feat: enhance AI prompt generation logic

- Refactor prompt generation to separate location
  description functionality
- Update user prompt generation for DALL-E 3
- Improve AI service's response handling

This change enhances the AiService by creating a more
modular approach to generating prompts. The introduction
of a `generate_location_desc` method improves the
detail and context provided in the generated prompts.
Furthermore, the `ask_ai` method centralizes AI request
logic, allowing for cleaner and more organized code.
These adjustments should improve the overall robustness
and readability of the prompt generation process.

app/services/ai_service.rb

@@ -8,22 +8,24 @@ class AiService
   end
 
   def generate_prompt(city, weather_data)
-    response = @client.chat(
-      parameters: {
-        model: "gpt-4",
-        messages: [ {
-                     role: "system",
-                     content: "You are a professional artist creating prompts for DALL-E 3. Create realistic, artistic weather scenes featuring iconic landmarks."
-                   }, {
-                     role: "user",
-                     content: generate_prompt_request(city, weather_data)
-                   } ],
-        temperature: 0.7,
-        max_tokens: 300
-      }
-    )
+    city_desc = generate_location_desc(city)
 
-    response.dig("choices", 0, "message", "content")
+    system_message =
+      "You are a professional artist creating prompts for DALL-E 3. Create realistic, artistic weather scenes featuring iconic landmarks."
+    user_message = generate_dall_e_3_prompt_request(city, weather_data, city_desc)
+    ask_ai(system_message, user_message)
+  end
+
+  def generate_location_desc(city)
+    region = city.country.region&.name || ""
+    country = city.country.name || ""
+    state = city.state&.name || ""
+
+    system_message =
+      "You are a global geography master, you understand the culture, geography, architecture, customs and other information of all cities around the world. Describe this city based on the city I gave you. Include details about its culture, climate, landmarks, and any unique features that make this place special. Condense the keyword into a description of about 50 words"
+    user_message =
+      "Describe the characteristics of the city of #{city.name}, located in the #{state}, #{country}, #{region}"
+    ask_ai(system_message, user_message)
   end
 
   def generate_image(prompt)
@@ -42,7 +44,26 @@ class AiService
 
   private
 
-  def generate_prompt_request(city, weather_data)
+  def ask_ai(system_message, user_message)
+    response = @client.chat(
+      parameters: {
+        model: "gpt-4",
+        message:
+          [ {
+              role: "System",
+              content: system_message
+            }, {
+              role: "User",
+              content: user_message
+            } ],
+        temperature: 0.7,
+        max_tokens: 300
+      }
+    )
+    response.dig("choices", 0, "message", "content")
+  end
+
+  def generate_dall_e_3_prompt_request(city, weather_data, city_desc)
     region = city.country.region&.name || ""
     country = city.country.name || ""
     state = city.state&.name || ""
@@ -50,6 +71,8 @@ class AiService
     <<~PROMPT
       Create a DALL-E 3 prompt for a weather scene in #{city.name}, #{state}, #{country}, #{region}.
 
+      Location Desc: #{city_desc}
+
       Weather conditions:
       - Temperature: #{weather_data[:temperature]}°C
       - Weather: #{weather_data[:description]}