create: database for the exchange

backend/src/database/Order.ts

@@ -0,0 +1,23 @@
+import { Field, Poseidon, PublicKey } from 'o1js'
+
+export class Order {
+    maker: string
+    amount: number
+    price: number
+
+    constructor(maker: string, amount: number, price: number) {
+        this.maker = maker
+        this.amount = amount
+        this.price = price
+    }
+
+    _GetHash(): Field {
+        const maker = PublicKey.fromBase58(this.maker)
+        const amount = new Field(this.amount)
+        const price = new Field(this.price)
+
+        const hash = Poseidon.hash([...maker.toFields(), ...amount.toFields(), ...price.toFields()])
+
+        return hash
+    }
+}

backend/src/database/Pair.ts

@@ -0,0 +1,59 @@
+import { Field, MerkleTree, Poseidon, PublicKey } from 'o1js'
+import { Order } from './Order'
+import { ORDERS_HEIGHT } from 'xane'
+
+interface AddOrder {
+    side: 'BUY' | 'SELL'
+    amount: number
+    price: number
+    maker: string
+}
+
+export class Pair {
+    baseCurrency: string
+    quoteCurrency: string
+    buyOrders: Array<Order>
+    sellOrders: Array<Order>
+    buyOrdersTree: MerkleTree
+    sellOrdersTree: MerkleTree
+
+    constructor(baseCurrency: string, quoteCurrency: string) {
+        this.baseCurrency = baseCurrency
+        this.quoteCurrency = quoteCurrency
+        this.buyOrders = []
+        this.sellOrders = []
+        this.buyOrdersTree = new MerkleTree(ORDERS_HEIGHT)
+        this.sellOrdersTree = new MerkleTree(ORDERS_HEIGHT)
+    }
+
+    _GetHash(): Field {
+        const baseCurrency = PublicKey.fromBase58(this.baseCurrency)
+        const quoteCurrency = PublicKey.fromBase58(this.quoteCurrency)
+        const buyOrdersRoot = this.buyOrdersTree.getRoot()
+        const sellOrdersRoot = this.sellOrdersTree.getRoot()
+
+        const hash = Poseidon.hash([
+            ...baseCurrency.toFields(),
+            ...quoteCurrency.toFields(),
+            buyOrdersRoot,
+            sellOrdersRoot,
+        ])
+
+        return hash
+    }
+
+    _AddOrder(params: AddOrder) {
+        const order = new Order(params.maker, params.amount, params.price)
+
+        switch (params.side) {
+            case 'BUY':
+                this.buyOrders.push(order)
+                this.buyOrdersTree.setLeaf(BigInt(this.buyOrders.length), order._GetHash())
+                break
+            case 'SELL':
+                this.sellOrders.push(order)
+                this.sellOrdersTree.setLeaf(BigInt(this.sellOrders.length), order._GetHash())
+                break
+        }
+    }
+}

backend/src/database/index.ts

@@ -0,0 +1,41 @@
+import { MerkleTree, PublicKey } from 'o1js'
+import { ORDERS_HEIGHT, PAIRS_HEIGHT } from 'xane'
+import { Pair } from './Pair'
+import { Errors } from 'xane/build/src/Exchange'
+
+export class Database {
+    #data: Array<Pair>
+    #tree: MerkleTree
+
+    constructor() {
+        this.#data = []
+        this.#tree = new MerkleTree(PAIRS_HEIGHT)
+    }
+
+    findPair(baseCurrency: string, quoteCurrency: string): Pair | undefined {
+        const index = this.#data.findIndex(
+            (pair) => pair.baseCurrency === baseCurrency && pair.quoteCurrency === quoteCurrency
+        )
+        return this.#data.at(index)
+    }
+
+    addPair(baseCurrency: string, quoteCurrency: string) {
+        const existingIndex = this.#data.findIndex(
+            (pair) => pair.baseCurrency === baseCurrency && pair.quoteCurrency === quoteCurrency
+        )
+
+        const existingIndexReversed = this.#data.findIndex(
+            (pair) => pair.baseCurrency === quoteCurrency && pair.quoteCurrency === baseCurrency
+        )
+
+        if (existingIndex) throw Errors.PairAlreadyExists
+        if (existingIndexReversed) throw Errors.PairAlreadyExists
+
+        const pairIndex = BigInt(this.#data.length)
+
+        const pair = new Pair(baseCurrency, quoteCurrency)
+
+        this.#data.push(pair)
+        this.#tree.setLeaf(pairIndex, pair._GetHash())
+    }
+}

backend/src/index.ts

@@ -1,6 +1,9 @@
 import { App } from '@tinyhttp/app'
 import { Encoding } from 'o1js'
 import  { Token } from 'xane'
+import { Database } from './database'
+
+const database = new Database()
 
 const app = new App()