# src/list.py

from __future__ import annotations

from dataclasses import dataclass
from typing import Dict, List, Any, Callable
import re


# -----------------------------
# Configuration algorithmique
# -----------------------------

@dataclass
class ListConfig:
    # n-grams
    max_ngram: int = 5
    min_doc_freq: int = 2

    # scoring
    window: int = 80
    score_threshold: float = 60.0

    # output
    top_k: int = 15


# -----------------------------
# Normalisation & tokens
# -----------------------------

def normalize(text: str) -> str:
    text = (text or "").lower()
    text = re.sub(r"[’']", " ", text)
    text = re.sub(r"[^a-zàâçéèêëîïôûùüÿñæœ\s]", " ", text)
    text = re.sub(r"\s+", " ", text).strip()
    return text


def tokenize(text: str) -> List[str]:
    return text.split()


def generate_ngrams(tokens: List[str], max_ngram: int) -> List[str]:
    ngrams: List[str] = []
    n = len(tokens)
    for size in range(1, min(max_ngram, n) + 1):
        for i in range(n - size + 1):
            ngrams.append(" ".join(tokens[i : i + size]))
    return ngrams


# -----------------------------
# Phrase pivot (corpus-driven)
# -----------------------------

def extract_phrase_pivot(query: str, articles: Dict[str, str], cfg: ListConfig) -> str | None:
    q_norm = normalize(query)
    tokens = tokenize(q_norm)
    candidates = generate_ngrams(tokens, cfg.max_ngram)

    stats = []

    for seg in candidates:
        seg_re = re.compile(rf"\b{re.escape(seg)}\b")
        doc_freq = 0

        for text in articles.values():
            if seg_re.search(normalize(text)):
                doc_freq += 1

        if doc_freq >= cfg.min_doc_freq:
            # longueur = nb de mots (préférence aux pivots plus spécifiques)
            stats.append((seg, len(seg.split()), doc_freq))

    if not stats:
        return None

    # priorité : longueur > doc_freq
    stats.sort(key=lambda x: (x[1], x[2]), reverse=True)
    return stats[0][0]


# -----------------------------
# Centralité normative
# -----------------------------

def centrality_factor(text: str, pivot: str) -> float:
    text_norm = normalize(text)
    pivot_norm = normalize(pivot)

    idx = text_norm.find(pivot_norm)
    if idx == -1:
        return 0.0

    pos = idx / max(len(text_norm), 1)

    if pos <= 0.20:
        return 1.4
    if pos <= 0.40:
        return 1.2
    if pos <= 0.60:
        return 1.0
    if pos <= 0.80:
        return 0.8
    return 0.6


# -----------------------------
# Score lexical
# -----------------------------

def lexical_score(text: str, pivot: str, window: int) -> int:
    text_norm = normalize(text)
    pivot_norm = normalize(pivot)

    score = 0
    for m in re.finditer(rf"\b{re.escape(pivot_norm)}\b", text_norm):
        start = max(0, m.start() - window)
        end = min(len(text_norm), m.end() + window)
        score += (end - start)

    return score


# -----------------------------
# Algorithme LIST (coeur)
# -----------------------------

def list_articles_lexical(query: str, articles: Dict[str, str], cfg: ListConfig) -> List[str]:
    pivot = extract_phrase_pivot(query, articles, cfg)
    if not pivot:
        return []

    scored: List[tuple[str, float]] = []

    for aid, text in articles.items():
        s_lex = lexical_score(text, pivot, cfg.window)
        if s_lex == 0:
            continue

        factor = centrality_factor(text, pivot)
        s_final = s_lex * factor

        if s_final >= cfg.score_threshold:
            scored.append((aid, s_final))

    scored.sort(key=lambda x: x[1], reverse=True)
    return [aid for aid, _ in scored[: cfg.top_k]]


# -----------------------------
# API attendue par rag_core.py
# -----------------------------

def list_articles(
    query: str,
    articles: Dict[str, str],
    vs: Any = None,  # fallback possible plus tard
    normalize_article_id: Callable[[str], str] | None = None,
    list_triggers: List[str] | None = None,
    cfg: ListConfig | None = None,
) -> Dict[str, Any]:
    """
    Signature compatible avec rag_core.py.

    Pour l'instant : lexical-only (ton algo).
    Le paramètre `vs` est accepté pour compatibilité, mais pas utilisé ici.
    """
    cfg = cfg or ListConfig()

    q = (query or "").strip()
    if not q:
        return {"mode": "LIST", "answer": "", "articles": []}

    ids = list_articles_lexical(q, articles, cfg)

    return {
        "mode": "LIST",
        "answer": "",
        "articles": ids,
    }