import io

import qrcode
from fastapi import APIRouter, Depends, Form, Request, status
from fastapi.responses import HTMLResponse, RedirectResponse, Response, StreamingResponse
from sqlalchemy import func, select
from sqlalchemy.ext.asyncio import AsyncSession
from sqlalchemy.orm import selectinload

from app.database import get_db
from app.models import AdminUser, Protocol, VpnClient, VpnServer
from app.services import vpn as vpn_service

router = APIRouter(prefix="/admin", tags=["admin"])


async def require_admin(request: Request, db: AsyncSession = Depends(get_db)) -> AdminUser | RedirectResponse:
    admin_id = request.session.get("admin_id")
    if not admin_id:
        return RedirectResponse("/admin/login", status_code=status.HTTP_303_SEE_OTHER)
    user = await db.get(AdminUser, admin_id)
    if not user or not user.is_active:
        request.session.clear()
        return RedirectResponse("/admin/login", status_code=status.HTTP_303_SEE_OTHER)
    return user


def _is_redirect(value: object) -> bool:
    return isinstance(value, RedirectResponse)


@router.get("", response_class=HTMLResponse)
async def dashboard(request: Request, db: AsyncSession = Depends(get_db), admin=Depends(require_admin)):
    if _is_redirect(admin):
        return admin

    servers = (await db.execute(select(VpnServer).order_by(VpnServer.id))).scalars().all()
    clients_total = await db.scalar(select(func.count()).select_from(VpnClient)) or 0
    clients_active = await db.scalar(
        select(func.count()).select_from(VpnClient).where(VpnClient.is_enabled.is_(True))
    ) or 0

    return request.app.state.templates.TemplateResponse(
        "admin/dashboard.html",
        {
            "request": request,
            "admin": admin,
            "servers": servers,
            "clients_total": clients_total,
            "clients_active": clients_active,
            "app_name": request.app.state.settings.app_name,
        },
    )


@router.get("/servers", response_class=HTMLResponse)
async def servers_page(request: Request, db: AsyncSession = Depends(get_db), admin=Depends(require_admin)):
    if _is_redirect(admin):
        return admin
    servers = (
        await db.execute(
            select(VpnServer).options(selectinload(VpnServer.clients)).order_by(VpnServer.id)
        )
    ).scalars().all()
    return request.app.state.templates.TemplateResponse(
        "admin/servers.html",
        {
            "request": request,
            "admin": admin,
            "servers": servers,
            "app_name": request.app.state.settings.app_name,
        },
    )


@router.post("/servers/{server_id}/sync")
async def sync_server(
    server_id: int,
    request: Request,
    db: AsyncSession = Depends(get_db),
    admin=Depends(require_admin),
):
    if _is_redirect(admin):
        return admin
    await vpn_service.sync_server_config(db, server_id)
    return RedirectResponse("/admin/servers", status_code=status.HTTP_303_SEE_OTHER)


@router.post("/servers/{server_id}")
async def update_server(
    server_id: int,
    public_host: str = Form(...),
    public_port: int = Form(...),
    dns: str = Form("1.1.1.1"),
    db: AsyncSession = Depends(get_db),
    admin=Depends(require_admin),
):
    if _is_redirect(admin):
        return admin
    server = await db.get(VpnServer, server_id)
    if server:
        server.public_host = public_host.strip()
        server.public_port = public_port
        server.dns = dns.strip() or "1.1.1.1"
        await db.commit()
        await vpn_service.sync_server_config(db, server_id)
    return RedirectResponse("/admin/servers", status_code=status.HTTP_303_SEE_OTHER)


@router.get("/clients", response_class=HTMLResponse)
async def clients_page(
    request: Request,
    protocol: str | None = None,
    db: AsyncSession = Depends(get_db),
    admin=Depends(require_admin),
):
    if _is_redirect(admin):
        return admin

    query = select(VpnClient).options(selectinload(VpnClient.server)).order_by(VpnClient.id.desc())
    if protocol:
        query = query.join(VpnServer).where(VpnServer.protocol == protocol)

    clients = (await db.execute(query)).scalars().all()
    servers = (await db.execute(select(VpnServer).order_by(VpnServer.id))).scalars().all()

    return request.app.state.templates.TemplateResponse(
        "admin/clients.html",
        {
            "request": request,
            "admin": admin,
            "clients": clients,
            "servers": servers,
            "filter_protocol": protocol,
            "protocols": Protocol,
            "app_name": request.app.state.settings.app_name,
            "flash": request.query_params.get("flash"),
        },
    )


@router.post("/clients")
async def create_client(
    request: Request,
    name: str = Form(...),
    server_id: int = Form(...),
    notes: str = Form(""),
    db: AsyncSession = Depends(get_db),
    admin=Depends(require_admin),
):
    if _is_redirect(admin):
        return admin
    try:
        await vpn_service.create_client(db, server_id=server_id, name=name, notes=notes or None)
    except Exception as exc:  # noqa: BLE001
        return RedirectResponse(
            f"/admin/clients?flash=error:{exc}",
            status_code=status.HTTP_303_SEE_OTHER,
        )
    return RedirectResponse("/admin/clients?flash=created", status_code=status.HTTP_303_SEE_OTHER)


@router.post("/clients/{client_id}/toggle")
async def toggle_client(
    client_id: int,
    db: AsyncSession = Depends(get_db),
    admin=Depends(require_admin),
):
    if _is_redirect(admin):
        return admin
    client = await db.get(VpnClient, client_id)
    if client:
        await vpn_service.set_client_enabled(db, client_id, not client.is_enabled)
    return RedirectResponse("/admin/clients", status_code=status.HTTP_303_SEE_OTHER)


@router.post("/clients/{client_id}/delete")
async def remove_client(
    client_id: int,
    db: AsyncSession = Depends(get_db),
    admin=Depends(require_admin),
):
    if _is_redirect(admin):
        return admin
    await vpn_service.delete_client(db, client_id)
    return RedirectResponse("/admin/clients?flash=deleted", status_code=status.HTTP_303_SEE_OTHER)


@router.get("/clients/{client_id}", response_class=HTMLResponse)
async def client_detail(
    client_id: int,
    request: Request,
    db: AsyncSession = Depends(get_db),
    admin=Depends(require_admin),
):
    if _is_redirect(admin):
        return admin
    result = await db.execute(
        select(VpnClient).options(selectinload(VpnClient.server)).where(VpnClient.id == client_id)
    )
    client = result.scalar_one_or_none()
    if not client:
        return RedirectResponse("/admin/clients", status_code=status.HTTP_303_SEE_OTHER)
    config = await vpn_service.get_client_config(db, client_id)
    return request.app.state.templates.TemplateResponse(
        "admin/client_detail.html",
        {
            "request": request,
            "admin": admin,
            "client": client,
            "config": config,
            "app_name": request.app.state.settings.app_name,
        },
    )


@router.get("/clients/{client_id}/config")
async def download_config(
    client_id: int,
    db: AsyncSession = Depends(get_db),
    admin=Depends(require_admin),
):
    if _is_redirect(admin):
        return admin
    client = await db.get(VpnClient, client_id)
    if not client:
        return RedirectResponse("/admin/clients", status_code=status.HTTP_303_SEE_OTHER)
    config = await vpn_service.get_client_config(db, client_id)
    filename = f"{client.name}.conf"
    return Response(
        content=config,
        media_type="text/plain",
        headers={"Content-Disposition": f'attachment; filename="{filename}"'},
    )


@router.get("/clients/{client_id}/qr")
async def client_qr(
    client_id: int,
    db: AsyncSession = Depends(get_db),
    admin=Depends(require_admin),
):
    if _is_redirect(admin):
        return admin
    config = await vpn_service.get_client_config(db, client_id)
    img = qrcode.make(config)
    buf = io.BytesIO()
    img.save(buf, format="PNG")
    buf.seek(0)
    return StreamingResponse(buf, media_type="image/png")