From 4d0f9573d724d426fc7f5393d454fcb25262cedb Mon Sep 17 00:00:00 2001
From: Shiva Nandan <shiva.nandan@juspay.in>
Date: Tue, 20 Aug 2024 17:35:09 +0530
Subject: [PATCH] refactor: refactor PreMountLoader

---
 src/Payments/PreMountLoader.res | 222 +++++++++++++-------------------
 1 file changed, 93 insertions(+), 129 deletions(-)

diff --git a/src/Payments/PreMountLoader.res b/src/Payments/PreMountLoader.res
index 4e3abf9a7..0ef19f3ad 100644
--- a/src/Payments/PreMountLoader.res
+++ b/src/Payments/PreMountLoader.res
@@ -1,63 +1,53 @@
-@react.component
-let make = (
-  ~sessionId,
-  ~publishableKey,
-  ~clientSecret,
-  ~endpoint,
-  ~ephemeralKey,
-  ~hyperComponentName: Types.hyperComponentName,
-  ~merchantHostname,
-) => {
-  open Utils
-  let (paymentMethodsResponseSent, setPaymentMethodsResponseSent) = React.useState(_ => false)
-  let (
-    customerPaymentMethodsResponseSent,
-    setCustomerPaymentMethodsResponseSent,
-  ) = React.useState(_ => false)
-  let (savedPaymentMethodsResponseSent, setSavedPaymentMethodsResponseSent) = React.useState(_ =>
-    false
-  )
-  let (sessionTokensResponseSent, setSessionTokensResponseSent) = React.useState(_ => false)
-  let logger = OrcaLogger.make(
-    ~sessionId,
-    ~source=Loader,
-    ~merchantId=publishableKey,
-    ~clientSecret,
-  )
+let sendPromiseData = (promise, key) => {
+  open Promise
+  promise
+  ->then(res => resolve(res))
+  ->catch(_err => resolve(JSON.Encode.null))
+  ->thenResolve(response => {
+    Utils.messageParentWindow([("response", response), ("data", key->JSON.Encode.string)])
+  })
+  ->ignore
+}
 
-  let (
-    paymentMethodsResponse,
-    customerPaymentMethodsResponse,
-    sessionTokensResponse,
-    savedPaymentMethodsResponse,
-  ) = React.useMemo0(() => {
-    let paymentMethodsResponse = switch hyperComponentName {
-    | Elements =>
-      PaymentHelpers.fetchPaymentMethodList(
+let useMessageHandler = getPromisesAndMessageHandler => {
+  React.useEffect0(() => {
+    let (promises, messageHandler) = getPromisesAndMessageHandler()
+
+    open Promise
+    Promise.all(promises)
+    ->thenResolve(_ => {
+      Utils.messageParentWindow([("preMountLoaderIframeUnMount", true->JSON.Encode.bool)])
+      Window.removeEventListener("message", messageHandler)
+    })
+    ->ignore
+
+    Utils.messageParentWindow([("preMountLoaderIframeMountedCallback", true->JSON.Encode.bool)])
+    Window.addEventListener("message", messageHandler)
+    Some(() => Window.removeEventListener("message", messageHandler))
+  })
+}
+
+module PreMountLoaderForElements = {
+  @react.component
+  let make = (~logger, ~publishableKey, ~clientSecret, ~endpoint, ~merchantHostname) => {
+    useMessageHandler(() => {
+      let paymentMethodsPromise = PaymentHelpers.fetchPaymentMethodList(
         ~clientSecret,
         ~publishableKey,
         ~logger,
         ~switchToCustomPod=false,
         ~endpoint,
       )
-    | _ => JSON.Encode.null->Promise.resolve
-    }
 
-    let customerPaymentMethodsResponse = switch hyperComponentName {
-    | Elements =>
-      PaymentHelpers.fetchCustomerPaymentMethodList(
+      let customerPaymentMethodsPromise = PaymentHelpers.fetchCustomerPaymentMethodList(
         ~clientSecret,
         ~publishableKey,
         ~optLogger=Some(logger),
         ~switchToCustomPod=false,
         ~endpoint,
       )
-    | _ => JSON.Encode.null->Promise.resolve
-    }
 
-    let sessionTokensResponse = switch hyperComponentName {
-    | Elements =>
-      PaymentHelpers.fetchSessions(
+      let sessionTokensPromise = PaymentHelpers.fetchSessions(
         ~clientSecret,
         ~publishableKey,
         ~optLogger=Some(logger),
@@ -65,101 +55,75 @@ let make = (
         ~endpoint,
         ~merchantHostname,
       )
-    | _ => JSON.Encode.null->Promise.resolve
-    }
 
-    let savedPaymentMethodsResponse = switch hyperComponentName {
-    | PaymentMethodsManagementElements =>
-      PaymentHelpers.fetchSavedPaymentMethodList(
+      let messageHandler = (ev: Window.event) => {
+        let json = ev.data->Utils.safeParse
+        let dict = json->Utils.getDictFromJson
+        if dict->Dict.get("sendPaymentMethodsResponse")->Option.isSome {
+          paymentMethodsPromise->sendPromiseData("payment_methods")
+        } else if dict->Dict.get("sendCustomerPaymentMethodsResponse")->Option.isSome {
+          customerPaymentMethodsPromise->sendPromiseData("customer_payment_methods")
+        } else if dict->Dict.get("sendSessionTokensResponse")->Option.isSome {
+          sessionTokensPromise->sendPromiseData("session_tokens")
+        }
+      }
+
+      let promises = [paymentMethodsPromise, customerPaymentMethodsPromise, sessionTokensPromise]
+      (promises, messageHandler)
+    })
+
+    React.null
+  }
+}
+
+module PreMountLoaderForPMMElements = {
+  @react.component
+  let make = (~logger, ~endpoint, ~ephemeralKey) => {
+    useMessageHandler(() => {
+      let savedPaymentMethodsPromise = PaymentHelpers.fetchSavedPaymentMethodList(
         ~ephemeralKey,
         ~optLogger=Some(logger),
         ~switchToCustomPod=false,
         ~endpoint,
       )
-    | _ => JSON.Encode.null->Promise.resolve
-    }
-
-    (
-      paymentMethodsResponse,
-      customerPaymentMethodsResponse,
-      sessionTokensResponse,
-      savedPaymentMethodsResponse,
-    )
-  })
 
-  let sendPromiseData = (promise, key) => {
-    open Promise
-    promise
-    ->then(res => {
-      messageParentWindow([("response", res), ("data", key->JSON.Encode.string)])
-      switch key {
-      | "payment_methods" => setPaymentMethodsResponseSent(_ => true)
-      | "session_tokens" => setSessionTokensResponseSent(_ => true)
-      | "customer_payment_methods" => setCustomerPaymentMethodsResponseSent(_ => true)
-      | "saved_payment_methods" => setSavedPaymentMethodsResponseSent(_ => true)
-      | _ => ()
+      let messageHandler = (ev: Window.event) => {
+        let json = ev.data->Utils.safeParse
+        let dict = json->Utils.getDictFromJson
+        if dict->Dict.get("sendSavedPaymentMethodsResponse")->Belt.Option.isSome {
+          savedPaymentMethodsPromise->sendPromiseData("saved_payment_methods")
+        }
       }
-      resolve()
-    })
-    ->catch(_err => {
-      messageParentWindow([("response", JSON.Encode.null), ("data", key->JSON.Encode.string)])
-      resolve()
+
+      let promises = [savedPaymentMethodsPromise]
+      (promises, messageHandler)
     })
-    ->ignore
-  }
 
-  let handle = (ev: Window.event) => {
-    let json = ev.data->safeParse
-    let dict = json->Utils.getDictFromJson
-    if dict->Dict.get("sendPaymentMethodsResponse")->Option.isSome {
-      paymentMethodsResponse->sendPromiseData("payment_methods")
-    } else if dict->Dict.get("sendCustomerPaymentMethodsResponse")->Option.isSome {
-      customerPaymentMethodsResponse->sendPromiseData("customer_payment_methods")
-    } else if dict->Dict.get("sendSessionTokensResponse")->Option.isSome {
-      sessionTokensResponse->sendPromiseData("session_tokens")
-    } else if dict->Dict.get("sendSavedPaymentMethodsResponse")->Belt.Option.isSome {
-      savedPaymentMethodsResponse->sendPromiseData("saved_payment_methods")
-    }
+    React.null
   }
+}
 
-  React.useEffect0(() => {
-    Window.addEventListener("message", handle)
-    messageParentWindow([("preMountLoaderIframeMountedCallback", true->JSON.Encode.bool)])
-    Some(
-      () => {
-        Window.removeEventListener("message", handle)
-      },
-    )
-  })
-
-  React.useEffect4(() => {
-    let handleUnmount = () => {
-      messageParentWindow([("preMountLoaderIframeUnMount", true->JSON.Encode.bool)])
-      Window.removeEventListener("message", handle)
-    }
-
-    switch hyperComponentName {
-    | Elements =>
-      if (
-        paymentMethodsResponseSent &&
-        customerPaymentMethodsResponseSent &&
-        sessionTokensResponseSent
-      ) {
-        handleUnmount()
-      }
-    | PaymentMethodsManagementElements =>
-      if savedPaymentMethodsResponseSent {
-        handleUnmount()
-      }
-    }
-
-    None
-  }, (
-    paymentMethodsResponseSent,
-    customerPaymentMethodsResponseSent,
-    sessionTokensResponseSent,
-    savedPaymentMethodsResponseSent,
-  ))
+@react.component
+let make = (
+  ~sessionId,
+  ~publishableKey,
+  ~clientSecret,
+  ~endpoint,
+  ~ephemeralKey,
+  ~hyperComponentName: Types.hyperComponentName,
+  ~merchantHostname,
+) => {
+  let logger = OrcaLogger.make(
+    ~sessionId,
+    ~source=Loader,
+    ~merchantId=publishableKey,
+    ~clientSecret,
+  )
 
-  React.null
+  switch hyperComponentName {
+  | Elements =>
+    <PreMountLoaderForElements logger publishableKey clientSecret endpoint merchantHostname />
+  | PaymentMethodsManagementElements =>
+    <PreMountLoaderForPMMElements logger endpoint ephemeralKey />
+  }
 }