"""User-facing inference for the Proposed model."""
from typing import Dict, List, Optional

import numpy as np
import pandas as pd
import torch

from . import config as cfg
from .evaluator import load_meta_acsa, format_aspect_summary


_EXPECTED_META_KEYS = (
    "features_text", "categories_text",
    "price", "average_rating", "rating_number",
)


def _meta_dict_to_df(meta: Dict) -> pd.DataFrame:
    """Build a one-row DataFrame the MetaEncoder can transform."""
    row = {k: meta.get(k) for k in _EXPECTED_META_KEYS}
    return pd.DataFrame([row])


def _attention_names(out: Dict, attn_array) -> List[str]:
    names = out.get("meta_token_names")
    if names is not None:
        return list(names)
    arr = np.asarray(attn_array)
    width = int(arr.shape[-1]) if arr.ndim else int(arr.size)
    if width == 3:
        return ["features", "categories", "numeric"]
    return [f"meta_chunk_{i + 1}" for i in range(width)]


def _attention_dict(names: List[str], weights) -> Dict[str, float]:
    arr = np.asarray(weights, dtype=np.float64).reshape(-1)
    return {name: float(w) for name, w in zip(names, arr)}

def _top_attention_item(attn: Dict[str, float]) -> Dict[str, float]:
    if not attn:
        return {"source": "", "weight": 0.0}
    source = max(attn, key=attn.get)
    return {"source": source, "weight": float(attn[source])}


def _meta_summary(meta: Dict) -> Dict[str, str]:
    features = str(meta.get("features_text") or meta.get("features") or "")[:420]
    categories = str(meta.get("categories_text") or meta.get("category") or "")[:220]
    numeric = []
    for key in ("price", "average_rating", "rating_number"):
        val = meta.get(key)
        if val is not None:
            numeric.append(f"{key}={val}")
    return {
        "features": features,
        "categories": categories,
        "numeric": ", ".join(numeric) if numeric else "not available",
    }

_ASPECT_EVIDENCE_KEYWORDS = {
    "SIZE": {"size", "fit", "fits", "fitting", "small", "large", "big", "tight", "loose", "xl", "medium", "waist", "length"},
    "MATERIAL": {"material", "fabric", "cotton", "polyester", "soft", "scratchy", "thin", "thick", "stretch", "leather", "wool"},
    "QUALITY": {"quality", "stitch", "stitching", "seam", "wash", "washed", "durable", "cheap", "broke", "tear", "torn"},
    "APPEARANCE": {"look", "looks", "color", "colour", "photo", "picture", "beautiful", "cute", "print", "design"},
    "STYLE": {"style", "stylish", "flattering", "casual", "formal", "dress", "shirt", "fashion", "compliments"},
    "VALUE": {"price", "worth", "value", "money", "cheap", "expensive", "discount", "penny", "cost"},
}

_SENTIMENT_EVIDENCE_KEYWORDS = {
    "good", "great", "love", "loved", "perfect", "nice", "excellent", "comfortable", "soft",
    "bad", "poor", "cheap", "terrible", "awful", "small", "large", "tight", "loose", "thin",
    "worth", "disappointed", "return", "returned", "recommend", "flattering", "beautiful",
}
_STOPWORDS = {
    "a", "an", "the", "and", "or", "but", "if", "then", "than", "so", "as", "at", "by", "for", "from",
    "in", "into", "of", "on", "to", "with", "without", "is", "are", "was", "were", "be", "been", "being",
    "it", "its", "this", "that", "these", "those", "i", "me", "my", "we", "our", "you", "your", "he", "she", "they",
    "them", "his", "her", "their", "very", "really", "just", "also", "too", "would", "could", "should", "can",
    "will", "did", "do", "does", "have", "has", "had", "there", "here", "about", "after", "before",
}


def _clean_term(term: str) -> str:
    return str(term).lower().strip(".,!?;:'\"()[]{}<>/\\|`~@#$%^&*_+=")


def _is_informative_term(term: str) -> bool:
    clean = _clean_term(term)
    if len(clean) < 2 or clean in _STOPWORDS:
        return False
    return any(ch.isalpha() for ch in clean)


def _text_evidence_by_aspect(review_text: str, top_k: int = 8) -> Dict[str, List[str]]:
    raw_terms = [_clean_term(t) for t in str(review_text).split()]
    result = {}
    for aspect, aspect_terms in _ASPECT_EVIDENCE_KEYWORDS.items():
        hits = []
        for term in raw_terms:
            if not _is_informative_term(term):
                continue
            if term in aspect_terms or term in _SENTIMENT_EVIDENCE_KEYWORDS:
                if term not in hits:
                    hits.append(term)
            if len(hits) >= top_k:
                break
        result[aspect] = hits
    return result

def _format_confidence(out: Dict, row_idx: int = 0) -> Dict[str, Dict[str, float]]:
    probs = torch.softmax(out["logits"][row_idx], dim=-1).detach().cpu().numpy()
    result = {}
    for i, aspect in enumerate(cfg.ASPECTS):
        cls = int(np.argmax(probs[i]))
        result[aspect] = {
            "label": cfg.LABEL_NAMES[cls],
            "confidence": float(probs[i, cls]),
            "class_probs": {
                cfg.LABEL_NAMES[j]: float(probs[i, j])
                for j in range(len(cfg.LABEL_NAMES))
            },
        }
    return result


def _attention_insights(attn_payload: Dict) -> Dict:
    insights = {}
    if "meta_attention" in attn_payload:
        insights["top_meta_source"] = _top_attention_item(attn_payload["meta_attention"])
    if "meta_attention_by_aspect" in attn_payload:
        insights["top_meta_source_by_aspect"] = {
            aspect: _top_attention_item(weights)
            for aspect, weights in attn_payload["meta_attention_by_aspect"].items()
        }
    return insights

def _format_attention(out: Dict) -> Dict:
    """Format legacy 1D attention or new aspect-specific 2D attention."""
    if "meta_attn_weights" not in out or out["meta_attn_weights"] is None:
        return {}

    aspect_attn = out["meta_attn_weights"].detach().cpu().numpy()[0]
    names = _attention_names(out, aspect_attn)

    if aspect_attn.ndim == 1:
        return {"meta_attention": _attention_dict(names, aspect_attn)}

    result = {
        "meta_attention_by_aspect": {
            aspect: _attention_dict(names, aspect_attn[i])
            for i, aspect in enumerate(cfg.ASPECTS)
        }
    }
    if "global_meta_attn_weights" in out and out["global_meta_attn_weights"] is not None:
        global_attn = out["global_meta_attn_weights"].detach().cpu().numpy()[0]
        result["meta_attention"] = _attention_dict(names, global_attn)
    else:
        result["meta_attention"] = _attention_dict(names, aspect_attn.mean(axis=0))
    return result


def _slice_model_out(out: Dict, start: int, end: int) -> Dict:
    sliced = {}
    for k, v in out.items():
        sliced[k] = v[start:end] if torch.is_tensor(v) else v
    return sliced


class AspectPredictor:
    """Load the Proposed model and expose one-shot and batch predictions."""

    def __init__(self, checkpoint_dir=None, device=None):
        self.model, self.tokenizer, self.meta_encoder, self.device = load_meta_acsa(
            checkpoint_dir=checkpoint_dir, device=device,
        )

    def predict(self, review_text: str, product_meta: Dict,
                return_attention: bool = True) -> Dict:
        enc = self.tokenizer(
            review_text,
            max_length=cfg.MAX_LENGTH,
            truncation=True,
            padding="max_length",
            return_tensors="pt",
        )
        input_ids = enc["input_ids"].to(self.device)
        attn_mask = enc["attention_mask"].to(self.device)

        meta_df = _meta_dict_to_df(product_meta)
        meta_vec = torch.from_numpy(self.meta_encoder.transform(meta_df)).float().to(self.device)

        with torch.no_grad():
            out = self.model(input_ids, attn_mask, meta_vec)

        preds = out["logits"][0].argmax(dim=-1).cpu().numpy()
        result = {
            "aspects": format_aspect_summary(preds),
            "aspect_details": _format_confidence(out, 0),
            "metadata_summary": _meta_summary(product_meta),
        }
        if "overall_logits" in out and out["overall_logits"] is not None:
            overall_probs = torch.softmax(out["overall_logits"][0], dim=-1).detach().cpu().numpy()
            overall_cls = int(np.argmax(overall_probs))
            result["overall"] = {
                "label": cfg.OVERALL_LABEL_NAMES[overall_cls],
                "confidence": float(overall_probs[overall_cls]),
                "class_probs": {
                    cfg.OVERALL_LABEL_NAMES[j]: float(overall_probs[j])
                    for j in range(len(cfg.OVERALL_LABEL_NAMES))
                },
            }
        if return_attention:
            attn_payload = _format_attention(out)
            result.update(attn_payload)
            result.update(_attention_insights(attn_payload))
        return result

    def predict_batch(self, reviews: List[Dict], batch_size: int = 16) -> List[Dict]:
        """Each item is {'review_text': str, 'product_meta': {...}}."""
        results = []
        for i in range(0, len(reviews), batch_size):
            chunk = reviews[i:i + batch_size]
            enc = self.tokenizer(
                [r["review_text"] for r in chunk],
                max_length=cfg.MAX_LENGTH,
                truncation=True,
                padding="max_length",
                return_tensors="pt",
            )
            input_ids = enc["input_ids"].to(self.device)
            attn_mask = enc["attention_mask"].to(self.device)

            meta_df = pd.concat(
                [_meta_dict_to_df(r["product_meta"]) for r in chunk],
                ignore_index=True,
            )
            meta_vec = torch.from_numpy(self.meta_encoder.transform(meta_df)).float().to(self.device)

            with torch.no_grad():
                out = self.model(input_ids, attn_mask, meta_vec)
            preds = out["logits"].argmax(dim=-1).cpu().numpy()

            for j in range(len(chunk)):
                item = {
                    "aspects": format_aspect_summary(preds[j]),
                    "aspect_details": _format_confidence(out, j),
                    "metadata_summary": _meta_summary(chunk[j]["product_meta"]),
                }
                if "overall_logits" in out and out["overall_logits"] is not None:
                    overall_probs = torch.softmax(out["overall_logits"][j], dim=-1).detach().cpu().numpy()
                    overall_cls = int(np.argmax(overall_probs))
                    item["overall"] = {
                        "label": cfg.OVERALL_LABEL_NAMES[overall_cls],
                        "confidence": float(overall_probs[overall_cls]),
                        "class_probs": {
                            cfg.OVERALL_LABEL_NAMES[k]: float(overall_probs[k])
                            for k in range(len(cfg.OVERALL_LABEL_NAMES))
                        },
                    }
                attn_payload = _format_attention(_slice_model_out(out, j, j + 1))
                item.update(attn_payload)
                item.update(_attention_insights(attn_payload))
                results.append(item)
        return results