From 95887332785a44ab076aab1120444a3c09da55a3 Mon Sep 17 00:00:00 2001
From: Adrian Bonpin <adrianbonpin@gmail.com>
Date: Sun, 26 Apr 2026 01:12:03 +0800
Subject: [PATCH] feat: add auth form validation schemas and password strength
 utility

---
 lib/auth/password-strength.ts | 93 +++++++++++++++++++++++++++++++++++
 lib/auth/validation.ts        | 49 ++++++++++++++++++
 2 files changed, 142 insertions(+)
 create mode 100644 lib/auth/password-strength.ts
 create mode 100644 lib/auth/validation.ts

diff --git a/lib/auth/password-strength.ts b/lib/auth/password-strength.ts
new file mode 100644
index 0000000..598fb61
--- /dev/null
+++ b/lib/auth/password-strength.ts
@@ -0,0 +1,93 @@
+export type StrengthLevel = "weak" | "fair" | "good" | "strong" | "excellent"
+
+export interface PasswordStrength {
+    score: number
+    level: StrengthLevel
+    feedback: string[]
+}
+
+const COMMON_PATTERNS = [
+    "password",
+    "123456",
+    "12345678",
+    "qwerty",
+    "abc123",
+    "monkey",
+    "master",
+    "dragon",
+    "login",
+    "admin",
+    "letmein",
+    "welcome",
+    "shadow",
+    "sunshine",
+    "trustno1",
+    "iloveyou",
+]
+
+export function checkPasswordStrength(password: string): PasswordStrength {
+    if (!password) {
+        return { score: 0, level: "weak", feedback: ["Enter a password"] }
+    }
+
+    let score = 0
+    const feedback: string[] = []
+
+    // Length scoring
+    if (password.length >= 10) score += 20
+    else feedback.push("Use at least 10 characters")
+
+    if (password.length >= 14) score += 10
+    else if (password.length >= 10) feedback.push("Use 14+ characters for extra security")
+
+    if (password.length >= 18) score += 10
+
+    // Character variety
+    const hasUpper = /[A-Z]/.test(password)
+    const hasLower = /[a-z]/.test(password)
+    const hasNumber = /[0-9]/.test(password)
+    const hasSpecial = /[^A-Za-z0-9]/.test(password)
+
+    if (hasUpper) score += 15
+    else feedback.push("Add an uppercase letter")
+
+    if (hasLower) score += 15
+    else feedback.push("Add a lowercase letter")
+
+    if (hasNumber) score += 15
+    else feedback.push("Add a number")
+
+    if (hasSpecial) score += 15
+    else feedback.push("Add a special character (!@#$%^&*)")
+
+    // Common pattern check
+    const lower = password.toLowerCase()
+    const isCommon = COMMON_PATTERNS.some((p) => lower.includes(p))
+    if (!isCommon) score += 10
+    else feedback.push("Avoid common passwords")
+
+    // Repeated characters
+    const hasRepeated = /(.)\1{2,}/.test(password)
+    if (!hasRepeated) score += 5
+    else feedback.push("Avoid repeated characters")
+
+    // Mixed positions (not all numbers at end, not all caps at start)
+    const endsWithNumbers = /[0-9]+$/.test(password) && !/[0-9]/.test(password.slice(0, -3))
+    const startsWithCaps = /^[A-Z]{3,}/.test(password) && !/[A-Z]/.test(password.slice(3))
+    if (!endsWithNumbers && !startsWithCaps) score += 5
+
+    // Determine level
+    let level: StrengthLevel
+    if (score <= 20) level = "weak"
+    else if (score <= 40) level = "fair"
+    else if (score <= 60) level = "good"
+    else if (score <= 80) level = "strong"
+    else level = "excellent"
+
+    // If all checks pass, clear feedback
+    if (feedback.length === 0) {
+        feedback.push("Great password!")
+    }
+
+    return { score, level, feedback }
+}
diff --git a/lib/auth/validation.ts b/lib/auth/validation.ts
new file mode 100644
index 0000000..f173e37
--- /dev/null
+++ b/lib/auth/validation.ts
@@ -0,0 +1,49 @@
+import { z } from "zod"
+
+export const loginEmailSchema = z.object({
+    email: z.string().email("Please enter a valid email address"),
+})
+
+export const loginSchema = z.object({
+    email: z.string().email("Please enter a valid email address"),
+    password: z.string().min(1, "Password is required"),
+})
+
+export const signupSchema = z.object({
+    name: z
+        .string()
+        .min(1, "Name is required")
+        .max(100, "Name must be 100 characters or less"),
+    email: z.string().email("Please enter a valid email address"),
+    password: z
+        .string()
+        .min(10, "Password must be at least 10 characters"),
+})
+
+export const otpSchema = z.object({
+    otp: z.string().length(6, "OTP must be exactly 6 digits"),
+})
+
+export const forgotPasswordSchema = z.object({
+    email: z.string().email("Please enter a valid email address"),
+})
+
+export const resetPasswordSchema = z
+    .object({
+        otp: z.string().length(6, "OTP must be exactly 6 digits"),
+        newPassword: z
+            .string()
+            .min(10, "Password must be at least 10 characters"),
+        confirmPassword: z.string().min(1, "Please confirm your password"),
+    })
+    .refine((data) => data.newPassword === data.confirmPassword, {
+        message: "Passwords do not match",
+        path: ["confirmPassword"],
+    })
+
+export type LoginEmailInput = z.infer<typeof loginEmailSchema>
+export type LoginInput = z.infer<typeof loginSchema>
+export type SignupInput = z.infer<typeof signupSchema>
+export type OtpInput = z.infer<typeof otpSchema>
+export type ForgotPasswordInput = z.infer<typeof forgotPasswordSchema>
+export type ResetPasswordInput = z.infer<typeof resetPasswordSchema>