from datetime import datetime, timezone
from typing import Any, Dict, Optional

from fastapi import Depends, HTTPException, Request, Response, status
from fastapi.security import OAuth2PasswordBearer

from .config import settings
from .installation_origin import managed_runtime
from .db import get_user_by_username, set_user_auth_provider, upsert_user_activity
from .network_security import request_trusts_forwarded_headers
from .security import TokenError, safe_decode_token, verify_password

oauth2_scheme = OAuth2PasswordBearer(tokenUrl="/auth/login", auto_error=False)


def _is_expired(expires_at: str | None) -> bool:
    if not isinstance(expires_at, str) or not expires_at.strip():
        return False
    candidate = expires_at.strip()
    if candidate.endswith("Z"):
        candidate = candidate[:-1] + "+00:00"
    try:
        parsed = datetime.fromisoformat(candidate)
    except ValueError:
        return False
    if parsed.tzinfo is None:
        parsed = parsed.replace(tzinfo=timezone.utc)
    return parsed <= datetime.now(timezone.utc)


def _extract_client_ip(request: Request) -> str:
    direct_host = request.client.host if request.client else None
    if request_trusts_forwarded_headers(direct_host):
        forwarded = request.headers.get("x-forwarded-for")
        if forwarded:
            parts = [part.strip() for part in forwarded.split(",") if part.strip()]
            if parts:
                return parts[0]
        real_ip = request.headers.get("x-real-ip")
        if real_ip:
            return real_ip.strip()
    if direct_host:
        return direct_host
    return "unknown"


def _cookie_settings() -> dict[str, Any]:
    samesite = str(settings.auth_cookie_samesite or "lax").strip().lower()
    if samesite not in {"lax", "strict", "none"}:
        samesite = "lax"
    secure = bool(settings.auth_cookie_secure)
    if managed_runtime():
        from .services.public_urls import magent_public_url
        # Follow the persisted operator-selected URL immediately, including
        # first login after setup; a restart is not required to protect cookies.
        secure = magent_public_url().startswith("https://")
    return {
        "secure": secure,
        "httponly": True,
        "samesite": samesite,
        "domain": settings.auth_cookie_domain or None,
        "path": "/",
    }


def _state_cookie_settings() -> dict[str, Any]:
    cookie = _cookie_settings()
    cookie["httponly"] = False
    return cookie


def set_auth_cookies(response: Response, token: str) -> None:
    max_age = max(60, int(settings.jwt_exp_minutes or 720) * 60)
    response.set_cookie(
        settings.auth_cookie_name,
        token,
        max_age=max_age,
        **_cookie_settings(),
    )
    response.set_cookie(
        settings.auth_state_cookie_name,
        "1",
        max_age=max_age,
        **_state_cookie_settings(),
    )


def clear_auth_cookies(response: Response) -> None:
    response.delete_cookie(settings.auth_cookie_name, path="/", domain=settings.auth_cookie_domain or None)
    response.delete_cookie(
        settings.auth_state_cookie_name,
        path="/",
        domain=settings.auth_cookie_domain or None,
    )


def _extract_access_token(request: Request, oauth_token: Optional[str]) -> Optional[str]:
    auth_header = request.headers.get("authorization", "")
    if auth_header.lower().startswith("bearer "):
        return auth_header.split(" ", 1)[1].strip()
    if oauth_token:
        return oauth_token
    cookie_token = request.cookies.get(settings.auth_cookie_name)
    if isinstance(cookie_token, str) and cookie_token.strip():
        return cookie_token.strip()
    return None


def resolve_user_auth_provider(user: Optional[Dict[str, Any]]) -> str:
    if not isinstance(user, dict):
        return "local"
    provider = str(user.get("auth_provider") or "local").strip().lower() or "local"
    if provider != "local":
        return provider
    password_hash = user.get("password_hash")
    if isinstance(password_hash, str) and password_hash:
        if verify_password("jellyfin-user", password_hash):
            return "jellyfin"
        if verify_password("jellyseerr-user", password_hash):
            return "jellyseerr"
    return provider


def normalize_user_auth_provider(user: Optional[Dict[str, Any]]) -> Dict[str, Any]:
    if not isinstance(user, dict):
        return {}
    resolved_provider = resolve_user_auth_provider(user)
    stored_provider = str(user.get("auth_provider") or "local").strip().lower() or "local"
    if resolved_provider != stored_provider:
        username = str(user.get("username") or "").strip()
        if username:
            set_user_auth_provider(username, resolved_provider)
            refreshed_user = get_user_by_username(username)
            if refreshed_user:
                user = refreshed_user
    normalized = dict(user)
    normalized["auth_provider"] = resolved_provider
    normalized["password_change_supported"] = resolved_provider in {"local", "jellyfin"}
    normalized["password_provider"] = (
        resolved_provider if resolved_provider in {"local", "jellyfin"} else None
    )
    return normalized


def _load_current_user_from_token(
    token: str,
    request: Optional[Request] = None,
    allowed_token_types: Optional[set[str]] = None,
) -> Dict[str, Any]:
    try:
        payload = safe_decode_token(token)
    except TokenError as exc:
        raise HTTPException(status_code=status.HTTP_401_UNAUTHORIZED, detail="Invalid token") from exc
    token_type = str(payload.get("typ") or "access").strip().lower()
    if allowed_token_types and token_type not in allowed_token_types:
        raise HTTPException(status_code=status.HTTP_401_UNAUTHORIZED, detail="Invalid token type")

    username = payload.get("sub")
    if not username:
        raise HTTPException(status_code=status.HTTP_401_UNAUTHORIZED, detail="Invalid token subject")

    user = get_user_by_username(username)
    if not user:
        raise HTTPException(status_code=status.HTTP_401_UNAUTHORIZED, detail="User not found")
    if user.get("is_blocked"):
        raise HTTPException(status_code=status.HTTP_403_FORBIDDEN, detail="User is blocked")
    if _is_expired(user.get("expires_at")):
        raise HTTPException(status_code=status.HTTP_403_FORBIDDEN, detail="User access has expired")
    token_version = payload.get("ver")
    if not isinstance(token_version, int) or token_version != int(user.get("auth_version") or 1):
        raise HTTPException(status_code=status.HTTP_401_UNAUTHORIZED, detail="Session has been revoked")

    user = normalize_user_auth_provider(user)
    from .feature_access import permissions
    features = permissions(user)

    if request is not None:
        ip = _extract_client_ip(request)
        user_agent = request.headers.get("user-agent", "unknown")
        upsert_user_activity(user["username"], ip, user_agent)

    return {
        "features": features,
        "username": user["username"],
        "email": user.get("email"),
        "role": user["role"],
        "auth_provider": user.get("auth_provider", "local"),
        "jellyseerr_user_id": user.get("jellyseerr_user_id"),
        "auto_search_enabled": bool(user.get("auto_search_enabled", True)),
        "invite_management_enabled": bool(user.get("invite_management_enabled", False)),
        "profile_id": user.get("profile_id"),
        "expires_at": user.get("expires_at"),
        "is_expired": bool(user.get("is_expired", False)),
        "password_change_supported": bool(user.get("password_change_supported", False)),
        "password_provider": user.get("password_provider"),
        "auth_version": int(user.get("auth_version") or 1),
    }


def get_current_user(
    request: Request,
    token: Optional[str] = Depends(oauth2_scheme),
) -> Dict[str, Any]:
    resolved_token = _extract_access_token(request, token)
    if not resolved_token:
        raise HTTPException(status_code=status.HTTP_401_UNAUTHORIZED, detail="Missing token")
    return _load_current_user_from_token(resolved_token, request)


def get_current_user_event_stream(
    request: Request,
    token: Optional[str] = Depends(oauth2_scheme),
) -> Dict[str, Any]:
    """EventSource cannot send Authorization headers, so allow a short-lived stream token via query."""
    resolved_token = _extract_access_token(request, token)
    stream_query_token = request.query_params.get("stream_token")
    if resolved_token:
        # Allow standard bearer tokens for non-browser EventSource clients.
        return _load_current_user_from_token(resolved_token, None)
    if not stream_query_token:
        raise HTTPException(status_code=status.HTTP_401_UNAUTHORIZED, detail="Missing token")
    return _load_current_user_from_token(
        str(stream_query_token),
        None,
        allowed_token_types={"sse"},
    )


def require_admin(user: Dict[str, Any] = Depends(get_current_user)) -> Dict[str, Any]:
    if user.get("role") != "admin":
        raise HTTPException(status_code=status.HTTP_403_FORBIDDEN, detail="Admin access required")
    return user


def require_admin_event_stream(
    user: Dict[str, Any] = Depends(get_current_user_event_stream),
) -> Dict[str, Any]:
    if user.get("role") != "admin":
        raise HTTPException(status_code=status.HTTP_403_FORBIDDEN, detail="Admin access required")
    return user