"""GitHub OAuth and LangSmith authentication utilities."""

from __future__ import annotations

import logging
import os
from datetime import UTC, datetime, timedelta
from typing import Any, Literal

import httpx
import jwt
from langgraph.config import get_config
from langgraph.graph.state import RunnableConfig
from langgraph_sdk import get_client

from .github_app import get_github_app_installation_token_with_expiry
from .github_token import cache_github_token_for_thread, get_github_token_from_thread
from .http import DEFAULT_HTTP_TIMEOUT
from .linear import comment_on_linear_issue
from .slack import post_slack_thread_reply

logger = logging.getLogger(__name__)

client = get_client()


class GitHubUserAuthRequired(RuntimeError):
    """Raised when a mapped user has no valid GitHub OAuth token.

    Signals that the run cannot proceed on the user's behalf and that the user
    must (re-)authenticate. The Slack webhook blocks before creating a run, so
    this is a defense-in-depth signal at execution time.
    """

    def __init__(self, source: str, github_login: str | None) -> None:
        self.source = source
        self.github_login = github_login
        super().__init__(f"GitHub authentication required for {source} user '{github_login}'")


LANGSMITH_API_KEY = os.environ.get("LANGSMITH_API_KEY_PROD", "")
LANGSMITH_API_URL = os.environ.get("LANGSMITH_ENDPOINT", "https://api.smith.langchain.com")
LANGSMITH_HOST_API_URL = os.environ.get("LANGSMITH_HOST_API_URL", "https://api.host.langchain.com")
GITHUB_OAUTH_PROVIDER_ID = os.environ.get("GITHUB_OAUTH_PROVIDER_ID", "")
X_SERVICE_AUTH_JWT_SECRET = os.environ.get("X_SERVICE_AUTH_JWT_SECRET", "")
USER_ID_API_KEY_MAP = os.environ.get("USER_ID_API_KEY_MAP", "")

logger.debug(
    "Auth env snapshot: LANGSMITH_API_KEY_PROD=%s LANGSMITH_ENDPOINT=%s "
    "LANGSMITH_HOST_API_URL=%s GITHUB_OAUTH_PROVIDER_ID=%s",
    "set" if LANGSMITH_API_KEY else "missing",
    "set" if LANGSMITH_API_URL else "missing",
    "set" if LANGSMITH_HOST_API_URL else "missing",
    "set" if GITHUB_OAUTH_PROVIDER_ID else "missing",
)


def is_bot_token_only_mode() -> bool:
    """Check if we're in bot-token-only mode.

    This is the case when LANGSMITH_API_KEY_PROD is set (deployed) but neither
    X_SERVICE_AUTH_JWT_SECRET nor USER_ID_API_KEY_MAP is configured, meaning we
    can't resolve per-user GitHub OAuth tokens. In this mode the GitHub App
    installation token is used for all git operations instead.
    """
    return bool(LANGSMITH_API_KEY and not X_SERVICE_AUTH_JWT_SECRET and not USER_ID_API_KEY_MAP)


def _retry_instruction(source: str) -> str:
    if source == "slack":
        return "Once authenticated, mention me again in this Slack thread to retry."
    return "Once authenticated, reply to this issue mentioning @openswe to retry."


def _source_account_label(source: str) -> str:
    if source == "slack":
        return "Slack"
    return "Linear"


def _auth_link_text(source: str, auth_url: str) -> str:
    if source == "slack":
        return auth_url
    return f"[Authenticate with GitHub]({auth_url})"


def _work_item_label(source: str) -> str:
    if source == "slack":
        return "thread"
    return "issue"


def get_secret_key_for_user(
    user_id: str, tenant_id: str, expiration_seconds: int = 300
) -> tuple[str, Literal["service", "api_key"]]:
    """Create a short-lived service JWT for authenticating as a specific user."""
    if not X_SERVICE_AUTH_JWT_SECRET:
        msg = "X_SERVICE_AUTH_JWT_SECRET is not configured. Cannot generate service keys."
        raise ValueError(msg)

    payload = {
        "sub": "unspecified",
        "exp": datetime.now(UTC) + timedelta(seconds=expiration_seconds),
        "user_id": user_id,
        "tenant_id": tenant_id,
    }
    return jwt.encode(payload, X_SERVICE_AUTH_JWT_SECRET, algorithm="HS256"), "service"


async def get_ls_user_id_from_email(email: str) -> dict[str, str | None]:
    """Get the LangSmith user ID and tenant ID from a user's email."""
    if not LANGSMITH_API_KEY:
        logger.warning("LangSmith API key not configured; cannot resolve LS user for %s", email)
        return {"ls_user_id": None, "tenant_id": None}

    url = f"{LANGSMITH_API_URL}/api/v1/workspaces/current/members/active"

    async with httpx.AsyncClient(timeout=DEFAULT_HTTP_TIMEOUT) as client:
        try:
            response = await client.get(
                url,
                headers={"X-API-Key": LANGSMITH_API_KEY},
                params={"emails": [email]},
            )
            response.raise_for_status()
            members = response.json()

            if members and len(members) > 0:
                member = members[0]
                return {
                    "ls_user_id": member.get("ls_user_id"),
                    "tenant_id": member.get("tenant_id"),
                }
        except Exception as e:
            logger.exception("Error getting LangSmith user info for email: %s", e)
        return {"ls_user_id": None, "tenant_id": None}


def _extract_expires_at(response_data: dict[str, Any]) -> str | None:
    """Pull an expiry from a LangSmith auth response in any of its known shapes."""
    expires_at = response_data.get("expires_at") or response_data.get("expiresAt")
    if isinstance(expires_at, str) and expires_at:
        return expires_at
    if isinstance(expires_at, int | float):
        return datetime.fromtimestamp(float(expires_at), tz=UTC).isoformat()
    expires_in = response_data.get("expires_in") or response_data.get("expiresIn")
    if isinstance(expires_in, int | float) and expires_in > 0:
        return (datetime.now(UTC) + timedelta(seconds=int(expires_in))).isoformat()
    return None


async def get_github_token_for_user(ls_user_id: str, tenant_id: str) -> dict[str, Any]:
    """Get GitHub OAuth token for a user via LangSmith agent auth."""
    if not GITHUB_OAUTH_PROVIDER_ID:
        logger.error("GitHub auth failed: GITHUB_OAUTH_PROVIDER_ID is not configured")
        return {"error": "GITHUB_OAUTH_PROVIDER_ID not configured"}

    try:
        headers = {
            "X-Tenant-Id": tenant_id,
            "X-User-Id": ls_user_id,
        }
        secret_key, secret_type = get_secret_key_for_user(ls_user_id, tenant_id)
        if secret_type == "api_key":
            headers["X-API-Key"] = secret_key
        else:
            headers["X-Service-Key"] = secret_key

        payload = {
            "provider": GITHUB_OAUTH_PROVIDER_ID,
            "scopes": ["repo"],
            "user_id": ls_user_id,
            "ls_user_id": ls_user_id,
        }

        async with httpx.AsyncClient(timeout=DEFAULT_HTTP_TIMEOUT) as client:
            response = await client.post(
                f"{LANGSMITH_HOST_API_URL}/v2/auth/authenticate",
                json=payload,
                headers=headers,
            )
            response.raise_for_status()
            response_data = response.json()

            token = response_data.get("token")
            auth_url = response_data.get("url")

            if token:
                result: dict[str, Any] = {"token": token}
                expires_at = _extract_expires_at(response_data)
                if expires_at:
                    result["expires_at"] = expires_at
                return result
            if auth_url:
                return {"auth_url": auth_url}
            # Log the full upstream body server-side only; the returned error becomes a
            # user-facing Slack/Linear comment, so never echo the raw response body.
            logger.error(
                "GitHub auth returned an unexpected result (no token/url): %s", response_data
            )
            return {"error": "GitHub auth returned an unexpected result"}

    except httpx.HTTPStatusError as e:
        # Log the full upstream body server-side only; the returned error becomes a
        # user-facing Slack/Linear comment, so never echo the raw response text.
        logger.error("GitHub auth API HTTP error: %s - %s", e.response.status_code, e.response.text)
        return {"error": f"GitHub auth failed (status {e.response.status_code})"}
    except Exception as e:  # noqa: BLE001
        logger.error("GitHub auth API call failed: %s: %s", type(e).__name__, str(e))
        return {"error": str(e)}


async def resolve_github_token_from_email(email: str) -> dict[str, Any]:
    """Resolve a GitHub token for a user identified by email.

    Chains get_ls_user_id_from_email -> get_github_token_for_user.

    Returns:
        Dict with one of:
        - {"token": str} on success
        - {"auth_url": str} if user needs to authenticate via OAuth
        - {"error": str} on failure; error="no_ls_user" if email not in LangSmith
    """
    user_info = await get_ls_user_id_from_email(email)
    ls_user_id = user_info.get("ls_user_id")
    tenant_id = user_info.get("tenant_id")

    if not ls_user_id or not tenant_id:
        logger.warning(
            "No LangSmith user found for email %s (ls_user_id=%s, tenant_id=%s)",
            email,
            ls_user_id,
            tenant_id,
        )
        return {"error": "no_ls_user", "email": email}

    auth_result = await get_github_token_for_user(ls_user_id, tenant_id)
    return auth_result


async def leave_failure_comment(
    source: str,
    message: str,
) -> None:
    """Leave an auth failure comment for the appropriate source."""
    config = get_config()
    configurable = config.get("configurable", {})

    if source == "linear":
        linear_issue = configurable.get("linear_issue", {})
        issue_id = linear_issue.get("id") if isinstance(linear_issue, dict) else None
        if issue_id:
            logger.info(
                "Posting auth failure comment to Linear issue %s (source=%s)",
                issue_id,
                source,
            )
            await comment_on_linear_issue(issue_id, message)
        return
    if source == "slack":
        slack_thread = configurable.get("slack_thread", {})
        channel_id = slack_thread.get("channel_id") if isinstance(slack_thread, dict) else None
        thread_ts = slack_thread.get("thread_ts") if isinstance(slack_thread, dict) else None
        if channel_id and thread_ts:
            # The auth-failure ``message`` can carry a per-user GitHub auth URL,
            # which must not be posted in a shared thread (anyone could complete
            # it and bind the wrong account). Post a generic, token-free notice and
            # let the user finish sign-in from their own authenticated dashboard.
            from ..dashboard.oauth import build_settings_url

            settings_url = build_settings_url()
            link = (
                f"<{settings_url}|your Open SWE settings>"
                if settings_url
                else "your Open SWE settings"
            )
            logger.info(
                "Posting generic auth-failure notice to Slack channel %s thread %s",
                channel_id,
                thread_ts,
            )
            await post_slack_thread_reply(
                channel_id,
                thread_ts,
                "⚠️ I couldn't resolve your GitHub account for this run. Sign in with GitHub and "
                f"connect your Slack account in {link}, then tag me again.",
            )
        return
    if source in ("github", "github_push"):
        logger.warning(
            "Auth failure for GitHub-triggered run (no token to post comment): %s", message
        )
        return
    raise ValueError(f"Unknown source: {source}")


def _current_repo() -> Any:
    """Best-effort read of the run's repo (owner/name) for cache binding."""
    try:
        configurable = get_config().get("configurable", {})
    except Exception:
        return None
    return configurable.get("repo") if isinstance(configurable, dict) else None


def _cache_resolved_github_token(
    thread_id: str, token: str, expires_at: str | None = None
) -> tuple[str, str | None]:
    cache_github_token_for_thread(thread_id, token, expires_at=expires_at, repo=_current_repo())
    return token, expires_at


async def resolve_token_from_email(
    email: str | None,
    source: str,
) -> tuple[str, str | None]:
    """Resolve and cache a GitHub token based on user email."""
    config = get_config()
    configurable = config.get("configurable", {})
    thread_id = configurable.get("thread_id")
    if not thread_id:
        raise ValueError("GitHub auth failed: missing thread_id")
    if not email:
        message = (
            "❌ **GitHub Auth Error**\n\n"
            "Failed to authenticate with GitHub: missing_user_email\n\n"
            "Please try again or contact support."
        )
        await leave_failure_comment(source, message)
        raise ValueError("GitHub auth failed: missing user_email")

    user_info = await get_ls_user_id_from_email(email)
    ls_user_id = user_info.get("ls_user_id")
    tenant_id = user_info.get("tenant_id")
    if not ls_user_id or not tenant_id:
        account_label = _source_account_label(source)
        message = (
            "🔐 **GitHub Authentication Required**\n\n"
            f"Could not find a LangSmith account for **{email}**.\n\n"
            "Please ensure this email is invited to the main LangSmith organization. "
            f"If your {account_label} account uses a different email than your LangSmith account, "
            "you may need to update one of them to match.\n\n"
            "Once your email is added to LangSmith, "
            f"{_retry_instruction(source)}"
        )
        await leave_failure_comment(source, message)
        raise ValueError(f"No ls_user_id found from email {email}")

    auth_result = await get_github_token_for_user(ls_user_id, tenant_id)
    auth_url = auth_result.get("auth_url")
    if auth_url:
        work_item_label = _work_item_label(source)
        auth_link_text = _auth_link_text(source, auth_url)
        message = (
            "🔐 **GitHub Authentication Required**\n\n"
            f"To allow the Open SWE agent to work on this {work_item_label}, "
            "please authenticate with GitHub by clicking the link below:\n\n"
            f"{auth_link_text}\n\n"
            f"{_retry_instruction(source)}"
        )
        await leave_failure_comment(source, message)
        raise ValueError("User not authenticated.")

    token = auth_result.get("token")
    if not token:
        error = auth_result.get("error", "unknown")
        message = (
            "❌ **GitHub Auth Error**\n\n"
            f"Failed to authenticate with GitHub: {error}\n\n"
            "Please try again or contact support."
        )
        await leave_failure_comment(source, message)
        raise ValueError(f"No token found: {error}")

    expires_at = auth_result.get("expires_at") if isinstance(auth_result, dict) else None
    return _cache_resolved_github_token(
        thread_id, token, expires_at=expires_at if isinstance(expires_at, str) else None
    )


async def _resolve_dashboard_user_token(
    thread_id: str, github_login: str
) -> tuple[str, str | None] | None:
    """Resolve a per-user GitHub token from the dashboard OAuth store."""
    login = github_login.strip()
    if not login:
        raise ValueError("missing github_login")

    from ..dashboard.profiles import OAUTH_TOKENS_NAMESPACE, get_valid_access_token
    from ..dashboard.profiles import _get_value as get_oauth_record

    token = await get_valid_access_token(login)
    if not token:
        return None
    record = await get_oauth_record(OAUTH_TOKENS_NAMESPACE, login)
    expires_at = record.get("token_expires_at") if isinstance(record, dict) else None
    return _cache_resolved_github_token(
        thread_id, token, expires_at=expires_at if isinstance(expires_at, str) else None
    )


async def _resolve_bot_installation_token(thread_id: str) -> tuple[str, str | None]:
    """Get a GitHub App installation token and cache it for the thread.

    AUTHZ-003 (accepted): in bot-token-only mode every run shares one GitHub App
    installation token, so its blast radius is the whole installation rather than
    a single user. This is a documented, accepted prod posture for this
    single-tenant deployment, not a defect.
    """
    bot_token, expires_at = await get_github_app_installation_token_with_expiry()
    if not bot_token:
        raise RuntimeError(
            "Bot-token-only mode is active (LANGSMITH_API_KEY_PROD set without "
            "X_SERVICE_AUTH_JWT_SECRET) but the GitHub App is not configured. "
            "Set GITHUB_APP_ID, GITHUB_APP_PRIVATE_KEY, and GITHUB_APP_INSTALLATION_ID."
        )
    logger.info(
        "Using GitHub App installation token for thread %s (bot-token-only mode)", thread_id
    )
    return _cache_resolved_github_token(thread_id, bot_token, expires_at=expires_at)


async def resolve_github_token(config: RunnableConfig, thread_id: str) -> tuple[str, str | None]:
    """Resolve a GitHub token from the run config based on the source.

    Routes to the correct auth method depending on the source. Sources that
    carry a mapped GitHub login (Slack, Linear, dashboard, schedule) resolve a
    per-user OAuth token from the dashboard store; GitHub runs are login-based;
    otherwise resolution falls back to email-based auth.

    In bot-token-only mode (LANGSMITH_API_KEY_PROD set without
    X_SERVICE_AUTH_JWT_SECRET), the GitHub App installation token is used
    for all operations instead of per-user OAuth tokens.

    Raises:
        RuntimeError: If source is missing or token resolution fails.
    """
    configurable = config["configurable"]
    source = configurable.get("source")
    if not source:
        logger.error("Missing source for thread %s; cannot route auth failure responses", thread_id)
        raise RuntimeError(f"GitHub auth failed for thread {thread_id}: missing source")

    github_login = configurable.get("github_login")

    # DEFAULT: Slack/Linear/dashboard/schedule runs use the GitHub App installation
    # token, so all git/gh operations + the PR come in as the app
    # `seahaven-openswe[bot]` (deterministic; matches GitHub-issue runs; eliminates
    # the self-review 422). OPT-IN: a profile with `author_prs_as_user: true`
    # restores the per-user OAuth token so the run is attributed to the triggering
    # user.
    if (
        source in ("slack", "linear", "dashboard", "schedule")
        and isinstance(github_login, str)
        and github_login.strip()
    ):
        from ..dashboard.agent_overrides import load_profile, profile_author_prs_as_user

        if profile_author_prs_as_user(await load_profile(github_login.strip())):
            try:
                user_token = await _resolve_dashboard_user_token(thread_id, github_login)
            except ValueError as exc:
                logger.error("GitHub auth failed for thread %s: %s", thread_id, str(exc))
                raise RuntimeError(str(exc)) from exc
            if user_token is not None:
                return user_token
            # Opt-in set but no valid user token: in bot-token-only mode fall back
            # to the bot; otherwise block and require auth.
            if not is_bot_token_only_mode():
                raise GitHubUserAuthRequired(source, github_login)
        return await _resolve_bot_installation_token(thread_id)

    if is_bot_token_only_mode():
        return await _resolve_bot_installation_token(thread_id)

    try:
        if source == "github":
            cached_token, cached_expires_at = await get_github_token_from_thread(
                thread_id, expected_repo=configurable.get("repo")
            )
            if cached_token:
                return cached_token, cached_expires_at
            from ..dashboard.user_mappings import email_for_login

            email = await email_for_login(github_login)
            if not email:
                raise ValueError(f"No email mapping found for GitHub user '{github_login}'")
            return await resolve_token_from_email(email, source)
        return await resolve_token_from_email(configurable.get("user_email"), source)
    except ValueError as exc:
        logger.error("GitHub auth failed for thread %s: %s", thread_id, str(exc))
        raise RuntimeError(str(exc)) from exc