app.py

from flask import Flask, request, jsonify
from flask_cors import CORS
import os
import json
import math
import traceback
import uuid
from typing import Tuple

import numpy as np
import pandas as pd
import joblib

import tensorflow as tf
from tensorflow.keras.utils import load_img, img_to_array

# Hybrid ARIMA
from statsmodels.tsa.arima.model import ARIMA

app = Flask(__name__)
CORS(app)

# ---------------------------------------------------------------------
# BASE DIRS
# ---------------------------------------------------------------------
BASE_DIR = os.path.dirname(__file__)
MODEL_DIR = os.path.join(BASE_DIR, "model")

# ---------------------------------------------------------------------
# (A) TEA PRICE (NEW HYBRID ARIMA + RF)
# ---------------------------------------------------------------------
TEA_ARTIFACT_DIR = os.getenv("TEA_ARTIFACT_DIR", os.path.join(BASE_DIR, "artifacts_tea_hybrid"))
TEA_DATA_PATH = os.getenv("TEA_DATA_PATH", os.path.join(BASE_DIR, "tea_auction_advanced_dataset.csv"))

TEA_MODEL_PATH = os.path.join(TEA_ARTIFACT_DIR, "hybrid_arima_rf_model.joblib")
TEA_CFG_PATH = os.path.join(TEA_ARTIFACT_DIR, "hybrid_config.json")

TEA_MIN_ARIMA_POINTS = int(os.getenv("TEA_MIN_ARIMA_POINTS", "60"))

tea_model = None
tea_cfg = None
tea_df_all = None
tea_load_error = None
tea_data_error = None

# derived
TEA_TARGET_COL = "auction_price_rs_per_kg"
TEA_DATE_COL = "date_week"
tea_cat_cols = ["elevation", "grade"]
tea_num_cols = []
TEA_ARIMA_ORDER = (2, 1, 2)
TEA_GROUP_COLS = ["elevation", "grade"]

tea_arima_models = {}  # key: (elevation, grade) -> fitted ARIMA
tea_ref_values = {}
tea_fallback_col = None
tea_global_median = None


def month_sin_cos(month_num: int):
    angle = 2.0 * np.pi * (month_num - 1) / 12.0
    return float(np.sin(angle)), float(np.cos(angle))


def _tea_safe_load():
    global tea_model, tea_cfg, tea_df_all
    global TEA_TARGET_COL, TEA_DATE_COL, tea_cat_cols, tea_num_cols, TEA_ARIMA_ORDER, TEA_GROUP_COLS
    global tea_load_error, tea_data_error
    global tea_fallback_col, tea_global_median, tea_ref_values

    # load artifacts
    try:
        if not os.path.exists(TEA_MODEL_PATH):
            raise FileNotFoundError(f"Missing tea model file: {TEA_MODEL_PATH}")
        if not os.path.exists(TEA_CFG_PATH):
            raise FileNotFoundError(f"Missing tea config file: {TEA_CFG_PATH}")

        tea_model = joblib.load(TEA_MODEL_PATH)

        with open(TEA_CFG_PATH, "r", encoding="utf-8") as f:
            tea_cfg = json.load(f)

        TEA_TARGET_COL = tea_cfg.get("TARGET_COL", TEA_TARGET_COL)
        TEA_DATE_COL = tea_cfg.get("DATE_COL", TEA_DATE_COL)
        tea_cat_cols = tea_cfg.get("cat_cols", tea_cat_cols)
        tea_num_cols = tea_cfg.get("num_cols", tea_num_cols)
        TEA_ARIMA_ORDER = tuple(tea_cfg.get("arima_order", list(TEA_ARIMA_ORDER)))
        TEA_GROUP_COLS = tea_cfg.get("group_cols", TEA_GROUP_COLS)

    except Exception as e:
        tea_load_error = f"Failed to load tea hybrid artifacts: {e}"
        tea_model = None
        tea_cfg = None

    # load data
    try:
        if not os.path.exists(TEA_DATA_PATH):
            raise FileNotFoundError(f"Missing tea dataset CSV: {TEA_DATA_PATH}")

        tea_df_all = pd.read_csv(TEA_DATA_PATH)
        tea_df_all[TEA_DATE_COL] = pd.to_datetime(tea_df_all[TEA_DATE_COL], errors="coerce")
        tea_df_all = tea_df_all.dropna(subset=[TEA_DATE_COL, TEA_TARGET_COL]).sort_values(TEA_DATE_COL).reset_index(drop=True)

        tea_fallback_col = "price_lag_1w_rs" if "price_lag_1w_rs" in tea_df_all.columns else None
        tea_global_median = float(tea_df_all[TEA_TARGET_COL].median())

        # typical values for local explanation
        tea_ref_values = {}
        for c in (tea_num_cols or []):
            if c in tea_df_all.columns and pd.api.types.is_numeric_dtype(tea_df_all[c]):
                tea_ref_values[c] = float(tea_df_all[c].median())
        for c in (tea_cat_cols or []):
            if c in tea_df_all.columns:
                mode = tea_df_all[c].dropna().mode()
                tea_ref_values[c] = str(mode.iloc[0]) if len(mode) else ""
        tea_ref_values["arima_pred"] = tea_global_median

    except Exception as e:
        tea_data_error = f"Failed to load tea dataset: {e}"
        tea_df_all = None


def _tea_fit_arima_models():
    if tea_df_all is None:
        return
    if not all(c in tea_df_all.columns for c in TEA_GROUP_COLS):
        return

    tea_arima_models.clear()

    for key, g in tea_df_all.groupby(TEA_GROUP_COLS):
        g = g.sort_values(TEA_DATE_COL)
        y = g[TEA_TARGET_COL].astype(float).values
        if len(y) < TEA_MIN_ARIMA_POINTS:
            continue
        try:
            tea_arima_models[tuple(key)] = ARIMA(y, order=TEA_ARIMA_ORDER).fit()
        except Exception:
            continue


def tea_build_next_week_input(elevation: str, grade: str, overrides=None):
    overrides = overrides or {}

    if tea_df_all is None:
        raise ValueError(f"Tea dataset not loaded. {tea_data_error or ''}".strip())

    if "elevation" not in tea_df_all.columns or "grade" not in tea_df_all.columns:
        raise ValueError("Tea dataset missing elevation/grade columns.")

    seg = tea_df_all[(tea_df_all["elevation"] == elevation) & (tea_df_all["grade"] == grade)].sort_values(TEA_DATE_COL)
    if len(seg) < 10:
        raise ValueError("Not enough history for this (elevation, grade). Need >= 10 rows.")

    last = seg.iloc[-1].copy()
    next_row = last.copy()

    # next week (+7 days)
    next_date = pd.to_datetime(last[TEA_DATE_COL]) + pd.Timedelta(days=7)
    next_row[TEA_DATE_COL] = next_date

    # calendar fields if present
    if "year" in tea_df_all.columns:
        next_row["year"] = int(next_date.year)
    if "month" in tea_df_all.columns:
        next_row["month"] = int(next_date.month)

    if "month_sin" in tea_df_all.columns and "month_cos" in tea_df_all.columns:
        s, c = month_sin_cos(int(next_date.month))
        next_row["month_sin"] = s
        next_row["month_cos"] = c

    # lag/rolling features if present
    if "price_lag_1w_rs" in tea_df_all.columns:
        next_row["price_lag_1w_rs"] = float(last[TEA_TARGET_COL])

    if "price_lag_4w_rs" in tea_df_all.columns and len(seg) >= 4:
        next_row["price_lag_4w_rs"] = float(seg.iloc[-4][TEA_TARGET_COL])

    if "price_lag_12w_rs" in tea_df_all.columns and len(seg) >= 12:
        next_row["price_lag_12w_rs"] = float(seg.iloc[-12][TEA_TARGET_COL])

    if "price_lag_48w_rs" in tea_df_all.columns and len(seg) >= 48:
        next_row["price_lag_48w_rs"] = float(seg.iloc[-48][TEA_TARGET_COL])

    if "price_rollmean_4w_rs" in tea_df_all.columns and len(seg) >= 4:
        next_row["price_rollmean_4w_rs"] = float(seg[TEA_TARGET_COL].tail(4).mean())

    if "price_rollmean_12w_rs" in tea_df_all.columns and len(seg) >= 12:
        next_row["price_rollmean_12w_rs"] = float(seg[TEA_TARGET_COL].tail(12).mean())

    if "price_rollmean_48w_rs" in tea_df_all.columns and len(seg) >= 48:
        next_row["price_rollmean_48w_rs"] = float(seg[TEA_TARGET_COL].tail(48).mean())

    # apply overrides
    for k, v in (overrides or {}).items():
        if k not in next_row.index:
            raise KeyError(f"Unknown override column: {k}")
        next_row[k] = v

    # target unknown
    next_row[TEA_TARGET_COL] = np.nan
    return next_row.to_frame().T


def tea_get_arima_pred(elevation: str, grade: str, built_row: pd.DataFrame):
    key = (elevation, grade)

    if key in tea_arima_models:
        try:
            return float(tea_arima_models[key].forecast(steps=1)[0])
        except Exception:
            pass

    if tea_fallback_col and tea_fallback_col in built_row.columns and not pd.isna(built_row[tea_fallback_col].iloc[0]):
        return float(built_row[tea_fallback_col].iloc[0])

    return float(tea_global_median) if tea_global_median is not None else 0.0


def tea_local_sensitivity_explain(model, X: pd.DataFrame, pred: float, ref_values: dict, top_k: int = 6):
    impacts = []
    for col in X.columns:
        if col not in ref_values:
            continue

        x_tmp = X.copy()
        original_val = x_tmp[col].iloc[0]
        typical_val = ref_values[col]

        try:
            if pd.isna(original_val) and pd.isna(typical_val):
                continue
            if str(original_val) == str(typical_val):
                continue
        except Exception:
            pass

        x_tmp[col] = typical_val
        try:
            pred_typical = float(model.predict(x_tmp)[0])
        except Exception:
            continue

        impact = pred - pred_typical
        impacts.append({
            "feature": col,
            "value": None if pd.isna(original_val) else (float(original_val) if isinstance(original_val, (int, float, np.number)) else str(original_val)),
            "typical": typical_val,
            "impact": float(impact)
        })

    impacts.sort(key=lambda d: abs(d["impact"]), reverse=True)
    return impacts[:top_k]


def tea_segment_context(elevation: str, grade: str):
    if tea_df_all is None:
        return None

    seg = tea_df_all[(tea_df_all["elevation"] == elevation) & (tea_df_all["grade"] == grade)].sort_values(TEA_DATE_COL)
    if len(seg) == 0:
        return None

    last_price = float(seg.iloc[-1][TEA_TARGET_COL])
    mean_4w = float(seg[TEA_TARGET_COL].tail(4).mean()) if len(seg) >= 4 else None
    mean_12w = float(seg[TEA_TARGET_COL].tail(12).mean()) if len(seg) >= 12 else None

    trend = None
    if mean_4w is not None:
        trend = "up" if last_price > mean_4w else ("down" if last_price < mean_4w else "flat")

    return {
        "last_price": last_price,
        "avg_4w": mean_4w,
        "avg_12w": mean_12w,
        "trend_vs_4w_avg": trend,
        "history_points": int(len(seg))
    }


def tea_describe_direction(val, typical):
    try:
        v = float(val); t = float(typical)
        if np.isfinite(v) and np.isfinite(t):
            if abs(v - t) <= (0.02 * (abs(t) + 1e-6)):
                return "close to usual"
            return "higher than usual" if v > t else "lower than usual"
    except Exception:
        pass
    return "different from usual"


def tea_feature_display_name(f):
    nice = {
        "fx_lkr_per_usd": "USD→LKR exchange rate",
        "rainfall_mm": "rainfall",
        "temperature_c": "temperature",
        "arima_pred": "recent price trend (time-series)",
        "price_lag_1w_rs": "last week price",
        "price_rollmean_4w_rs": "last 4-week average price",
        "price_rollmean_12w_rs": "last 12-week average price",
    }
    return nice.get(f, f.replace("_", " "))


def tea_build_explanation_text(pred, factors, segment_ctx=None, top_k=5):
    top = factors[:top_k]
    bullets = []

    for item in top:
        f = item["feature"]
        val = item["value"]
        typical = item["typical"]
        impact = item["impact"]

        if abs(impact) < 0.5:
            continue

        if f == "arima_pred":
            if segment_ctx and segment_ctx.get("trend_vs_4w_avg"):
                trend = segment_ctx["trend_vs_4w_avg"]
                bullets.append(
                    f"Recent segment trend looks **{trend}**, which {'pushes up' if impact > 0 else 'pulls down'} the prediction (time-series effect)."
                )
            else:
                bullets.append("Recent price pattern in this segment influences the forecast (time-series effect).")
            continue

        name = tea_feature_display_name(f)
        direction = tea_describe_direction(val, typical)

        if impact > 0:
            bullets.append(f"{name} is **{direction}** ({val} vs typical {typical}), so the model expects price to be **higher**.")
        else:
            bullets.append(f"{name} is **{direction}** ({val} vs typical {typical}), so the model expects price to be **lower**.")

    seg_line = None
    if segment_ctx:
        lp = segment_ctx.get("last_price")
        a4 = segment_ctx.get("avg_4w")
        if lp is not None and a4 is not None:
            seg_line = f"Last recorded price was **{lp:.2f}** and the 4-week average is **{a4:.2f}**."

    if bullets:
        main_push = "higher" if sum([f["impact"] for f in top]) > 0 else "lower"
        summary = f"Predicted price is **{pred:.2f}** mainly because the strongest inputs/trend signals push the model **{main_push}** compared to typical conditions."
    else:
        summary = f"Predicted price is **{pred:.2f}** based on learned patterns from history for this segment and the provided inputs."

    if seg_line:
        summary = summary + " " + seg_line

    return summary, bullets


# init tea
_tea_safe_load()
if tea_model is not None and tea_df_all is not None:
    _tea_fit_arima_models()

# ---------------------------------------------------------------------
# (B) YIELD MODEL (KEEP EXISTING)
# ---------------------------------------------------------------------
YIELD_MODEL_PATH = os.getenv("YIELD_MODEL_PATH", os.path.join(MODEL_DIR, "smarttea_yield_model.joblib"))
YIELD_DATA_PATH = os.getenv("YIELD_DATA_PATH", os.path.join(BASE_DIR, "data/smarttea_monthly_yield_dataset_sri_lanka_synthetic_2000_2025.csv"))
YIELD_DATE_COL = os.getenv("YIELD_DATE_COL", "date")
YIELD_TARGET_COL = os.getenv("YIELD_TARGET_COL", "yield_kg_per_ha")

REGION_DEFAULTS = {
    "Nuwara_Eliya": {"elevation_band": "high", "elevation_m": 1850, "country": "Sri_Lanka"},
    "Uva": {"elevation_band": "mid", "elevation_m": 1200, "country": "Sri_Lanka"},
    "Kandy": {"elevation_band": "mid", "elevation_m": 900, "country": "Sri_Lanka"},
    "Sabaragamuwa": {"elevation_band": "low", "elevation_m": 300, "country": "Sri_Lanka"},
    "Galle": {"elevation_band": "low", "elevation_m": 50, "country": "Sri_Lanka"},
}

yield_model = None
yield_feature_cols = None
yield_load_error = None

yield_df = None
yield_data_error = None


def unwrap_model(obj):
    if isinstance(obj, dict):
        model = obj.get("model", obj)
        feature_cols = obj.get("feature_cols")
        target = obj.get("target")
        return model, feature_cols, target
    model = obj
    feature_cols = getattr(model, "feature_names_in_", None)
    target = None
    return model, (list(feature_cols) if feature_cols is not None else None), target


try:
    if os.path.exists(YIELD_MODEL_PATH):
        yield_model_raw = joblib.load(YIELD_MODEL_PATH)
        yield_model, yield_feature_cols, _ = unwrap_model(yield_model_raw)
    else:
        yield_load_error = f"Yield model file not found at: {YIELD_MODEL_PATH}"
except Exception as e:
    yield_load_error = f"Failed to load YIELD model: {e}"

try:
    if os.path.exists(YIELD_DATA_PATH):
        yield_df = pd.read_csv(YIELD_DATA_PATH)
        yield_df[YIELD_DATE_COL] = pd.to_datetime(yield_df[YIELD_DATE_COL], errors="coerce")
        yield_df = yield_df.dropna(subset=[YIELD_DATE_COL]).sort_values([YIELD_DATE_COL]).reset_index(drop=True)
    else:
        yield_data_error = f"Yield dataset not found at: {YIELD_DATA_PATH}"
except Exception as e:
    yield_data_error = f"Failed to load YIELD dataset: {e}"


YIELD_REQUIRED_INPUTS = [
    "region", "year", "month",
    "rainfall_mm", "temp_avg_c", "temp_min_c", "temp_max_c",
    "humidity_pct", "soil_ph", "soil_ec_ds_m",
    "fertilizer_kg_per_ha", "disease_index",
]


def get_region_history(region: str, current_date: pd.Timestamp) -> pd.DataFrame:
    if yield_df is None or "region" not in yield_df.columns:
        return pd.DataFrame()
    h = yield_df[(yield_df["region"] == region) & (yield_df[YIELD_DATE_COL] < current_date)].copy()
    return h.sort_values(YIELD_DATE_COL)


def compute_yield_lags_rolls(region_hist: pd.DataFrame):
    if region_hist is None or len(region_hist) == 0 or YIELD_TARGET_COL not in region_hist.columns:
        return {
            "yield_lag_1": None, "yield_lag_3": None, "yield_lag_12": None,
            "yield_rollmean_3": None, "yield_rollmean_6": None, "yield_rollmean_12": None,
        }

    y = region_hist[YIELD_TARGET_COL].astype(float).values

    def lag(k):
        if len(y) >= k:
            return float(y[-k])
        return float(y[0])

    def roll(k):
        k = min(k, len(y))
        return float(np.mean(y[-k:]))

    return {
        "yield_lag_1": lag(1),
        "yield_lag_3": lag(3) if len(y) >= 3 else lag(1),
        "yield_lag_12": lag(12) if len(y) >= 12 else lag(1),
        "yield_rollmean_3": roll(3),
        "yield_rollmean_6": roll(6),
        "yield_rollmean_12": roll(12),
    }


def compute_exog_rolls(region_hist: pd.DataFrame):
    def rmean(col, n):
        if region_hist is None or len(region_hist) == 0 or col not in region_hist.columns:
            return None
        vals = region_hist[col].astype(float).values
        if len(vals) >= n:
            return float(np.mean(vals[-n:]))
        return float(np.mean(vals)) if len(vals) else None

    return {
        "rain_rollmean_3": rmean("rainfall_mm", 3),
        "rain_rollmean_6": rmean("rainfall_mm", 6),
        "temp_rollmean_3": rmean("temp_avg_c", 3),
        "temp_rollmean_6": rmean("temp_avg_c", 6),
        "fert_rollmean_3": rmean("fertilizer_kg_per_ha", 3),
        "fert_rollmean_6": rmean("fertilizer_kg_per_ha", 6),
        "disease_rollmean_3": rmean("disease_index", 3),
        "disease_rollmean_6": rmean("disease_index", 6),
    }


def local_feature_impact(model_pipeline, X_row: pd.DataFrame, numeric_features, steps=0.03, top_n=6):
    base = float(model_pipeline.predict(X_row)[0])
    impacts = []

    for f in numeric_features:
        if f not in X_row.columns:
            continue

        v = X_row.iloc[0][f]
        if pd.isna(v):
            continue

        delta = max(abs(float(v)) * steps, 0.01)

        X_up = X_row.copy()
        X_dn = X_row.copy()

        X_up.loc[X_up.index[0], f] = float(v) + delta
        X_dn.loc[X_dn.index[0], f] = float(v) - delta

        p_up = float(model_pipeline.predict(X_up)[0])
        p_dn = float(model_pipeline.predict(X_dn)[0])

        effect = (p_up - p_dn) / 2.0

        impacts.append({
            "feature": f,
            "impact_kg_per_ha": round(float(effect), 3),
            "direction": "increases" if effect > 0 else "decreases"
        })

    impacts.sort(key=lambda x: abs(x["impact_kg_per_ha"]), reverse=True)
    return base, impacts[:top_n]


def build_yield_row(payload: dict):
    if yield_model is None:
        raise ValueError("Yield model is not loaded. Check YIELD_MODEL_PATH.")

    missing = [k for k in YIELD_REQUIRED_INPUTS if k not in payload]
    if missing:
        raise ValueError(f"Missing required fields: {missing}")

    region = str(payload["region"])
    year = int(payload["year"])
    month = int(payload["month"])
    current_date = pd.Timestamp(f"{year}-{month:02d}-01")

    defaults = REGION_DEFAULTS.get(region)
    if not defaults:
        raise ValueError(f"Unknown region '{region}'. Allowed: {list(REGION_DEFAULTS.keys())}")

    ms, mc = month_sin_cos(month)

    region_hist = get_region_history(region, current_date)
    lag_feats = compute_yield_lags_rolls(region_hist)
    exog_rolls = compute_exog_rolls(region_hist)

    row = {
        "region": region,
        "country": defaults["country"],
        "elevation_band": defaults["elevation_band"],
        "elevation_m": defaults["elevation_m"],
        "year": year,
        "month": month,
        "month_sin": ms,
        "month_cos": mc,

        "rainfall_mm": float(payload["rainfall_mm"]),
        "temp_avg_c": float(payload["temp_avg_c"]),
        "temp_min_c": float(payload["temp_min_c"]),
        "temp_max_c": float(payload["temp_max_c"]),
        "humidity_pct": float(payload["humidity_pct"]),
        "soil_ph": float(payload["soil_ph"]),
        "soil_ec_ds_m": float(payload["soil_ec_ds_m"]),
        "fertilizer_kg_per_ha": float(payload["fertilizer_kg_per_ha"]),
        "disease_index": float(payload["disease_index"]),
    }

    row.update(lag_feats)
    row.update(exog_rolls)

    X = pd.DataFrame([row])

    if yield_feature_cols:
        for c in yield_feature_cols:
            if c not in X.columns:
                X[c] = np.nan
        X = X[yield_feature_cols]

    return X, str(current_date.date()), int(len(region_hist))

# ---------------------------------------------------------------------
# (C) LEAF DISEASE MODEL (KEEP EXISTING)
# ---------------------------------------------------------------------
LEAF_WEIGHTS_PATH = os.getenv("LEAF_WEIGHTS_PATH", os.path.join(MODEL_DIR, "tea_mobilenet_v2.weights.h5"))
LEAF_LABELS_PATH = os.getenv("LEAF_LABELS_PATH", os.path.join(MODEL_DIR, "labels.json"))
UPLOAD_DIR = os.getenv("UPLOAD_DIR", os.path.join(BASE_DIR, "uploads"))
IMG_SIZE: Tuple[int, int] = (224, 224)
os.makedirs(UPLOAD_DIR, exist_ok=True)

leaf_class_names = None
leaf_model = None
leaf_load_error = None


def build_leaf_model(num_classes: int) -> tf.keras.Model:
    base_model = tf.keras.applications.MobileNetV2(
        input_shape=IMG_SIZE + (3,),
        include_top=False,
        weights="imagenet",
    )
    base_model.trainable = False

    inputs = tf.keras.Input(shape=IMG_SIZE + (3,), name="input_layer_1")
    x = tf.keras.applications.mobilenet_v2.preprocess_input(inputs)
    x = base_model(x, training=False)
    x = tf.keras.layers.GlobalAveragePooling2D(name="global_avg_pool")(x)
    x = tf.keras.layers.Dropout(0.2, name="dropout")(x)
    outputs = tf.keras.layers.Dense(num_classes, activation="softmax", name="dense")(x)
    return tf.keras.Model(inputs, outputs, name="tea_mobilenet_v2_inference")


try:
    if os.path.exists(LEAF_LABELS_PATH):
        with open(LEAF_LABELS_PATH, "r", encoding="utf-8") as f:
            leaf_class_names = json.load(f)
    else:
        raise FileNotFoundError(f"Leaf labels not found at: {LEAF_LABELS_PATH}")

    leaf_model = build_leaf_model(num_classes=len(leaf_class_names))

    if not os.path.exists(LEAF_WEIGHTS_PATH):
        raise FileNotFoundError(f"Leaf weights not found at: {LEAF_WEIGHTS_PATH}")

    leaf_model.load_weights(LEAF_WEIGHTS_PATH)

except Exception as e:
    leaf_load_error = f"Failed to load LEAF model: {e}"
    leaf_model = None
    leaf_class_names = None


def predict_leaf_image(image_path: str):
    if leaf_model is None or leaf_class_names is None:
        raise RuntimeError(leaf_load_error or "Leaf model not loaded.")

    img = load_img(image_path, target_size=IMG_SIZE)
    img_array = img_to_array(img)
    img_batch = np.expand_dims(img_array, axis=0)

    probs = leaf_model.predict(img_batch, verbose=0)[0]
    pred_index = int(np.argmax(probs))
    pred_label = leaf_class_names[pred_index]
    confidence = float(probs[pred_index])

    probs_list = [float(p) for p in probs]
    probs_dict = {leaf_class_names[i]: probs_list[i] for i in range(len(leaf_class_names))}
    return pred_label, confidence, probs_dict

# ---------------------------------------------------------------------
# ROUTES
# ---------------------------------------------------------------------
@app.get("/health")
def health():
    return jsonify({
        "status": "ok",
        "tea_price_hybrid_loaded": tea_model is not None,
        "tea_price_segments_with_arima": int(len(tea_arima_models)) if tea_model is not None else 0,
        "yield_model_loaded": yield_model is not None,
        "leaf_model_loaded": leaf_model is not None,
        "paths": {
            "tea_artifact_dir": TEA_ARTIFACT_DIR,
            "tea_model_path": TEA_MODEL_PATH,
            "tea_cfg_path": TEA_CFG_PATH,
            "tea_data_path": TEA_DATA_PATH,
            "yield_model_path": YIELD_MODEL_PATH,
            "yield_data_path": YIELD_DATA_PATH,
            "leaf_weights_path": LEAF_WEIGHTS_PATH,
            "leaf_labels_path": LEAF_LABELS_PATH,
        },
        "errors": {
            "tea_load_error": tea_load_error,
            "tea_data_error": tea_data_error,
            "yield_load_error": yield_load_error,
            "yield_data_error": yield_data_error,
            "leaf_load_error": leaf_load_error,
        },
        "endpoints": {
            "GET /tea-price/meta": "Tea price metadata (elevations, grades, override keys)",
            "POST /tea-price/predict-next-week": "Tea price next-week forecast (elevation+grade + overrides + explain)",
            "POST /predict/yield-simple": "Yield prediction",
            "POST /predict/leaf": "Leaf disease prediction (image upload)",
        }
    })


# -------------------------
# TEA PRICE: health/meta/predict-next-week
# -------------------------
@app.get("/tea-price/health")
def tea_price_health():
    return jsonify({
        "ok": True,
        "model_loaded": tea_model is not None,
        "cfg_loaded": tea_cfg is not None,
        "rows_in_history": int(len(tea_df_all)) if tea_df_all is not None else 0,
        "segments_with_arima": int(len(tea_arima_models)),
        "target": TEA_TARGET_COL,
        "date_col": TEA_DATE_COL,
        "error": tea_load_error or tea_data_error
    })


@app.get("/tea-price/meta")
def tea_price_meta():
    if tea_df_all is None:
        return jsonify({"ok": False, "error": tea_data_error or "Tea dataset not loaded"}), 500

    return jsonify({
        "ok": True,
        "target": TEA_TARGET_COL,
        "date_col": TEA_DATE_COL,
        "cat_cols": tea_cat_cols,
        "num_cols": tea_num_cols,
        "example_override_keys": [c for c in tea_df_all.columns if c not in [TEA_TARGET_COL]],
        "unique_elevations": sorted(tea_df_all["elevation"].dropna().unique().tolist()) if "elevation" in tea_df_all.columns else [],
        "unique_grades": sorted(tea_df_all["grade"].dropna().unique().tolist()) if "grade" in tea_df_all.columns else [],
    })


@app.post("/tea-price/predict-next-week")
def tea_price_predict_next_week():
    if tea_model is None:
        return jsonify({"ok": False, "error": tea_load_error or "Tea hybrid model not loaded"}), 500
    if tea_df_all is None:
        return jsonify({"ok": False, "error": tea_data_error or "Tea dataset not loaded"}), 500

    body = request.get_json(silent=True) or {}

    elevation = str(body.get("elevation", "")).strip()
    grade = str(body.get("grade", "")).strip()
    overrides = body.get("overrides") or {}

    if not elevation or not grade:
        return jsonify({"ok": False, "error": "elevation and grade are required"}), 400
    if not isinstance(overrides, dict):
        return jsonify({"ok": False, "error": "overrides must be an object/dict"}), 400

    try:
        row = tea_build_next_week_input(elevation, grade, overrides=overrides)
        arima_pred = tea_get_arima_pred(elevation, grade, row)

        # build X exactly like notebook expects
        needed_cols = (tea_cat_cols or []) + (tea_num_cols or [])
        X = row.copy()

        # ensure required cols exist
        for c in needed_cols:
            if c not in X.columns:
                X[c] = np.nan

        X = X[needed_cols].copy()
        X["arima_pred"] = arima_pred

        pred = float(tea_model.predict(X)[0])

        want_explain = bool(body.get("explain", False))
        explain_payload = None

        if want_explain:
            factors = tea_local_sensitivity_explain(tea_model, X, pred, tea_ref_values, top_k=8)
            seg_ctx = tea_segment_context(elevation, grade)
            summary, bullets = tea_build_explanation_text(pred, factors, seg_ctx, top_k=5)

            explain_payload = {
                "summary": summary,
                "reasons": bullets,
                "top_factors": factors,
                "segment_context": seg_ctx,
                "disclaimer": "These reasons explain what the model learned from data (correlations), not guaranteed real-world causation."
            }

        return jsonify({
            "ok": True,
            "elevation": elevation,
            "grade": grade,
            "predicted_price": pred,
            "arima_pred": arima_pred,
            "next_date": str(pd.to_datetime(row[TEA_DATE_COL].iloc[0]).date()),
            "explanation": explain_payload
        })

    except KeyError as e:
        return jsonify({"ok": False, "error": str(e)}), 400
    except Exception as e:
        return jsonify({"ok": False, "error": str(e), "trace": traceback.format_exc()}), 500


# -------------------------
# YIELD
# -------------------------
@app.get("/debug/yield-model")
def debug_yield_model():
    try:
        obj = joblib.load(YIELD_MODEL_PATH)
        return jsonify({
            "ok": True,
            "path": YIELD_MODEL_PATH,
            "type": str(type(obj)),
            "keys": list(obj.keys()) if isinstance(obj, dict) else None
        })
    except Exception as e:
        return jsonify({"ok": False, "error": str(e), "trace": traceback.format_exc()}), 500


@app.post("/predict/yield-simple")
def predict_yield():
    try:
        if yield_model is None:
            return jsonify({
                "success": False,
                "error": "Yield model not loaded",
                "details": yield_load_error,
                "hint": "Put your yield .joblib file in the model folder and set YIELD_MODEL_PATH if needed."
            }), 500

        payload = request.get_json(silent=True) or {}
        X, pred_date, history_months = build_yield_row(payload)

        pred = float(yield_model.predict(X)[0])

        numeric_for_explain = [
            "rainfall_mm", "temp_avg_c", "humidity_pct",
            "soil_ph", "soil_ec_ds_m", "fertilizer_kg_per_ha", "disease_index",
            "yield_lag_1", "yield_lag_3", "yield_lag_12",
            "rain_rollmean_3", "rain_rollmean_6",
            "temp_rollmean_3", "temp_rollmean_6",
            "fert_rollmean_3", "fert_rollmean_6",
            "disease_rollmean_3", "disease_rollmean_6",
        ]

        base_pred, top_impacts = local_feature_impact(yield_model, X, numeric_for_explain)

        pos = [i for i in top_impacts if i["impact_kg_per_ha"] > 0][:2]
        neg = [i for i in top_impacts if i["impact_kg_per_ha"] < 0][:2]

        parts = []
        if pos:
            parts.append("higher " + " & ".join([p["feature"] for p in pos]))
        if neg:
            parts.append("lower " + " & ".join([n["feature"] for n in neg]))

        explain_sentence = "Prediction is mainly influenced by " + (", and ".join(parts) if parts else "the input factors.")

        # labour estimation
        area_ha = float(payload.get("area_ha", 1.0))
        plucking_days = int(payload.get("plucking_days", 22))
        productivity = float(payload.get("productivity_kg_per_worker_day", 20.0))
        efficiency = float(payload.get("efficiency", 0.9))

        total_harvest_kg = pred * area_ha
        den = productivity * plucking_days * max(efficiency, 0.01)
        labourers_needed = int(math.ceil(total_harvest_kg / den))

        warnings = []
        if history_months < 12 and yield_df is not None:
            warnings.append(
                f"Only {history_months} months of history were available before {pred_date}; some lag/rolling features may be weak."
            )

        return jsonify({
            "success": True,
            "prediction": {
                "yield_kg_per_ha": round(pred, 2),
                "for_month": pred_date,
                "area_ha": area_ha,
                "total_harvest_kg": round(total_harvest_kg, 2),
                "labourers_needed": labourers_needed,
                "assumptions": {
                    "plucking_days": plucking_days,
                    "productivity_kg_per_worker_day": productivity,
                    "efficiency": efficiency
                }
            },
            "explainability": {
                "summary": explain_sentence,
                "top_factors": top_impacts
            },
            "meta": {
                "region": payload.get("region"),
                "history_months_used": history_months,
                "warnings": warnings
            }
        })

    except Exception as e:
        return jsonify({"success": False, "error": str(e), "trace": traceback.format_exc()}), 400


# -------------------------
# LEAF
# -------------------------
@app.post("/predict/leaf")
def predict_leaf():
    if leaf_model is None or leaf_class_names is None:
        return jsonify({
            "ok": False,
            "error": "Leaf model not loaded",
            "details": leaf_load_error,
            "hint": "Make sure model/labels.json and model/tea_mobilenet_v2.weights.h5 exist."
        }), 500

    if "image" not in request.files:
        return jsonify({"ok": False, "error": "No file part 'image' in the request"}), 400

    file = request.files["image"]
    if file.filename == "":
        return jsonify({"ok": False, "error": "No file selected"}), 400

    allowed_ext = (".jpg", ".jpeg", ".png")
    if not file.filename.lower().endswith(allowed_ext):
        return jsonify({"ok": False, "error": "Unsupported file type. Use JPG or PNG."}), 400

    temp_filename = f"{uuid.uuid4().hex}_{file.filename}"
    temp_path = os.path.join(UPLOAD_DIR, temp_filename)
    file.save(temp_path)

    try:
        label, confidence, probs_dict = predict_leaf_image(temp_path)
        return jsonify({
            "ok": True,
            "prediction": label,
            "confidence": confidence,
            "probabilities": probs_dict
        })
    except Exception as e:
        return jsonify({
            "ok": False,
            "error": "Failed to process image",
            "details": str(e),
            "trace": traceback.format_exc()
        }), 500
    finally:
        try:
            if os.path.exists(temp_path):
                os.remove(temp_path)
        except Exception:
            pass


# ---------------------------------------------------------------------
# MAIN
# ---------------------------------------------------------------------
if __name__ == "__main__":
    port = int(os.getenv("PORT", "7860"))
    app.run(host="0.0.0.0", port=port)