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

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

from .db import get_user_by_username, set_user_auth_provider, upsert_user_activity
from .security import safe_decode_token, TokenError, verify_password

oauth2_scheme = OAuth2PasswordBearer(tokenUrl="/auth/login")


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:
    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 request.client and request.client.host:
        return request.client.host
    return "unknown"


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")

    user = normalize_user_auth_provider(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 {
        "username": user["username"],
        "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"),
    }


def get_current_user(token: str = Depends(oauth2_scheme), request: Request = None) -> Dict[str, Any]:
    return _load_current_user_from_token(token, request)


def get_current_user_event_stream(request: Request) -> Dict[str, Any]:
    """EventSource cannot send Authorization headers, so allow a short-lived stream token via query."""
    token = None
    stream_query_token = None
    auth_header = request.headers.get("authorization", "")
    if auth_header.lower().startswith("bearer "):
        token = auth_header.split(" ", 1)[1].strip()
    if not token:
        stream_query_token = request.query_params.get("stream_token")
    if not token and not stream_query_token:
        raise HTTPException(status_code=status.HTTP_401_UNAUTHORIZED, detail="Missing token")
    if token:
        # Allow standard bearer tokens in Authorization for non-browser EventSource clients.
        return _load_current_user_from_token(token, None)
    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