app.py

import streamlit as st
import matplotlib.pyplot as plt
import numpy as np
import re
import os
import io
import json
import requests
import base64
from PIL import Image
from gtts import gTTS
from duckduckgo_search import DDGS
import warnings
warnings.filterwarnings('ignore')

# -----------------------------------------------------------------------------
# 1. PAGE CONFIGURATION
# -----------------------------------------------------------------------------
st.set_page_config(
    page_title="H2 Physics Feynman Bot",
    page_icon="⚛️",
    layout="centered",
    initial_sidebar_state="expanded"
)

# -----------------------------------------------------------------------------
# 2. HELPER FUNCTIONS
# -----------------------------------------------------------------------------

@st.cache_data(show_spinner=False, ttl=3600)
def generate_audio(text):
    """Generates MP3 audio from text."""
    clean_text = re.sub(r'```.*?```', 'I have generated a graph.', text, flags=re.DOTALL)
    clean_text = re.sub(r'\[IMAGE:.*?\]', 'Here is a diagram.', clean_text)
    
    if len(clean_text) > 1000:
        clean_text = clean_text[:1000] + "..."
    
    try:
        tts = gTTS(text=clean_text, lang='en', slow=False)
        audio_fp = io.BytesIO()
        tts.write_to_fp(audio_fp)
        audio_fp.seek(0)
        return audio_fp
    except Exception as e:
        return None

def google_search_api(query, api_key, cx):
    """Google Custom Search API."""
    try:
        url = "https://www.googleapis.com/customsearch/v1"
        params = {
            "q": query,
            "cx": cx,
            "key": api_key,
            "searchType": "image",
            "num": 3,
            "safe": "active"
        }
        
        response = requests.get(url, params=params, timeout=10)
        
        if response.status_code in [403, 429]:
            return None
            
        data = response.json()
        
        if "items" in data and len(data["items"]) > 0:
            for item in data["items"]:
                link = item["link"]
                if link.lower().endswith(('.jpg', '.jpeg', '.png', '.webp')):
                    return link
            return data["items"][0]["link"]
            
    except Exception as e:
        return None
    return None

def duckduckgo_search_api(query):
    """DuckDuckGo image search."""
    try:
        with DDGS() as ddgs:
            results = list(ddgs.images(query, max_results=1))
            if results:
                return results[0]['image']
    except Exception as e:
        return None
    return None

@st.cache_data(show_spinner=False, ttl=300)
def search_image(query):
    """Image search with fallback."""
    try:
        # Check secrets
        if hasattr(st, 'secrets'):
            cx = st.secrets.get("GOOGLE_CX", "")
            key1 = st.secrets.get("GOOGLE_SEARCH_KEY", "")
            key2 = st.secrets.get("GOOGLE_SEARCH_KEY_2", "")
            
            if key1 and cx:
                url = google_search_api(query, key1, cx)
                if url: return url
            
            if key2 and cx:
                url = google_search_api(query, key2, cx)
                if url: return url
        
        # Fallback to DuckDuckGo
        return duckduckgo_search_api(query)
        
    except Exception as e:
        return None

def analyze_image_with_huggingface(image, query="What physics concepts are shown?", hf_token=None):
    """Analyze image using Hugging Face Inference API."""
    try:
        # Convert image to base64
        buffered = io.BytesIO()
        
        # Convert to RGB if necessary
        if image.mode != 'RGB':
            image = image.convert('RGB')
            
        image.save(buffered, format="JPEG", quality=85)
        img_base64 = base64.b64encode(buffered.getvalue()).decode('utf-8')
        
        # Use Hugging Face Inference API
        # Model: Qwen/Qwen-VL-Chat
        api_url = "https://api-inference.huggingface.co/models/Qwen/Qwen-VL-Chat"
        
        headers = {
            "Authorization": f"Bearer {hf_token}",
            "Content-Type": "application/json"
        }
        
        # Prepare the payload for Qwen-VL
        payload = {
            "inputs": {
                "question": query,
                "image": img_base64
            },
            "parameters": {
                "max_new_tokens": 500,
                "temperature": 0.7
            }
        }
        
        # Make API call
        response = requests.post(api_url, json=payload, headers=headers, timeout=60)
        
        if response.status_code == 200:
            result = response.json()
            
            # Handle different response formats
            if isinstance(result, dict) and "generated_text" in result:
                return result["generated_text"]
            elif isinstance(result, list) and len(result) > 0:
                if "generated_text" in result[0]:
                    return result[0]["generated_text"]
                else:
                    return str(result[0])[:500]
            else:
                return str(result)[:500]
        else:
            return f"API Error {response.status_code}: {response.text[:200]}"
            
    except Exception as e:
        return f"Image analysis error: {str(e)[:100]}"

def analyze_image_with_openrouter(image, query="What physics concepts are shown?", api_key=None):
    """Analyze image using OpenRouter API (multiple providers)."""
    try:
        # Convert image to base64
        buffered = io.BytesIO()
        
        if image.mode != 'RGB':
            image = image.convert('RGB')
            
        image.save(buffered, format="JPEG", quality=85)
        img_base64 = base64.b64encode(buffered.getvalue()).decode('utf-8')
        
        api_url = "https://openrouter.ai/api/v1/chat/completions"
        
        headers = {
            "Authorization": f"Bearer {api_key}",
            "HTTP-Referer": "https://h2-feynman-bot.vercel.app",
            "X-Title": "H2 Physics Feynman Bot"
        }
        
        # Try different vision models available on OpenRouter
        payload = {
            "model": "google/gemini-pro-vision",  # Free tier available
            "messages": [
                {
                    "role": "user",
                    "content": [
                        {
                            "type": "text",
                            "text": query
                        },
                        {
                            "type": "image_url",
                            "image_url": {
                                "url": f"data:image/jpeg;base64,{img_base64}"
                            }
                        }
                    ]
                }
            ],
            "max_tokens": 1000,
            "temperature": 0.7
        }
        
        response = requests.post(api_url, json=payload, headers=headers, timeout=60)
        
        if response.status_code == 200:
            result = response.json()
            return result["choices"][0]["message"]["content"]
        else:
            # Fallback to another model
            payload["model"] = "claude-3-haiku-20240307"
            response = requests.post(api_url, json=payload, headers=headers, timeout=60)
            if response.status_code == 200:
                result = response.json()
                return result["choices"][0]["message"]["content"]
            else:
                return f"API Error: {response.status_code}"
                
    except Exception as e:
        return f"Image analysis error: {str(e)[:100]}"

def analyze_image_with_togetherai(image, query="What physics concepts are shown?", api_key=None):
    """Analyze image using Together.ai API (supports Qwen-VL)."""
    try:
        # Convert image to base64
        buffered = io.BytesIO()
        
        if image.mode != 'RGB':
            image = image.convert('RGB')
            
        image.save(buffered, format="JPEG", quality=85)
        img_base64 = base64.b64encode(buffered.getvalue()).decode('utf-8')
        
        api_url = "https://api.together.xyz/v1/chat/completions"
        
        headers = {
            "Authorization": f"Bearer {api_key}",
            "Content-Type": "application/json"
        }
        
        # Together.ai supports Qwen-VL models
        payload = {
            "model": "Qwen/Qwen-VL-Chat",  # or "Qwen/Qwen-VL-Chat-Int4" for faster
            "messages": [
                {
                    "role": "user",
                    "content": [
                        {
                            "type": "text",
                            "text": query
                        },
                        {
                            "type": "image_url",
                            "image_url": {
                                "url": f"data:image/jpeg;base64,{img_base64}"
                            }
                        }
                    ]
                }
            ],
            "max_tokens": 1000,
            "temperature": 0.7
        }
        
        response = requests.post(api_url, json=payload, headers=headers, timeout=60)
        
        if response.status_code == 200:
            result = response.json()
            return result["choices"][0]["message"]["content"]
        else:
            return f"API Error {response.status_code}: {response.text[:200]}"
            
    except Exception as e:
        return f"Image analysis error: {str(e)[:100]}"

        
        
def analyze_image_local_fallback(image, query):
    """Simple local image analysis fallback."""
    try:
        # Get basic image info
        width, height = image.size
        format_info = image.format if image.format else "Unknown"
        mode = image.mode
        
        analysis = f"Image analysis: {width}x{height} pixels, format: {format_info}, mode: {mode}. "
        
        # Try to detect if it's a physics-related image
        if width > height:
            analysis += "The image appears to be landscape orientation. "
        else:
            analysis += "The image appears to be portrait orientation. "
        
        # Add physics context
        analysis += "For physics analysis, please describe what you see in the image, and I'll help explain the physics concepts."
        
        return analysis
    except:
        return "Image received. Please describe what you see in the image for physics analysis."

# -----------------------------------------------------------------------------
# 4. GRAPH FUNCTIONS
# -----------------------------------------------------------------------------

def execute_plotting_code(code_snippet):
    """Execute Python plotting code."""
    try:
        plt.close('all')
        fig, ax = plt.subplots(figsize=(10, 6))
        
        namespace = {
            'plt': plt,
            'np': np,
            'ax': ax,
            'fig': fig,
            'math': __import__('math')
        }
        
        cleaned_code = code_snippet.strip()
        
        # Ensure imports
        if 'import matplotlib' not in cleaned_code:
            cleaned_code = 'import matplotlib.pyplot as plt\nimport numpy as np\n' + cleaned_code
        
        # Ensure plotting
        plot_keywords = ['plt.plot(', 'ax.plot(', 'plt.scatter(', 'ax.scatter(']
        has_plot = any(keyword in cleaned_code for keyword in plot_keywords)
        
        if not has_plot:
            cleaned_code += '\n\n# Sample plot\nx = np.linspace(0, 10, 100)\ny = np.sin(x)\nplt.plot(x, y, "b-", linewidth=2, label="sin(x)")\n'
        
        # Remove plt.show
        cleaned_code = cleaned_code.replace('plt.show()', '')
        
        # Add labels if missing
        if 'plt.xlabel' not in cleaned_code:
            cleaned_code += '\nplt.xlabel("X-axis", fontsize=12)'
        if 'plt.ylabel' not in cleaned_code:
            cleaned_code += '\nplt.ylabel("Y-axis", fontsize=12)'
        if 'plt.grid' not in cleaned_code:
            cleaned_code += '\nplt.grid(True, linestyle="--", alpha=0.6)'
        
        exec(cleaned_code, namespace)
        
        ax = plt.gca()
        if not ax.get_title():
            ax.set_title('Physics Graph', fontsize=14)
        
        st.pyplot(fig)
        plt.close(fig)
        
    except Exception as e:
        st.error(f"Graph Error: {str(e)[:100]}")
        
        # Fallback plot
        try:
            fig, ax = plt.subplots(figsize=(10, 6))
            x = np.linspace(0, 10, 100)
            y = x**2
            ax.plot(x, y, 'b-', linewidth=2, label='y = x²')
            ax.set_xlabel('X', fontsize=12)
            ax.set_ylabel('Y', fontsize=12)
            ax.set_title('Sample Graph', fontsize=14)
            ax.grid(True, linestyle='--', alpha=0.6)
            ax.legend()
            st.pyplot(fig)
            plt.close(fig)
        except:
            st.warning("Could not generate graph.")

def display_message(role, content, enable_voice=False):
    """Display chat message."""
    with st.chat_message(role):
        
        text_to_display = content
        
        # Extract code blocks
        code_pattern = r'```python\s*(.*?)```'
        code_matches = list(re.finditer(code_pattern, content, re.DOTALL))
        
        for match in reversed(code_matches):
            text_to_display = text_to_display.replace(match.group(0), "")
        
        # Check for image tags
        image_match = re.search(r'\[IMAGE:\s*(.*?)\]', text_to_display, re.IGNORECASE)
        image_result = None
        
        if image_match and role == "assistant":
            search_query = image_match.group(1)
            text_to_display = text_to_display.replace(image_match.group(0), "")
            with st.spinner(f"Searching for '{search_query}'..."):
                image_result = search_image(search_query)

        # Display text
        st.markdown(text_to_display)

        # Show code and graph
        if code_matches and role == "assistant":
            for match in code_matches:
                code_content = match.group(1).strip()
                if code_content:
                    with st.expander("📝 View Python Code", expanded=False):
                        st.code(code_content, language='python')
                    
                    with st.expander("📊 Generated Graph", expanded=True):
                        execute_plotting_code(code_content)
        
        # Show image
        if image_match and role == "assistant":
            if image_result and "http" in str(image_result):
                try:
                    st.image(image_result, caption=f"📷 {image_match.group(1)}", width=500)
                    st.markdown(f"🔗 [Open Image]({image_result})")
                except:
                    st.warning("Could not display image.")
            else:
                st.warning(f"Image search failed.")

        # Audio output
        if enable_voice and role == "assistant" and len(text_to_display.strip()) > 10:
            audio_bytes = generate_audio(text_to_display)
            if audio_bytes:
                st.audio(audio_bytes, format='audio/mp3')

# -----------------------------------------------------------------------------
# 5. GROQ API FUNCTION
# -----------------------------------------------------------------------------

def call_groq_api(api_key, messages, max_tokens=2000):
    """Call Groq API."""
    url = "https://api.groq.com/openai/v1/chat/completions"
    
    headers = {
        "Authorization": f"Bearer {api_key}",
        "Content-Type": "application/json"
    }
    
    formatted_messages = []
    for msg in messages:
        if msg["role"] == "system":
            formatted_messages.append({
                "role": "system",
                "content": msg["content"]
            })
        elif msg["role"] in ["user", "assistant"]:
            formatted_messages.append({
                "role": msg["role"],
                "content": msg["content"]
            })
    
    models_to_try = [
        "llama-3.1-8b-instant",
        "llama-3.2-3b-preview",
    ]
    
    for model in models_to_try:
        data = {
            "model": model,
            "messages": formatted_messages,
            "max_tokens": max_tokens,
            "temperature": 0.7,
            "stream": False
        }
        
        try:
            response = requests.post(url, headers=headers, json=data, timeout=30)
            
            if response.status_code == 200:
                result = response.json()
                return result["choices"][0]["message"]["content"]
            elif response.status_code == 429:
                continue
                
        except:
            continue
    
    return "Service temporarily unavailable. Please try again."
    
# System Instructions for the AI - Part 5a (Start)
SYSTEM_INSTRUCTIONS = """
**Identity:** Richard Feynman. Tutor for Singapore H2 Physics (9478).
**CORE DIRECTIVE:** STRICTLY adhere to the Syllabus 9478 topics below. Reject non-included topics from UK A-level syllabus.
**✅ SYLLABUS TOPICS & FORMULAS (9478):**
1. **Measurement:** SI units (mass, length, time, current, temp, mol), prefixes (p to T), homogeneity, scalars/vectors (resolution/addition), errors (random/systematic), uncertainty.
2. **Forces:** Normal, buoyant, drag (qualitative only; no viscosity coeff), Hooke’s Law ($F=kx$), Moments/Torque (couples, center of gravity), Equilibrium (no resultant F or Torque).
3. **Motion:** Kinematics ($s, u, v, a, t$ graphs & equations), Newton’s Laws (1, 2, 3), Momentum ($p=mv$), Impulse, $F_{net}=ma$ (const mass).
4. **Energy:** Stores/Transfers, Work ($W=Fs$), $E_k=\frac{1}{2}mv^2$, $E_p$ (grav/elastic/electric), Power ($P=Fv$), Efficiency, Conservation of Energy.
5. **Projectile:** Parabolic motion, $\Delta E_p=mg\Delta h$, Terminal velocity.
6. **Collisions:** Conservation of Momentum, Elastic vs Inelastic, Relative speeds (elastic). *Excluded: Coeff of restitution.*
7. **Circular Motion:** Radians, $\omega$, $v=r\omega$, $a=r\omega^2=v^2/r$, $F_c=mv^2/r$.
8. **Gravitation:** $F=G\frac{Mm}{r^2}$, Field $g=G\frac{M}{r^2}$, Potential $\phi=-\frac{GM}{r}$, $U=-\frac{GMm}{r}$, $g=-\frac{d\phi}{dr}$, Escape velocity, Orbits ($F_g=F_c$), Geostationary satellites.
9. **Oscillations (SHM):** $a=-\omega^2x$, $x=x_0\sin\omega t$, $v=\pm\omega\sqrt{x_0^2-x^2}$, Energy interchange, Damping (light/critical/heavy), Resonance (frequency response).
10. **Waves:** Transverse/Longitudinal, $v=f\lambda$, Intensity $\propto A^2$, Inverse square law, Polarization (Malus’ Law $I \propto \cos^2\theta$).
11. **Superposition:** Standing waves (nodes/antinodes), Path/Phase difference, Coherence, Double-slit ($\lambda=\frac{ax}{D}$), Diffraction grating ($d\sin\theta=n\lambda$), Single slit ($b\sin\theta=\lambda$ for min), Rayleigh criterion ($\theta \approx \lambda/b$).
12. **Thermal:** Kelvin ($T_K = T_C + 273.15$), Ideal Gas ($pV=NkT$), Avogadro ($N_A$), Kinetic Theory assumptions, $pV=\frac{1}{3}Nm\langle c^2\rangle$, Mean $E_k = \frac{3}{2}kT$.
13. **Thermodynamics:** Internal Energy ($U$), 1st Law ($\Delta U = Q+W$), Work on gas ($W=-p\Delta V$ implied) or by gas ($W=p\Delta V$), Specific Heat/Latent Heat.
14. **E-Fields:** Coulomb's $F=\frac{Q_1Q_2}{4\pi\varepsilon_0 r^2}$, Field $E=\frac{Q}{4\pi\varepsilon_0 r^2}$, Potential $V=\frac{Q}{4\pi\varepsilon_0 r}$, $U=\frac{Q_1Q_2}{4\pi\varepsilon_0 r}$, $E=-\frac{dV}{dr}$, Uniform field $E=V/d$, Capacitance $C=Q/V$, Energy $U=\frac{1}{2}CV^2$.
15. **Currents:** $I=Q/t$, $I=nAvq$, $V=W/Q$, $P=VI=I^2R$, EMF vs PD, AC (rms $I_0/\sqrt{2}$), Half-wave rectification.
16. **Circuits:** Symbols, $V=IR$, $R=\rho l/A$, I-V graphs (diode, lamp, NTC), Int. Resistance, Series/Parallel R & C, Potential Divider, Charging/Discharging ($x=x_0 e^{-t/RC}$).
17. **EM Forces:** B-fields (wire, coil, solenoid), Flux density $B$, Force on wire ($F=BIl\sin\theta$), Force on charge ($F=Bqv\sin\theta$), Velocity selector, Hall effect concept.
18. **EM Induction:** Flux $\Phi=BA$, Linkage $N\Phi$, Faraday’s & Lenz’s Laws, Transformers ($N_s/N_p = V_s/V_p = I_p/I_s$).
19. **Modern Physics:** Photoelectric ($E=hf$, Work function), Photon momentum ($p=h/\lambda$), De Broglie ($\lambda=h/p$), Wavefunction $\psi$, Uncertainty ($\Delta x \Delta p \gtrsim h$), Infinite well ($E_n = \frac{n^2 h^2}{8 m L^2}$), Line spectra.
20. **Nuclear:** Rutherford, Notation $^A_Z X$, Decay ($A=\lambda N$, $x=x_0e^{-\lambda t}$, $t_{1/2}=\ln 2/\lambda$), $E=mc^2$, Mass defect, Binding energy (curve), Fusion/Fission.

**GRAPH GENERATION RULES (CRITICAL):**
When asked to create a graph, you MUST write COMPLETE, EXECUTABLE Python code that:
1. Starts with: import matplotlib.pyplot as plt, import numpy as np
2. Creates a figure: plt.figure(figsize=(10, 6)) or fig, ax = plt.subplots(figsize=(10, 6))
3. Generates or uses appropriate physics data
4. Plots the data with plt.plot(), plt.scatter(), etc.
5. Adds proper labels: plt.xlabel(), plt.ylabel(), plt.title()
6. Adds grid: plt.grid(True, linestyle='--', alpha=0.6)
7. Adds legend if needed: plt.legend()

**IMPORTANT GRAPH RULES:**
- You MUST include ACTUAL DATA in your graph code
- Example of BAD code (won't show graph):
  ```python
  import matplotlib.pyplot as plt
  plt.figure(figsize=(10, 6))
  # Missing actual plot() command!
  plt.show()


**EXAMPLE OF GOOD GRAPH CODE:**
import matplotlib.pyplot as plt
import numpy as np

plt.figure(figsize=(10, 6))
x = np.linspace(0, 10, 100)
y = np.sin(x)
plt.plot(x, y, 'b-', linewidth=2, label='sin(x)')
plt.xlabel('X Variable', fontsize=12)
plt.ylabel('Y Variable', fontsize=12)
plt.title('Physics Graph', fontsize=14)
plt.grid(True, linestyle='--', alpha=0.6)
plt.legend()

**DIAGRAMS:**
When you need to show a diagram, use: [IMAGE: search query]
Example: "Here's the setup: [IMAGE: double slit experiment diagram]"

**TEACHING METHOD:**
1. Ask ONE question at a time
2. Use analogies to explain complex concepts
3. Guide, don't give answers immediately
4. Validate understanding frequently
5. Teach with clarity, enthusiasm, and the Feynman method
6. Only give full solutions when student says "I give up"
7. Summarize each concept with a clear summary in > blockquote
**FORMATTING:**
- Use LaTeX for equations: $F = ma$, $E = mc^2$
- Use **bold** for key terms
- Keep responses concise but thorough
- Be enthusiastic and encouraging
"""

## **PART 6: SIDEBAR CONFIGURATION**

# Sidebar Configuration - SIMPLIFIED
# -----------------------------------------------------------------------------
# 6. SIDEBAR CONFIGURATION
# -----------------------------------------------------------------------------
# -----------------------------------------------------------------------------
# 6. SIDEBAR CONFIGURATION
# -----------------------------------------------------------------------------
with st.sidebar:
    # Header
    col1, col2 = st.columns([1, 3])
    with col1:
        st.image("https://upload.wikimedia.org/wikipedia/en/4/42/Richard_Feynman_Nobel.jpg", 
                width=80)
    with col2:
        st.markdown("### ⚛️ H2 Physics")
        st.caption("Feynman Tutor")
    
    st.divider()
    
    # Settings
    st.header("⚙️ Settings")
    topic = st.selectbox(
        "Topic Focus:",
        [
            "General / Any",
            "Measurement & Uncertainty", 
            "Kinematics & Dynamics",
            "Forces & Turning Effects", 
            "Work, Energy, Power",
            "Circular Motion", 
            "Gravitational Fields",
            "Thermal Physics", 
            "Oscillations & Waves",
            "Electricity & DC Circuits", 
            "Electromagnetism (EMI/AC)",
            "Modern Physics (Quantum/Nuclear)",
            "Paper 4: Practical Skills"
        ]
    )
    
    enable_voice = st.toggle("🗣️ Text-to-Speech", value=False)
    
    st.divider()
    
    # Image Analysis Settings
    st.header("🖼️ Image Analysis")
    
    image_analysis_mode = st.radio(
        "Analysis Service:",
        ["Hugging Face", "Together.ai", "OpenRouter", "Basic"],
        index=0,
        help="Choose image analysis service"
    )
    
    # Initialize variables - FIXED SECRETS CHECKING
    hf_token = None
    together_key = None
    openrouter_key = None
    
    # Safe secrets checking function
    def get_secret(key, default=None):
        """Safely get a secret from st.secrets or environment."""
        try:
            # First try st.secrets (Hugging Face Spaces)
            if hasattr(st, 'secrets'):
                # Check if secrets is loaded and has the key
                secrets_dict = dict(st.secrets)
                if key in secrets_dict:
                    return secrets_dict[key]
        except:
            pass
        
        # Fallback to environment variables
        return os.environ.get(key, default)
    
    if image_analysis_mode == "Hugging Face":
        hf_token = get_secret("HF_TOKEN")
        if hf_token:
            st.success("✓ Hugging Face Token configured")
        else:
            st.warning("Add HF_TOKEN to secrets")
            st.info("Get token: huggingface.co/settings/tokens")
    
    elif image_analysis_mode == "Together.ai":
        together_key = get_secret("TOGETHER_API_KEY")
        if together_key:
            st.success("✓ Together.ai API configured")
        else:
            st.warning("Add TOGETHER_API_KEY to secrets")
            st.info("Get key: together.ai (free credits available)")
    
    elif image_analysis_mode == "OpenRouter":
        openrouter_key = get_secret("OPENROUTER_API_KEY")
        if openrouter_key:
            st.success("✓ OpenRouter API configured")
        else:
            st.warning("Add OPENROUTER_API_KEY to secrets")
            st.info("Get key: openrouter.ai (free credits available)")
    
    else:  # Basic
        st.info("Basic image analysis mode")
    #st.divider()
    st.divider()
    
    # Media Input
    st.header("📤 Input Methods")
    
    visual_content = None
    image_analysis = None
    
    # Method selection
    input_method = st.radio(
        "Choose input method:",
        ["Camera", "Upload"],
        horizontal=True
    )
    
    if input_method == "Camera":
        st.subheader("📷 Camera")
        camera_photo = st.camera_input("Take a photo of physics problem")
        
        if camera_photo:
            try:
                image = Image.open(camera_photo)
                visual_content = image
                st.image(image, caption="Camera Capture", width=200)
                st.success("✓ Photo captured")
                
                # Analyze immediately based on selected mode
                with st.spinner("Analyzing image..."):
                    if image_analysis_mode == "Hugging Face" and hf_token:
                        image_analysis = analyze_image_with_huggingface(
                            image, 
                            "Analyze this physics image. What concepts, diagrams, or equations do you see?",
                            hf_token
                        )
                    elif image_analysis_mode == "Together.ai" and together_key:
                        image_analysis = analyze_image_with_togetherai(
                            image,
                            "Analyze this physics image. What concepts, diagrams, or equations do you see?",
                            together_key
                        )
                    elif image_analysis_mode == "OpenRouter" and openrouter_key:
                        image_analysis = analyze_image_with_openrouter(
                            image,
                            "Analyze this physics image. What concepts, diagrams, or equations do you see?",
                            openrouter_key
                        )
                    else:
                        image_analysis = analyze_image_local_fallback(
                            image,
                            "Analyze this physics image"
                        )
                        
                if image_analysis:
                    st.info(f"📋 Analysis: {image_analysis[:150]}...")
                    
            except Exception as e:
                st.error(f"Camera error: {e}")
    
    else:  # Upload
        st.subheader("📁 Upload")
        uploaded_file = st.file_uploader(
            "Choose image", 
            type=["jpg", "jpeg", "png"],
            help="Upload physics diagrams or problems"
        )
        
        if uploaded_file:
            try:
                image = Image.open(uploaded_file)
                visual_content = image
                st.image(image, caption="Uploaded Image", width=200)
                st.success("✓ Image loaded")
                
                # Analyze immediately based on selected mode
                with st.spinner("Analyzing image..."):
                    if image_analysis_mode == "Hugging Face" and hf_token:
                        image_analysis = analyze_image_with_huggingface(
                            image, 
                            "Analyze this physics image. What concepts, diagrams, or equations do you see?",
                            hf_token
                        )
                    elif image_analysis_mode == "Together.ai" and together_key:
                        image_analysis = analyze_image_with_togetherai(
                            image,
                            "Analyze this physics image. What concepts, diagrams, or equations do you see?",
                            together_key
                        )
                    elif image_analysis_mode == "OpenRouter" and openrouter_key:
                        image_analysis = analyze_image_with_openrouter(
                            image,
                            "Analyze this physics image. What concepts, diagrams, or equations do you see?",
                            openrouter_key
                        )
                    else:
                        image_analysis = analyze_image_local_fallback(
                            image,
                            "Analyze this physics image"
                        )
                        
                if image_analysis:
                    st.info(f"📋 Analysis: {image_analysis[:150]}...")
                    
            except Exception as e:
                st.error(f"Upload error: {e}")
    
    st.divider()
    
    # Controls
    if st.button("🧹 Clear Chat History", use_container_width=True):
        st.session_state.messages = []
        st.rerun()
    
    st.divider()
    st.caption("H2 Physics 9478 | AI Image Analysis")
    st.caption("Made with ❤️ for JPJC H2 Physics students | Powered by Groq AI")

# 7 Main Chat Interface
# -----------------------------------------------------------------------------
# 7. MAIN CHAT INTERFACE
# -----------------------------------------------------------------------------

# Initialize session state
if "messages" not in st.session_state:
    st.session_state.messages = [
        {"role": "system", "content": SYSTEM_INSTRUCTIONS},
        {"role": "assistant", "content": "**Hello! I'm Richard Feynman, ready to help you master H2 Physics!** ⚛️\n\nI can:\n- 📊 **Plot graphs** with Python\n- 🖼️ **Find diagrams** online\n- 📷 **Analyze images** from camera/upload\n- 💬 **Explain concepts** with analogies\n\n**Try:**\n1. Take a photo of a physics problem\n2. Ask me to plot a graph\n3. Request a diagram\n\n**What would you like to learn today?**"}
    ]

# Title
st.title("⚛️ H2 Physics Feynman Tutor")
st.caption(f"**Topic:** {topic} | **Image Analysis:** {image_analysis_mode}")

# Display chat history
for message in st.session_state.messages:
    if message["role"] != "system":
        display_message(message["role"], message["content"], enable_voice)

# Chat input
user_input = st.chat_input("Type your question or describe the image...")

# Process input
if user_input or visual_content or image_analysis:
    # Build user message
    user_message = ""
    
    if user_input:
        user_message += user_input + " "
    
    if visual_content:
        user_message += "[I have uploaded/taken a photo of a physics problem] "
    
    if image_analysis:
        user_message += f"[Image Analysis: {image_analysis}] "
    
    if topic != "General / Any":
        user_message += f"(Focus on: {topic})"
    
    # Add to history
    st.session_state.messages.append({"role": "user", "content": user_message})
    
    # Display user message
    with st.chat_message("user"):
        if user_input:
            st.markdown(user_input)
        
        if visual_content:
            st.image(visual_content, caption="Your Image", width=300)
        
        if image_analysis:
            with st.expander("📋 Image Analysis Details"):
                st.write(image_analysis)
    
    # Check for Groq API key - FIXED VERSION
    groq_key = None
    try:
        # First try environment variable (Hugging Face method)
        groq_key = os.environ.get("GROQ_API_KEY")
        
        # If not found in env, try to get from st.secrets (only if it exists)
        if not groq_key and hasattr(st, 'secrets'):
            try:
                # Convert secrets to dict safely
                secrets_dict = dict(st.secrets)
                if "GROQ_API_KEY" in secrets_dict:
                    groq_key = secrets_dict["GROQ_API_KEY"]
            except:
                # st.secrets exists but can't be accessed
                pass
    except:
        pass
    
    if not groq_key:
        st.error(
            "**❌ API Configuration Required**\n\n"
            "Groq API key not found. Please ensure GROQ_API_KEY is set in:\n"
            "1. Hugging Face Space Secrets (recommended)\n"
            "2. Environment variables\n\n"
            "Get free API key: console.groq.com"
        )
        st.stop()
    
    # Prepare API call
    try:
        conversation_context = []
        conversation_context.append({"role": "system", "content": SYSTEM_INSTRUCTIONS})
        
        recent_messages = st.session_state.messages[-8:]
        for msg in recent_messages:
            if msg["role"] != "system":
                conversation_context.append(msg)
        
        # Call Groq API
        with st.spinner("Feynman is thinking... ⚛️"):
            response_text = call_groq_api(groq_key, conversation_context)
        
        if response_text:
            st.session_state.messages.append({"role": "assistant", "content": response_text})
            display_message("assistant", response_text, enable_voice)
            
            # Clear image content after processing
            if 'visual_content' in locals():
                visual_content = None
            if 'image_analysis' in locals():
                image_analysis = None
                
        else:
            st.error("Failed to get response. Please try again.")
            
    except Exception as e:
        st.error(f"Error: {str(e)[:200]}")

# Footer
st.divider()
st.markdown("**H2 Physics Feynman Tutor** | Singapore H2 Physics (9478) Syllabus")
st.markdown("Powered by Groq AI + AI Image Analysis")
st.markdown("*AI tutoring assistant. Verify with official syllabus.*")