feat: listing

src/backend/Cargo.toml

@@ -10,8 +10,12 @@ crate-type = ["cdylib"]
 [dependencies]
 base64 = "0.21.5"
 candid = { version = "0.9.11", features = ["parser"] }
+crc32fast = "1.3.2"
+data-encoding = "2.5.0"
+hex = "0.4.3"
 ic-cdk = "0.11.3"
 ic-cdk-macros = "0.8.1"
+ic-cdk-timers = "0.5.1"
 ic-certified-map = "0.4.0"
 ic-ledger-types = "0.8.0"
 serde = { version = "1.0.192", features = ["derive"] }

src/backend/icp.rs

@@ -0,0 +1,82 @@
+use candid::Principal;
+use ic_cdk::api::id;
+use ic_ledger_types::{
+    AccountBalanceArgs, AccountIdentifier, BlockIndex, Memo, Subaccount, Tokens, TransferArgs,
+    TransferResult, DEFAULT_FEE, DEFAULT_SUBACCOUNT, MAINNET_LEDGER_CANISTER_ID,
+};
+
+use crate::read;
+
+pub fn revenue_account() -> AccountIdentifier {
+    AccountIdentifier::new(
+        &read(|state| state.revenue_account).expect("no revenue subaccount set"),
+        &DEFAULT_SUBACCOUNT,
+    )
+}
+pub fn user_account(principal: Principal) -> AccountIdentifier {
+    AccountIdentifier::new(&id(), &principal_to_subaccount(&principal))
+}
+
+pub fn main_account() -> AccountIdentifier {
+    AccountIdentifier::new(&id(), &DEFAULT_SUBACCOUNT)
+}
+
+pub async fn transfer(
+    to: AccountIdentifier,
+    amount: Tokens,
+    memo: Memo,
+    sub_account: Option<Subaccount>,
+) -> Result<BlockIndex, String> {
+    if amount < DEFAULT_FEE {
+        return Err("can't transfer amounts smaller than the fee".into());
+    }
+    let (result,): (TransferResult,) = ic_cdk::call(
+        MAINNET_LEDGER_CANISTER_ID,
+        "transfer",
+        (TransferArgs {
+            created_at_time: None,
+            memo,
+            amount: amount - DEFAULT_FEE,
+            fee: DEFAULT_FEE,
+            to,
+            from_subaccount: sub_account,
+        },),
+    )
+    .await
+    .map_err(|err| format!("call to ledger failed: {:?}", err))?;
+    result.map_err(|err| {
+        format!(
+            "transfer of `{}` ICP from `{}` failed: {:?}",
+            amount,
+            AccountIdentifier::new(&id(), &sub_account.unwrap_or(DEFAULT_SUBACCOUNT)),
+            err
+        )
+    })
+}
+
+pub async fn account_balance_of_principal(principal: Principal) -> Tokens {
+    account_balance(AccountIdentifier::new(
+        &id(),
+        &principal_to_subaccount(&principal),
+    ))
+    .await
+}
+
+async fn account_balance(account: AccountIdentifier) -> Tokens {
+    let (balance,): (Tokens,) = ic_cdk::call(
+        MAINNET_LEDGER_CANISTER_ID,
+        "account_balance",
+        (AccountBalanceArgs { account },),
+    )
+    .await
+    .expect("couldn't check balance");
+    balance
+}
+
+pub fn principal_to_subaccount(principal_id: &Principal) -> Subaccount {
+    let mut subaccount = [0; std::mem::size_of::<Subaccount>()];
+    let principal_id = principal_id.as_slice();
+    subaccount[0] = principal_id.len() as u8;
+    subaccount[1..1 + principal_id.len()].copy_from_slice(principal_id);
+    Subaccount(subaccount)
+}