Contract Open-Sourcing

.github/workflows/ci.yml

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+name: CI
+
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+
+# cancel in-progress runs on new commits to same PR (gitub.event.number)
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.number || github.sha }}
+  cancel-in-progress: true
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    continue-on-error: true
+    steps:
+      - name: 📥 Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Setup Aiken
+        uses: aiken-lang/setup-aiken@v1
+        with:
+          version: v1.0.29-alpha
+
+      - name: 🧪 Run fmt check
+        run: aiken fmt --check
+
+      - name: 🧪 Run lint
+        run: aiken check -s -D
+
+      - name: 🎁 Run build
+        run: aiken build
+
+      - name: 🧪 Run test
+        run: aiken check

.gitignore

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+build

README.md

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+# butane-contracts
+
+Smart contracts for the Butane Protocol.

aiken.lock

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+# This file was generated by Aiken
+# You typically do not need to edit this file
+
+[[requirements]]
+name = "aiken-lang/stdlib"
+version = "1.9.0"
+source = "github"
+
+[[requirements]]
+name = "aiken-lang/fuzz"
+version = "1.0.0"
+source = "github"
+
+[[packages]]
+name = "aiken-lang/stdlib"
+version = "1.9.0"
+requirements = []
+source = "github"
+
+[[packages]]
+name = "aiken-lang/fuzz"
+version = "1.0.0"
+requirements = []
+source = "github"
+
+[etags]

aiken.toml

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+name = "butaneprotocol/butane-contracts"
+version = "0.0.1"
+licenses = []
+description = "Contracts for the Butane Protocol"
+dependencies = [
+  { name = "aiken-lang/stdlib", version = "1.9.0", source = "github" },
+  { name = "aiken-lang/fuzz", version = "1.0.0", source = "github" },
+]

lib/butane/prices.ak

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+use aiken/builtin
+use aiken/dict.{Dict}
+use aiken/math
+use aiken/math/rational.{Rational}
+use aiken/transaction/value.{AssetName, PolicyId, Value}
+use butane/types
+use butane/unsafe
+
+// Gets the raw collateralization ratio (CR) and health factor (HF) of a CDP
+pub fn get_collateral_finances(
+  p_list: List<Int>,
+  p_dom: Int,
+  v: Value,
+  assets: List<types.AssetClass>,
+  w_list: List<Int>,
+  w_dom: Int,
+  max_proportions_list: List<Int>,
+  synth_amount: Int,
+  callback: fn(Rational, Rational) -> a,
+) -> a {
+  let v2: Pairs<PolicyId, Dict<AssetName, Int>> =
+    v |> value.to_dict |> dict.to_pairs
+  let unweighted_capacity, capacity <-
+    do_get_borrowing_capacity(
+      u_value: v2,
+      debt: synth_amount,
+      unweighted_capacity: 0,
+      borrowing_capacity: 0,
+      collateral_assets: assets,
+      collateral_prices: p_list,
+      prices_denom: p_dom,
+      weights_denom: w_dom,
+      collateral_weights: w_list,
+      collateral_max_proportions: max_proportions_list,
+      callback: _,
+    )
+  let cr =
+    unsafe.unsome(rational.new(unweighted_capacity, p_dom * synth_amount))
+  let hf = unsafe.unsome(rational.new(capacity, synth_amount))
+  callback(cr, hf)
+}
+
+pub fn do_get_borrowing_capacity(
+  u_value: Pairs<PolicyId, Dict<AssetName, Int>>,
+  debt: Int,
+  unweighted_capacity: Int,
+  borrowing_capacity: Int,
+  collateral_assets: List<types.AssetClass>,
+  collateral_prices: List<Int>,
+  prices_denom: Int,
+  weights_denom: Int,
+  collateral_weights: List<Int>,
+  collateral_max_proportions: List<Int>,
+  callback: fn(Int, Int) -> a,
+) -> a {
+  when u_value is {
+    [Pair(pol, pol_v), ..vs] ->
+      do_get_borrowing_capacity_2(
+        pol: pol,
+        pol_v: pol_v |> dict.to_pairs,
+        and_finally: do_get_borrowing_capacity(vs, _, _, _, _, _, _, _, _, _, _),
+        debt: debt,
+        unweighted_capacity: unweighted_capacity,
+        borrowing_capacity: borrowing_capacity,
+        collateral_assets: collateral_assets,
+        collateral_prices: collateral_prices,
+        prices_denom: prices_denom,
+        weights_denom: weights_denom,
+        collateral_weights: collateral_weights,
+        collateral_max_proportions: collateral_max_proportions,
+        callback: callback,
+      )
+    _ -> callback(unweighted_capacity, borrowing_capacity)
+  }
+}
+
+pub fn do_get_borrowing_capacity_2(
+  pol: PolicyId,
+  pol_v: Pairs<AssetName, Int>,
+  and_finally: fn(
+    Int,
+    Int,
+    Int,
+    List<types.AssetClass>,
+    List<Int>,
+    Int,
+    Int,
+    List<Int>,
+    List<Int>,
+    fn(Int, Int) -> a,
+  ) ->
+    a,
+  debt: Int,
+  unweighted_capacity: Int,
+  borrowing_capacity: Int,
+  collateral_assets: List<types.AssetClass>,
+  collateral_prices: List<Int>,
+  prices_denom: Int,
+  weights_denom: Int,
+  collateral_weights: List<Int>,
+  collateral_max_proportions: List<Int>,
+  callback: fn(Int, Int) -> a,
+) -> a {
+  when pol_v is {
+    [Pair(token_name, qty), ..vs] ->
+      get_asset_price_then(
+        s: types.AssetClass { policy_id: pol, asset_name: token_name },
+        debt: debt,
+        unweighted_capacity: unweighted_capacity,
+        borrowing_capacity: borrowing_capacity,
+        qty: qty,
+        asset_list: collateral_assets,
+        price_list: collateral_prices,
+        prices_denom: prices_denom,
+        weights_denom: weights_denom,
+        weights_list: collateral_weights,
+        max_proportion_list: collateral_max_proportions,
+        continue_with: do_get_borrowing_capacity_2(
+          pol,
+          vs,
+          and_finally,
+          _,
+          _,
+          _,
+          _,
+          _,
+          _,
+          _,
+          _,
+          _,
+          _,
+        ),
+        callback: callback,
+      )
+    _ ->
+      and_finally(
+        debt,
+        unweighted_capacity,
+        borrowing_capacity,
+        collateral_assets,
+        collateral_prices,
+        prices_denom,
+        weights_denom,
+        collateral_weights,
+        collateral_max_proportions,
+        callback,
+      )
+  }
+}
+
+fn get_asset_price_then(
+  s: types.AssetClass,
+  debt: Int,
+  unweighted_capacity: Int,
+  borrowing_capacity: Int,
+  qty: Int,
+  asset_list: List<types.AssetClass>,
+  price_list: List<Int>,
+  prices_denom: Int,
+  weights_denom: Int,
+  weights_list: List<Int>,
+  max_proportion_list: List<Int>,
+  continue_with: fn(
+    Int,
+    Int,
+    Int,
+    List<types.AssetClass>,
+    List<Int>,
+    Int,
+    Int,
+    List<Int>,
+    List<Int>,
+    fn(Int, Int) -> a,
+  ) ->
+    a,
+  callback: fn(Int, Int) -> a,
+) -> a {
+  expect [asset_name, ..] = asset_list
+  if s == asset_name {
+    expect [price, ..] = price_list
+    let numerator = qty * price
+    continue_with(
+      debt,
+      unweighted_capacity + numerator,
+      borrowing_capacity + math.min(
+        // First case: the asset is not limited by the max proportion
+        numerator * weights_denom / builtin.head_list(weights_list) / prices_denom,
+        // Second case: the asset is limited by the max proportion
+        debt * builtin.head_list(max_proportion_list) / types.bp_precision,
+      ),
+      builtin.tail_list(asset_list),
+      builtin.tail_list(price_list),
+      prices_denom,
+      weights_denom,
+      builtin.tail_list(weights_list),
+      builtin.tail_list(max_proportion_list),
+      callback,
+    )
+  } else {
+    get_asset_price_then(
+      s: s,
+      debt: debt,
+      unweighted_capacity: unweighted_capacity,
+      borrowing_capacity: borrowing_capacity,
+      qty: qty,
+      asset_list: builtin.tail_list(asset_list),
+      price_list: builtin.tail_list(price_list),
+      prices_denom: prices_denom,
+      weights_denom: weights_denom,
+      weights_list: builtin.tail_list(weights_list),
+      max_proportion_list: builtin.tail_list(max_proportion_list),
+      continue_with: continue_with,
+      callback: callback,
+    )
+  }
+}
+
+test basic_bc_test() {
+  let
+    a,
+    b,
+  <-
+    do_get_borrowing_capacity(
+      value.from_asset("", "", 10)
+        |> value.to_dict
+        |> dict.to_pairs,
+      100,
+      0,
+      0,
+      [types.AssetClass { policy_id: "", asset_name: "" }],
+      [2],
+      1,
+      1,
+      [3],
+      [10_000],
+    )
+  (a, b) == (20, 6)
+}
+
+test basic_bc_test_2() {
+  let
+    a,
+    b,
+  <-
+    do_get_borrowing_capacity(
+      value.from_asset("", "", 10)
+        |> value.merge(value.from_asset("a", "b", 20))
+        |> value.to_dict
+        |> dict.to_pairs,
+      100,
+      0,
+      0,
+      [
+        types.AssetClass { policy_id: "", asset_name: "" },
+        types.AssetClass { policy_id: "a", asset_name: "b" },
+      ],
+      [2, 2],
+      1,
+      1,
+      [3, 3],
+      [10_000, 10_000],
+    )
+  (a, b) == (60, 19)
+}
+
+test basic_bc_test_m() {
+  let
+    a,
+    b,
+  <-
+    do_get_borrowing_capacity(
+      value.from_asset("", "", 10)
+        |> value.merge(value.from_asset("a", "b", 20))
+        |> value.merge(value.from_asset("c", "d", 20))
+        |> value.merge(value.from_asset("e", "f", 20))
+        |> value.merge(value.from_asset("g", "h", 20))
+        |> value.merge(value.from_asset("i", "j", 20))
+        |> value.to_dict
+        |> dict.to_pairs,
+      100,
+      0,
+      0,
+      [
+        types.AssetClass { policy_id: "", asset_name: "" },
+        types.AssetClass { policy_id: "a", asset_name: "b" },
+        types.AssetClass { policy_id: "c", asset_name: "d" },
+        types.AssetClass { policy_id: "e", asset_name: "f" },
+        types.AssetClass { policy_id: "g", asset_name: "h" },
+        types.AssetClass { policy_id: "i", asset_name: "j" },
+      ],
+      [2, 2, 2, 2, 2, 2],
+      1,
+      1,
+      [3, 3, 3, 3, 3, 3],
+      [10_000, 10_000, 10_000, 10_000, 10_000, 10_000],
+    )
+  (a, b) == (220, 71)
+}