app.py

from models.resnet_cnn import ResNet1D
from models.figure2_cnn import Figure2CNN
import hashlib
import gc
import time
import io
from PIL import Image
import matplotlib.pyplot as plt
import matplotlib
import numpy as np
import torch
import torch.nn.functional as F
import streamlit as st
import os
import sys
from pathlib import Path

# Ensure 'utils' directory is in the Python path
utils_path = Path(__file__).resolve().parent / "utils"
if utils_path.is_dir() and str(utils_path) not in sys.path:
    sys.path.append(str(utils_path))
matplotlib.use("Agg")  # ensure headless rendering in Spaces

# Import local modules
from utils.preprocessing import resample_spectrum

KEEP_KEYS = {
    # === global UI context we want to keep after "Reset" ===
    "model_select",     # sidebar model key
    "input_mode",       # radio for Upload|Sample
    "uploader_version", # version counter for file uploader
    "input_registry",   # radio controlling Upload vs Sample
}

# Configuration
st.set_page_config(
    page_title="ML Polymer Classification",
    page_icon="🔬",
    layout="wide",
    initial_sidebar_state="expanded"
)

# Stabilize tab panel height on HF Spaces to prevent visible column jitter.
# This sets a minimum height for the content area under the tab headers.
st.markdown("""
<style>
/*  Tabs content area: the sibling after the tablist */
    div[data-testid="stTabs"] > div[role="tablist"] + div { min-height: 420px;}
</style>
""", unsafe_allow_html=True)

# Constants
TARGET_LEN = 500
SAMPLE_DATA_DIR = Path("sample_data")
# Prefer env var, else 'model_weights' if present; else canonical 'outputs'
MODEL_WEIGHTS_DIR = (
    os.getenv("WEIGHTS_DIR")
    or ("model_weights" if os.path.isdir("model_weights") else "outputs")
)

# Model configuration
MODEL_CONFIG = {
    "Figure2CNN (Baseline)": {
        "class": Figure2CNN,
        "path": f"{MODEL_WEIGHTS_DIR}/figure2_model.pth",
        "emoji": "🔬",
        "description": "Baseline CNN with standard filters",
        "accuracy": "94.80%",
        "f1": "94.30%"
    },
    "ResNet1D (Advanced)": {
        "class": ResNet1D,
        "path": f"{MODEL_WEIGHTS_DIR}/resnet_model.pth",
        "emoji": "🧠",
        "description": "Residual CNN with deeper feature learning",
        "accuracy": "96.20%",
        "f1": "95.90%"
    }
}

# Label mapping
LABEL_MAP = {0: "Stable (Unweathered)", 1: "Weathered (Degraded)"}


# === UTILITY FUNCTIONS ===
def init_session_state():
    defaults = {
        "status_message": "Ready to analyze polymer spectra 🔬",
        "status_type": "info",
        "input_text": None,
        "filename": None,
        "input_source": None,     # "upload" or "sample"
        "sample_select": "-- Select Sample --",
        "input_mode": "Upload File",   # controls which pane is visible
        "inference_run_once": False,
        "x_raw": None, "y_raw": None, "y_resampled": None,
        "log_messages": [],
        "uploader_version": 0,
        "current_upload_key": "upload_txt_0",
    }
    for k, v in defaults.items():
        st.session_state.setdefault(k, v)

    for key, default_value in defaults.items():
        if key not in st.session_state:
            st.session_state[key] = default_value


def label_file(filename: str) -> int:
    """Extract label from filename based on naming convention"""
    name = Path(filename).name.lower()
    if name.startswith("sta"):
        return 0
    elif name.startswith("wea"):
        return 1
    else:
        # Return None for unknown patterns instead of raising error
        return -1  # Default value for unknown patterns


@st.cache_data
def load_state_dict(_mtime, model_path):
    """Load state dict with mtime in cache key to detect file changes"""
    try:
        return torch.load(model_path, map_location="cpu", weights_only=True)
    except (FileNotFoundError, RuntimeError) as e:
        st.warning(f"Error loading state dict: {e}")
        return None


@st.cache_resource
def load_model(model_name):
    """Load and cache the specified model with error handling"""
    try:
        config = MODEL_CONFIG[model_name]
        model_class = config["class"]
        model_path = config["path"]

        # Initialize model
        model = model_class(input_length=TARGET_LEN)

        # Check if model file exists
        if not os.path.exists(model_path):
            st.warning(f"⚠️ Model weights not found: {model_path}")
            st.info("Using randomly initialized model for demonstration purposes.")
            return model, False

        # Get mtime for cache invalidation
        mtime = os.path.getmtime(model_path)

        # Load weights
        state_dict = load_state_dict(mtime, model_path)
        if state_dict:
            model.load_state_dict(state_dict, strict=True)
            if model is None:
                raise ValueError(
                    "Model is not loaded. Please check the model configuration or weights.")
            model.eval()
            return model, True
        else:
            return model, False

    except (FileNotFoundError, KeyError) as e:
        st.error(f"❌ Error loading model {model_name}: {str(e)}")
        return None, False


def cleanup_memory():
    """Clean up memory after inference"""
    gc.collect()
    if torch.cuda.is_available():
        torch.cuda.empty_cache()


@st.cache_data
def get_sample_files():
    """Get list of sample files if available"""
    sample_dir = Path(SAMPLE_DATA_DIR)
    if sample_dir.exists():
        return sorted(list(sample_dir.glob("*.txt")))
    return []


def parse_spectrum_data(raw_text):
    """Parse spectrum data from text with robust error handling and validation"""
    x_vals, y_vals = [], []

    for line in raw_text.splitlines():
        line = line.strip()
        if not line or line.startswith('#'):  # Skip empty lines and comments
            continue

        try:
            # Handle different separators
            parts = line.replace(",", " ").split()
            numbers = [p for p in parts if p.replace('.', '', 1).replace(
                '-', '', 1).replace('+', '', 1).isdigit()]

            if len(numbers) >= 2:
                x, y = float(numbers[0]), float(numbers[1])
                x_vals.append(x)
                y_vals.append(y)

        except ValueError:
            # Skip problematic lines but don't fail completely
            continue

    if len(x_vals) < 10:  # Minimum reasonable spectrum length
        raise ValueError(
            f"Insufficient data points: {len(x_vals)}. Need at least 10 points.")

    x = np.array(x_vals)
    y = np.array(y_vals)

    # Check for NaNs
    if np.any(np.isnan(x)) or np.any(np.isnan(y)):
        raise ValueError("Input data contains NaN values")

    # Check monotonic increasing x
    if not np.all(np.diff(x) > 0):
        raise ValueError("Wavenumbers must be strictly increasing")

    # Check reasonable range for Raman spectroscopy
    if min(x) < 0 or max(x) > 10000 or (max(x) - min(x)) < 100:
        raise ValueError(
            f"Invalid wavenumber range: {min(x)} - {max(x)}. Expected ~400-4000 cm⁻¹ with span >100")

    return x, y


def create_spectrum_plot(x_raw, y_raw, x_resampled, y_resampled):
    """Create spectrum visualization plot"""
    fig, ax = plt.subplots(1, 2, figsize=(13, 5), dpi=100)

    # == Raw spectrum ==
    ax[0].plot(x_raw, y_raw, label="Raw", color="dimgray", linewidth=1)
    ax[0].set_title("Raw Input Spectrum")
    ax[0].set_xlabel("Wavenumber (cm⁻¹)")
    ax[0].set_ylabel("Intensity")
    ax[0].grid(True, alpha=0.3)
    ax[0].legend()

    # == Resampled spectrum ==
    ax[1].plot(x_resampled, y_resampled, label="Resampled", color="steelblue", linewidth=1)
    ax[1].set_title(f"Resampled ({len(y_resampled)} points)")
    ax[1].set_xlabel("Wavenumber (cm⁻¹)")
    ax[1].set_ylabel("Intensity")
    ax[1].grid(True, alpha=0.3)
    ax[1].legend()

    plt.tight_layout()
    # == Convert to image ==
    buf = io.BytesIO()
    plt.savefig(buf, format='png', bbox_inches='tight', dpi=100)
    buf.seek(0)
    plt.close(fig)  # Prevent memory leaks

    return Image.open(buf)

def render_confidence_bar(probabilities, class_labels):
    bar = lambda p: "█" * int(p * 20)
    for label, prob in zip(class_labels, probabilities):
        st.write(f"**{label}**: {bar(prob)} {prob*100:.1f}%")


def get_confidence_description(logit_margin):
    """Get human-readable confidence description"""
    if logit_margin > 1000:
        return "VERY HIGH", "🟢"
    elif logit_margin > 250:
        return "HIGH", "🟡"
    elif logit_margin > 100:
        return "MODERATE", "🟠"
    else:
        return "LOW", "🔴"

def log_message(msg: str):
    """Append a timestamped line to the in-app log, creating the buffer if needed."""
    if "log_messages" not in st.session_state or st.session_state["log_messages"] is None:
        st.session_state["log_messages"] = []
    st.session_state["log_messages"].append(
        f"[{time.strftime('%Y-%m-%d %H:%M:%S')}] {msg}"
    )

def trigger_run():
    """Set a flag so we can detect button press reliably across reruns"""
    st.session_state['run_requested'] = True

def on_sample_change():
    """Read selected sample once and persist as text."""
    sel = st.session_state.get("sample_select", "-- Select Sample --")
    if sel == "-- Select Sample --":
        return
    try:
        text = (Path(SAMPLE_DATA_DIR / sel).read_text(encoding="utf-8"))
        st.session_state["input_text"] = text
        st.session_state["filename"] = sel
        st.session_state["input_source"] = "sample"
        # 🔧 Clear previous results so right column resets immediately
        reset_results("New sample selected")
        st.session_state["status_message"] = f"📁 Sample '{sel}' ready for analysis"
        st.session_state["status_type"] = "success"
    except (FileNotFoundError, IOError) as e:
        st.session_state["status_message"] = f"❌ Error loading sample: {e}"
        st.session_state["status_type"] = "error"

def on_input_mode_change():
    """Reset sample when switching to Upload"""
    if st.session_state["input_mode"] == "Upload File":
        st.session_state["sample_select"] = "-- Select Sample --"
    # 🔧 Reset when switching modes to prevent stale right-column visuals
    reset_results("Switched input mode")

def on_model_change():
    """Force the right column back to init state when the model changes"""
    reset_results("Model changed")

def reset_results(reason: str = ""):
    """Clear previous inference artifacts so the right column returns to initial state."""
    st.session_state["inference_run_once"] = False
    st.session_state["x_raw"] = None
    st.session_state["y_raw"] = None
    st.session_state["y_resampled"] = None
    # ||== Clear logs between runs ==||
    st.session_state["log_messages"] = []
    # ||== Always reset the status box ==||
    st.session_state["status_message"] = (
        f"ℹ️ {reason}"
        if reason else "Ready to analyze polymer spectra 🔬"
    )
    st.session_state["status_type"] = "info"

def reset_ephemeral_state():
    # === remove everything except KEPT global UI context ===
    for k in list(st.session_state.keys()):
        if k not in KEEP_KEYS:
            st.session_state.pop(k, None)

    # == bump the uploader version → new widget instance with empty value ==
    st.session_state["uploader_version"] += 1
    st.session_state["current_upload_key"] = f"upload_txt_{st.session_state['uploader_version']}"
    
    # == reseed other emphemeral state ==
    st.session_state["input_text"] =  None
    st.session_state["filename"] = None
    st.session_state["input_source"] = None
    st.session_state["sample_select"] = "-- Select Sample --"
    # == return the UI to a clean state ==
    st.session_state["inference_run_once"] = False
    st.session_state["x_raw"] = None
    st.session_state["y_raw"] = None
    st.session_state["y_resampled"] = None
    st.session_state["log_messages"] = []
    st.session_state["status_message"] = "Ready to analyze polymer spectra 🔬"
    st.session_state["status_type"] = "info"
    
    st.rerun()

def plot_confidence_bar(probabilities: list[float], class_labels: list[str]) -> None:
    """Renders a horizontal bar chart of prediction confidences per class."""
    fig, ax = plt.subplots(figsize=(4, 1.5))
    bars = ax.barh(class_labels, probabilities, color=[
        "green" if i == np.argmax(probabilities) else "gray"
        for i in range(len(probabilities))
    ])
    ax.set_xlabel("Confidence")
    ax.set_title("Prediction Confidence")
    ax.xaxis.set_ticks([0, 0.5, 1.0])
    ax.set_xlim(0, 1.0)
    for i, (label, prob) in enumerate(zip(class_labels, probabilities)):
        ax.text(prob + 0.01, i, f"{prob*100:.1f}%", va='center', fontsize=8)

    st.pyplot(fig)


# Main app
def main():
    init_session_state()
    # Header
    st.title("🔬 AI-Driven Polymer Classification")
    st.markdown(
        "**Predict polymer degradation states using Raman spectroscopy and deep learning**")
    st.info(
        "**Prototype Notice:** v0.1 Raman-only. "
        "Multi-model CNN evaluation in progress. "
        "FTIR support planned.",
        icon="⚡"
    )

    # Sidebar
    with st.sidebar:
        st.header("ℹ️ About This App")
        st.sidebar.markdown("""
        AI-Driven Polymer Aging Prediction and Classification

        🎯 **Purpose**: Classify polymer degradation using AI  
        📊 **Input**: Raman spectroscopy `.txt` files  
        🧠 **Models**: CNN architectures for binary classification  
        💾 **Current**: Figure2CNN (baseline)  
        📈 **Next**: More trained CNNs in evaluation pipeline

        ---

        **Team**  
        Dr. Sanmukh Kuppannagari (Mentor)  
        Dr. Metin Karailyan (Mentor)  
        👨‍💻 Jaser Hasan (Author)

        ---

        **Links**  
        🔗 [Live HF Space](https://huggingface.co/spaces/dev-jas/polymer-aging-ml)  
        📂 [GitHub Repository](https://github.com/KLab-AI3/ml-polymer-recycling)

        ---

        **Model Credit**  
        Baseline model inspired by *Figure 2 CNN* from:  
        > Neo, E.R.K., Low, J.S.C., Goodship, V., Debattista, K. (2023).  
        > *Deep learning for chemometric analysis of plastic spectral data from infrared and Raman databases*.  
        > _Resources, Conservation & Recycling_, **188**, 106718.

        [https://doi.org/10.1016/j.resconrec.2022.106718](https://doi.org/10.1016/j.resconrec.2022.106718)
        """)

        st.markdown("---")

        # Model selection
        st.subheader("🧠 Model Selection")
        model_labels = [
            f"{MODEL_CONFIG[name]['emoji']} {name}" for name in MODEL_CONFIG.keys()]
        selected_label = st.selectbox("Choose AI model:", model_labels,
                                    key="model_select", on_change=on_model_change)
        model_choice = selected_label.split(" ", 1)[1]

        # Model info
        config = MODEL_CONFIG[model_choice]
        st.markdown(f"""
        **📈 {config['emoji']} Model Details**
        
        *{config['description']}*
        
        - **Accuracy**: `{config['accuracy']}`
        - **F1 Score**: `{config['f1']}`
        """)

    # Main content area
    col1, col2 = st.columns([1, 1.5], gap="large")

    with col1:
        st.subheader("📁 Data Input")

        mode = st.radio(
            "Input mode",
            ["Upload File", "Sample Data"],
            key="input_mode",
            horizontal=True,
            on_change=on_input_mode_change
        )

        # ---- Upload tab ----
        if mode == "Upload File":
            upload_key = st.session_state["current_upload_key"]
            up = st.file_uploader(
                "Upload Raman spectrum (.txt)",
                type="txt",
                help="Upload a text file with wavenumber and intensity columns",
                key=upload_key,     # ← versioned key
            )

            # == process change immediately (no on_change; simpler & reliable) ==
            if up is not None:
                raw = up.read()
                text = raw.decode("utf-8") if isinstance(raw, bytes) else raw
                # == only reparse if its a different file|source ==
                if st.session_state.get("filename") != getattr(up, "name", None) or st.session_state.get("input_source") != "upload":
                    st.session_state["input_text"] = text 
                    st.session_state["filename"] = getattr(up, "name", "uploaded.txt")
                    st.session_state["input_source"] = "upload"

                    # == clear right column immediately ==
                    reset_results("New file selected")
                    st.session_state["status_message"] = f"📁 File '{st.session_state['filename']}' ready for analysis"
                    st.session_state["status_type"] = "success"

            if up:
                st.success(f"✅ Loaded: {up.name}")

        # ---- Sample tab ----
        else:
            sample_files = get_sample_files()
            if sample_files:
                options = ["-- Select Sample --"] + \
                    [p.name for p in sample_files]
                sel = st.selectbox(
                    "Choose sample spectrum:",
                    options,
                    key="sample_select",
                    on_change=on_sample_change,  # <-- critical
                )
                if sel != "-- Select Sample --":
                    st.success(f"✅ Loaded sample: {sel}")
            else:
                st.info("No sample data available")

        # ---- Status box ----
        st.subheader("🚦 Status")
        msg = st.session_state.get("status_message", "Ready")
        typ = st.session_state.get("status_type", "info")
        if typ == "success":
            st.success(msg)
        elif typ == "error":
            st.error(msg)
        else:
            st.info(msg)

        # ---- Model load ----
        model, model_loaded = load_model(model_choice)
        if not model_loaded:
            st.warning("⚠️ Model weights not available - using demo mode")

        # Ready to run if we have text and a model
        inference_ready = bool(st.session_state.get(
            "input_text")) and (model is not None)

        # === Run Analysis (form submit batches state) ===
        with st.form("analysis_form", clear_on_submit=False):
            submitted = st.form_submit_button(
                "▶️ Run Analysis",
                type="primary",
                disabled=not inference_ready,
            )

        if st.button("Reset", help="Clear current file(s), plots, and results"):
            reset_ephemeral_state()

            

        if submitted and inference_ready:
            # parse → preprocess → predict → render
            # Handles the submission of the analysis form and performs spectrum data processing
            try:
                raw_text = st.session_state["input_text"]
                filename = st.session_state.get("filename") or "unknown.txt"

                # Parse
                with st.spinner("Parsing spectrum data..."):
                    x_raw, y_raw = parse_spectrum_data(raw_text)

                # Resample
                with st.spinner("Resampling spectrum..."):
                    # ===Resample Unpack===
                    r1, r2 = resample_spectrum(x_raw, y_raw, TARGET_LEN)

                    def _is_strictly_increasing(a):
                        try:
                            a = np.asarray(a)
                            return a.ndim == 1  and a.size >= 2 and np.all(np.diff(a) > 0)
                        except Exception:
                            return False

                    if _is_strictly_increasing(r1) and not _is_strictly_increasing(r2):
                        x_resampled, y_resampled = np.asarray(r1), np.asarray(r2)
                    elif _is_strictly_increasing(r2) and not _is_strictly_increasing(r1):
                        x_resampled, y_resampled = np.asarray(r2), np.asarray(r1)
                    else:
                        # == Ambigous; assume (x, y) and log
                        x_resampled, y_resampled = np.asarray(r1), np.asarray(r2)
                        log_message("Resample outputs ambigous; assumed (x, y).")

                    # ===Persists for plotting + inference===
                    st.session_state["x_raw"] = x_raw
                    st.session_state["y_raw"] = y_raw
                    st.session_state["x_resampled"] = x_resampled   #  ←-- NEW 
                    st.session_state["y_resampled"] = y_resampled

                # Persist results (drives right column)
                st.session_state["x_raw"] = x_raw
                st.session_state["y_raw"] = y_raw
                st.session_state["y_resampled"] = y_resampled
                st.session_state["inference_run_once"] = True
                st.session_state["status_message"] = f"🔍 Analysis completed for: {filename}"
                st.session_state["status_type"] = "success"

                st.rerun()

            except (ValueError, TypeError) as e:
                st.error(f"❌ Analysis failed: {e}")
                st.session_state["status_message"] = f"❌ Error: {e}"
                st.session_state["status_type"] = "error"

    # Results column
    with col2:
        if st.session_state.get("inference_run_once", False):
            st.subheader("📊 Analysis Results")

            # Get data from session state
            x_raw = st.session_state.get('x_raw')
            y_raw = st.session_state.get('y_raw')
            x_resampled = st.session_state.get('x_resampled')   # ← NEW
            y_resampled = st.session_state.get('y_resampled')
            filename = st.session_state.get('filename', 'Unknown')

            if all(v is not None for v in [x_raw, y_raw, y_resampled]):

                # Create and display plot
                try:
                    spectrum_plot = create_spectrum_plot(x_raw, y_raw, x_resampled, y_resampled)
                    st.image(
                        spectrum_plot, caption="Spectrum Preprocessing Results", use_container_width=True)
                except (ValueError, RuntimeError, TypeError) as e:
                    st.warning(f"Could not generate plot: {e}")
                    log_message(f"Plot generation error: {e}")

                # Run inference
                try:
                    with st.spinner("Running AI inference..."):
                        start_time = time.time()

                        # Prepare input tensor
                        input_tensor = torch.tensor(
                            y_resampled, dtype=torch.float32).unsqueeze(0).unsqueeze(0)

                        # Run inference
                        model.eval()
                        with torch.no_grad():
                            if model is None:
                                raise ValueError(
                                    "Model is not loaded. Please check the model configuration or weights.")
                            logits = model(input_tensor)
                            prediction = torch.argmax(logits, dim=1).item()
                            logits_list = logits.detach().numpy().tolist()[0]

                        probs = F.softmax(logits.detach(), dim=1).cpu().numpy().flatten()


                        inference_time = time.time() - start_time
                        log_message(
                            f"Inference completed in {inference_time:.2f}s, prediction: {prediction}")

                        # Clean up memory
                        cleanup_memory()

                    # Get ground truth if available
                    true_label_idx = label_file(filename)
                    true_label_str = LABEL_MAP.get(
                        true_label_idx, "Unknown") if true_label_idx is not None else "Unknown"

                    # Get prediction
                    predicted_class = LABEL_MAP.get(
                        int(prediction), f"Class {int(prediction)}")

                    # Calculate confidence metrics
                    logit_margin = abs(
                        logits_list[0] - logits_list[1]) if len(logits_list) >= 2 else 0
                    confidence_desc, confidence_emoji = get_confidence_description(
                        logit_margin)

                    # Display results
                    st.markdown("### 🎯 Prediction Results")

                    # Main prediction
                    st.markdown(f"""
                    **🔬 Sample**: `{filename}`  
                    **🧠 Model**: `{model_choice}`  
                    **⏱️ Processing Time**: `{inference_time:.2f}s`
                    """)

                    # Prediction box
                    if predicted_class == "Stable (Unweathered)":
                        st.success(f"🟢 **Prediction**: {predicted_class}")
                    else:
                        st.warning(f"🟡 **Prediction**: {predicted_class}")

                    # Confidence
                    st.markdown(
                        f"**{confidence_emoji} Confidence**: {confidence_desc} (margin: {logit_margin:.1f})")

                    # Ground truth comparison
                    if true_label_idx is not None:
                        if predicted_class == true_label_str:
                            st.success(
                                f"✅ **Ground Truth**: {true_label_str} - **Correct!**")
                        else:
                            st.error(
                                f"❌ **Ground Truth**: {true_label_str} - **Incorrect**")
                    else:
                        st.info(
                            "ℹ️ **Ground Truth**: Unknown (filename doesn't follow naming convention)")

                    # ===display confidence results===
                    class_labels = ["Stable", "Weathered"]
                    plot_confidence_bar(probabilities=probs.tolist(), class_labels=class_labels)

                    # ===Detailed results tabs===
                    tab1, tab2, tab3 = st.tabs(
                        ["📊 Details", "🔬 Technical", "📘 Explanation"])

                    with tab1:
                        st.markdown("**Model Output (Logits)**")
                        for i, score in enumerate(logits_list):
                            label = LABEL_MAP.get(i, f"Class {i}")
                            st.metric(label, f"{score:.2f}")

                        st.markdown("**Spectrum Statistics**")
                        st.json({
                            "Original Length": len(x_raw) if x_raw is not None else 0,
                            "Resampled Length": TARGET_LEN,
                            "Wavenumber Range": f"{min(x_raw):.1f} - {max(x_raw):.1f} cm⁻¹" if x_raw is not None else "N/A",
                            "Intensity Range": f"{min(y_raw):.1f} - {max(y_raw):.1f}" if y_raw is not None else "N/A",
                            "Model Confidence": confidence_desc
                        })

                    with tab2:
                        st.markdown("**Technical Information**")
                        model_path = MODEL_CONFIG[model_choice]["path"]
                        mtime = os.path.getmtime(model_path) if os.path.exists(
                            model_path) else "N/A"
                        file_hash = hashlib.md5(open(model_path, 'rb').read(
                        )).hexdigest() if os.path.exists(model_path) else "N/A"
                        st.json({
                            "Model Architecture": model_choice,
                            "Model Path": model_path,
                            "Weights Last Modified": time.strftime('%Y-%m-%d %H:%M:%S', time.localtime(mtime)) if mtime != "N/A" else "N/A",
                            "Weights Hash": file_hash,
                            "Input Shape": list(input_tensor.shape),
                            "Output Shape": list(logits.shape),
                            "Inference Time": f"{inference_time:.3f}s",
                            "Device": "CPU",
                            "Model Loaded": model_loaded
                        })

                        if not model_loaded:
                            st.warning(
                                "⚠️ Demo mode: Using randomly initialized weights")

                        # Debug log
                        st.markdown("**Debug Log**")
                        st.text_area("Logs", "\n".join(
                            st.session_state.get("log_messages", [])), height=200)

                        try:
                            resampler_mod = getattr(resample_spectrum, "__module__", "unknown")
                            resampler_doc = getattr(resample_spectrum, "__doc__", None)
                            resampler_doc = resampler_doc.splitlines()[0] if isinstance(resampler_doc, str) and resampler_doc else "no doc"

                            y_rs = st.session_state.get("y_resampled", None)
                            diag = {}
                            if y_rs is not None:
                                arr = np.asarray(y_rs)
                                diag = {
                                    "y_resampled_len": int(arr.size),
                                    "y_resampled_min": float(np.min(arr)) if arr.size else None,
                                    "y_resampled_max": float(np.max(arr)) if arr.size else None,
                                    "y_resampled_ptp": float(np.ptp(arr)) if arr.size else None,
                                    "y_resampled_unique": int(np.unique(arr).size) if arr.size else None,
                                    "y_resampled_all_equal": bool(np.ptp(arr) == 0.0) if arr.size else None,
                                }

                            st.markdown("**Resampler Info")
                            st.json({
                                "module": resampler_mod,
                                "doc": resampler_doc,
                                **({"y_resampled_stats": diag} if diag else {})
                            })
                        except Exception as _e:
                            st.warning(f"Diagnostics skipped: {_e}")

                    with tab3:
                        st.markdown("""
                        **🔍 Analysis Process**
                        
                        1. **Data Upload**: Raman spectrum file loaded
                        2. **Preprocessing**: Data parsed and resampled to 500 points
                        3. **AI Inference**: CNN model analyzes spectral patterns
                        4. **Classification**: Binary prediction with confidence scores
                        
                        **🧠 Model Interpretation**
                        
                        The AI model identifies spectral features indicative of:
                        - **Stable polymers**: Well-preserved molecular structure
                        - **Weathered polymers**: Degraded/oxidized molecular bonds
                        
                        **🎯 Applications**
                        
                        - Material longevity assessment
                        - Recycling viability evaluation  
                        - Quality control in manufacturing
                        - Environmental impact studies
                        """)

                except (ValueError, RuntimeError) as e:
                    st.error(f"❌ Inference failed: {str(e)}")
                    log_message(f"Inference error: {str(e)}")

            else:
                st.error(
                    "❌ Missing spectrum data. Please upload a file and run analysis.")
        else:
            # Welcome message
            st.markdown("""
            ### 👋 Welcome to AI Polymer Classification
            
            **Get started by:**
            1. 🧠 Select an AI model in the sidebar
            2. 📁 Upload a Raman spectrum file or choose a sample
            3. ▶️ Click "Run Analysis" to get predictions
            
            **Supported formats:**
            - Text files (.txt) with wavenumber and intensity columns
            - Space or comma-separated values
            - Any length (automatically resampled to 500 points)
            
            **Example applications:**
            - 🔬 Research on polymer degradation
            - ♻️ Recycling feasibility assessment
            - 🌱 Sustainability impact studies
            - 🏭 Quality control in manufacturing
            """)


# Run the application
main()