#!/usr/bin/env python3

"""Shared anime title normalization and matching helpers."""

import re
import unicodedata


def normalize_title_key(value):
    text = unicodedata.normalize("NFKD", str(value or ""))
    text = "".join(char for char in text if not unicodedata.combining(char))
    text = text.lower()
    text = re.sub(r"\((19|20)\d{2}\)", " ", text)
    text = re.sub(r"[^a-z0-9]+", " ", text)
    return re.sub(r"\s+", " ", text).strip()


def normalize_identity_title_key(value):
    text = normalize_title_key(value)
    if not text:
        return ""
    text = re.sub(r"\b(\d+)(st|nd|rd|th)\s+season\b", r"season \1", text)
    return re.sub(r"\s+", " ", text).strip()


def base_title_variants(value):
    text = str(value or "").strip()
    variants = []
    if text:
        variants.append(text)
    patterns = [
        r"\s+\((19|20)\d{2}\)\s*$",
        r"\s+season\s+\d+\s*$",
        r"\s+part\s+\d+\s*$",
        r"\s+cour\s+\d+\s*$",
        r"\s+\d+(st|nd|rd|th)\s+season\s*$",
    ]
    changed = True
    current = text
    while current and changed:
        changed = False
        for pattern in patterns:
            trimmed = re.sub(pattern, "", current, flags=re.IGNORECASE).strip(" -:")
            if trimmed and trimmed != current:
                current = trimmed
                if current not in variants:
                    variants.append(current)
                changed = True
    return variants


def title_match_variants(value):
    variants = set()
    for raw_value in base_title_variants(value):
        normalized = normalize_title_key(raw_value)
        if normalized:
            variants.add(normalized)
        stripped = re.sub(r"\b(19|20)\d{2}\b", " ", normalized)
        stripped = re.sub(r"\s+", " ", stripped).strip()
        if stripped:
            variants.add(stripped)
    return variants


def identity_title_variants(value):
    variants = set()
    normalized = normalize_identity_title_key(value)
    if normalized:
        variants.add(normalized)
        stripped = re.sub(r"\b(19|20)\d{2}\b", " ", normalized)
        stripped = re.sub(r"\s+", " ", stripped).strip()
        if stripped:
            variants.add(stripped)
    return variants


def title_lookup_queries(value):
    queries = []
    for raw_value in base_title_variants(value):
        text = str(raw_value or "").strip()
        if text and text not in queries:
            queries.append(text)
    return queries