# -----------------------------------------------------------------------------
# Immo-Ka — Agrégateur de maisons à vendre (province de Québec)
# Auteur : Simon-Pierre Boucher — contact@spboucher.ai
# mortgage/providers/national_bank.py : Banque Nationale — JSON double-échappé
#   setProductMap(JSON.parse("…")) dans la page des taux. c1 = produits
#   hypothécaires (par productConditionName). ⚠️ Séparateurs décimaux mixtes :
#   affichés « 6.090 » (point), promos « 4,84 » (virgule) — les tacNans sont
#   les APR des promos. Le tauxBase du produit variable est un ÉCART, pas la
#   prime : la prime vient du tauxBase du produit fixe.
# -----------------------------------------------------------------------------
from __future__ import annotations

import json
import re

from .base import RateProvider

PAGE_URL = "https://www.nbc.ca/personal/mortgages/rates.html"

MAP_RX = re.compile(r'setProductMap\(JSON\.parse\("(.*?)"\)\)', re.S)

# champs affichés fixes (fermés) -> terme mois ; taux1moisF exclu (< 3 mois)
FIXED_POSTED = {
    "taux3moisF": 3, "taux6moisF": 6, "taux1anF": 12, "taux2ansF": 24,
    "taux3ansF": 36, "taux4ansF": 48, "taux5ansF": 60, "taux6ansF": 72,
    "taux7ansF": 84, "taux10ansF": 120,
}
FIXED_OPEN = {"taux6moisO": 6, "taux1anO": 12}
# promo -> (terme mois, champ APR)
FIXED_PROMO = {
    "tauxPromo3ansF": (36, "tac3ans"),
    "tauxPromo4ansF": (48, "tac4ans"),
    "tauxPromo5ansF": (60, "tac5ans"),
}


def _num(v) -> float | None:
    if v in (None, ""):
        return None
    try:
        return float(str(v).replace("\xa0", "").replace(",", ".").strip())
    except ValueError:
        return None


class NationalBankProvider(RateProvider):
    provider_id = "national_bank"
    institution = "Banque Nationale"
    source_url = PAGE_URL
    request_delay = 1.5

    def fetch(self) -> list[dict]:
        return self.parse(self.get(self.source_url).text)

    def parse(self, payload: str) -> list[dict]:
        m = MAP_RX.search(payload)
        if not m:
            raise ValueError("setProductMap introuvable (structure changée)")
        dec = (m.group(1).replace("\\x22", '"')
               .replace("\\\\", "\\").replace("\\/", "/"))
        # la chaîne JS se termine par «"), true);» : raw_decode ignore la suite
        obj, _ = json.JSONDecoder().raw_decode(dec)
        products = json.loads(obj.get("c1") or "[]")
        by_name = {p.get("productConditionName"): p
                   for p in products if isinstance(p, dict)}
        out: list[dict] = []
        fixed = by_name.get("Mortgage fixed rate") or {}
        for field, term in FIXED_POSTED.items():
            rate = _num(fixed.get(field))
            if rate and rate > 0:
                out.append(self.make_product(
                    rate=rate, rate_type="fixed", term_months=term,
                    kind="posted",
                    product_name=f"Fixe fermé {_label(term)}",
                    raw={"field": field, "value": fixed.get(field)}))
        for field, term in FIXED_OPEN.items():
            rate = _num(fixed.get(field))
            if rate and rate > 0:
                out.append(self.make_product(
                    rate=rate, rate_type="fixed", term_months=term,
                    kind="posted",
                    product_name=f"Fixe ouvert {_label(term)}",
                    raw={"field": field, "value": fixed.get(field)}))
        for field, (term, apr_field) in FIXED_PROMO.items():
            rate = _num(fixed.get(field))
            if rate and rate > 0:
                out.append(self.make_product(
                    rate=rate, rate_type="fixed", term_months=term,
                    kind="special", apr=_num(fixed.get(apr_field)),
                    product_name=f"Fixe fermé {_label(term)} (promotion)",
                    raw={"field": field, "value": fixed.get(field)}))
        prime = _num(fixed.get("tauxBase"))
        if prime and prime > 0:
            out.append(self.make_product(
                rate=prime, rate_type="other", term_months=12, kind="posted",
                product_name="Taux préférentiel BNC", purpose="unknown",
                raw={"field": "tauxBase", "value": fixed.get("tauxBase")}))
        variable = by_name.get("Mortgage variable rate") or {}
        v_posted = _num(variable.get("taux5ansO"))
        if v_posted and v_posted > 0:
            out.append(self.make_product(
                rate=v_posted, rate_type="variable", term_months=60,
                kind="posted", product_name="Variable 5 ans",
                conditions="Base = taux préférentiel BNC",
                raw={"field": "taux5ansO", "value": variable.get("taux5ansO")}))
        v_promo = _num(variable.get("tauxPromo5ansF"))
        if v_promo and v_promo > 0:
            out.append(self.make_product(
                rate=v_promo, rate_type="variable", term_months=60,
                kind="special", apr=_num(variable.get("tac5ans")),
                product_name="Variable 5 ans (promotion)",
                raw={"field": "tauxPromo5ansF",
                     "value": variable.get("tauxPromo5ansF")}))
        capped = by_name.get("Variable capped-rate mortgage") or {}
        c_rate = _num(capped.get("taux5ansO"))
        if c_rate and c_rate > 0:
            cap = _num(capped.get("tauxPlafond"))
            out.append(self.make_product(
                rate=c_rate, rate_type="variable", term_months=60,
                kind="posted", product_name="Variable plafonné 5 ans",
                conditions=f"Taux plafond {cap} %" if cap else None,
                raw={"field": "taux5ansO", "value": capped.get("taux5ansO"),
                     "tauxPlafond": capped.get("tauxPlafond")}))
        return out


def _label(months: int) -> str:
    if months < 12:
        return f"{months} mois"
    years = months // 12
    return f"{years} an" if years == 1 else f"{years} ans"