"""Trakt.tv API client.

Uses OAuth 2.0 device code flow:
  1. POST /oauth/device/code with client_id → get device_code + user_code + verification_url
  2. User visits trakt.tv/activate, enters user_code
  3. Poll POST /oauth/device/token with device_code until user approves → access_token + refresh_token
  4. Use access_token as Bearer for all subsequent calls.

Scrobble: POST /scrobble/{start|pause|stop} with movie/episode + progress (0-100).
"""
import requests
from typing import Dict, Optional

BASE = "https://api.trakt.tv"


def _headers(client_id: str, access_token: Optional[str] = None) -> dict:
    h = {
        "Content-Type": "application/json",
        "trakt-api-version": "2",
        "trakt-api-key": client_id,
    }
    if access_token:
        h["Authorization"] = f"Bearer {access_token}"
    return h


def device_code(client_id: str) -> Dict:
    r = requests.post(f"{BASE}/oauth/device/code", json={"client_id": client_id}, timeout=15)
    r.raise_for_status()
    d = r.json()
    return {
        "device_code": d["device_code"],
        "user_code": d["user_code"],
        "verification_url": d["verification_url"],
        "expires_in": d["expires_in"],
        "interval": d["interval"],
    }


def poll_token(client_id: str, client_secret: str, device_code_val: str) -> Optional[Dict]:
    """Returns access_token dict on success, None if still pending, raises on error."""
    r = requests.post(f"{BASE}/oauth/device/token", json={
        "code": device_code_val,
        "client_id": client_id,
        "client_secret": client_secret,
    }, timeout=15)
    if r.status_code == 200:
        return r.json()  # {access_token, refresh_token, expires_in, created_at, ...}
    if r.status_code in (400, 404):  # pending / expired
        return None
    r.raise_for_status()
    return None


def refresh(client_id: str, client_secret: str, refresh_token: str) -> Dict:
    r = requests.post(f"{BASE}/oauth/token", json={
        "refresh_token": refresh_token,
        "client_id": client_id,
        "client_secret": client_secret,
        "grant_type": "refresh_token",
    }, timeout=15)
    r.raise_for_status()
    return r.json()


def user_settings(client_id: str, access_token: str) -> Dict:
    r = requests.get(f"{BASE}/users/settings", headers=_headers(client_id, access_token), timeout=15)
    r.raise_for_status()
    return r.json()


def _scrobble(action: str, client_id: str, access_token: str, payload: dict):
    r = requests.post(f"{BASE}/scrobble/{action}",
                      headers=_headers(client_id, access_token),
                      json=payload, timeout=15)
    if r.status_code in (409, 429):  # duplicate / rate-limit
        return None
    r.raise_for_status()
    return r.json()


def scrobble_movie(client_id: str, access_token: str, tmdb_id: int, progress: float, action: str = "stop"):
    return _scrobble(action, client_id, access_token, {
        "movie": {"ids": {"tmdb": int(tmdb_id)}},
        "progress": max(0.0, min(100.0, float(progress))),
    })


def scrobble_episode(client_id: str, access_token: str, tvdb_id: Optional[int], tmdb_id: Optional[int],
                     season: int, episode: int, progress: float, action: str = "stop"):
    ids = {}
    if tvdb_id: ids["tvdb"] = int(tvdb_id)
    if tmdb_id: ids["tmdb"] = int(tmdb_id)
    if not ids:
        return None
    return _scrobble(action, client_id, access_token, {
        "show": {"ids": ids},
        "episode": {"season": int(season), "number": int(episode)},
        "progress": max(0.0, min(100.0, float(progress))),
    })