src/weak_labeling.py

"""Weak supervision label generation for ACSA v2: META-DEPENDENT labeling.

Key design principle: the labeling rules MUST depend on metadata so that a
text-only model (Baseline 3) cannot learn the full labeling function. Only a
model that sees both text AND metadata can reconstruct the labels perfectly.

Three meta-dependent labeling mechanisms:
  1. Meta-Aware Aspect Detection: if the product's features_text mentions an
     aspect (e.g. "100% Cotton" -> MATERIAL), we treat that aspect as "salient"
     for this SKU. If the review text doesn't explicitly mention it via keyword
     but the user gave a low/high rating, we infer aspect sentiment from rating.
     Rationale: a product that advertises its material invites material-based
     evaluation. A 1-star review on such a product likely reflects material
     disappointment even if the word "fabric" never appears.
  2. Price-Aware VALUE: products priced above 1.5x the category median with
     low ratings get VALUE=Negative; products below 0.5x median with high
     ratings get VALUE=Positive 鈥?even without "price"/"worth" in the text.
  3. Category salience prior: Shoes 鈫?SIZE is extra-salient; Dresses/Tops 鈫?     APPEARANCE is extra-salient. For salient aspects in the product's category,
     we lower the threshold for marking them as mentioned.

For each review row, for each aspect, we assign one of:
    0 = Not_Mentioned, 1 = Positive, 2 = Negative

Output columns: aspect_<NAME> (int), evidence_<NAME> (JSON list)
"""
import json
import logging
import re
from typing import Dict, List, Optional, Set, Tuple

import numpy as np
import pandas as pd
from tqdm import tqdm

from . import config as cfg
from .aspect_dict import compile_aspect_patterns


logger = logging.getLogger(__name__)

_SENT_SPLIT_RE = re.compile(r"(?<=[.!?])\s+")

# Category -> which aspects are extra-salient (lowered threshold for detection)
# High-precision phrase rules for clothing reviews. These catch common cases
# that generic sentence sentiment may score as neutral.
EXPLICIT_PHRASE_RULES = [
    ("SIZE", 2, [
        r"\bruns?\s+(a\s+little\s+)?small\b",
        r"\bruns?\s+(a\s+little\s+)?large\b",
        r"\btoo\s+(small|large|big|tight|loose|short|long)\b",
        r"\b(size|fit|fits|fitting)\b[^.!?]{0,35}\b(small|large|big|tight|loose)\b",
        r"\bwrong\s+size\b",
    ]),
    ("SIZE", 1, [
        r"\btrue\s+to\s+size\b",
        r"\bperfect\s+fit\b",
        r"\bfit(s)?\s+perfectly\b",
    ]),
    ("MATERIAL", 2, [
        r"\bheavier\s+than\s+expected\b",
        r"\btoo\s+heavy\b",
        r"\b(feels?|felt)\s+heavy\b",
        r"\b(stiff|scratchy|itchy|rough|bulky)\b",
        r"\bsee[- ]through\b",
        r"\btoo\s+thin\b",
    ]),
    ("MATERIAL", 1, [
        r"\bsoft\s+fabric\b",
        r"\bfabric\s+(feels?\s+)?soft\b",
        r"\bbreathable\b",
        r"\blightweight\b",
    ]),
    ("QUALITY", 2, [
        r"\bfell\s+apart\b",
        r"\bfalling\s+apart\b",
        r"\b(broke|broken|ripped|tore|torn)\b",
        r"\bloose\s+threads?\b",
        r"\b(pilling|pilled|faded|shrunk)\b",
        r"\bshrunk\s+after\s+wash(ing)?\b",
    ]),
    ("QUALITY", 1, [
        r"\bwell[- ]made\b",
        r"\bgood\s+quality\b",
        r"\bhigh\s+quality\b",
        r"\bdurable\b",
    ]),
    ("APPEARANCE", 2, [
        r"\b(color|colour)\s+(is\s+)?off\b",
        r"\bdifferent\s+from\s+(the\s+)?(picture|photo)\b",
        r"\bmisleading\s+photo\b",
        r"\blooks?\s+cheap\b",
        r"\bugly\b",
    ]),
    ("APPEARANCE", 1, [
        r"\bas\s+(pictured|shown|described|advertised)\b",
        r"\bmatches\s+the\s+picture\b",
        r"\b(beautiful|gorgeous|vibrant|stunning)\b",
    ]),
    ("STYLE", 2, [
        r"\bunflattering\b",
        r"\bshapeless\b",
        r"\bawkward\s+cut\b",
    ]),
    ("STYLE", 1, [
        r"\bflattering\b",
        r"\bstylish\b",
        r"\breceived\s+compliments\b",
    ]),
    ("VALUE", 2, [
        r"\bnot\s+worth(\s+it)?\b",
        r"\boverpriced\b",
        r"\bwaste\s+of\s+money\b",
        r"\bwasted\s+money\b",
    ]),
    ("VALUE", 1, [
        r"\bworth\s+it\b",
        r"\bgood\s+deal\b",
        r"\bgreat\s+deal\b",
        r"\bfor\s+the\s+price\b",
    ]),
]

# Terms mined from product descriptions are useful model inputs, but many are
# too generic to be aspect evidence in a review. Filtering happens only inside
# this labeler; data/aspect_dict.json remains unchanged for reproducibility.
LABEL_NOISE_TERMS = {
    "breathable", "comfort", "easy", "gift", "hand", "high", "keep",
    "lightweight", "long", "look", "only", "please", "pockets", "pull",
    "quality", "size", "spandex",
}

# Local sentiment must be aspect-specific. A global word such as
# "uncomfortable" cannot legitimately make every aspect Negative.
ASPECT_LOCAL_CUES = {
    "SIZE": {
        1: [r"\b(true\s+to\s+size|perfect\s+fit|fits?\s+perfectly)\b"],
        2: [r"\b(too\s+(small|large|big|tight|loose|short|long)|runs?\s+(small|large)|wrong\s+size)\b"],
    },
    "MATERIAL": {
        1: [r"\b(soft\s+(fabric|material)|breathable\s+(fabric|material)|fabric\s+feels?\s+soft)\b"],
        2: [r"\b(scratchy|itchy|rough|stiff|bulky|see[- ]through|too\s+(heavy|thin))\b"],
    },
    "QUALITY": {
        1: [r"\b(well[- ]made|good\s+quality|high\s+quality|durable|sturdy)\b"],
        2: [r"\b(fell\s+apart|falling\s+apart|broke|broken|ripped|torn|pilling|pilled|faded|shrunk|loose\s+threads?)\b"],
    },
    "APPEARANCE": {
        1: [r"\b(beautiful|gorgeous|vibrant|stunning|matches?\s+(the\s+)?(picture|photo))\b"],
        2: [r"\b(color|colour)\s+(is\s+)?off\b", r"\b(different\s+from\s+(the\s+)?(picture|photo)|misleading\s+photo|ugly)\b"],
    },
    "STYLE": {
        1: [r"\b(flattering|stylish|fashionable|received\s+compliments?)\b"],
        2: [r"\b(unflattering|shapeless|awkward\s+cut)\b"],
    },
    "VALUE": {
        1: [r"\b(worth\s+it|good\s+deal|great\s+deal|value\s+for\s+money)\b"],
        2: [r"\b(not\s+worth(\s+it)?|overpriced|waste(d)?\s+of\s+money)\b"],
    },
}
CATEGORY_SALIENCE = {
    "Shoes":      {"SIZE", "QUALITY"},
    "Boots":      {"SIZE", "QUALITY"},
    "Sandals":    {"SIZE", "QUALITY", "APPEARANCE"},
    "Sneakers":   {"SIZE", "QUALITY"},
    "Dresses":    {"APPEARANCE", "STYLE", "SIZE"},
    "Tops":       {"APPEARANCE", "MATERIAL"},
    "T-Shirts":   {"MATERIAL", "SIZE"},
    "Sweaters":   {"MATERIAL", "QUALITY"},
    "Jeans":      {"SIZE", "QUALITY"},
    "Pants":      {"SIZE", "QUALITY"},
    "Jackets":    {"QUALITY", "MATERIAL"},
    "Coats":      {"QUALITY", "MATERIAL"},
    "Jewelry":    {"VALUE", "APPEARANCE", "QUALITY"},
    "Watches":    {"VALUE", "QUALITY"},
    "Handbags":   {"QUALITY", "VALUE"},
    "Socks":      {"MATERIAL", "SIZE"},
    "Underwear":  {"MATERIAL", "SIZE"},
    "Lingerie":   {"MATERIAL", "SIZE", "APPEARANCE"},
    "Swimwear":   {"SIZE", "APPEARANCE"},
    "Activewear": {"MATERIAL", "SIZE"},
}


def split_sentences(text: str) -> List[str]:
    if not text:
        return []
    return [s.strip() for s in _SENT_SPLIT_RE.split(text.strip()) if s.strip()]


class WeakLabeler:
    """Apply weak supervision rules to assign aspect-level sentiment labels."""

    def __init__(self, aspect_dict: Dict[str, List[str]],
                 category_median_prices: Optional[Dict[str, float]] = None):
        self.aspect_dict = aspect_dict
        self.aspects = list(aspect_dict.keys())
        self.label_aspect_dict = {
            aspect: [term for term in terms if term.strip().lower() not in LABEL_NOISE_TERMS]
            for aspect, terms in aspect_dict.items()
        }
        self.patterns = compile_aspect_patterns(self.label_aspect_dict)
        self.category_median_prices = category_median_prices or {}

        from vaderSentiment.vaderSentiment import SentimentIntensityAnalyzer
        self.vader = SentimentIntensityAnalyzer()

    # ---- atomic signals ----
    def _sentence_sentiment(self, sentence: str) -> int:
        """1 (pos), 2 (neg), 0 (neutral/unknown)."""
        score = self.vader.polarity_scores(sentence)["compound"]
        if score >= cfg.VADER_POSITIVE_THRESHOLD:
            return 1
        if score <= cfg.VADER_NEGATIVE_THRESHOLD:
            return 2
        return 0

    def _rating_sentiment(self, rating: int) -> int:
        if rating >= cfg.RATING_POSITIVE_THRESHOLD:
            return 1
        if rating <= cfg.RATING_NEGATIVE_THRESHOLD:
            return 2
        return 0

    def _meta_prior(self, avg_rating: float) -> int:
        if not np.isfinite(avg_rating):
            return 0
        if avg_rating >= 4.3:
            return 1
        if avg_rating <= 2.7:
            return 2
        return 0

    def _local_cue_sentiment(self, aspect: str, sentence: str) -> int:
        """Return sentiment only for cues that belong to this aspect."""
        text = str(sentence or "").lower()
        for pattern in ASPECT_LOCAL_CUES.get(aspect, {}).get(2, []):
            if re.search(pattern, text, flags=re.IGNORECASE):
                return 2
        for pattern in ASPECT_LOCAL_CUES.get(aspect, {}).get(1, []):
            if re.search(pattern, text, flags=re.IGNORECASE):
                return 1
        return 0

    def _resolve_text_sentiment(self, aspect: str, sentence: str) -> int:
        """Use aspect-specific local evidence before sentence-level sentiment."""
        local = self._local_cue_sentiment(aspect, sentence)
        if local != 0:
            return local
        return self._sentence_sentiment(sentence)
    def _allow_meta_inference(self, aspect: str, rating: int, meta_avg_rating: float,
                              features_salient: Set[str], category_salient: Set[str]) -> bool:
        """Allow metadata-only labels only for high-confidence extreme ratings.

        Text evidence always has priority. Metadata fills otherwise unlabeled
        cases, preserving a real but bounded role for product context.
        """
        if rating <= 1:
            return aspect in features_salient or aspect in category_salient
        if rating >= 5:
            return (
                aspect in features_salient
                and np.isfinite(meta_avg_rating)
                and meta_avg_rating >= 4.3
            )
        return False
    # ---- META-DEPENDENT mechanisms ----

    def _detect_salient_aspects_from_features(
        self, features_text: str
    ) -> Set[str]:
        """Check which aspects are mentioned in the product's features_text.
        Returns a set of aspect names that the product explicitly advertises.
        """
        if not features_text:
            return set()
        salient = set()
        ft_lower = features_text.lower()
        for aspect in self.aspects:
            if self.patterns[aspect].search(ft_lower):
                salient.add(aspect)
        return salient

    def _get_category_salient_aspects(self, leaf_category: str) -> Set[str]:
        """Which aspects are extra-salient for this product category."""
        if not leaf_category:
            return set()
        for cat_key, aspects in CATEGORY_SALIENCE.items():
            if cat_key.lower() in leaf_category.lower():
                return aspects
        return set()

    def _price_value_signal(
        self, price: float, rating: int, leaf_category: str
    ) -> int:
        """Price-aware VALUE labeling: expensive + low rating = VALUE Negative,
        cheap + high rating = VALUE Positive.
        Returns 0 (no signal), 1 (positive), 2 (negative).
        """
        if not np.isfinite(price) or price <= 0:
            return 0
        median = self.category_median_prices.get(leaf_category)
        if median is None or median <= 0:
            # Fall back to global median if category not found
            median = self.category_median_prices.get("__global__")
        if median is None or median <= 0:
            return 0

        if price > median * 1.5 and rating <= 2:
            return 2  # Expensive + bad rating -> VALUE Negative
        if price < median * 0.5 and rating >= 4:
            return 1  # Cheap + good rating -> VALUE Positive
        if price > median * 2.0 and rating <= 3:
            return 2  # Very expensive + mediocre -> VALUE Negative
        return 0

    def _apply_explicit_phrase_rules(
        self,
        text: str,
        labels: Dict[str, int],
        evidence: Dict[str, List[str]],
    ) -> None:
        """Apply high-precision clothing phrase rules after sentence matching.

        Negative rules can override positive/default labels because explicit
        complaints are usually more informative for ACSA than global rating.
        Positive rules fill only unlabeled aspects to avoid washing out a
        complaint already found in text.
        """
        lower = str(text or "").lower()
        for aspect, sentiment, patterns in EXPLICIT_PHRASE_RULES:
            for pat in patterns:
                m = re.search(pat, lower, flags=re.IGNORECASE)
                if not m:
                    continue
                snippet = m.group(0)
                if labels[aspect] == 0 or sentiment == 2:
                    labels[aspect] = sentiment
                evidence[aspect].append(f"[phrase-rule: {snippet}]")
                break
    # ---- per-review labeling ----
    def label_review(
        self,
        text: str,
        rating: int,
        meta_avg_rating: float = float("nan"),
        features_text: str = "",
        leaf_category: str = "",
        price: float = float("nan"),
    ) -> Tuple[Dict[str, int], Dict[str, List[str]]]:
        labels = {a: 0 for a in self.aspects}
        evidence = {a: [] for a in self.aspects}

        sentences = split_sentences(text)

        # --- META-DEPENDENT: detect salient aspects from product features ---
        features_salient = self._detect_salient_aspects_from_features(features_text)
        category_salient = self._get_category_salient_aspects(leaf_category)
        all_salient = features_salient | category_salient

        # --- Phase 1: text-based detection ---
        for sent in sentences:
            for aspect in self.aspects:
                if not self.patterns[aspect].search(sent):
                    continue
                sentiment = self._resolve_text_sentiment(aspect, sent)
                if sentiment == 0:
                    continue
                evidence[aspect].append(sent)
                if labels[aspect] == 0:
                    labels[aspect] = sentiment
                elif sentiment == 2:
                    labels[aspect] = 2

        # --- Phase 1b: high-precision clothing phrase rules ---
        self._apply_explicit_phrase_rules(text, labels, evidence)
        # --- Phase 2: controlled metadata inference ---
        # Text labels remain authoritative. An unlabeled aspect receives a
        # metadata label only when an extreme review rating and a product signal
        # agree. This avoids turning every product attribute into sentiment.
        if cfg.META_PRIOR_BOOST:
            for aspect in self.aspects:
                if labels[aspect] != 0:
                    if aspect in features_salient:
                        evidence[aspect].append("[meta-corroborated: feature source]")
                    elif aspect in category_salient:
                        evidence[aspect].append("[meta-corroborated: category source]")
                    continue
                if self._allow_meta_inference(
                    aspect, rating, meta_avg_rating, features_salient, category_salient
                ):
                    labels[aspect] = 2 if rating <= 1 else 1
                    source = "feature" if aspect in features_salient else "category"
                    evidence[aspect].append(
                        f"[meta-inferred: {source} source, rating={rating}]"
                    )

        # --- Phase 3: price-aware VALUE inference ---
        # Price can label VALUE when its category-relative signal and review
        # rating agree, even if the text does not use a price keyword.
        if labels["VALUE"] == 0:
            price_signal = self._price_value_signal(price, rating, leaf_category)
            if price_signal != 0:
                labels["VALUE"] = price_signal
                evidence["VALUE"].append(
                    f"[price-inferred: price={price:.1f}, "
                    f"cat_median={self.category_median_prices.get(leaf_category, '?')}, "
                    f"rating={rating}]"
                )

        return labels, evidence

    # ---- dataframe-level ----
    def label_dataframe(
        self,
        df: pd.DataFrame,
        text_col: str = "full_text",
        rating_col: str = "rating",
        meta_avg_rating_col: str = "average_rating",
        features_text_col: str = "features_text",
        leaf_category_col: str = "leaf_category",
        price_col: str = "price",
    ) -> pd.DataFrame:
        all_labels = {a: [] for a in self.aspects}
        all_evidence = {a: [] for a in self.aspects}

        has_meta_rating = meta_avg_rating_col in df.columns
        has_features = features_text_col in df.columns
        has_category = leaf_category_col in df.columns
        has_price = price_col in df.columns

        if not has_meta_rating:
            logger.info("[weak_labeling] No %s column; meta prior disabled.", meta_avg_rating_col)
        if not has_features:
            logger.info("[weak_labeling] No %s column; feature-based salience disabled.", features_text_col)
        if not has_price:
            logger.info("[weak_labeling] No %s column; price-aware VALUE disabled.", price_col)

        for _, row in tqdm(df.iterrows(), total=len(df), desc="weak labeling"):
            meta_avg = float(row[meta_avg_rating_col]) if has_meta_rating else float("nan")
            feat_text = str(row[features_text_col]) if has_features else ""
            cat = str(row[leaf_category_col]) if has_category else ""
            price = float(row[price_col]) if has_price else float("nan")

            labels, evidence = self.label_review(
                str(row[text_col]),
                int(row[rating_col]),
                meta_avg_rating=meta_avg,
                features_text=feat_text,
                leaf_category=cat,
                price=price,
            )
            for a in self.aspects:
                all_labels[a].append(labels[a])
                all_evidence[a].append(evidence[a])

        result = df.copy()
        for a in self.aspects:
            result[f"aspect_{a}"] = all_labels[a]
            result[f"evidence_{a}"] = [json.dumps(e) for e in all_evidence[a]]
        return result


def compute_category_median_prices(df: pd.DataFrame,
                                   price_col: str = "price",
                                   cat_col: str = "leaf_category") -> Dict[str, float]:
    """Compute median price per leaf category. Used by Price-Aware VALUE labeling."""
    result = {}
    if price_col not in df.columns or cat_col not in df.columns:
        return result
    prices = pd.to_numeric(df[price_col], errors="coerce")
    global_median = float(prices.median())
    if np.isfinite(global_median):
        result["__global__"] = global_median
    for cat, group in df.groupby(cat_col):
        cat_prices = pd.to_numeric(group[price_col], errors="coerce").dropna()
        if len(cat_prices) >= 5:
            result[str(cat)] = float(cat_prices.median())
    logger.info("Computed median prices for %d categories (global=%.1f)",
                len(result) - 1, result.get("__global__", 0))
    return result


def label_distribution_summary(df: pd.DataFrame) -> pd.DataFrame:
    rows = []
    for a in cfg.ASPECTS:
        col = f"aspect_{a}"
        if col not in df.columns:
            continue
        vc = df[col].value_counts().sort_index()
        rows.append({
            "aspect": a,
            "not_mentioned": int(vc.get(0, 0)),
            "positive": int(vc.get(1, 0)),
            "negative": int(vc.get(2, 0)),
            "mentioned_pct": round(100 * (1 - vc.get(0, 0) / max(len(df), 1)), 2),
        })
    return pd.DataFrame(rows)


def save_audit_sample(df: pd.DataFrame, n: int = cfg.AUDIT_SAMPLE_SIZE, path=None):
    if path is None:
        path = cfg.REPORT_DIR / "weak_label_audit_sample.csv"

    cols = ["full_text", "rating", "overall_label", "parent_asin",
            "average_rating", "leaf_category", "price", "features_text"]
    cols += [f"aspect_{a}" for a in cfg.ASPECTS]
    cols += [f"evidence_{a}" for a in cfg.ASPECTS]
    cols = [c for c in cols if c in df.columns]

    by_rating = df.groupby("rating", group_keys=False)
    sample = by_rating.apply(lambda x: x.sample(n=min(max(n // 5, 1), len(x)),
                                                random_state=cfg.RANDOM_SEED))
    sample = sample.reset_index(drop=True)
    if len(sample) > n:
        sample = sample.sample(n=n, random_state=cfg.RANDOM_SEED)
    keep = [c for c in cols if c in sample.columns]
    sample[keep].to_csv(path, index=False)
    logger.info("Saved %d audit samples to %s", len(sample), path)
    return sample