import os
import gradio as gr
import requests

class GPT5Model:
    """
    GPT5Model handles interactions with the GPT-5 API.
    It includes system prompts, request construction, timeout handling,
    and graceful error responses if the API can't be reached.
    """
    def __init__(self, api_key: str):
        self.api_key = api_key
        self.system_prompt = (
            "You are GPT-5, the most advanced AI model available. "
            "Answer accurately, intelligently, and helpfully."
        )

    def generate_response(self, prompt: str) -> str:
        """
        Sends a prompt to the GPT-5 API and returns the response text.
        If there's a connection error, timeout, or invalid API key, returns a friendly error message.
        """
        url = "https://api.pplx.ai/v1/generate"
        headers = {
            "Authorization": f"Bearer {self.api_key}",
            "Content-Type": "application/json"
        }
        full_prompt = f"{self.system_prompt}\nUser: {prompt}\nGPT-5:"
        payload = {"prompt": full_prompt, "max_tokens": 500}

        try:
            response = requests.post(url, json=payload, headers=headers, timeout=15)
        except requests.exceptions.Timeout:
            return "Error: Request timed out. Please check your network or try again later."
        except requests.exceptions.ConnectionError:
            return "Error: Could not reach API. Please check network settings."
        except requests.exceptions.RequestException as e:
            return f"Error: Unexpected error occurred: {e}"

        if response.status_code == 401:
            return "Error: API key invalid or expired."
        if response.status_code != 200:
            return f"Error: API returned status {response.status_code}."

        try:
            data = response.json()
            text = data.get("choices", [{}])[0].get("text", "").strip()
            if not text:
                return "Error: No response content. API key may be exhausted."
            return text
        except ValueError:
            return "Error: Could not parse API response."

# === Load API Key ===
api_key = os.getenv("PPLX_API_KEY")
if not api_key:
    raise EnvironmentError("API key not found. Please set PPLX_API_KEY environment variable.")

model = GPT5Model(api_key)

def respond(message, chat_history):
    reply = model.generate_response(message)
    chat_history.append((message, reply))
    return "", chat_history

# === Gradio UI ===
with gr.Blocks(css="""
     #title {text-align: center; font-size: 28px; font-weight: bold;}
     #footer {text-align: center; font-size: 14px; color: gray;}
""") as demo:
    gr.Markdown("<div id='title'>🚀 GPT-5 Model Interface</div>")
    chatbot = gr.Chatbot(label="Conversation with GPT-5", height=400)
    with gr.Row():
        txt = gr.Textbox(show_label=False, placeholder="Type your message here…", container=False)
        send_btn = gr.Button("Send", variant="primary")
    gr.Markdown("<div id='footer'>Powered by GPT-5 API Simulation | © 2025</div>")

    send_btn.click(respond, [txt, chatbot], [txt, chatbot])
    txt.submit(respond, [txt, chatbot], [txt, chatbot])

demo.launch()