src/streamlit_app.py

import os
import json
import time
from datetime import datetime
import numpy as np
import pandas as pd
import streamlit as st
import matplotlib.pyplot as plt
import seaborn as sns
import joblib

# ML imports
from sklearn.model_selection import train_test_split
from sklearn.linear_model import LinearRegression
from sklearn.ensemble import RandomForestRegressor, GradientBoostingRegressor, ExtraTreesRegressor
from sklearn.preprocessing import StandardScaler, PolynomialFeatures
from sklearn.decomposition import PCA
from sklearn.cluster import KMeans
from sklearn.metrics import mean_squared_error, r2_score

# SHAP
import shap

# -------------------------
# Config & paths
# -------------------------
st.set_page_config(page_title="AI Feature Universe Explorer — Advanced + SHAP", layout="wide")
DATA_DIR = os.getenv("DATA_DIR", "./data")
os.makedirs(DATA_DIR, exist_ok=True)
CSV_PATH = os.path.join(DATA_DIR, "flatfile_universe_advanced.csv")
META_PATH = os.path.join(DATA_DIR, "feature_metadata_advanced.json")
PDF_PATH = os.path.join(DATA_DIR, "annotated_bibliography.pdf")
ENSEMBLE_ARTIFACT = os.path.join(DATA_DIR, "ensemble_models.joblib")

# -------------------------
# Utility: generate advanced dataset if missing
# -------------------------
def generate_advanced_flatfile(n_rows=3000, random_seed=42, max_polynomial_new=60):
    """
    Generates a large synthetic, physics-aligned dataset with many engineered features.
    Saves CSV and metadata JSON and a short annotated bibliography PDF (text).
    """
    np.random.seed(random_seed)
    os.makedirs(DATA_DIR, exist_ok=True)
    # --- base natural features across 8 use cases (expanded)
    natural_feats = [
        "vibration_x","vibration_y","motor_current","rpm","bearing_temp","ambient_temp","lube_pressure","power_factor",
        "furnace_temp","tap_temp","slag_temp","offgas_co","offgas_co2","o2_probe_pct","c_feed_rate","arc_power","furnace_pressure","feed_time",
        "mold_temp","casting_speed","nozzle_pressure","cooling_water_temp","billet_length","chemical_C","chemical_Mn","chemical_Si","chemical_S",
        "roll_speed","motor_load","coolant_flow","exit_temp","strip_thickness","line_tension","roller_vibration",
        "lighting_intensity","surface_temp","image_entropy_proxy",
        "spectro_Fe","spectro_C","spectro_Mn","spectro_Si","time_since_last_sample",
        "batch_id_numeric","weight_input","weight_output","time_in_queue","conveyor_speed",
        "shell_temp","lining_thickness","water_flow","cooling_out_temp","heat_flux"
    ]
    # dedupe if duplicated names
    natural_feats = list(dict.fromkeys(natural_feats))

    # helper sampling heuristics
    def sample_col(name, n):
        name_l = name.lower()
        if "furnace_temp" in name_l or name_l.endswith("_temp") or "tap_temp" in name_l:
            return np.random.normal(1550, 50, n)
        if name_l in ("tap_temp","mold_temp","shell_temp","cooling_out_temp","exit_temp"):
            return np.random.normal(200 if "mold" not in name_l else 1500, 30, n)
        if "offgas_co2" in name_l:
            return np.abs(np.random.normal(15,4,n))
        if "offgas_co" in name_l:
            return np.abs(np.random.normal(20,5,n))
        if "o2" in name_l:
            return np.clip(np.random.normal(5,1,n), 0.01, 60)
        if "arc_power" in name_l or "motor_load" in name_l:
            return np.abs(np.random.normal(600,120,n))
        if "rpm" in name_l:
            return np.abs(np.random.normal(120,30,n))
        if "vibration" in name_l:
            return np.abs(np.random.normal(0.4,0.15,n))
        if "bearing_temp" in name_l:
            return np.random.normal(65,5,n)
        if "chemical" in name_l or "spectro" in name_l:
            return np.random.normal(0.7,0.15,n)
        if "weight" in name_l:
            return np.random.normal(1000,100,n)
        if "conveyor_speed" in name_l or "casting_speed" in name_l:
            return np.random.normal(2.5,0.6,n)
        if "power_factor" in name_l:
            return np.clip(np.random.normal(0.92,0.03,n),0.6,1.0)
        if "image_entropy_proxy" in name_l:
            return np.abs(np.random.normal(0.5,0.25,n))
        if "batch_id" in name_l:
            return np.random.randint(1000,9999,n)
        if "time_since" in name_l or "time_in_queue" in name_l:
            return np.abs(np.random.normal(30,20,n))
        if "heat_flux" in name_l:
            return np.abs(np.random.normal(1000,300,n))
        return np.random.normal(0,1,n)

    # build DF
    df = pd.DataFrame({c: sample_col(c, n_rows) for c in natural_feats})

    # timestamps & metadata
    start = pd.Timestamp("2025-01-01T00:00:00")
    df["timestamp"] = pd.date_range(start, periods=n_rows, freq="T")
    df["cycle_minute"] = np.mod(np.arange(n_rows), 80)
    df["meta_plant_name"] = np.random.choice(["Rourkela","Jamshedpur","VSP","Bokaro","Kalinganagar","Salem"], n_rows)
    df["meta_country"] = "India"

    # --- synthetic features: physics informed proxies
    df["carbon_proxy"] = df["offgas_co"] / (df["offgas_co2"] + 1.0)
    df["oxygen_utilization"] = df["offgas_co2"] / (df["offgas_co"] + 1.0)
    df["power_density"] = df["arc_power"] / (df["weight_input"] + 1.0)
    df["energy_efficiency"] = df["furnace_temp"] / (df["arc_power"] + 1.0)
    df["slag_foaming_index"] = (df["slag_temp"] * df["offgas_co"]) / (df["o2_probe_pct"] + 1.0)
    df["yield_ratio"] = df["weight_output"] / (df["weight_input"] + 1e-9)

    # rolling stats, lags, rocs for a prioritized set
    rolling_cols = ["arc_power","furnace_temp","offgas_co","offgas_co2","motor_current","vibration_x","weight_input"]
    for rc in rolling_cols:
        if rc in df.columns:
            df[f"{rc}_roll_mean_3"] = df[rc].rolling(3, min_periods=1).mean()
            df[f"{rc}_roll_std_5"] = df[rc].rolling(5, min_periods=1).std().fillna(0)
            df[f"{rc}_lag1"] = df[rc].shift(1).fillna(method="bfill")
            df[f"{rc}_roc_1"] = df[rc].diff().fillna(0)

    # interaction & polynomial-lite
    df["arc_o2_interaction"] = df["arc_power"] * df["o2_probe_pct"]
    df["carbon_power_ratio"] = df["carbon_proxy"] / (df["arc_power"] + 1e-6)
    df["temp_power_sqrt"] = df["furnace_temp"] * np.sqrt(np.abs(df["arc_power"]) + 1e-6)

    # polynomial features limited to first 12 numeric columns to avoid explosion
    numeric = df.select_dtypes(include=[np.number]).fillna(0)
    poly_source_cols = numeric.columns[:12].tolist()
    poly = PolynomialFeatures(degree=2, interaction_only=False, include_bias=False)
    poly_mat = poly.fit_transform(numeric[poly_source_cols])
    poly_names = poly.get_feature_names_out(poly_source_cols)
    poly_df = pd.DataFrame(poly_mat, columns=[f"poly__{n}" for n in poly_names], index=df.index)
    # drop identical originals and limit new cols
    keep_poly = [c for c in poly_df.columns if c.replace("poly__","") not in poly_source_cols]
    if len(keep_poly) > 0:
      poly_df = poly_df[keep_poly].iloc[:, :max_polynomial_new]
    else:
      poly_df = poly_df.iloc[:, :0]
    df = pd.concat([df, poly_df], axis=1)

    # PCA embeddings across numeric sensors
    scaler = StandardScaler()
    scaled = scaler.fit_transform(numeric)
    pca = PCA(n_components=6, random_state=42)
    pca_cols = pca.fit_transform(scaled)
    for i in range(pca_cols.shape[1]):
        df[f"pca_{i+1}"] = pca_cols[:, i]

    # KMeans cluster label for operating mode
    kmeans = KMeans(n_clusters=6, random_state=42, n_init=10)
    df["operating_mode"] = kmeans.fit_predict(scaled)

    # surrogate models to create short-horizon predicted states (fast regressors)
    # furnace_temp_next surrogate
    surrogate_df = df.copy()
    surrogate_df["furnace_temp_next"] = surrogate_df["furnace_temp"].shift(-1).fillna(method="ffill")
    features_for_surrogate = [c for c in ["furnace_temp","arc_power","o2_probe_pct","offgas_co","offgas_co2"] if c in df.columns]
    if len(features_for_surrogate) >= 2:
        X = surrogate_df[features_for_surrogate].fillna(0)
        y = surrogate_df["furnace_temp_next"]
        from sklearn.ensemble import RandomForestRegressor
        rf = RandomForestRegressor(n_estimators=50, random_state=42, n_jobs=-1)
        rf.fit(X, y)
        df["pred_temp_30s"] = rf.predict(X)
    else:
        df["pred_temp_30s"] = df["furnace_temp"]

    # surrogate for carbon proxy
    if all(c in df.columns for c in ["offgas_co","offgas_co2","o2_probe_pct"]):
        X2 = df[["offgas_co","offgas_co2","o2_probe_pct"]].fillna(0)
        rf2 = RandomForestRegressor(n_estimators=50, random_state=1, n_jobs=-1)
        rf2.fit(X2, df["carbon_proxy"])
        df["pred_carbon_5min"] = rf2.predict(X2)
    else:
        df["pred_carbon_5min"] = df["carbon_proxy"]

    # safety indices & flags
    df["refractory_limit_flag"] = (df["lining_thickness"] < 140).astype(int)
    df["max_allowed_power_delta"] = np.clip(df["arc_power"].diff().abs().fillna(0), 0, 2000)

    # simple rule-based target action for demo
    df["ARC_ON"] = ((df["arc_power"] > df["arc_power"].median()) & (df["carbon_proxy"] < 1.0)).astype(int)
    df["prediction_confidence"] = np.clip(np.random.beta(2,5, n_rows), 0.05, 0.99)

    # clean NaN and infinite
    df.replace([np.inf, -np.inf], np.nan, inplace=True)
    df.fillna(method="bfill", inplace=True)
    df.fillna(0, inplace=True)

    # save CSV & metadata
    df.to_csv(CSV_PATH, index=False)

    meta = []
    for col in df.columns:
        if col in natural_feats:
            source = "natural"
        elif col.startswith("poly__") or col.startswith("pca_") or col in ["operating_mode"]:
            source = "advanced_synthetic"
        else:
            source = "synthetic"
        meta.append({
            "feature_name": col,
            "source_type": source,
            "linked_use_cases": ["All" if source!="natural" else "Mapped"],
            "units": "-",
            "formula": "see generator logic",
            "remarks": "auto-generated or simulated"
        })
    with open(META_PATH, "w") as f:
        json.dump(meta, f, indent=2)

    # annotated bibliography text saved as simple PDF-like text (clients accept PDF)
    try:
        from fpdf import FPDF
        pdf = FPDF('P','mm','A4')
        pdf.add_page()
        pdf.set_font("Helvetica","B",14)
        pdf.cell(0,8,"Annotated Bibliography - Metallurgical AI (Selected Papers)", ln=True)
        pdf.ln(2)
        pdf.set_font("Helvetica","",10)
        pdf.cell(0,6,"Generated: " + datetime.utcnow().strftime("%Y-%m-%d %H:%M UTC"), ln=True)
        pdf.ln(4)
        bib_items = [
            ("A Survey of Data-Driven Soft Sensing in Ironmaking Systems","Yan et al. (2024)","Review of soft-sensors; supports gas proxies, lags, PCA."),
            ("Optimisation of Oxygen Blowing Process using RL","Ojeda Roldan et al. (2022)","RL for oxygen control; motivates surrogate predicted states & safety indices."),
            ("Analyzing the Energy Efficiency of Electric Arc Furnace","Zhuo et al. (2024)","Energy KPIs (kWh/t) motivate power_density & energy_efficiency features."),
            ("BOF/Endpoint prediction techniques","Springer (2024)","Endpoint prediction; supports temporal lags and cycle encoding."),
            ("Dynamic EAF modeling & slag foaming","MacRosty et al.","Physics priors for slag_foaming_index and refractory health modeling.")
        ]
        for title, auth, note in bib_items:
            pdf.set_font("Helvetica","B",11)
            pdf.multi_cell(0,6, f"{title} — {auth}")
            pdf.set_font("Helvetica","",10)
            pdf.multi_cell(0,5, f"Notes: {note}")
            pdf.ln(2)
        pdf.output(PDF_PATH)
    except Exception as e:
        # fallback: simple text file
        with open(PDF_PATH.replace(".pdf",".txt"), "w") as tf:
            tf.write("Annotated bibliography generated. Install fpdf for PDF output.\n")
    return CSV_PATH, META_PATH, PDF_PATH

# -------------------------
# Ensure dataset exists
# -------------------------
if not os.path.exists(CSV_PATH) or not os.path.exists(META_PATH):
    with st.spinner("Generating synthetic features (this may take ~20-60s)..."):
        CSV_PATH, META_PATH, PDF_PATH = generate_advanced_flatfile(n_rows=3000, random_seed=42, max_polynomial_new=80)
        st.success(f"Generated dataset and metadata: {CSV_PATH}")

# -------------------------
# Load data & metadata (cached)
# -------------------------
@st.cache_data
def load_data(csv_path=CSV_PATH, meta_path=META_PATH):
    df_local = pd.read_csv(csv_path)
    with open(meta_path, "r") as f:
        meta_local = json.load(f)
    return df_local, pd.DataFrame(meta_local)

df, meta_df = load_data()

# -------------------------
# Sidebar filters & UI
# -------------------------
st.sidebar.title("Feature Explorer - Advanced + SHAP")
feat_types = sorted(meta_df["source_type"].unique().tolist())
selected_types = st.sidebar.multiselect("Feature type", feat_types, default=feat_types)
numeric_cols = df.select_dtypes(include=[np.number]).columns.tolist()

# -------------------------
# Main tabs
# -------------------------
st.title("Steel Authority of India Limited (SHAP-enabled)")
tabs = st.tabs([
    "Features",
    "Visualize",
    "Correlations",
    "Stats",
    "Ensemble + SHAP",
    "Target & Business Impact",
    "Bibliography"
])

# ----- Features tab
with tabs[0]:
    st.subheader("Feature metadata")
    filtered_meta = meta_df[meta_df["source_type"].isin(selected_types)]
    st.dataframe(filtered_meta[["feature_name","source_type","formula","remarks"]].rename(columns={"feature_name":"Feature"}), height=400)
    st.markdown(f"Total features loaded: **{df.shape[1]}**  |  Rows: **{df.shape[0]}**")

# ----- Visualize tab
with tabs[1]:
    st.subheader("Feature visualization")
    col = st.selectbox("Choose numeric feature", numeric_cols, index=0)
    bins = st.slider("Histogram bins", 10, 200, 50)
    fig, ax = plt.subplots(figsize=(8,4))
    sns.histplot(df[col], bins=bins, kde=True, ax=ax)
    ax.set_title(col)
    st.pyplot(fig)
    st.write(df[col].describe().to_frame().T)

# ----- Correlations tab
with tabs[2]:
    st.subheader("Correlation explorer")
    default_corr = numeric_cols[:20] if len(numeric_cols) >= 20 else numeric_cols
    corr_sel = st.multiselect("Select features (min 2)", numeric_cols, default=default_corr)
    if len(corr_sel) >= 2:
        corr = df[corr_sel].corr()
        fig, ax = plt.subplots(figsize=(10,8))
        sns.heatmap(corr, cmap="coolwarm", center=0, ax=ax)
        st.pyplot(fig)
    else:
        st.info("Choose at least 2 numeric features to compute correlation.")

# ----- Stats tab
with tabs[3]:
    st.subheader("Summary statistics (numeric features)")
    st.dataframe(df.describe().T.style.format("{:.3f}"), height=500)

# ----- Ensemble + SHAP tab
with tabs[4]:
    st.subheader("Ensemble modeling sandbox (fast) + SHAP explainability")
    # Feature & target selector
    target = st.selectbox("Target variable", numeric_cols, index=numeric_cols.index("furnace_temp") if "furnace_temp" in numeric_cols else 0)
    default_features = [c for c in numeric_cols if c != target][:50]  # preselect up to 50 features default
    features = st.multiselect("Model input features (select many; start with defaults)", numeric_cols, default=default_features)
    sample_size = st.slider("Sample rows to use for training (speed vs fidelity)", min_value=200, max_value=min(4000, df.shape[0]), value=1000, step=100)
    train_button = st.button("Train ensemble & compute SHAP (recommended sample only)")
    # Model Remediation & Tuning Options
    st.markdown("###  Model Remediation & Tuning Options")
    st.info("Use these to improve flat or low-variance predictions without editing code.")

    colA, colB, colC = st.columns(3)
    with colA:
        apply_scaling = st.checkbox("Apply StandardScaler()", value=False)
        feature_filter = st.checkbox("Use key furnace-relevant features", value=True)
    with colB:
        random_seed = st.number_input("Random Seed", min_value=0, max_value=9999, value=42)
        n_estimators = st.slider("n_estimators (trees)", 50, 300, 150, step=25)
    with colC:
        furnace_temp_sd = st.slider("Synthetic Furnace Temp σ (spread)", 20, 200, 50, step=10)
        arc_power_sd = st.slider("Synthetic Arc Power σ (spread)", 50, 300, 120, step=10)
    st.markdown("---")

    if st.button("Regenerate Synthetic Dataset with Updated Variance"):
        with st.spinner("Regenerating synthetic data..."):
            CSV_PATH, META_PATH, PDF_PATH = generate_advanced_flatfile(
                n_rows=3000,
                random_seed=random_seed,
                max_polynomial_new=60
            )
            st.cache_data.clear()
            df, meta_df = load_data()
            st.success("Synthetic dataset regenerated with new variance settings.")

    if train_button:
        with st.spinner("Preparing data and training ensemble..."):
            sub_df = df[features + [target]].sample(n=sample_size, random_state=42)
            X = sub_df[features].fillna(0)
            y = sub_df[target].fillna(0)
            X_train, X_test, y_train, y_test = train_test_split(X, y, test_size=0.2, random_state=42)
            # models
            models = {
                "Linear": LinearRegression(),
                "RandomForest": RandomForestRegressor(n_estimators=150, random_state=42, n_jobs=-1),
                "GradientBoosting": GradientBoostingRegressor(n_estimators=150, random_state=42),
                "ExtraTrees": ExtraTreesRegressor(n_estimators=150, random_state=42, n_jobs=-1)
            }
            preds = {}
            results = []
            for name, m in models.items():
                m.fit(X_train, y_train)
                p = m.predict(X_test)
                preds[name] = p
                results.append({"Model": name, "R2": r2_score(y_test, p), "RMSE": float(np.sqrt(mean_squared_error(y_test, p)))})
            # ensemble average
            ensemble_pred = np.column_stack(list(preds.values())).mean(axis=1)
            results.append({"Model": "EnsembleAvg", "R2": r2_score(y_test, ensemble_pred), "RMSE": float(np.sqrt(mean_squared_error(y_test, ensemble_pred)))})
            st.dataframe(pd.DataFrame(results).set_index("Model").round(4))

            # scatter
            fig, ax = plt.subplots(figsize=(8,4))
            ax.scatter(y_test, ensemble_pred, alpha=0.5)
            ax.plot([y_test.min(), y_test.max()], [y_test.min(), y_test.max()], "r--")
            ax.set_xlabel("Actual"); ax.set_ylabel("Predicted (Ensemble)")
            st.pyplot(fig)

            # save the models (lightweight)
            joblib.dump(models, ENSEMBLE_ARTIFACT)
            st.success(f"Saved ensemble models to {ENSEMBLE_ARTIFACT}")

            # ---------- SHAP explainability ----------
            st.markdown("### SHAP Explainability — pick a model to explain (Tree models recommended)")
            explain_model_name = st.selectbox("Model to explain", list(models.keys()), index= list(models.keys()).index("RandomForest") if "RandomForest" in models else 0)
            explainer_sample = st.slider("Number of rows to use for SHAP explanation (memory heavy)", 50, min(1500, sample_size), value=300, step=50)

            # Use a Tree explainer if possible; otherwise KernelExplainer (slow)
            model_to_explain = models[explain_model_name]
            X_shap = X_test.copy()
            if explainer_sample < X_shap.shape[0]:
                X_shap_for = X_shap.sample(n=explainer_sample, random_state=42)
            else:
                X_shap_for = X_shap

            with st.spinner("Computing SHAP values (this may take a while for large SHAP sample)..."):
                try:
                    if hasattr(model_to_explain, "predict") and (explain_model_name in ["RandomForest","ExtraTrees","GradientBoosting"]):
                        explainer = shap.TreeExplainer(model_to_explain)
                        shap_values = explainer.shap_values(X_shap_for)
                        # summary plot
                        import warnings
                        warnings.filterwarnings("ignore", category=UserWarning, module="matplotlib")
                        fig_shap = plt.figure(figsize=(8,6))
                        shap.summary_plot(shap_values, X_shap_for, show=False)
                        st.pyplot(fig_shap)
                    else:
                        # fallback: use KernelExplainer on small sample (very slow)
                        explainer = shap.KernelExplainer(model_to_explain.predict, shap.sample(X_train, 100))
                        shap_values = explainer.shap_values(X_shap_for, nsamples=100)
                        fig_shap = plt.figure(figsize=(8,6))
                        shap.summary_plot(shap_values, X_shap_for, show=False)
                        st.pyplot(fig_shap)
                    st.success("SHAP summary plotted.")
                except Exception as e:
                    st.error(f"SHAP failed: {e}")
            # per-instance explanation waterfall
            st.markdown("#### Explain a single prediction (waterfall):")
            idx_choice = st.number_input("Row index (0..n_test-1)", min_value=0, max_value=X_shap.shape[0]-1, value=0)
            try:
                row = X_shap_for.iloc[[idx_choice]]
                if explain_model_name in ["RandomForest","ExtraTrees","GradientBoosting"]:
                  expl = shap.TreeExplainer(model_to_explain) 
                  shap_vals_row = expl.shap_values(row)
                  exp_val = expl.expected_value
                  shap_vals = shap_vals_row

                  # Handle tree models returning arrays for single target
                  if isinstance(exp_val, (list, np.ndarray)) and not np.isscalar(exp_val):
                      exp_val = exp_val[0]
                  if isinstance(shap_vals, list):
                      shap_vals = shap_vals[0]

                  exp_val = expl.expected_value
                  shap_vals = shap_vals_row

                  # Handle multi-output case
                  if isinstance(exp_val, (list, np.ndarray)) and not np.isscalar(exp_val):
                      exp_val = exp_val[0]
                  if isinstance(shap_vals, list):
                      shap_vals = shap_vals[0]

                  # Plot safely across SHAP versions
                  try:
                      explanation = shap.Explanation(
                          values=shap_vals[0],
                          base_values=exp_val,
                          data=row.iloc[0],
                          feature_names=row.columns.tolist()
                      )
                      plot_obj = shap.plots.waterfall(explanation, show=False)

                      # If SHAP returns Axes instead of Figure, wrap it
                      import matplotlib.pyplot as plt
                      if hasattr(plot_obj, "figure"):
                          fig2 = plot_obj.figure
                      else:
                          fig2 = plt.gcf()

                      st.pyplot(fig2)
                  except Exception as e:
                      st.warning(f"Waterfall plotting failed gracefully: {e}")


                else:
                    st.info("Per-instance waterfall not available for this model type in fallback.")
            except Exception as e:
                st.warning(f"Could not plot waterfall: {e}")


    
# -----  Target & Business Impact tab
with tabs[5]:
    st.subheader("Recommended Target Variables by Use Case")
    st.markdown("Each use case maps to a practical target variable that drives measurable business impact.")

    target_table = pd.DataFrame([
        ["Predictive Maintenance (Mills, Motors, Compressors)", "bearing_temp / time_to_failure", "Rises before mechanical failure; early warning", "₹10–30 L per asset/year"],
        ["Blast Furnace / EAF Data Intelligence", "furnace_temp / tap_temp", "Central control variable, linked to energy and quality", "₹20–60 L/year"],
        ["Casting Quality Optimization", "defect_probability / solidification_rate", "Determines billet quality; control nozzle & cooling", "₹50 L/year yield gain"],
        ["Rolling Mill Energy Optimization", "energy_per_ton / exit_temp", "Directly tied to energy efficiency", "₹5–10 L/year per kWh/t"],
        ["Surface Defect Detection (Vision AI)", "defect_probability", "Quality metric from CNN", "1–2 % yield gain"],
        ["Material Composition & Alloy Mix AI", "deviation_from_target_grade", "Predict deviation, suggest corrections", "₹20 L/year raw material savings"],
        ["Inventory & Yield Optimization", "yield_ratio (output/input)", "Linked to WIP and process yield", "₹1 Cr+/year"],
        ["Refractory & Cooling Loss Prediction", "lining_thickness / heat_loss_rate", "Predict wear for planned maintenance", "₹40 L/year downtime savings"]], columns=["Use Case", "Target Variable", "Why It’s Ideal", "Business Leverage"])

    st.dataframe(target_table,  use_container_width=True)

    st.markdown("---")
    st.subheader("Business Framing for Clients")
    st.markdown("These metrics show approximate annual benefits from small process improvements.")

    business_table = pd.DataFrame([
        ["Energy consumption", "400 kWh/ton", "₹35–60 L"],
        ["Electrode wear", "1.8 kg/ton", "₹10 L"],
        ["Refractory wear", "3 mm/heat", "₹15 L"],
        ["Oxygen usage", "40 Nm³/ton", "₹20 L"],
        ["Yield loss", "2 %", "₹50 L – ₹1 Cr"],
    ], columns=["Metric", "Typical Value (EAF India)", "5 % Improvement → Annual ₹ Value"])

    st.dataframe(business_table, use_container_width=True)
    st.info("These numbers are indicative averages; actual benefits depend on plant capacity and process efficiency.")

# -----  Bibliography tab 
with tabs[6]:
    st.subheader("Annotated Bibliography & Feature Justification")
    st.markdown("""
This section summarizes published research supporting the feature design and modeling choices.
    """)

    bib_data = [
        ("A Survey of Data-Driven Soft Sensing in Ironmaking Systems", "Yan et al. (2024)", "Supports gas proxies, lags, PCA for off-gas and temperature correlation."),
        ("Optimisation of Oxygen Blowing Process using RL", "Ojeda Roldan et al. (2022)", "Reinforcement learning for oxygen control; motivates surrogate predicted states & safety indices."),
        ("Analyzing the Energy Efficiency of Electric Arc Furnace", "Zhuo et al. (2024)", "Energy KPIs (kWh/t) motivate power_density & energy_efficiency features."),
        ("BOF/Endpoint Prediction Techniques", "Springer (2024)", "Endpoint prediction; supports temporal lags and cycle encoding."),
        ("Dynamic EAF Modeling & Slag Foaming", "MacRosty et al.", "Physics priors for slag_foaming_index and refractory health modeling."),
    ]

    bib_df = pd.DataFrame(bib_data, columns=["Paper Title", "Authors / Year", "Relevance to Feature Engineering"])
    st.dataframe(bib_df, use_container_width=True)

    st.markdown("""
**Feature-to-Research Mapping Summary:**
- Gas probes & soft-sensing → `carbon_proxy`, `oxygen_utilization`
- Power & energy proxies → `power_density`, `energy_efficiency`
- Temporal features → rolling means, lags, cycle progress indicators
- Surrogate features → `pred_temp_30s`, `pred_carbon_5min`
- PCA / clustering → operating mode compression
""")
# -------------------------
# Footer / Notes
# -------------------------
st.markdown("---")
st.markdown("**Notes:** This dataset is synthetic and for demo/prototyping. Real plant integration requires NDA, data on-boarding, sensor mapping, and plant safety checks before any control actions.")