"""Next-stop recommendation scoring — ported from NomadCNA logic, adapted to nomadro destinations."""

from __future__ import annotations

from typing import Any


def _parse_nomads_count(value: str) -> int:
  digits = "".join(ch for ch in str(value) if ch.isdigit())
  return int(digits) if digits else 0


def score_destination(
  dest: dict[str, Any],
  *,
  budget: int,
  internet: int,
  climate: str,
  tags: list[str],
  priority: str = "balanced",
) -> tuple[float, list[str]]:
  """Return (score, match_reasons) for a destination dict."""
  cost = int(dest.get("cost") or 0)
  speed = int(dest.get("speed") or 0)
  temp = int(dest.get("temperature") or 20)
  rating = float(dest.get("rating") or 0)
  nomads = _parse_nomads_count(dest.get("nomads_count") or "0")
  highlights = dest.get("highlights") or []
  tag = str(dest.get("tag") or "")
  reasons: list[str] = []

  score = rating * 8

  # Budget fit (monthly cost in CNY-ish units)
  if cost <= budget:
    score += 28
    reasons.append("预算内")
  elif cost <= budget * 1.2:
    score += 14
    reasons.append("略超预算")
  else:
    score += max(0, 10 - (cost - budget) / 800)

  # Internet
  if speed >= internet:
    score += 22
    reasons.append("网络达标")
  else:
    score += max(0, 22 - (internet - speed) / 4)
    reasons.append("需确认住处网络")

  # Climate preference
  if climate == "warm":
    score += 18 if temp >= 24 else max(0, 18 - (24 - temp) * 2)
    if temp >= 24:
      reasons.append("气候偏暖")
  elif climate == "cool":
    score += 18 if temp <= 18 else max(0, 18 - (temp - 18) * 2)
    if temp <= 18:
      reasons.append("气候清爽")
  else:  # mild
    score += 18 if 18 <= temp <= 26 else max(0, 18 - abs(temp - 22) * 2)
    if 18 <= temp <= 26:
      reasons.append("气候温和")

  # Tag overlap (NomadCNA-style lifestyle tags)
  dest_tags = set(highlights + [tag])
  overlap = [t for t in tags if any(t in dt or dt in t for dt in dest_tags)]
  if overlap:
    score += min(15, len(overlap) * 5)
    reasons.append(f"标签匹配：{overlap[0]}")

  # Community density
  if nomads >= 8000:
    score += 12
    reasons.append("社区活跃")
  elif nomads >= 3000:
    score += 6

  # Priority boost
  if priority == "cost":
    score += (14000 - cost) / 120
  elif priority == "speed":
    score += speed / 5
  elif priority == "community":
    score += nomads / 400

  if not reasons:
    reasons.append("综合评分推荐")

  return round(score, 1), reasons[:3]


def recommend_destinations(
  destinations: list[dict[str, Any]],
  *,
  budget: int = 8000,
  internet: int = 50,
  climate: str = "mild",
  tags: list[str] | None = None,
  priority: str = "balanced",
  limit: int = 12,
) -> list[dict[str, Any]]:
  tags = tags or []
  scored: list[tuple[float, dict[str, Any], list[str]]] = []
  for dest in destinations:
    s, reasons = score_destination(
      dest,
      budget=budget,
      internet=internet,
      climate=climate,
      tags=tags,
      priority=priority,
    )
    scored.append((s, dest, reasons))

  scored.sort(key=lambda x: x[0], reverse=True)
  items = []
  for s, dest, reasons in scored[:limit]:
    items.append({
      **dest,
      "match_score": s,
      "match_reasons": reasons,
    })
  return items