From ea71d3825e08377470138f54d08dc03d17d4df32 Mon Sep 17 00:00:00 2001
From: Juan Rodriguez <sjdonado@icloud.com>
Date: Wed, 31 Jul 2024 22:07:57 +0200
Subject: [PATCH] fix: generate slug by user + check existing link on update

---
 app/controllers/link.cr | 15 +++++++++++++--
 app/services/slug.cr    |  5 +++--
 spec/spec_helper.cr     |  2 +-
 3 files changed, 17 insertions(+), 5 deletions(-)

diff --git a/app/controllers/link.cr b/app/controllers/link.cr
index 17eb987..6a84c22 100644
--- a/app/controllers/link.cr
+++ b/app/controllers/link.cr
@@ -27,7 +27,7 @@ module App::Controllers::Link
       link.id = UUID.v4.to_s
       link.url = url
       link.user = user
-      link.slug = SlugService.shorten_url(url)
+      link.slug = SlugService.shorten_url(url, user.id.to_s)
 
       changeset = Database.insert(link)
       if !changeset.valid?
@@ -118,6 +118,7 @@ module App::Controllers::Link
   class Update < App::Lib::BaseController
     include App::Models
     include App::Lib
+    include App::Services
 
     def call(env)
       user = env.get("user").as(User)
@@ -130,7 +131,17 @@ module App::Controllers::Link
       raise App::NotFoundException.new(env) if link.nil?
       raise App::ForbiddenException.new(env) if link.user_id != user.id
 
-      link.url = body["url"].to_s
+      new_url = body["url"].to_s
+
+      existing_query = Database::Query.where(url: new_url, user_id: user.id.to_s).limit(1)
+      existing_link = Database.all(Link, existing_query).first?
+
+      if existing_link
+        raise App::UnprocessableEntityException.new(env, { "url" => ["URL already exists"] })
+      end
+
+      link.url = new_url
+      link.slug = SlugService.shorten_url(new_url, user.id.to_s)
 
       changeset = Database.update(link)
       if !changeset.valid?
diff --git a/app/services/slug.cr b/app/services/slug.cr
index 0352cf7..4a89ecb 100644
--- a/app/services/slug.cr
+++ b/app/services/slug.cr
@@ -2,8 +2,9 @@ require "digest"
 require "base64"
 
 module App::Services::SlugService
-  def self.shorten_url(url : String) : String
-    crc32_hash = Digest::CRC32.digest(url)
+  def self.shorten_url(url : String, user_id : String) : String
+    combined = "#{user_id}-#{url}"
+    crc32_hash = Digest::CRC32.digest(combined)
     base62_encoded = Base64.urlsafe_encode(crc32_hash).strip.tr("-_=", "")
 
     base62_encoded
diff --git a/spec/spec_helper.cr b/spec/spec_helper.cr
index 9adf39d..961ec4d 100644
--- a/spec/spec_helper.cr
+++ b/spec/spec_helper.cr
@@ -40,7 +40,7 @@ end
 def create_test_link(user, url)
   link = App::Models::Link.new
   link.id = UUID.v4.to_s
-  link.slug = App::Services::SlugService.shorten_url(url)
+  link.slug = App::Services::SlugService.shorten_url(url, user.id.to_s)
   link.url = url
   link.user = user