"""Google Code Assist API client — project discovery, onboarding, quota.

The Code Assist API powers Google's official gemini-cli. It sits at
``cloudcode-pa.googleapis.com`` and provides:

- Free tier access (generous daily quota) for personal Google accounts
- Paid tier access via GCP projects with billing / Workspace / Standard / Enterprise

This module handles the control-plane dance needed before inference:

1. ``load_code_assist()`` — probe the user's account to learn what tier they're on
   and whether a ``cloudaicompanionProject`` is already assigned.
2. ``onboard_user()`` — if the user hasn't been onboarded yet (new account, fresh
   free tier, etc.), call this with the chosen tier + project id. Supports LRO
   polling for slow provisioning.
3. ``retrieve_user_quota()`` — fetch the ``buckets[]`` array showing remaining
   quota per model, used by the ``/gquota`` slash command.

VPC-SC handling: enterprise accounts under a VPC Service Controls perimeter
will get ``SECURITY_POLICY_VIOLATED`` on ``load_code_assist``. We catch this
and force the account to ``standard-tier`` so the call chain still succeeds.

Derived from opencode-gemini-auth (MIT) and clawdbot/extensions/google. The
request/response shapes are specific to Google's internal Code Assist API,
documented nowhere public — we copy them from the reference implementations.
"""

from __future__ import annotations

import json
import logging
import os
import time
import urllib.error
import urllib.parse
import urllib.request
import uuid
from dataclasses import dataclass, field
from typing import Any, Dict, List, Optional

logger = logging.getLogger(__name__)


# =============================================================================
# Constants
# =============================================================================

CODE_ASSIST_ENDPOINT = "https://cloudcode-pa.googleapis.com"

# Fallback endpoints tried when prod returns an error during project discovery
FALLBACK_ENDPOINTS = [
    "https://daily-cloudcode-pa.sandbox.googleapis.com",
    "https://autopush-cloudcode-pa.sandbox.googleapis.com",
]

# Tier identifiers that Google's API uses
FREE_TIER_ID = "free-tier"
LEGACY_TIER_ID = "legacy-tier"
STANDARD_TIER_ID = "standard-tier"

# Default HTTP headers matching gemini-cli's fingerprint.
# Google may reject unrecognized User-Agents on these internal endpoints.
_GEMINI_CLI_USER_AGENT = "google-api-nodejs-client/9.15.1 (gzip)"
_X_GOOG_API_CLIENT = "gl-node/24.0.0"
_DEFAULT_REQUEST_TIMEOUT = 30.0
_ONBOARDING_POLL_ATTEMPTS = 12
_ONBOARDING_POLL_INTERVAL_SECONDS = 5.0


class CodeAssistError(RuntimeError):
    def __init__(self, message: str, *, code: str = "code_assist_error") -> None:
        super().__init__(message)
        self.code = code


class ProjectIdRequiredError(CodeAssistError):
    def __init__(self, message: str = "GCP project id required for this tier") -> None:
        super().__init__(message, code="code_assist_project_id_required")


# =============================================================================
# HTTP primitive (auth via Bearer token passed per-call)
# =============================================================================

def _build_headers(access_token: str, *, user_agent_model: str = "") -> Dict[str, str]:
    ua = _GEMINI_CLI_USER_AGENT
    if user_agent_model:
        ua = f"{ua} model/{user_agent_model}"
    return {
        "Content-Type": "application/json",
        "Accept": "application/json",
        "Authorization": f"Bearer {access_token}",
        "User-Agent": ua,
        "X-Goog-Api-Client": _X_GOOG_API_CLIENT,
        "x-activity-request-id": str(uuid.uuid4()),
    }


def _client_metadata() -> Dict[str, str]:
    """Match Google's gemini-cli exactly — unrecognized metadata may be rejected."""
    return {
        "ideType": "IDE_UNSPECIFIED",
        "platform": "PLATFORM_UNSPECIFIED",
        "pluginType": "GEMINI",
    }


def _post_json(
    url: str,
    body: Dict[str, Any],
    access_token: str,
    *,
    timeout: float = _DEFAULT_REQUEST_TIMEOUT,
    user_agent_model: str = "",
) -> Dict[str, Any]:
    data = json.dumps(body).encode("utf-8")
    request = urllib.request.Request(
        url, data=data, method="POST",
        headers=_build_headers(access_token, user_agent_model=user_agent_model),
    )
    try:
        with urllib.request.urlopen(request, timeout=timeout) as response:
            raw = response.read().decode("utf-8", errors="replace")
            return json.loads(raw) if raw else {}
    except urllib.error.HTTPError as exc:
        detail = ""
        try:
            detail = exc.read().decode("utf-8", errors="replace")
        except Exception:
            pass
        # Special case: VPC-SC violation should be distinguishable
        if _is_vpc_sc_violation(detail):
            raise CodeAssistError(
                f"VPC-SC policy violation: {detail}",
                code="code_assist_vpc_sc",
            ) from exc
        raise CodeAssistError(
            f"Code Assist HTTP {exc.code}: {detail or exc.reason}",
            code=f"code_assist_http_{exc.code}",
        ) from exc
    except urllib.error.URLError as exc:
        raise CodeAssistError(
            f"Code Assist request failed: {exc}",
            code="code_assist_network_error",
        ) from exc


def _is_vpc_sc_violation(body: str) -> bool:
    """Detect a VPC Service Controls violation from a response body."""
    if not body:
        return False
    try:
        parsed = json.loads(body)
    except (json.JSONDecodeError, ValueError):
        return "SECURITY_POLICY_VIOLATED" in body
    # Walk the nested error structure Google uses
    error = parsed.get("error") if isinstance(parsed, dict) else None
    if not isinstance(error, dict):
        return False
    details = error.get("details") or []
    if isinstance(details, list):
        for item in details:
            if isinstance(item, dict):
                reason = item.get("reason") or ""
                if reason == "SECURITY_POLICY_VIOLATED":
                    return True
    msg = str(error.get("message", ""))
    return "SECURITY_POLICY_VIOLATED" in msg


# =============================================================================
# load_code_assist — discovers current tier + assigned project
# =============================================================================

@dataclass
class CodeAssistProjectInfo:
    """Result from ``load_code_assist``."""
    current_tier_id: str = ""
    cloudaicompanion_project: str = ""   # Google-managed project (free tier)
    allowed_tiers: List[str] = field(default_factory=list)
    raw: Dict[str, Any] = field(default_factory=dict)


def load_code_assist(
    access_token: str,
    *,
    project_id: str = "",
    user_agent_model: str = "",
) -> CodeAssistProjectInfo:
    """Call ``POST /v1internal:loadCodeAssist`` with prod → sandbox fallback.

    Returns whatever tier + project info Google reports. On VPC-SC violations,
    returns a synthetic ``standard-tier`` result so the chain can continue.
    """
    body: Dict[str, Any] = {
        "metadata": {
            "duetProject": project_id,
            **_client_metadata(),
        },
    }
    if project_id:
        body["cloudaicompanionProject"] = project_id

    endpoints = [CODE_ASSIST_ENDPOINT] + FALLBACK_ENDPOINTS
    last_err: Optional[Exception] = None
    for endpoint in endpoints:
        url = f"{endpoint}/v1internal:loadCodeAssist"
        try:
            resp = _post_json(url, body, access_token, user_agent_model=user_agent_model)
            return _parse_load_response(resp)
        except CodeAssistError as exc:
            if exc.code == "code_assist_vpc_sc":
                logger.info("VPC-SC violation on %s — defaulting to standard-tier", endpoint)
                return CodeAssistProjectInfo(
                    current_tier_id=STANDARD_TIER_ID,
                    cloudaicompanion_project=project_id,
                )
            last_err = exc
            logger.warning("loadCodeAssist failed on %s: %s", endpoint, exc)
            continue
    if last_err:
        raise last_err
    return CodeAssistProjectInfo()


def _parse_load_response(resp: Dict[str, Any]) -> CodeAssistProjectInfo:
    current_tier = resp.get("currentTier") or {}
    tier_id = str(current_tier.get("id") or "") if isinstance(current_tier, dict) else ""
    project = str(resp.get("cloudaicompanionProject") or "")
    allowed = resp.get("allowedTiers") or []
    allowed_ids: List[str] = []
    if isinstance(allowed, list):
        for t in allowed:
            if isinstance(t, dict):
                tid = str(t.get("id") or "")
                if tid:
                    allowed_ids.append(tid)
    return CodeAssistProjectInfo(
        current_tier_id=tier_id,
        cloudaicompanion_project=project,
        allowed_tiers=allowed_ids,
        raw=resp,
    )


# =============================================================================
# onboard_user — provisions a new user on a tier (with LRO polling)
# =============================================================================

def onboard_user(
    access_token: str,
    *,
    tier_id: str,
    project_id: str = "",
    user_agent_model: str = "",
) -> Dict[str, Any]:
    """Call ``POST /v1internal:onboardUser`` to provision the user.

    For paid tiers, ``project_id`` is REQUIRED (raises ProjectIdRequiredError).
    For free tiers, ``project_id`` is optional — Google will assign one.

    Returns the final operation response. Polls ``/v1internal/<name>`` for up
    to ``_ONBOARDING_POLL_ATTEMPTS`` × ``_ONBOARDING_POLL_INTERVAL_SECONDS``
    (default: 12 × 5s = 1 min).
    """
    if tier_id != FREE_TIER_ID and tier_id != LEGACY_TIER_ID and not project_id:
        raise ProjectIdRequiredError(
            f"Tier {tier_id!r} requires a GCP project id. "
            "Set HERMES_GEMINI_PROJECT_ID or GOOGLE_CLOUD_PROJECT."
        )

    body: Dict[str, Any] = {
        "tierId": tier_id,
        "metadata": _client_metadata(),
    }
    if project_id:
        body["cloudaicompanionProject"] = project_id

    endpoint = CODE_ASSIST_ENDPOINT
    url = f"{endpoint}/v1internal:onboardUser"
    resp = _post_json(url, body, access_token, user_agent_model=user_agent_model)

    # Poll if LRO (long-running operation)
    if not resp.get("done"):
        op_name = resp.get("name", "")
        if not op_name:
            return resp
        for attempt in range(_ONBOARDING_POLL_ATTEMPTS):
            time.sleep(_ONBOARDING_POLL_INTERVAL_SECONDS)
            poll_url = f"{endpoint}/v1internal/{op_name}"
            try:
                poll_resp = _post_json(poll_url, {}, access_token, user_agent_model=user_agent_model)
            except CodeAssistError as exc:
                logger.warning("Onboarding poll attempt %d failed: %s", attempt + 1, exc)
                continue
            if poll_resp.get("done"):
                return poll_resp
        logger.warning("Onboarding did not complete within %d attempts", _ONBOARDING_POLL_ATTEMPTS)
    return resp


# =============================================================================
# retrieve_user_quota — for /gquota
# =============================================================================

@dataclass
class QuotaBucket:
    model_id: str
    token_type: str = ""
    remaining_fraction: float = 0.0
    reset_time_iso: str = ""
    raw: Dict[str, Any] = field(default_factory=dict)


def retrieve_user_quota(
    access_token: str,
    *,
    project_id: str = "",
    user_agent_model: str = "",
) -> List[QuotaBucket]:
    """Call ``POST /v1internal:retrieveUserQuota`` and parse ``buckets[]``."""
    body: Dict[str, Any] = {}
    if project_id:
        body["project"] = project_id
    url = f"{CODE_ASSIST_ENDPOINT}/v1internal:retrieveUserQuota"
    resp = _post_json(url, body, access_token, user_agent_model=user_agent_model)
    raw_buckets = resp.get("buckets") or []
    buckets: List[QuotaBucket] = []
    if not isinstance(raw_buckets, list):
        return buckets
    for b in raw_buckets:
        if not isinstance(b, dict):
            continue
        buckets.append(QuotaBucket(
            model_id=str(b.get("modelId") or ""),
            token_type=str(b.get("tokenType") or ""),
            remaining_fraction=float(b.get("remainingFraction") or 0.0),
            reset_time_iso=str(b.get("resetTime") or ""),
            raw=b,
        ))
    return buckets


# =============================================================================
# Project context resolution
# =============================================================================

@dataclass
class ProjectContext:
    """Resolved state for a given OAuth session."""
    project_id: str = ""           # effective project id sent on requests
    managed_project_id: str = ""   # Google-assigned project (free tier)
    tier_id: str = ""
    source: str = ""               # "env", "config", "discovered", "onboarded"


def resolve_project_context(
    access_token: str,
    *,
    configured_project_id: str = "",
    env_project_id: str = "",
    user_agent_model: str = "",
) -> ProjectContext:
    """Figure out what project id + tier to use for requests.

    Priority:
      1. If configured_project_id or env_project_id is set, use that directly
         and short-circuit (no discovery needed).
      2. Otherwise call loadCodeAssist to see what Google says.
      3. If no tier assigned yet, onboard the user (free tier default).
    """
    # Short-circuit: caller provided a project id
    if configured_project_id:
        return ProjectContext(
            project_id=configured_project_id,
            tier_id=STANDARD_TIER_ID,  # assume paid since they specified one
            source="config",
        )
    if env_project_id:
        return ProjectContext(
            project_id=env_project_id,
            tier_id=STANDARD_TIER_ID,
            source="env",
        )

    # Discover via loadCodeAssist
    info = load_code_assist(access_token, user_agent_model=user_agent_model)

    effective_project = info.cloudaicompanion_project
    tier = info.current_tier_id

    if not tier:
        # User hasn't been onboarded — provision them on free tier
        onboard_resp = onboard_user(
            access_token,
            tier_id=FREE_TIER_ID,
            project_id="",
            user_agent_model=user_agent_model,
        )
        # Re-parse from the onboard response
        response_body = onboard_resp.get("response") or {}
        if isinstance(response_body, dict):
            effective_project = (
                effective_project
                or str(response_body.get("cloudaicompanionProject") or "")
            )
        tier = FREE_TIER_ID
        source = "onboarded"
    else:
        source = "discovered"

    return ProjectContext(
        project_id=effective_project,
        managed_project_id=effective_project if tier == FREE_TIER_ID else "",
        tier_id=tier,
        source=source,
    )