feat: add FeePerGramStats to ffi library (#4114)

Description
---
Add ffi function for getting the fee per gram stats.

How Has This Been Tested?
---
`npm test -- -p none --name "As a client I want to get fee per gram stats"`

base_layer/core/src/mempool/unconfirmed_pool/unconfirmed_pool.rs

@@ -564,8 +564,7 @@ impl UnconfirmedPool {
             let mut total_fees = MicroTari::zero();
             let mut min_fee_per_gram = MicroTari::from(u64::MAX);
             let mut max_fee_per_gram = MicroTari::zero();
-            let mut last_count = 0;
-            for (i, key) in self.tx_by_priority.values().rev().enumerate().skip(offset) {
+            for key in self.tx_by_priority.values().rev().skip(offset) {
                 let tx = self.tx_by_key.get(key).ok_or(UnconfirmedPoolError::StorageOutofSync)?;
                 let weight = tx.weight;
 
@@ -574,23 +573,23 @@ impl UnconfirmedPool {
                 }
 
                 let total_tx_fee = tx.transaction.body.get_total_fee();
-                last_count = i + 1;
+                offset += 1;
                 let fee_per_gram = total_tx_fee / weight;
                 min_fee_per_gram = min_fee_per_gram.min(fee_per_gram);
                 max_fee_per_gram = max_fee_per_gram.max(fee_per_gram);
                 total_fees += total_tx_fee;
                 total_weight += weight;
             }
-            if last_count > 0 {
-                let stat = FeePerGramStat {
-                    order: start as u64,
-                    min_fee_per_gram,
-                    avg_fee_per_gram: total_fees / total_weight,
-                    max_fee_per_gram,
-                };
-                stats.push(stat);
+            if total_weight == 0 {
+                break;
             }
-            offset = last_count;
+            let stat = FeePerGramStat {
+                order: start as u64,
+                min_fee_per_gram,
+                avg_fee_per_gram: total_fees / total_weight,
+                max_fee_per_gram,
+            };
+            stats.push(stat);
         }
 
         Ok(stats)

base_layer/wallet_ffi/src/lib.rs

@@ -204,6 +204,8 @@ pub struct TariContacts(Vec<TariContact>);
 pub type TariContact = tari_wallet::contacts_service::storage::database::Contact;
 pub type TariCompletedTransaction = tari_wallet::transaction_service::storage::models::CompletedTransaction;
 pub type TariTransactionSendStatus = tari_wallet::transaction_service::handle::TransactionSendStatus;
+pub type TariFeePerGramStats = tari_wallet::transaction_service::handle::FeePerGramStatsResponse;
+pub type TariFeePerGramStat = tari_core::mempool::FeePerGramStat;
 pub type TariContactsLivenessData = tari_wallet::contacts_service::handle::ContactsLivenessData;
 pub type TariBalance = tari_wallet::output_manager_service::service::Balance;
 pub type TariMnemonicLanguage = tari_key_manager::mnemonic::MnemonicLanguage;
@@ -6630,6 +6632,278 @@ pub unsafe extern "C" fn log_debug_message(msg: *const c_char, error_out: *mut c
     }
 }
 
+/// ------------------------------------- FeePerGramStats ------------------------------------ ///
+
+/// Get the TariFeePerGramStats from a TariWallet.
+///
+/// ## Arguments
+/// `wallet` - The TariWallet pointer
+/// `count` - The maximum number of blocks to be checked
+/// `error_out` - Pointer to an int which will be modified to an error code should one occur, may not be null. Functions
+/// as an out parameter
+///
+/// ## Returns
+/// `*mut TariCompletedTransactions` - returns the transactions, note that it returns ptr::null_mut() if
+/// wallet is null or an error is encountered.
+///
+/// # Safety
+/// The ```fee_per_gram_stats_destroy``` method must be called when finished with a TariFeePerGramStats to prevent
+/// a memory leak.
+#[no_mangle]
+pub unsafe extern "C" fn wallet_get_fee_per_gram_stats(
+    wallet: *mut TariWallet,
+    count: c_uint,
+    error_out: *mut c_int,
+) -> *mut TariFeePerGramStats {
+    let mut error = 0;
+    ptr::swap(error_out, &mut error as *mut c_int);
+
+    if wallet.is_null() {
+        error = LibWalletError::from(InterfaceError::NullError("wallet".to_string())).code;
+        ptr::swap(error_out, &mut error as *mut c_int);
+        return ptr::null_mut();
+    }
+
+    match (*wallet).runtime.block_on(
+        (*wallet)
+            .wallet
+            .transaction_service
+            .get_fee_per_gram_stats_per_block(count as usize),
+    ) {
+        Ok(estimates) => Box::into_raw(Box::new(estimates)),
+        Err(e) => {
+            error!(target: LOG_TARGET, "Error getting the fee estimates: {:?}", e);
+            error = LibWalletError::from(WalletError::TransactionServiceError(e)).code;
+            ptr::swap(error_out, &mut error as *mut c_int);
+            ptr::null_mut()
+        },
+    }
+}
+
+/// Get length of stats from the TariFeePerGramStats.
+///
+/// ## Arguments
+/// `fee_per_gram_stats` - The pointer to a TariFeePerGramStats
+/// `error_out` - Pointer to an int which will be modified to an error code should one occur, may not be null. Functions
+/// as an out parameter
+///
+/// ## Returns
+/// `c_uint` - length of stats in TariFeePerGramStats
+///
+/// # Safety
+/// None
+#[no_mangle]
+pub unsafe extern "C" fn fee_per_gram_stats_get_length(
+    fee_per_gram_stats: *mut TariFeePerGramStats,
+    error_out: *mut c_int,
+) -> c_uint {
+    let mut error = 0;
+    ptr::swap(error_out, &mut error as *mut c_int);
+    let mut len = 0;
+    if fee_per_gram_stats.is_null() {
+        error = LibWalletError::from(InterfaceError::NullError("fee_per_gram_stats".to_string())).code;
+        ptr::swap(error_out, &mut error as *mut c_int);
+    } else {
+        len = (*fee_per_gram_stats).stats.len();
+    }
+    len as c_uint
+}
+
+/// Get TariFeePerGramStat at position from the TariFeePerGramStats.
+///
+/// ## Arguments
+/// `fee_per_gram_stats` - The pointer to a TariFeePerGramStats.
+/// `position` - The integer position.
+/// `error_out` - Pointer to an int which will be modified to an error code should one occur, may not be null. Functions
+/// as an out parameter.
+///
+/// ## Returns
+/// `*mut TariCompletedTransactions` - returns the TariFeePerGramStat, note that it returns ptr::null_mut() if
+/// fee_per_gram_stats is null or an error is encountered.
+///
+/// # Safety
+/// The ```fee_per_gram_stat_destroy``` method must be called when finished with a TariCompletedTransactions to 4prevent
+/// a memory leak.
+#[no_mangle]
+pub unsafe extern "C" fn fee_per_gram_stats_get_at(
+    fee_per_gram_stats: *mut TariFeePerGramStats,
+    position: c_uint,
+    error_out: *mut c_int,
+) -> *mut TariFeePerGramStat {
+    let mut error = 0;
+    ptr::swap(error_out, &mut error as *mut c_int);
+    if fee_per_gram_stats.is_null() {
+        error = LibWalletError::from(InterfaceError::NullError("fee_per_gram_stats".to_string())).code;
+        ptr::swap(error_out, &mut error as *mut c_int);
+        return ptr::null_mut();
+    }
+    let len = fee_per_gram_stats_get_length(fee_per_gram_stats, error_out);
+    if *error_out != 0 {
+        return ptr::null_mut();
+    }
+    if len == 0 || position > len - 1 {
+        error = LibWalletError::from(InterfaceError::PositionInvalidError).code;
+        ptr::swap(error_out, &mut error as *mut c_int);
+        return ptr::null_mut();
+    }
+    Box::into_raw(Box::new((*fee_per_gram_stats).stats[position as usize].clone()))
+}
+
+/// Frees memory for a TariFeePerGramStats
+///
+/// ## Arguments
+/// `fee_per_gram_stats` - The TariFeePerGramStats pointer
+///
+/// ## Returns
+/// `()` - Does not return a value, equivalent to void in C
+///
+/// # Safety
+/// None
+#[no_mangle]
+pub unsafe extern "C" fn fee_per_gram_stats_destroy(fee_per_gram_stats: *mut TariFeePerGramStats) {
+    if !fee_per_gram_stats.is_null() {
+        Box::from_raw(fee_per_gram_stats);
+    }
+}
+
+/// ------------------------------------------------------------------------------------------ ///
+
+/// ------------------------------------- FeePerGramStat ------------------------------------- ///
+
+/// Get the order of TariFeePerGramStat
+///
+/// ## Arguments
+/// `fee_per_gram_stats` - The TariFeePerGramStat pointer
+/// `error_out` - Pointer to an int which will be modified to an error code should one occur, may not be null. Functions
+/// as an out parameter.
+///
+/// ## Returns
+/// `c_ulonglong` - Returns order
+///
+/// # Safety
+/// None
+#[no_mangle]
+pub unsafe extern "C" fn fee_per_gram_stat_get_order(
+    fee_per_gram_stat: *mut TariFeePerGramStat,
+    error_out: *mut c_int,
+) -> c_ulonglong {
+    let mut error = 0;
+    ptr::swap(error_out, &mut error as *mut c_int);
+    let mut order = 0;
+    if fee_per_gram_stat.is_null() {
+        error = LibWalletError::from(InterfaceError::NullError("fee_per_gram_stat".to_string())).code;
+        ptr::swap(error_out, &mut error as *mut c_int);
+    } else {
+        order = (*fee_per_gram_stat).order;
+    }
+    order
+}
+
+/// Get the minimum fee per gram of TariFeePerGramStat
+///
+/// ## Arguments
+/// `fee_per_gram_stats` - The TariFeePerGramStat pointer
+/// `error_out` - Pointer to an int which will be modified to an error code should one occur, may not be null. Functions
+/// as an out parameter.
+///
+/// ## Returns
+/// `c_ulonglong` - Returns minimum fee per gram
+///
+/// # Safety
+/// None
+#[no_mangle]
+pub unsafe extern "C" fn fee_per_gram_stat_get_min_fee_per_gram(
+    fee_per_gram_stat: *mut TariFeePerGramStat,
+    error_out: *mut c_int,
+) -> c_ulonglong {
+    let mut error = 0;
+    ptr::swap(error_out, &mut error as *mut c_int);
+    let mut fee_per_gram = 0;
+    if fee_per_gram_stat.is_null() {
+        error = LibWalletError::from(InterfaceError::NullError("fee_per_gram_stat".to_string())).code;
+        ptr::swap(error_out, &mut error as *mut c_int);
+    } else {
+        fee_per_gram = (*fee_per_gram_stat).min_fee_per_gram.as_u64();
+    }
+    fee_per_gram
+}
+
+/// Get the average fee per gram of TariFeePerGramStat
+///
+/// ## Arguments
+/// `fee_per_gram_stats` - The TariFeePerGramStat pointer
+/// `error_out` - Pointer to an int which will be modified to an error code should one occur, may not be null. Functions
+/// as an out parameter.
+///
+/// ## Returns
+/// `c_ulonglong` - Returns average fee per gram
+///
+/// # Safety
+/// None
+#[no_mangle]
+pub unsafe extern "C" fn fee_per_gram_stat_get_avg_fee_per_gram(
+    fee_per_gram_stat: *mut TariFeePerGramStat,
+    error_out: *mut c_int,
+) -> c_ulonglong {
+    let mut error = 0;
+    ptr::swap(error_out, &mut error as *mut c_int);
+    let mut fee_per_gram = 0;
+    if fee_per_gram_stat.is_null() {
+        error = LibWalletError::from(InterfaceError::NullError("fee_per_gram_stat".to_string())).code;
+        ptr::swap(error_out, &mut error as *mut c_int);
+    } else {
+        fee_per_gram = (*fee_per_gram_stat).avg_fee_per_gram.as_u64();
+    }
+    fee_per_gram
+}
+
+/// Get the maximum fee per gram of TariFeePerGramStat
+///
+/// ## Arguments
+/// `fee_per_gram_stats` - The TariFeePerGramStat pointer
+/// `error_out` - Pointer to an int which will be modified to an error code should one occur, may not be null. Functions
+/// as an out parameter.
+///
+/// ## Returns
+/// `c_ulonglong` - Returns maximum fee per gram
+///
+/// # Safety
+/// None
+#[no_mangle]
+pub unsafe extern "C" fn fee_per_gram_stat_get_max_fee_per_gram(
+    fee_per_gram_stat: *mut TariFeePerGramStat,
+    error_out: *mut c_int,
+) -> c_ulonglong {
+    let mut error = 0;
+    ptr::swap(error_out, &mut error as *mut c_int);
+    let mut fee_per_gram = 0;
+    if fee_per_gram_stat.is_null() {
+        error = LibWalletError::from(InterfaceError::NullError("fee_per_gram_stat".to_string())).code;
+        ptr::swap(error_out, &mut error as *mut c_int);
+    } else {
+        fee_per_gram = (*fee_per_gram_stat).max_fee_per_gram.as_u64();
+    }
+    fee_per_gram
+}
+
+/// Frees memory for a TariFeePerGramStat
+///
+/// ## Arguments
+/// `fee_per_gram_stats` - The TariFeePerGramStat pointer
+///
+/// ## Returns
+/// `()` - Does not return a value, equivalent to void in C
+///
+/// # Safety
+/// None
+#[no_mangle]
+pub unsafe extern "C" fn fee_per_gram_stat_destroy(fee_per_gram_stat: *mut TariFeePerGramStat) {
+    if !fee_per_gram_stat.is_null() {
+        Box::from_raw(fee_per_gram_stat);
+    }
+}
+
+/// ------------------------------------------------------------------------------------------ ///
 #[cfg(test)]
 mod test {
     use std::{

base_layer/wallet_ffi/wallet.h

@@ -86,6 +86,10 @@ struct EmojiSet;
 
 struct TariTransactionKernel;
 
+struct TariFeePerGramStats;
+
+struct TariFeePerGramStat;
+
 /// -------------------------------- Transport Types ----------------------------------------------- ///
 
 // Creates a memory transport type
@@ -896,6 +900,22 @@ bool wallet_start_recovery(struct TariWallet *wallet, struct TariPublicKey *base
 /// None
 bool wallet_set_one_sided_payment_message(struct TariWallet *wallet, const char *message, int *error_out);
 
+struct TariFeePerGramStats* wallet_get_fee_per_gram_stats(struct TariWallet *wallet, unsigned int count, int *error_out);
+
+unsigned int fee_per_gram_stats_get_length(struct TariFeePerGramStats *fee_per_gram_stats, int *error_out);
+
+struct TariFeePerGramStat* fee_per_gram_stats_get_at(struct TariFeePerGramStats *fee_per_gram_stats, unsigned int position, int *error_out);
+
+void fee_per_gram_stats_destroy(struct TariFeePerGramStats *fee_per_gram_stats);
+
+unsigned long long fee_per_gram_stat_get_order(struct TariFeePerGramStat *fee_per_gram_stat, int *error_out);
+
+unsigned long long fee_per_gram_stat_get_min_fee_per_gram(struct TariFeePerGramStat *fee_per_gram_stat, int *error_out);
+
+unsigned long long fee_per_gram_stat_get_avg_fee_per_gram(struct TariFeePerGramStat *fee_per_gram_stat, int *error_out);
+
+unsigned long long fee_per_gram_stat_get_max_fee_per_gram(struct TariFeePerGramStat *fee_per_gram_stat, int *error_out);
+
 // Frees memory for a TariWallet
 void wallet_destroy(struct TariWallet *wallet);