key(),
             duration_seconds: args.duration_seconds,
+            fee_decay_duration_seconds: ctx.accounts.bid_wall.fee_decay_duration_seconds,
+            max_fee_bps: ctx.accounts.bid_wall.max_fee_bps,
+            min_fee_bps: ctx.accounts.bid_wall.min_fee_bps,
             pda_bump: ctx.bumps.bid_wall,
         });
 

programs/bid_wall/src/instructions/sell_tokens.rs

@@ -2,7 +2,7 @@ use crate::{
     error::BidWallError,
     events::{BidWallTokensSoldEvent, CommonFields},
     state::BidWall,
-    usdc_mint, FEE_BPS, TOKENS_TO_PARTICIPANTS,
+    usdc_mint, TOKENS_TO_PARTICIPANTS,
 };
 
 use anchor_lang::prelude::*;
@@ -87,6 +87,8 @@ impl SellTokens<'_> {
     pub fn handle(ctx: Context<Self>, args: SellTokensArgs) -> Result<()> {
         let SellTokensArgs { amount_in } = args;
 
+        let clock = Clock::get()?;
+
         // We calculate the total NAV as as sum of:
         // - The initial quote reserves of the Futarchy AMM
         // - The quote tokens in the DAO treasury (which can be spent by the DAO)
@@ -109,8 +111,22 @@ impl SellTokens<'_> {
             BidWallError::InsufficientQuoteReserves
         );
 
+        let bid_wall_age_seconds = clock.unix_timestamp - ctx.accounts.bid_wall.created_timestamp;
+
+        let min_fee_bps = ctx.accounts.bid_wall.min_fee_bps as u128;
+        let max_fee_bps = ctx.accounts.bid_wall.max_fee_bps as u128;
+
+        // Calculate the fee in basis points based on the bid wall age.
+        // Formula is simple linear decay based on the fee decay duration.
+        // max_fee - (max_fee - min_fee) * bid_wall_age / fee_decay_duration_seconds
+        let fee_bps = min_fee_bps.max(
+            max_fee_bps
+                - (max_fee_bps - min_fee_bps) * bid_wall_age_seconds as u128
+                    / ctx.accounts.bid_wall.fee_decay_duration_seconds as u128,
+        );
+
         let amount_out_after_fee =
-            ((10_000_u128 - FEE_BPS as u128) * amount_out_before_fee as u128 / 10_000_u128) as u64;
+            ((10_000_u128 - fee_bps) * amount_out_before_fee as u128 / 10_000_u128) as u64;
 
         let fee = amount_out_before_fee - amount_out_after_fee;
 
@@ -157,7 +173,7 @@ impl SellTokens<'_> {
         ctx.accounts.bid_wall.seq_num += 1;
 
         emit_cpi!(BidWallTokensSoldEvent {
-            common: CommonFields::new(&Clock::get()?, ctx.accounts.bid_wall.seq_num),
+            common: CommonFields::new(&clock, ctx.accounts.bid_wall.seq_num),
             bid_wall: ctx.accounts.bid_wall.key(),
             amount_in: amount_in,
             amount_out: amount_out_after_fee,

programs/bid_wall/src/lib.rs

@@ -34,8 +34,6 @@ pub mod usdc_mint {
     declare_id!("EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v");
 }
 
-pub const FEE_BPS: u16 = 100;
-
 pub const TOKEN_SCALE: u64 = 1_000_000;
 /// 10M tokens with 6 decimals - the exact amount of tokens that end up in floating supply at launch
 pub const TOKENS_TO_PARTICIPANTS: u64 = 10_000_000 * TOKEN_SCALE;

programs/bid_wall/src/state/bid_wall.rs

@@ -31,6 +31,12 @@ pub struct BidWall {
     pub fee_recipient: Pubkey,
     /// The minimum duration in seconds before the bid wall can be closed.
     pub duration_seconds: u32,
+    /// The duration in seconds over which the fee linearly decays from the max fee to the min fee.
+    pub fee_decay_duration_seconds: u32,
+    /// The maximum fee in basis points.
+    pub max_fee_bps: u16,
+    /// The minimum fee in basis points.
+    pub min_fee_bps: u16,
     /// The PDA bump.
     pub pda_bump: u8,
 }

programs/v07_launchpad/src/instructions/complete_launch.rs

@@ -29,6 +29,8 @@ use futarchy::{InitialSpendingLimit, InitializeDaoParams, ProvideLiquidityParams
 
 use damm_v2_cpi::program::DammV2Cpi;
 
+pub const PASS_THRESHOLD_BPS: u16 = 300; // 3%
+
 /// Static accounts for completing a launch, used to reduce code duplication
 /// and conserve stack space.
 #[derive(Accounts)]
@@ -425,7 +427,7 @@ impl CompleteLaunch<'_> {
                 // We're providing liquidity, so that can be used for proposals
                 min_quote_futarchic_liquidity: 0,
                 min_base_futarchic_liquidity: 0,
-                pass_threshold_bps: 300,
+                pass_threshold_bps: PASS_THRESHOLD_BPS,
                 base_to_stake: TOKENS_TO_PARTICIPANTS / 20,
                 seconds_per_proposal: 3 * 24 * 60 * 60,
                 twap_start_delay_seconds: 24 * 60 * 60,
@@ -478,6 +480,9 @@ impl CompleteLaunch<'_> {
                 nonce: 0,
                 initial_amm_quote_reserves: usdc_to_lp,
                 duration_seconds: 3 * 30 * 24 * 60 * 60, // 3 months
+                fee_decay_duration_seconds: 14 * 24 * 60 * 60, // 14 days
+                max_fee_bps: PASS_THRESHOLD_BPS + 200,   // 2% more than the pass threshold = 5%
+                min_fee_bps: PASS_THRESHOLD_BPS, // Set min_fee to be the same as the pass threshold
             },
         )
     }

sdk/src/v0.7/BidWallClient.ts

@@ -56,6 +56,9 @@ export class BidWallClient {
   initializeBidWallIx({
     amount,
     durationSeconds,
+    feeDecayDurationSeconds,
+    maxFeeBps,
+    minFeeBps,
     initialAmmQuoteReserves,
     daoTreasury,
     authority,
@@ -68,6 +71,9 @@ export class BidWallClient {
   }: {
     amount: number;
     durationSeconds: number;
+    feeDecayDurationSeconds: number;
+    maxFeeBps: number;
+    minFeeBps: number;
     initialAmmQuoteReserves: number;
     daoTreasury: PublicKey;
     creator?: PublicKey;
@@ -98,6 +104,9 @@ export class BidWallClient {
         nonce,
         durationSeconds,
         initialAmmQuoteReserves: new BN(initialAmmQuoteReserves),
+        feeDecayDurationSeconds,
+        maxFeeBps,
+        minFeeBps,
       })
       .accounts({
         bidWall,

sdk/src/v0.7/types/bid_wall.ts

@@ -439,6 +439,23 @@ export type BidWall = {
             ];
             type: "u32";
           },
+          {
+            name: "feeDecayDurationSeconds";
+            docs: [
+              "The duration in seconds over which the fee linearly decays from the max fee to the min fee.",
+            ];
+            type: "u32";
+          },
+          {
+            name: "maxFeeBps";
+            docs: ["The maximum fee in basis points."];
+            type: "u16";
+          },
+          {
+            name: "minFeeBps";
+            docs: ["The minimum fee in basis points."];
+            type: "u16";
+          },
           {
             name: "pdaBump";
             docs: ["The PDA bump."];
@@ -490,6 +507,18 @@ export type BidWall = {
             name: "durationSeconds";
             type: "u32";
           },
+          {
+            name: "feeDecayDurationSeconds";
+            type: "u32";
+          },
+          {
+            name: "maxFeeBps";
+            type: "u16";
+          },
+          {
+            name: "minFeeBps";
+            type: "u16";
+          },
         ];
       };
     },
@@ -567,6 +596,21 @@ export type BidWall = {
           type: "u32";
           index: false;
         },
+        {
+          name: "feeDecayDurationSeconds";
+          type: "u32";
+          index: false;
+        },
+        {
+          name: "maxFeeBps";
+          type: "u16";
+          index: false;
+        },
+        {
+          name: "minFeeBps";
+          type: "u16";
+          index: false;
+        },
         {
           name: "pdaBump";
           type: "u8";
@@ -719,6 +763,11 @@ export type BidWall = {
       name: "InvalidCrankAddress";
       msg: "Invalid crank address";
     },
+    {
+      code: 6007;
+      name: "InvalidFeeDecayDuration";
+      msg: "Invalid fee decay duration. Must be greater than 0";
+    },
   ];
 };
 
@@ -1163,6 +1212,23 @@ export const IDL: BidWall = {
             ],
             type: "u32",
           },
+          {
+            name: "feeDecayDurationSeconds",
+            docs: [
+              "The duration in seconds over which the fee linearly decays from the max fee to the min fee.",
+            ],
+            type: "u32",
+          },
+          {
+            name: "maxFeeBps",
+            docs: ["The maximum fee in basis points."],
+            type: "u16",
+          },
+          {
+            name: "minFeeBps",
+            docs: ["The minimum fee in basis points."],
+            type: "u16",
+          },
           {
             name: "pdaBump",
             docs: ["The PDA bump."],
@@ -1214,6 +1280,18 @@ export const IDL: BidWall = {
             name: "durationSeconds",
             type: "u32",
           },
+          {
+            name: "feeDecayDurationSeconds",
+            type: "u32",
+          },
+          {
+            name: "maxFeeBps",
+            type: "u16",
+          },
+          {
+            name: "minFeeBps",
+            type: "u16",
+          },
         ],
       },
     },
@@ -1291,6 +1369,21 @@ export const IDL: BidWall = {
           type: "u32",
           index: false,
         },
+        {
+          name: "feeDecayDurationSeconds",
+          type: "u32",
+          index: false,
+        },
+        {
+          name: "maxFeeBps",
+          type: "u16",
+          index: false,
+        },
+        {
+          name: "minFeeBps",
+          type: "u16",
+          index: false,
+        },
         {
           name: "pdaBump",
           type: "u8",
@@ -1443,5 +1536,10 @@ export const IDL: BidWall = {
       name: "InvalidCrankAddress",
       msg: "Invalid crank address",
     },
+    {
+      code: 6007,
+      name: "InvalidFeeDecayDuration",
+      msg: "Invalid fee decay duration. Must be greater than 0",
+    },
   ],
 };

tests/bidWall/unit/cancelBidWall.test.ts

@@ -149,6 +149,9 @@ export default function suite() {
       .initializeBidWallIx({
         amount: 100_000_000000,
         durationSeconds,
+        feeDecayDurationSeconds: 2,
+        maxFeeBps: 200,
+        minFeeBps: 100,
         initialAmmQuoteReserves: ammQuoteVaultReserves.toNumber(),
         authority: this.payer.publicKey,
         creator: this.payer.publicKey,
@@ -229,10 +232,10 @@ export default function suite() {
       authorityUsdcBalanceAfter,
       authorityUsdcBalanceBefore + 50_000_000000n,
     );
-    // Fee recipient received 500 USDC in fees
+    // Fee recipient received 1000 USDC in fees
     assert.equal(
       feeRecipientUsdcBalanceAfter,
-      feeRecipientUsdcBalanceBefore + 500_000000n,
+      feeRecipientUsdcBalanceBefore + 1_000_000000n,
     );
   });