import logging
from pathlib import Path

from fastapi import APIRouter, Depends, Request, status
from fastapi.responses import HTMLResponse, RedirectResponse, Response
from fastapi.templating import Jinja2Templates

from app.config import Settings, get_settings
from app.dependencies import get_app_settings, get_auth_db, get_current_auth_session
from app.services.auth import AuthenticatedSession
from app.services.config_page import (
    ConfigSaveError,
    build_config_sections,
    is_ticktick_oauth_ready,
    save_config_updates,
)
from sqlalchemy.orm import Session

templates = Jinja2Templates(directory=str(Path(__file__).resolve().parents[2] / "templates"))
router = APIRouter(tags=["pages"])
logger = logging.getLogger(__name__)


def _ticktick_oauth_notice(status_value: str | None) -> tuple[str | None, str | None]:
    if status_value == "success":
        return "TickTick authorization completed successfully.", None
    if status_value == "invalid-state":
        return None, "TickTick authorization failed due to invalid OAuth state. Start the flow again."
    if status_value == "invalid-callback":
        return None, "TickTick authorization callback was missing required parameters."
    if status_value == "failed":
        return None, "TickTick authorization failed. Check server logs for the provider response and verify TickTick app credentials and redirect URI."
    return None, None


@router.get("/", response_class=HTMLResponse)
def home(
    request: Request,
    current_auth: AuthenticatedSession | None = Depends(get_current_auth_session),
) -> RedirectResponse:
    if current_auth is None:
        return RedirectResponse(url="/login", status_code=status.HTTP_303_SEE_OTHER)
    return RedirectResponse(url="/config", status_code=status.HTTP_303_SEE_OTHER)


@router.get("/admin", response_class=HTMLResponse)
def admin_redirect(
    request: Request,
    current_auth: AuthenticatedSession | None = Depends(get_current_auth_session),
) -> RedirectResponse:
    if current_auth is None:
        return RedirectResponse(url="/login", status_code=status.HTTP_303_SEE_OTHER)
    return RedirectResponse(url="/config", status_code=status.HTTP_303_SEE_OTHER)


@router.get("/config", response_class=HTMLResponse)
def config_page(
    request: Request,
    auth_db_session: Session = Depends(get_auth_db),
    settings: Settings = Depends(get_app_settings),
    current_auth: AuthenticatedSession | None = Depends(get_current_auth_session),
) -> Response:
    if current_auth is None:
        return RedirectResponse(url="/login", status_code=status.HTTP_303_SEE_OTHER)

    ticktick_oauth_notice, ticktick_oauth_error = _ticktick_oauth_notice(
        request.query_params.get("ticktick_oauth")
    )

    context = {
        "app_name": settings.app_name,
        "app_env": settings.app_env,
        "current_username": current_auth.user.username,
        "csrf_token": current_auth.session.csrf_token,
        "force_password_change": current_auth.user.force_password_change,
        "password_change_error": None,
        "config_error": None,
        "config_saved": request.query_params.get("saved") == "1",
        "config_sections": build_config_sections(auth_db_session, settings),
        "ticktick_oauth_ready": is_ticktick_oauth_ready(settings),
        "ticktick_oauth_notice": ticktick_oauth_notice,
        "ticktick_oauth_error": ticktick_oauth_error,
    }
    return templates.TemplateResponse(request, "config.html", context)


@router.post("/config", response_class=HTMLResponse)
async def config_submit(
    request: Request,
    auth_db_session: Session = Depends(get_auth_db),
    settings: Settings = Depends(get_app_settings),
    current_auth: AuthenticatedSession | None = Depends(get_current_auth_session),
) -> Response:
    if current_auth is None:
        return RedirectResponse(url="/login", status_code=status.HTTP_303_SEE_OTHER)

    form = await request.form()
    csrf_token = form.get("csrf_token")
    if csrf_token != current_auth.session.csrf_token:
        logger.warning("Rejected config update due to CSRF validation failure")
        context = {
            "app_name": settings.app_name,
            "app_env": settings.app_env,
            "current_username": current_auth.user.username,
            "csrf_token": current_auth.session.csrf_token,
            "force_password_change": current_auth.user.force_password_change,
            "password_change_error": None,
            "config_error": "invalid config update request",
            "config_saved": False,
            "config_sections": build_config_sections(auth_db_session, settings),
            "ticktick_oauth_ready": is_ticktick_oauth_ready(settings),
            "ticktick_oauth_notice": None,
            "ticktick_oauth_error": None,
        }
        return templates.TemplateResponse(
            request,
            "config.html",
            context,
            status_code=status.HTTP_400_BAD_REQUEST,
        )

    try:
        save_config_updates(auth_db_session, dict(form), settings)
    except ConfigSaveError:
        logger.warning("Rejected config update due to invalid submitted values")
        refreshed_settings = get_settings()
        context = {
            "app_name": refreshed_settings.app_name,
            "app_env": refreshed_settings.app_env,
            "current_username": current_auth.user.username,
            "csrf_token": current_auth.session.csrf_token,
            "force_password_change": current_auth.user.force_password_change,
            "password_change_error": None,
            "config_error": "invalid config submission",
            "config_saved": False,
            "config_sections": build_config_sections(auth_db_session, refreshed_settings),
            "ticktick_oauth_ready": is_ticktick_oauth_ready(refreshed_settings),
            "ticktick_oauth_notice": None,
            "ticktick_oauth_error": None,
        }
        return templates.TemplateResponse(
            request,
            "config.html",
            context,
            status_code=status.HTTP_400_BAD_REQUEST,
        )

    return RedirectResponse(url="/config?saved=1", status_code=status.HTTP_303_SEE_OTHER)