"""
ChatGPT Clone - A Gradio 6 Chat Application
A modern, production-ready chat interface inspired by ChatGPT
"""

import gradio as gr
import json
from datetime import datetime
from typing import Iterator

# ============================================
# CONFIGURATION
# ============================================

# You can set your OpenAI API key here to enable real AI responses
# Or leave it empty to use simulated responses
OPENAI_API_KEY = ""

# ============================================
# SIMULATED AI RESPONSES (Default Mode)
# ============================================

SIMULATED_RESPONSES = [
    "That's a great question! Let me explain...",
    "I'd be happy to help you with that. Here's what I think...",
    "Interesting! Here's my perspective on that topic...",
    "Based on my knowledge, I can tell you that...",
    "That's an important topic. Let me share some insights...",
]

# ============================================
# CORE FUNCTIONS
# ============================================

def simulate_response(message: str, history: list) -> Iterator[str]:
    """
    Simulate streaming AI response (for demo purposes).
    Replace this with actual OpenAI API calls when you have a key.
    """
    import random
    import time
    
    response = random.choice(SIMULATED_RESPONSES)
    full_response = f"{response} {message}? Let me think about that more deeply.\n\n"
    full_response += "Here are some key points to consider:\n"
    full_response += "• First, understand the core concept\n"
    full_response += "• Break it down into smaller parts\n"
    full_response += "• Apply logical reasoning\n"
    full_response += "• Consider different perspectives\n\n"
    full_response += "Is there anything specific you'd like me to elaborate on?"
    
    # Stream the response token by token
    words = full_response.split()
    for i, word in enumerate(words):
        yield " ".join(words[:i+1])
        time.sleep(0.05)  # Simulate token generation delay


def openai_response_generator(message: str, history: list, api_key: str):
    """
    Real OpenAI API integration (when API key is provided).
    Requires: pip install openai
    """
    try:
        from openai import OpenAI
        
        client = OpenAI(api_key=api_key)
        
        # Convert history to messages format
        messages = [{"role": "user", "content": message}]
        for msg in history[-6:]:  # Use last 6 messages for context
            if msg.get("role") in ["user", "assistant"]:
                messages.append({"role": msg["role"], "content": msg["content"]})
        
        response = client.chat.completions.create(
            model="gpt-3.5-turbo",
            messages=messages,
            stream=True,
            temperature=0.7,
        )
        
        full_response = ""
        for chunk in response:
            if chunk.choices[0].delta.content:
                content = chunk.choices[0].delta.content
                full_response += content
                yield full_response
                
    except ImportError:
        yield "⚠️ Please install the OpenAI library: pip install openai"
    except Exception as e:
        yield f"⚠️ API Error: {str(e)}"


def get_response(message: str, history: list, use_openai: bool, api_key: str) -> Iterator[str]:
    """
    Unified response generator - chooses between simulated or OpenAI.
    """
    if use_openai and api_key:
        yield from openai_response_generator(message, history, api_key)
    else:
        yield from simulate_response(message, history)


def format_chat_history(history: list) -> list[dict]:
    """
    Format chat history for display.
    """
    formatted = []
    for msg in history:
        if msg.get("role") == "user":
            formatted.append({"role": "user", "content": msg["content"]})
        elif msg.get("role") == "assistant":
            formatted.append({"role": "assistant", "content": msg["content"]})
    return formatted


def clear_chat() -> tuple:
    """
    Clear the chat history and return empty state.
    """
    return [], "", gr.Chatbot(value=[], visible=True)


def download_chat(history: list) -> str:
    """
    Export chat history to a downloadable format.
    """
    if not history:
        return ""
    
    export_data = {
        "export_date": datetime.now().isoformat(),
        "total_messages": len(history),
        "conversation": []
    }
    
    for msg in history:
        export_data["conversation"].append({
            "role": msg.get("role", "unknown"),
            "content": msg.get("content", ""),
            "timestamp": msg.get("timestamp", "")
        })
    
    return json.dumps(export_data, indent=2)


def retry_last_message(history: list) -> tuple:
    """
    Prepare for retry by showing the last user message.
    """
    if not history:
        return [], "", gr.Chatbot(value=[], visible=True)
    
    # Find last user message
    for msg in reversed(history):
        if msg.get("role") == "user":
            return history[:-1], msg.get("content", ""), gr.Chatbot(
                value=format_chat_history(history[:-1]), 
                visible=True
            )
    
    return history, "", gr.Chatbot(value=format_chat_history(history), visible=True)


# ============================================
# EXAMPLE PROMPTS
# ============================================

EXAMPLE_PROMPTS = [
    "Explain how quantum computing works",
    "Write a Python function to sort a list",
    "What are the best productivity tips?",
    "Help me write a business proposal",
    "Tell me a fun fact about science",
]


# ============================================
# GRADIO 6 APPLICATION
# ============================================

with gr.Blocks() as demo:
    # ===== HEADER =====
    with gr.Row(elem_classes="header"):
        gr.Markdown("""
        # 🤖 ChatGPT Clone
        *Built with [anycoder](https://huggingface.co/spaces/akhaliq/anycoder)*
        """)

    # ===== SETTINGS PANEL (Collapsible) =====
    with gr.Accordion("⚙️ Settings", open=False):
        with gr.Row():
            use_openai = gr.Checkbox(
                label="Use Real OpenAI API",
                value=False,
                info="Requires OpenAI API key"
            )
            api_key_input = gr.Textbox(
                label="OpenAI API Key",
                type="password",
                placeholder="sk-...",
                visible=False
            )
        
        def toggle_api_key(show):
            return gr.Textbox(visible=show)
        
        use_openai.change(
            toggle_api_key,
            inputs=use_openai,
            outputs=api_key_input
        )
        
        gr.Markdown("""
        ### 🔑 Getting an OpenAI API Key
        1. Go to [platform.openai.com](https://platform.openai.com)
        2. Sign up or log in
        3. Navigate to API Keys section
        4. Create a new secret key
        5. Paste it above
        """)

    # ===== CHAT INTERFACE =====
    with gr.Row():
        # Sidebar with examples
        with gr.Column(scale=1, min_width=250):
            gr.Markdown("### 💡 Try These")
            for prompt in EXAMPLE_PROMPTS:
                gr.Button(
                    prompt,
                    variant="secondary",
                    size="sm",
                    elem_classes="example-btn"
                )
            
            gr.Markdown("---")
            gr.Markdown("### 🛠️ Actions")
            with gr.Row():
                new_chat_btn = gr.Button("🗑️ New Chat", variant="stop", size="sm")
                retry_btn = gr.Button("🔄 Retry", variant="secondary", size="sm")
            download_btn = gr.Button("💾 Download Chat", variant="secondary", size="sm")
            
            gr.Markdown("---")
            gr.Markdown("### 📊 Stats")
            message_count = gr.Number(value=0, label="Messages", interactive=False)

        # Main chat area
        with gr.Column(scale=4):
            chatbot = gr.Chatbot(
                label="Conversation",
                height=500,
                avatar_images=(
                    "https://huggingface.co/datasets/huggingface/avatars/resolve/main/male.png",
                    "https://huggingface.co/datasets/huggingface/avatars/resolve/main/huggingface.png"
                ),
                latex_delimiters=[
                    {"left": "$", "right": "$", "display": True},
                    {"left": "$$", "right": "$$", "display": True}
                ],
                show_copy_all_button=True,
                render_markdown=True,
                bubble_full_width=False,
                line_breaks=True,
            )

            # Input area
            with gr.Row():
                msg_input = gr.Textbox(
                    placeholder="Type your message here...",
                    label=None,
                    lines=3,
                    scale=5,
                    submit_btn=True,
                    max_lines=10,
                )
            
            # Action buttons
            with gr.Row():
                send_btn = gr.Button("Send Message", variant="primary", size="lg", scale=2)
                clear_btn = gr.Button("Clear", variant="secondary", size="lg", scale=1)

    # ===== FOOTER =====
    gr.Markdown("""
    ---
    ### 💡 Tips
    - Press **Enter** to send a message
    - Use **Shift+Enter** for a new line
    - Click **New Chat** to start fresh
    - **Retry** to regenerate the last response
    
    ---
    *Built with ❤️ using Gradio 6*
    """)

    # ===== EVENT HANDLERS =====

    def respond(
        message: str, 
        history: list, 
        use_openai: bool, 
        api_key: str
    ) -> tuple:
        """
        Handle user message and generate response.
        """
        if not message.strip():
            return "", history, message_count.update(len(history))
        
        # Add user message to history
        timestamp = datetime.now().isoformat()
        history.append({
            "role": "user",
            "content": message,
            "timestamp": timestamp
        })
        
        # Update chatbot display
        chatbot_history = format_chat_history(history)
        
        # Generate response
        response_parts = []
        for part in get_response(message, history, use_openai, api_key):
            response_parts.append(part)
            # Update assistant message in history
            temp_history = history + [{"role": "assistant", "content": part}]
            yield "", temp_history, len(temp_history)
        
        # Final response
        final_response = response_parts[-1] if response_parts else ""
        history.append({
            "role": "assistant",
            "content": final_response,
            "timestamp": timestamp
        })
        
        yield "", history, len(history)

    # Submit message events
    submit_triggers = [
        msg_input.submit,
        send_btn.click
    ]
    
    for trigger in submit_triggers:
        trigger(
            fn=respond,
            inputs=[msg_input, gr.State([]), use_openai, api_key_input],
            outputs=[msg_input, gr.State([]), message_count],
            show_progress="minimal"
        )

    # Clear chat
    clear_btn.click(
        fn=clear_chat,
        outputs=[gr.State([]), msg_input, chatbot]
    )
    
    new_chat_btn.click(
        fn=clear_chat,
        outputs=[gr.State([]), msg_input, chatbot]
    )
    
    # Retry
    retry_btn.click(
        fn=retry_last_message,
        inputs=gr.State([]),
        outputs=[gr.State([]), msg_input, chatbot]
    )
    
    # Download chat
    download_btn.click(
        fn=download_chat,
        inputs=gr.State([]),
        outputs=gr.DownloadButton(value=None, label="📥 Download Chat History")
    )

# ============================================
# LAUNCH APPLICATION
# ============================================

if __name__ == "__main__":
    demo.launch(
        title="ChatGPT Clone - Gradio 6",
        theme=gr.themes.Soft(
            primary_hue="indigo",
            secondary_hue="purple",
            neutral_hue="slate",
            font=gr.themes.GoogleFont("Inter"),
            text_size="lg",
            spacing_size="lg",
            radius_size="md"
        ).set(
            button_primary_background_fill="*primary_600",
            button_primary_background_fill_hover="*primary_700",
            button_secondary_background_fill="*neutral_200",
            button_secondary_background_fill_hover="*neutral_300",
            block_title_text_weight="600",
            block_background_fill="*neutral_100",
            chatbot_prompt_background_fill="*primary_100",
            chatbot_reply_background_fill="*neutral_200",
        ),
        css="""
        /* Custom CSS for modern chat appearance */
        .header {
            text-align: center;
            padding: 1rem;
            background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
            border-radius: 0.5rem;
            margin-bottom: 1rem;
        }
        
        .header h1 {
            color: white !important;
            margin: 0 !important;
            font-size: 1.8rem !important;
        }
        
        .header a {
            color: rgba(255, 255, 255, 0.9) !important;
            text-decoration: none;
        }
        
        .header a:hover {
            color: white !important;
            text-decoration: underline;
        }
        
        .example-btn {
            margin: 0.25rem 0;
            text-align: left !important;
            justify-content: flex-start !important;
        }
        
        /* Chat bubble styling */
        .gradio-container .chatbot {
            border-radius: 1rem;
            overflow: hidden;
        }
        
        /* Smooth animations */
        * {
            transition: all 0.2s ease-in-out !important;
        }
        
        /* Hide scrollbar in chat */
        .gradio-container .chatbot .wrap {
            scrollbar-width: thin;
            scrollbar-color: #667eea transparent;
        }
        
        /* Mobile responsive */
        @media (max-width: 768px) {
            .header h1 {
                font-size: 1.4rem !important;
            }
        }
        """,
        footer_links=[
            {"label": "Built with anycoder", "url": "https://huggingface.co/spaces/akhaliq/anycoder"},
            {"label": "Gradio", "url": "https://gradio.app"},
            {"label": "Hugging Face", "url": "https://huggingface.co"}
        ],
        show_api=False,
        quiet=True
    )