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Terser token to token function
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@konchunas
konchunas committed Jun 16, 2021
1 parent 83b7d91 commit baf6630
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Showing 2 changed files with 105 additions and 119 deletions.
12 changes: 12 additions & 0 deletions contracts/partials/ITTDex.ligo
View file
Original file line number Diff line number Diff line change
Expand Up @@ -55,6 +55,18 @@ type swap_slice_type is record [
operation : swap_type;
]

type swap_side is record [
pool : nat;
token : address;
id: nat;
standard: token_type;
]

type swap_data is record [
to_: swap_side;
from_: swap_side;
]

type internal_swap_type is record [
s : dex_storage;
amount_in : nat;
Expand Down
212 changes: 93 additions & 119 deletions contracts/partials/TTMethodDex.ligo
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Original file line number Diff line number Diff line change
Expand Up @@ -26,6 +26,45 @@ function get_pair (const key : tokens_info; const s : dex_storage) : (pair_info
end;
} with (pair, token_id)

function form_pools(const from_pool: nat; const to_pool: nat; const supply: nat; const direction: swap_type) : pair_info is
case direction of
Buy -> record [
token_a_pool = to_pool;
token_b_pool = from_pool;
total_supply = supply;
]
| Sell -> record [
token_a_pool = from_pool;
token_b_pool = to_pool;
total_supply = supply;
]
end;

function form_swap_data(const pair: pair_info; const swap: tokens_info; const direction: swap_type) : swap_data is
block {
const side_a : swap_side = record [
pool = pair.token_a_pool;
token = swap.token_a_address;
id = swap.token_a_id;
standard = swap.token_a_type;
];
const side_b : swap_side = record [
pool = pair.token_b_pool;
token = swap.token_b_address;
id = swap.token_b_id;
standard = swap.token_b_type;
];
} with case direction of
Sell -> record [
from_ = side_a;
to_ = side_b;
]
| Buy -> record [
from_ = side_b;
to_ = side_a;
]
end;

(* Helper function to prepare the token transfer *)
function wrap_fa2_transfer_trx(const owner : address; const receiver : address; const value : nat; const token_id : nat) : transfer_type_fa2 is
TransferTypeFA2(list[
Expand Down Expand Up @@ -91,6 +130,17 @@ function transfer_fa12(
get_fa12_token_contract(contract_address)
);

function typed_transfer(
const sender_ : address;
const receiver : address;
const amount_ : nat;
const token_id : nat;
const contract_address : address;
const standard: token_type) : operation is
case standard of
Fa12 -> transfer_fa12(sender_, receiver, amount_, contract_address)
| Fa2 -> transfer_fa2(sender_, receiver, amount_, token_id, contract_address)
end;

#include "../partials/TTMethodFA2.ligo"

Expand Down Expand Up @@ -249,125 +299,49 @@ function token_to_token (const p : dex_action; const s : dex_storage; const this
then skip
else failwith ("Dex/zero-min-amount-out");

case params.operation of
| Sell -> {
(* calculate amount out *)
const token_a_in_with_fee : nat = params.amount_in * 997n;
const numerator : nat = token_a_in_with_fee * pair.token_b_pool;
const denominator : nat = pair.token_a_pool * 1000n + token_a_in_with_fee;

(* calculate swapped token amount *)
const token_b_out : nat = numerator / denominator;

(* ensure requirements *)
if token_b_out >= params.min_amount_out (* minimal XTZ amount out is sutisfied *)
then skip else failwith("Dex/wrong-min-out");

(* ensure requirements *)
if token_b_out <= pair.token_b_pool / 3n (* the price impact isn't to high *)
then {
(* update XTZ pool *)
pair.token_b_pool := abs(pair.token_b_pool - token_b_out);
pair.token_a_pool := pair.token_a_pool + params.amount_in;
} else failwith("Dex/high-out");

(* prepare operations to withdraw user's tokens and transfer XTZ *)
case params.pair.token_a_type of
| Fa12 -> {
operations := transfer_fa12(
Tezos.sender,
this,
params.amount_in,
params.pair.token_a_address) # operations;
}
| Fa2 -> {
operations := transfer_fa2(
Tezos.sender,
this,
params.amount_in,
params.pair.token_a_id,
params.pair.token_a_address) # operations;
}
end;
case params.pair.token_b_type of
| Fa12 -> {
operations :=
transfer_fa12(
this,
params.receiver,
token_b_out,
params.pair.token_b_address) # operations;
}
| Fa2 -> {
operations :=
transfer_fa2(
this,
params.receiver,
token_b_out,
params.pair.token_b_id,
params.pair.token_b_address) # operations;
}
end;
}
| Buy -> {
(* calculate amount out *)
const token_b_in_with_fee : nat = params.amount_in * 997n;
const numerator : nat = token_b_in_with_fee * pair.token_a_pool;
const denominator : nat = pair.token_b_pool * 1000n + token_b_in_with_fee;

(* calculate swapped token amount *)
const token_a_out : nat = numerator / denominator;

(* ensure requirements *)
if token_a_out >= params.min_amount_out (* minimal XTZ amount out is sutisfied *)
then skip else failwith("Dex/wrong-min-out");

(* ensure requirements *)
if token_a_out <= pair.token_a_pool / 3n (* the price impact isn't to high *)
then {
(* update XTZ pool *)
pair.token_a_pool := abs(pair.token_a_pool - token_a_out);
pair.token_b_pool := pair.token_b_pool + params.amount_in;
} else failwith("Dex/high-out");

(* prepare operations to withdraw user's tokens and transfer XTZ *)
case params.pair.token_a_type of
| Fa12 -> {
operations := transfer_fa12(
this,
params.receiver,
token_a_out,
params.pair.token_a_address) # operations;
}
| Fa2 -> {
operations := transfer_fa2(
this,
params.receiver,
token_a_out,
params.pair.token_a_id,
params.pair.token_a_address) # operations;
}
end;
case params.pair.token_b_type of
| Fa12 -> {
operations := transfer_fa12(
Tezos.sender,
this,
params.amount_in,
params.pair.token_b_address) # operations;
}
| Fa2 -> {
operations := transfer_fa2(
Tezos.sender,
this,
params.amount_in,
params.pair.token_b_id,
params.pair.token_b_address) # operations;
}
end;
}
end;
s.pairs[token_id] := pair;
const swap: swap_data = form_swap_data(pair, params.pair, params.operation);

(* calculate amount out *)
const from_in_with_fee : nat = params.amount_in * 997n;
const numerator : nat = from_in_with_fee * swap.to_.pool;
const denominator : nat = swap.from_.pool * 1000n + from_in_with_fee;

(* calculate swapped token amount *)
const out : nat = numerator / denominator;

(* ensure requirements *)
if out >= params.min_amount_out (* minimal XTZ amount out is sutisfied *)
then skip else failwith("Dex/wrong-min-out");

(* ensure requirements *)
if out <= swap.to_.pool / 3n (* the price impact isn't too high *)
then {
(* update XTZ pool *)
swap.to_.pool := abs(swap.to_.pool - out);
swap.from_.pool := swap.from_.pool + params.amount_in;

const updated_pair : pair_info = form_pools(swap.from_.pool, swap.to_.pool, pair.total_supply, params.operation);
s.pairs[token_id] := updated_pair;

} else failwith("Dex/high-out");

(* prepare operations to withdraw user's tokens and transfer XTZ *)
operations := list [
(* from *)
typed_transfer(Tezos.sender, this, params.amount_in,
swap.from_.id,
swap.from_.token,
swap.from_.standard
);
(* to *)
typed_transfer(this, params.receiver, out,
swap.to_.id,
swap.to_.token,
swap.to_.standard
)
];

(* TODO saving pool to storage *)
}
| InvestLiquidity(n) -> skip
| DivestLiquidity(n) -> skip
Expand Down

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