Move form validation to golang backend

components/app.vue

@@ -11,7 +11,7 @@
 </div>
 
 <home :user="user" v-else-if="active == 1" />
-<new-estimate :user="user" :fees="fees" v-else-if="active == 2" />
+<new-estimate :user="user" :fees="fees" :token="token" v-else-if="active == 2" />
 <estimates :user="user" :fees="fees" v-else-if="active == 3" />
 <settings :user="user" v-else-if="active == 4" />
 <sign-out :user="user" v-else-if="active == 5" />
@@ -43,6 +43,7 @@ function getCookie(name) {
 
 function refreshToken() {
 	const token = getCookie("skouter")
+	this.token = token
 
 	fetch(`/api/token`,
 		{method: 'GET',
@@ -62,6 +63,7 @@ function refreshToken() {
 
 function getUser() {
 	const token = getCookie("skouter")
+	this.token = token
 
 	return fetch(`/api/user`,
 		{method: 'GET',
@@ -101,20 +103,6 @@ function getFees() {
 
 }
 
-// The default fees of a new loan. Percentage values take precedent over amounts
-const fees = [
-	{ name: 'Processing fee', type: 'Lender Fees', amount: 500, perc: 0 },
-	{ name: 'Underwriting fee', type: 'Lender Fees', amount: 500, perc: 0 },
-	{ name: 'Credit Report', type: 'Services Required by Lender',
-	amount: 52.50 },
-	{ name: 'Appraisal', type: 'Services Required by Lender', amount: 52.50 },
-	{ name: 'Title Services', type: 'Title Company', amount: 1000 },
-	{ name: 'Lender\'s Title Insurance', type: 'Title Company', amount: 1599 },
-	{ name: 'Owner\'s Title Insurance', type: 'Title Company', amount: 451.00 },
-	{ name: 'Recording Charges', type: 'Government', amount: 99.00 },
-	{ name: 'State Tax', type: 'Government', amount: 2411.00 },
-]
-
 // Used to check the current section of the app generally without a regex match
 // each time.
 function active() {
@@ -183,6 +171,7 @@ export default {
 			hash: window.location.hash,
 			fees: [],
 			loadingError: "",
+			token: '',
 		}
 	},
 	created() {

components/new/details.vue

@@ -3,7 +3,7 @@
 <section class="form inputs">
 <h3>Loan</h3>
 <label>Name</label>
-<input :value="loans[sel].title" required
+<input :value="loan.title" required
 @input="(e) => $emit('update:name', stripLetters(e))">
 <button @click="() => $emit('del')">Delete</button>
 </section>
@@ -71,19 +71,19 @@
 <input type="radio"
     name="loan_type"
     value="fha"
-    :checked="loans[sel].type == 'fha'"
+    :checked="loan.type == 'fha'"
     @change="(e) => $emit('update:loanType', e.target.value)">
 <label>FHA</label>
 <input type="radio"
     name="loan_type"
     value="va"
-    :checked="loans[sel].type == 'va'"
+    :checked="loan.type == 'va'"
     @change="(e) => $emit('update:loanType', e.target.value)">
 <label>VA</label>
 <input type="radio"
     name="loan_type"
     value="usda"
-    :checked="loans[sel].type == 'usda'"
+    :checked="loan.type == 'usda'"
     @change="(e) => $emit('update:loanType', e.target.value)">
 <label>USDA</label>
 </section>
@@ -91,12 +91,12 @@
 <section class="form inputs">
 <h3>Loan Details</h3>
 <label>Loan Term (years)</label>
-<input :value="loans[sel].term"
+<input :value="loan.term"
 @input="(e) => $emit('update:term', stripInt(e))">
 
 <label>Loan Program</label>
 <select id="" name=""
-    :value="loans[sel].program"
+    :value="loan.program"
     @change="(e) => $emit('update:program', e.target.value)">
 	<option value="none">None</option>
 </select>
@@ -107,39 +107,39 @@
 <input :value="loan.amount"
 @input="(e) => $emit('update:amount', e)">
 <label>Housing Expense DTI (%) - Optional</label>
-<input :value="loans[sel].housingDti"
+<input :value="loan.housingDti"
 @input="(e) => $emit('update:housingDti', e)">
 <label>Total DTI (%) - Optional</label>
-<input :value="loans[sel].dti" @input="(e) => $emit('update:dti', e)">
+<input :value="loan.dti" @input="(e) => $emit('update:dti', e)">
 <label>Home Owner's Association ($/month)</label>
-<input :value="loans[sel].hoa"
+<input :value="loan.hoa"
 @input="(e) => { $emit('update:hoa', strip(e)) }">
 
 <label>Interest Rate (%)</label>
-<input :value="loans[sel].interest"
+<input :value="loan.interest"
 @input="(e) => { $emit('update:interest', stripPerc(e)) }">
 <label>Days of Interest</label>
-<input :value="loans[sel].interestDays"
+<input :value="loan.interestDays"
 @input="(e) => $emit('update:interestDays', stripInt(e))">
 
 <label>Hazard Insurance Escrow (months)</label>
-<input :value="loans[sel].hazardEscrow"
+<input :value="loan.hazardEscrow"
 @input="(e) => { $emit('update:hazardEscrow', stripInt(e)) }">
 <label>Hazard Insurance ($/month)</label>
-<input :value="loans[sel].hazard"
+<input :value="loan.hazard"
 @input="(e) => $emit('update:hazard', strip(e))">
 
 <label>Real Estate Tax Escrow (months)</label>
-<input :value="loans[sel].taxEscrow"
+<input :value="loan.taxEscrow"
 @input="e => $emit('update:taxEscrow', stripInt(e))">
 <label>Real Estate Tax ($/month)</label>
-<input :value="loans[sel].tax"
+<input :value="loan.tax"
 @input="(e) => $emit('update:tax', strip(e))">
 </section>
 
 <section class="form inputs">
 <h3>Fees</h3>
-<div v-for="(fee, indx) in estimate.loans[sel].fees"
+<div v-for="(fee, indx) in loan.fees"
 :key="fee.name + indx" class="fee"
 >
 	<label>
@@ -147,7 +147,7 @@
 	{{fee.type}}
 	</label>
 	<img width="21" height="21" src="/assets/image/icon/x-red.svg"
-	@click="() => estimate.loans[sel].fees.splice(indx, 1)">
+	@click="() => loan.fees.splice(indx, 1)">
 </div>
 <button @click="resetFees">Reset</button>
 <button @click="createFee">New</button>
@@ -165,18 +165,18 @@
 <h3>Mortgage Insurance</h3>
 <div class="row">
     <input checked type="radio" name="mi"/><label>Manual %</label>
-    <input type="checkbox" :checked="loans[sel].mi.monthly"
+    <input type="checkbox" :checked="loan.mi.monthly"
     @change="e => $emit('toggle:manualMIMonthly')" />
     <label>monthly</label>
 </div>
 <div class="row">
-<input :value="loans[sel].mi.rate" @input="e => $emit('update:manualMI', stripPerc(e))" />
+<input :value="loan.mi.rate" @input="e => $emit('update:manualMI', stripPerc(e))" />
 </div>
 </section>
 
 <section class="form inputs">
 
-	<button @click="() => validate() && $emit('continue')">Continue</button>
+	<button @click="validate">Continue</button>
 
 	<ul class="errors">
 	<li v-for="e in errors">{{e}}</li>
@@ -205,12 +205,25 @@ function createFee() {
 function addFee(fee, isDebit) {
 
 	if (!isDebit) fee.amount = fee.amount * -1
-	this.estimate.loans[this.sel].fees.push(fee)
+	this.loan.fees.push(fee)
 	this.newFee = null
 }
 
-
 function validate() {
+    fetch(`/api/estimate/validate`,
+		{method: 'POST',
+		    body: JSON.stringify(this.estimate),
+    		headers: {
+        	"Accept": "application/json",
+        	"Authorization": `Bearer ${this.token}`,
+    		},
+	}).then(response => {
+		if (response.ok) { return response.json() }
+		response.text().then(t => this.errors = [t])
+	}).then(result => {
+		if (result) this.$emit('continue', result)
+	})
+    /* 
 	let errors = []
 	const estimate = this.estimate
 
@@ -252,6 +265,7 @@ function validate() {
 	}
 	
 	return true
+	*/
 }
 
 function generate() {
@@ -268,7 +282,7 @@ export default {
 		strip, stripInt, stripLetters, stripPerc, createFee, addFee, validate,
 		generate
 	},
-	props: ['estimate', 'loans', 'sel', 'loan'],
+	props: ['estimate', 'loan', 'token'],
 	// Loan updates assume the currently selected loan is being modified, and
 	// $emit has no need to clarify.
 	emits: [

components/new/new.vue

@@ -25,6 +25,7 @@ class="bi bi-plus" viewBox="0 0 16 16"> <path d="M8 4a.5.5 0 0 1 .5.5v3h3a.5.5 0
   :loans="estimate.loans"
   :sel="sel"
   :loan="loan"
+  :token="token"
   
   @update:name="(name) => loans[sel].title = name"
   @del="del"
@@ -85,7 +86,7 @@ const example = {
 		pud: true, // Property under development
 		zip: '',
 		fees: [],
-		mi: {monthly: false, rate: 0}
+		mi: { monthly: false, rate: 0 }
 }
 
 // The default loans on a new estimate
@@ -192,7 +193,7 @@ function setHousingDti(e) {
 }
 
 function generate() {
-	window.location.hash = 'new/summary'
+    window.location.hash = 'new/summary'
 }
   
 // Percentage values of fees always take precedent over amounts. The conversion
@@ -204,7 +205,7 @@ export default {
 		setDti, setHousingDti
 	},
 	computed: { loan },
-	props: ['user', 'fees'],
+	props: ['user', 'fees', 'token'],
 	data() {
 		return {
 				estimate: estimate,
@@ -216,7 +217,8 @@ export default {
 	},
 	created() {
 		this.estimate.loans.forEach(l => l.fees = this.createFees())
-		window.addEventListener("hashchange", () => this.hash = window.location.hash)
+		window.addEventListener("hashchange",
+		() => this.hash = window.location.hash)
 	}
 }
 </script>

skouter.go

@@ -130,7 +130,7 @@ type Estimate struct {
 	Id		int 	`json:"id"`
 	User		int 	`json:"user"`
 	Borrower	Borrower 	`json:"borrower"`
-	Transaction	string 	`json:"transaction"`
+	Transaction	int 	`json:"transaction"`
 	Price		int 	`json:"price"`
 	Property	string 	`json:"property"`
 	Occupancy	string	`json:"occupancy"`
@@ -499,9 +499,9 @@ func fetchMi(db *sql.DB, estimate *Estimate, pos int) []MI {
 		"Condo Hi-rise": "CON",
 	}
 
-	var purposeCodes = map[string]string {
-		"Purchase": "PUR",
-		"Refinance": "RRT",
+	var purposeCodes = map[int]string {
+		1: "PUR",
+		2: "RRT",
 	}
 
 	body, err := json.Marshal(map[string]any{
@@ -632,10 +632,6 @@ func getToken(w http.ResponseWriter, db *sql.DB, r *http.Request) {
 		http.StatusInternalServerError)}
 }
 
-func validateEstimate() {
-	return
-}
-
 func getClaims(r *http.Request) (UserClaims, error) {
 	claims := new(UserClaims)
 	_, tokenStr, found := strings.Cut(r.Header.Get("Authorization"), " ")
@@ -886,11 +882,104 @@ func createEstimate(w http.ResponseWriter, db *sql.DB, r *http.Request) {
 	err := json.NewDecoder(r.Body).Decode(&estimate)
 	if err != nil { http.Error(w, "Invalid fields.", 422); return }
 
-	if err != nil { http.Error(w, "Error creating user.", 422); return }
-
 	json.NewEncoder(w).Encode(estimate)
 }
 
+func checkConventional(l Loan, b Borrower) error {
+	if b.Credit < 620 {
+		return errors.New("Credit score too low for conventional loan")
+	}
+	
+	// Buyer needs to put down 20% to avoid mortgage insurance
+	if (l.Ltv > 80 && l.Mi.Rate == 0) {
+		return errors.New(fmt.Sprintln(
+			l.Name,
+			"down payment must be 20% to avoid insurance",
+			))
+	}
+	
+	return nil
+}
+
+func checkFHA(l Loan, b Borrower) error {
+	if b.Credit < 500 {
+		return errors.New("Credit score too low for FHA loan")
+	}
+	
+	if (l.Ltv > 96.5) {
+		return errors.New("FHA down payment must be at least 3.5%")
+	}
+	
+	if (b.Credit < 580 && l.Ltv > 90) {
+		return errors.New("FHA down payment must be at least 10%")
+	}
+	
+	// Debt-to-income must be below 45% if credit score is below 580.
+	if (b.Credit < 580 && l.Dti > 45) {
+		return errors.New(fmt.Sprintln(
+			l.Name, "debt to income is too high for credit score.",
+		))
+	}
+	
+	return nil
+}
+
+// Should also check loan amount limit maybe with an API.
+func checkEstimate(e Estimate) error {
+	if e.Property == "" { return errors.New("Empty property type") }
+	if e.Price == 0 { return errors.New("Empty property price") }
+	if e.Borrower.Num == 0 {
+		return errors.New("Missing number of borrowers")
+	}
+	if e.Borrower.Credit == 0 {
+		return errors.New("Missing borrower credit score")
+	}
+	if e.Borrower.Income == 0 {
+		return errors.New("Missing borrower credit income")
+	}
+	
+	for _, l := range e.Loans {
+		if l.Amount == 0 {
+			return errors.New(fmt.Sprintln(l.Name, "loan amount cannot be zero"))
+		}
+		if l.Term == 0 {
+			return errors.New(fmt.Sprintln(l.Name, "loan term cannot be zero"))
+		}
+		if l.Interest == 0 {
+			return errors.New(fmt.Sprintln(l.Name, "loan interest cannot be zero"))
+		}
+		
+		// Can be used to check rules for specific loan types
+		var err error
+		switch l.Type.Name {
+		case "Conventional":
+			err = checkConventional(l, e.Borrower)
+		case "FHA":
+			err = checkFHA(l, e.Borrower)
+		case "VA":
+			err = checkConventional(l, e.Borrower)
+		case "USDA":
+			err = checkConventional(l, e.Borrower)
+		}
+		
+		if err != nil { return err }
+	}
+	
+	println("done")
+	return nil
+	
+}
+
+func validateEstimate(w http.ResponseWriter, db *sql.DB, r *http.Request) {
+	var estimate Estimate
+	err := json.NewDecoder(r.Body).Decode(&estimate)
+
+	if err != nil { http.Error(w, "Invalid fields.", 422); return }
+	
+	err = checkEstimate(estimate)
+	if err != nil { http.Error(w, err.Error(), 406); return }
+}
+
 func api(w http.ResponseWriter, r *http.Request) {
 	var args []string
 
@@ -946,6 +1035,10 @@ func api(w http.ResponseWriter, r *http.Request) {
 	r.Method == http.MethodPost &&
 	guard(r, 1):
 		createEstimate(w, db, r)
+	case match(p, "/api/estimate/validate", &args) &&
+	r.Method == http.MethodPost &&
+	guard(r, 1):
+		validateEstimate(w, db, r)
 	}
 
 	db.Close()