fix: validate template_params for WhatsApp (#6881)

- Add JsonSchemaValidator, which takes a declarative schema and validates it for a given property.
- Add specs for JsonSchemaValidator
- Enable the validator for template_params

spec/models/concerns/json_schema_validator_spec.rb

@@ -0,0 +1,112 @@
+require 'rails_helper'
+
+RSpec.describe JsonSchemaValidator, type: :validator do
+  schema = {
+    'type' => 'object',
+    'properties' => {
+      'name' => { 'type' => 'string' },
+      'age' => { 'type' => 'integer' },
+      'is_active' => { 'type' => 'boolean' },
+      'tags' => { 'type' => 'array' },
+      'address' => {
+        'type' => 'object',
+        'properties' => {
+          'street' => { 'type' => 'string' },
+          'city' => { 'type' => 'string' }
+        },
+        'required' => %w[street city]
+      }
+    },
+    :required => %w[name age]
+  }.to_json.freeze
+
+  # Create a simple test model for validation
+  before_all do
+    # rubocop:disable Lint/ConstantDefinitionInBlock
+    # rubocop:disable RSpec/LeakyConstantDeclaration
+    TestModelForJSONValidation = Struct.new(:additional_attributes) do
+      include ActiveModel::Validations
+
+      validates_with JsonSchemaValidator, schema: schema
+    end
+    # rubocop:enable Lint/ConstantDefinitionInBlock
+    # rubocop:enable RSpec/LeakyConstantDeclaration
+  end
+
+  context 'with valid data' do
+    let(:valid_data) do
+      {
+        'name' => 'John Doe',
+        'age' => 30,
+        'tags' => %w[tag1 tag2],
+        'is_active' => true,
+        'address' => {
+          'street' => '123 Main St',
+          'city' => 'Iceland'
+        }
+      }
+    end
+
+    it 'passes validation' do
+      model = TestModelForJSONValidation.new(valid_data)
+      expect(model.valid?).to be true
+      expect(model.errors.full_messages).to be_empty
+    end
+  end
+
+  context 'with missing required attributes' do
+    let(:invalid_data) do
+      {
+        'name' => 'John Doe',
+        'address' => {
+          'street' => '123 Main St',
+          'city' => 'Iceland'
+        }
+      }
+    end
+
+    it 'fails validation' do
+      model = TestModelForJSONValidation.new(invalid_data)
+      expect(model.valid?).to be false
+      expect(model.errors.messages).to eq({ :age => ['is required'] })
+    end
+  end
+
+  context 'with incorrect address hash' do
+    let(:invalid_data) do
+      {
+        'name' => 'John Doe',
+        'age' => 30,
+        'address' => 'not-a-hash'
+      }
+    end
+
+    it 'fails validation' do
+      model = TestModelForJSONValidation.new(invalid_data)
+      expect(model.valid?).to be false
+      expect(model.errors.messages).to eq({ :address => ['must be of type hash'] })
+    end
+  end
+
+  context 'with incorrect types' do
+    let(:invalid_data) do
+      {
+        'name' => 'John Doe',
+        'age' => '30',
+        'is_active' => 'some-value',
+        'tags' => 'not-an-array',
+        'address' => {
+          'street' => 123,
+          'city' => 'Iceland'
+        }
+      }
+    end
+
+    it 'fails validation' do
+      model = TestModelForJSONValidation.new(invalid_data)
+      expect(model.valid?).to be false
+      expect(model.errors.messages).to eq({ :age => ['must be of type integer'], :'address/street' => ['must be of type string'],
+                                            :is_active => ['must be of type boolean'], :tags => ['must be of type array'] })
+    end
+  end
+end