Use the crosschain doc in the router

Author: peachbits

src/v3/router.ts

@@ -1,13 +1,19 @@
+import { asCouchDoc, syncedDocument } from 'edge-server-tools'
 import { HttpResponse } from 'serverlet'
 import { ExpressRequest } from 'serverlet/express'
 
 import { ONE_MINUTE } from './constants'
 import { getRates } from './getRates'
+import { dbSettings } from './providers/couch'
 import {
+  asCrossChainMapping,
   asIncomingGetRatesParams,
+  asStringNullMap,
+  CrossChainMapping,
   GetRatesParams,
   IncomingGetRatesParams
 } from './types'
+import { toCryptoKey } from './utils'
 
 const fixIncomingGetRatesParams = (
   rawParams: IncomingGetRatesParams,
@@ -49,16 +55,91 @@ const fixIncomingGetRatesParams = (
   return params as GetRatesParams
 }
 
+// Map incoming crypto assets to their cross-chain canonical versions
+// Also return a mapping from each original asset key to its canonical key
+const applyCrossChainMappings = (
+  params: GetRatesParams,
+  mapping: CrossChainMapping
+): {
+  mappedParams: GetRatesParams
+  originalToCanonicalKey: Map<string, string>
+} => {
+  const originalToCanonicalKey = new Map<string, string>()
+  const mappedCrypto = params.crypto.map(c => {
+    const originalKey = toCryptoKey(c.asset)
+    const cross = mapping[originalKey]
+    if (cross == null) {
+      originalToCanonicalKey.set(originalKey, originalKey)
+      return c
+    }
+    const canonicalAsset = {
+      pluginId: cross.destChain,
+      tokenId: cross.tokenId
+    }
+    const canonicalKey = toCryptoKey(canonicalAsset)
+    originalToCanonicalKey.set(originalKey, canonicalKey)
+    return {
+      ...c,
+      asset: canonicalAsset
+    }
+  })
+  return {
+    mappedParams: { ...params, crypto: mappedCrypto },
+    originalToCanonicalKey
+  }
+}
+
+const crosschainMappings = syncedDocument(
+  'crosschain:automated',
+  asCrossChainMapping
+)
+crosschainMappings.sync(dbSettings).catch(e => {
+  console.error('crosschainMappings sync error', e)
+})
+
 export const ratesV3 = async (
   request: ExpressRequest
 ): Promise<HttpResponse> => {
   try {
     const rightNow = new Date()
     const params = fixIncomingGetRatesParams(request.req.body, rightNow)
-    const result = await getRates(params, rightNow)
+
+    // Map all incoming crypto assets to their canonical versions
+    const { mappedParams, originalToCanonicalKey } = applyCrossChainMappings(
+      params,
+      crosschainMappings.doc
+    )
+    const result = await getRates(mappedParams, rightNow)
+
+    // Build a quick lookup from canonical key + isoDate -> rate
+    const canonicalLookup = new Map<string, number>()
+    for (const r of result.crypto) {
+      if (r.rate == null) continue
+      const key = `${r.isoDate.toISOString()}_${toCryptoKey(r.asset)}`
+      canonicalLookup.set(key, r.rate)
+    }
+
+    // Rebuild crypto results for the original requested assets
+    const remappedCrypto = params.crypto.map(c => {
+      const originalKey = toCryptoKey(c.asset)
+      const maybeCanonical = originalToCanonicalKey.get(originalKey)
+      const canonicalKey = maybeCanonical ?? originalKey
+      const lookupKey = `${c.isoDate.toISOString()}_${canonicalKey}`
+      const rate = canonicalLookup.get(lookupKey)
+      return {
+        isoDate: c.isoDate,
+        asset: c.asset,
+        rate
+      }
+    })
+
     return {
       headers: { 'content-type': 'application/json' },
-      body: JSON.stringify(result)
+      body: JSON.stringify({
+        targetFiat: params.targetFiat,
+        crypto: remappedCrypto,
+        fiat: result.fiat
+      })
     }
   } catch (e) {
     return {

src/v3/types.ts

@@ -155,7 +155,7 @@ export type RateDocument = ReturnType<typeof asRateDocument>
 const asTokenMappingsDoc = asCouchDoc(asTokenMap)
 export const wasExistingMappings = uncleaner(asTokenMappingsDoc)
 
-const asCrossChainMapping = asObject(
+export const asCrossChainMapping = asObject(
   asObject({
     sourceChain: asString,
     destChain: asString,