From 71b8066f1636427a98ad44cfc7c71d036a4303dc Mon Sep 17 00:00:00 2001
From: Martin Hansen <dontbeevilpls@gmail.com>
Date: Mon, 17 Jan 2022 18:46:55 +0100
Subject: [PATCH] refactor: auth improvements

---
 reader/nordigen/auth.go     | 90 +++++++++++++++++++++++--------------
 reader/nordigen/nordigen.go |  7 ++-
 2 files changed, 63 insertions(+), 34 deletions(-)

diff --git a/reader/nordigen/auth.go b/reader/nordigen/auth.go
index 0942f8d..1e317ef 100644
--- a/reader/nordigen/auth.go
+++ b/reader/nordigen/auth.go
@@ -2,6 +2,7 @@ package nordigen
 
 import (
 	"encoding/json"
+	"errors"
 	"fmt"
 	"log"
 	"os"
@@ -14,71 +15,94 @@ import (
 
 const redirectPort = ":3000"
 
-func requisitionFileLocation(endUserId string) string {
-	return fmt.Sprintf("%s/%s.json", ynabber.DataDir(), endUserId)
+type Authorization struct {
+	Client    nordigen.Client
+	BankID    string
+	EndUserId string
+}
+
+func (auth Authorization) Store() string {
+	return fmt.Sprintf("%s/%s.json", ynabber.DataDir(), auth.EndUserId)
 }
 
 // AuthorizationWrapper tries to get requisition from disk, if it fails it will
 // create a new and store that one to disk.
-func AuthorizationWrapper(cli nordigen.Client, bankId string, endUserId string) (nordigen.Requisition, error) {
-	store := requisitionFileLocation(endUserId)
-	requisitionFile, err := os.ReadFile(store)
-    if err != nil {
-		log.Print("No existing requisition found, creating a new...")
-        requisition, err := GetAuthorization(cli, bankId, endUserId)
-		if err != nil {
-			return nordigen.Requisition{}, err
-		}
-		err = StoreAuthorization(requisition, endUserId)
-		if err != nil {
-			log.Printf("Failed to write requisition to disk: %s", err)
-		}
-		log.Printf("Requisition stored for reuse: %s", store)
-		return requisition, nil
-    }
+func (auth Authorization) Wrapper() (nordigen.Requisition, error) {
+	requisitionFile, err := os.ReadFile(auth.Store())
+	if errors.Is(err, os.ErrNotExist) {
+		log.Print("Requisition is not found")
+		return auth.CreateAndSave()
+	} else if err != nil {
+		return nordigen.Requisition{}, fmt.Errorf("ReadFile: %w", err)
+	}
 
 	var requisition nordigen.Requisition
 	err = json.Unmarshal(requisitionFile, &requisition)
 	if err != nil {
-		return nordigen.Requisition{}, err
+		log.Print("Failed to parse requisition file")
+		return auth.CreateAndSave()
+	}
+
+	switch requisition.Status {
+	case "EX":
+		log.Printf("Requisition is expired")
+		return auth.CreateAndSave()
+	case "LN":
+		return requisition, nil
+	default:
+		log.Printf("Unsupported requisition status: %s", requisition.Status)
+		return auth.CreateAndSave()
+	}
+}
+
+func (auth Authorization) CreateAndSave() (nordigen.Requisition, error) {
+	log.Print("Creating new requisition...")
+	requisition, err := auth.Create()
+	if err != nil {
+		return nordigen.Requisition{}, fmt.Errorf("AuthorizationCreate: %w", err)
+	}
+	err = auth.Save(requisition)
+	if err != nil {
+		log.Printf("Failed to write requisition to disk: %s", err)
 	}
-	log.Print("Found existing requisition, using it...")
+	log.Printf("Requisition stored for reuse: %s", auth.Store())
 	return requisition, nil
 }
 
-func StoreAuthorization(requisition nordigen.Requisition, endUserId string) error {
-	store := requisitionFileLocation(endUserId)
+func (auth Authorization) Save(requisition nordigen.Requisition) error {
 	requisitionFile, err := json.Marshal(requisition)
 	if err != nil {
 		return err
 	}
 
-	err = os.WriteFile(store, requisitionFile, 0644)
+	err = os.WriteFile(auth.Store(), requisitionFile, 0644)
 	if err != nil {
 		return err
 	}
 	return nil
 }
 
-func GetAuthorization(cli nordigen.Client, bankId string, endUserId string) (nordigen.Requisition, error) {
+func (auth Authorization) Create() (nordigen.Requisition, error) {
 	requisition := nordigen.Requisition{
-		Redirect:  "http://localhost" + redirectPort,
-		Reference: strconv.Itoa(int(time.Now().Unix())),
-		Agreement: "",
+		Redirect:      "http://localhost" + redirectPort,
+		Reference:     strconv.Itoa(int(time.Now().Unix())),
+		Agreement:     "",
+		InstitutionId: auth.BankID,
 	}
 
-	r, err := cli.CreateRequisition(requisition)
+	r, err := auth.Client.CreateRequisition(requisition)
 	if err != nil {
-		return nordigen.Requisition{}, err
+		return nordigen.Requisition{}, fmt.Errorf("CreateRequisition: %w", err)
 	}
 
-	log.Printf("Initiate requisition by going to: %s", r.Redirect)
+	log.Printf("Initiate requisition by going to: %s", r.Link)
 
-	for r.Status == "CR" {
-		r, err = cli.GetRequisition(r.Id)
+	// Keep waiting for the user to accept the requisition
+	for r.Status != "LN" {
+		r, err = auth.Client.GetRequisition(r.Id)
 
 		if err != nil {
-			return nordigen.Requisition{}, err
+			return nordigen.Requisition{}, fmt.Errorf("GetRequisition: %w", err)
 		}
 		time.Sleep(1 * time.Second)
 	}
diff --git a/reader/nordigen/nordigen.go b/reader/nordigen/nordigen.go
index d174928..f74a47c 100644
--- a/reader/nordigen/nordigen.go
+++ b/reader/nordigen/nordigen.go
@@ -53,7 +53,12 @@ func BulkReader() (t []ynabber.Transaction, err error) {
 	if err != nil {
 		return nil, fmt.Errorf("failed to create client: %w", err)
 	}
-	r, err := AuthorizationWrapper(*c, bankId, "ynabber")
+	Authorization := Authorization{
+		Client:    *c,
+		BankID:    bankId,
+		EndUserId: "ynabber",
+	}
+	r, err := Authorization.Wrapper()
 	if err != nil {
 		return nil, fmt.Errorf("failed to authorize: %w", err)
 	}