"""Récupération de l'usage de l'abonnement Claude via l'endpoint OAuth `/usage`.

Validé empiriquement (compte Max 5x) :
  GET https://api.anthropic.com/api/oauth/usage
  headers: Authorization: Bearer <token>, anthropic-beta: oauth-2025-04-20,
           User-Agent: claude-code/<version>, Content-Type: application/json
  réponse: { five_hour:{utilization,resets_at}, seven_day:{...},
             seven_day_opus, seven_day_sonnet, extra_usage }

⚠️ L'endpoint exige le scope OAuth `user:profile`. Le token `claude setup-token` ne l'a PAS
(403). On utilise donc les credentials d'un **login Claude isolé dédié** (CLAUDE_CONFIG_DIR
séparé) : structure `{ claudeAiOauth: { accessToken, refreshToken, expiresAt(ms) } }`.

Le token expire (~8 h) ; on le rafraîchit via platform.claude.com et on réécrit le fichier
isolé de façon atomique. On ne touche jamais le ~/.claude partagé.
"""
from __future__ import annotations

import asyncio
import json
import os
import subprocess
import tempfile
import time
from dataclasses import dataclass
from datetime import datetime, timezone

import httpx

from config import config

USAGE_URL = "https://api.anthropic.com/api/oauth/usage"
REFRESH_URL = "https://platform.claude.com/v1/oauth/token"
CLIENT_ID = "9d1c250a-e61b-44d9-88ed-5944d1962f5e"  # client public Claude Code
EXPIRY_BUFFER_MS = 120_000  # rafraîchit 2 min avant expiration

_refresh_lock = asyncio.Lock()


@dataclass
class Window:
    """Une fenêtre glissante d'usage (5h ou 7j)."""

    utilization: float  # 0..100
    resets_at: datetime | None

    @property
    def remaining_pct(self) -> float:
        return max(0.0, 100.0 - self.utilization)

    @property
    def resets_in_human(self) -> str:
        if not self.resets_at:
            return ""
        delta = self.resets_at - datetime.now(timezone.utc)
        secs = int(delta.total_seconds())
        if secs <= 0:
            return "bientôt"
        h, m = divmod(secs // 60, 60)
        if h >= 24:
            return f"{h // 24}j {h % 24}h"
        if h:
            return f"{h}h{m:02d}"
        return f"{m}min"


@dataclass
class ExtraUsage:
    """Crédits « extra usage » (pay-as-you-go au-delà de l'abonnement)."""

    used: float
    limit: float | None
    currency: str = "EUR"

    @property
    def label(self) -> str:
        sym = "€" if self.currency == "EUR" else self.currency
        if self.limit:
            return f"Extra : {self.used:.0f}{sym} / {self.limit:.0f}{sym}"
        return f"Extra : {self.used:.0f}{sym}"


@dataclass
class ClaudeUsage:
    ok: bool
    error: str | None = None
    five_hour: Window | None = None
    seven_day: Window | None = None
    seven_day_opus: Window | None = None
    seven_day_sonnet: Window | None = None
    extra: ExtraUsage | None = None
    burn_rate: float | None = None  # tokens/min (ccusage, optionnel)


def _parse_window(raw: dict | None) -> Window | None:
    if not raw:
        return None
    util = float(raw.get("utilization", 0) or 0)
    resets = raw.get("resets_at")
    dt = None
    if resets:
        try:
            dt = datetime.fromisoformat(str(resets).replace("Z", "+00:00"))
        except ValueError:
            dt = None
    return Window(utilization=util, resets_at=dt)


def _load_creds() -> dict:
    with open(config.claude_creds_path) as f:
        return json.load(f)


def _write_creds(data: dict) -> None:
    """Écriture atomique du fichier de credentials isolé (mode 0600)."""
    path = config.claude_creds_path
    fd, tmp = tempfile.mkstemp(dir=os.path.dirname(path) or ".")
    try:
        with os.fdopen(fd, "w") as f:
            json.dump(data, f)
        os.chmod(tmp, 0o600)
        os.replace(tmp, path)
    except BaseException:
        if os.path.exists(tmp):
            os.unlink(tmp)
        raise


async def _refresh(data: dict) -> str:
    """Rafraîchit l'access token, réécrit le fichier isolé, renvoie le nouvel access token."""
    o = data["claudeAiOauth"]
    body = {
        "grant_type": "refresh_token",
        "refresh_token": o["refreshToken"],
        "client_id": CLIENT_ID,
    }
    async with httpx.AsyncClient(timeout=20) as client:
        resp = await client.post(
            REFRESH_URL, json=body,
            headers={"Content-Type": "application/json", "User-Agent": config.claude_ua},
        )
    resp.raise_for_status()
    tok = resp.json()
    o["accessToken"] = tok["access_token"]
    o["refreshToken"] = tok["refresh_token"]
    o["expiresAt"] = int(time.time() * 1000) + int(tok["expires_in"]) * 1000
    _write_creds(data)
    return o["accessToken"]


async def _valid_token() -> str:
    """Renvoie un access token valide, en rafraîchissant si nécessaire (sérialisé)."""
    data = _load_creds()
    o = data["claudeAiOauth"]
    if int(o.get("expiresAt", 0)) - int(time.time() * 1000) > EXPIRY_BUFFER_MS:
        return o["accessToken"]
    async with _refresh_lock:
        # Re-lecture après acquisition du lock : un autre coroutine a peut-être déjà rafraîchi.
        data = _load_creds()
        o = data["claudeAiOauth"]
        if int(o.get("expiresAt", 0)) - int(time.time() * 1000) > EXPIRY_BUFFER_MS:
            return o["accessToken"]
        return await _refresh(data)


async def _get_usage(token: str) -> httpx.Response:
    headers = {
        "Authorization": f"Bearer {token}",
        "anthropic-beta": "oauth-2025-04-20",
        "User-Agent": config.claude_ua,
        "Content-Type": "application/json",
    }
    async with httpx.AsyncClient(timeout=15) as client:
        return await client.get(USAGE_URL, headers=headers)


def _burn_rate_from_ccusage() -> float | None:
    """Burn rate du bloc 5h actif via `ccusage blocks --json` (best-effort)."""
    try:
        proc = subprocess.run(
            ["ccusage", "blocks", "--active", "--json"],
            capture_output=True, text=True, timeout=20,
        )
        if proc.returncode != 0:
            return None
        data = json.loads(proc.stdout)
        for b in data.get("blocks") or []:
            if b.get("isActive"):
                bp = b.get("burnRate") or {}
                rate = bp.get("tokensPerMinute") or bp.get("tokensPerMinuteForIndicator")
                return float(rate) if rate is not None else None
    except (subprocess.SubprocessError, json.JSONDecodeError, ValueError, FileNotFoundError):
        return None
    return None


async def fetch_usage() -> ClaudeUsage:
    if not os.path.exists(config.claude_creds_path):
        return ClaudeUsage(ok=False, error="credentials Claude absents — login isolé requis")

    try:
        token = await _valid_token()
    except (OSError, KeyError, json.JSONDecodeError) as exc:
        return ClaudeUsage(ok=False, error=f"credentials illisibles: {exc}")
    except httpx.HTTPError as exc:
        return ClaudeUsage(ok=False, error=f"refresh échoué: {exc}")

    try:
        resp = await _get_usage(token)
        # Token rejeté malgré le buffer -> une tentative de refresh forcé.
        if resp.status_code == 401:
            data = _load_creds()
            async with _refresh_lock:
                token = await _refresh(data)
            resp = await _get_usage(token)
    except httpx.HTTPError as exc:
        return ClaudeUsage(ok=False, error=f"réseau: {exc}")

    if resp.status_code == 401:
        return ClaudeUsage(ok=False, error="auth invalide — relancer le login isolé")
    if resp.status_code == 403:
        return ClaudeUsage(ok=False, error="scope insuffisant (login complet requis)")
    if resp.status_code != 200:
        return ClaudeUsage(ok=False, error=f"HTTP {resp.status_code}")

    data = resp.json()
    burn = _burn_rate_from_ccusage() if config.ccusage_enabled else None

    extra = None
    eu = data.get("extra_usage") or {}
    if eu.get("is_enabled") and eu.get("used_credits"):
        extra = ExtraUsage(
            used=float(eu.get("used_credits", 0)),
            limit=float(eu["monthly_limit"]) if eu.get("monthly_limit") else None,
            currency=eu.get("currency", "EUR"),
        )

    return ClaudeUsage(
        ok=True,
        five_hour=_parse_window(data.get("five_hour")),
        seven_day=_parse_window(data.get("seven_day")),
        seven_day_opus=_parse_window(data.get("seven_day_opus")),
        seven_day_sonnet=_parse_window(data.get("seven_day_sonnet")),
        extra=extra,
        burn_rate=burn,
    )