"""
Help page router.

Routes:
  GET /help  → full-page help viewer (requires auth)
"""

import logging
from pathlib import Path

import jwt
from fastapi import APIRouter, Request
from fastapi.responses import HTMLResponse, RedirectResponse

from auth_utils import COOKIE_NAME, decode_token, _read_auth
from persona import list_user_personas

logger = logging.getLogger(__name__)
router = APIRouter()

_STATIC = Path(__file__).parent.parent / "static"


_LAST_PERSONA_COOKIE = "cx_last_persona"


def _get_session_user(request: Request) -> str | None:
    token = request.cookies.get(COOKIE_NAME)
    if not token:
        return None
    try:
        return decode_token(token)
    except jwt.InvalidTokenError:
        return None


def _preferred_persona(request: Request, username: str) -> str:
    names = list_user_personas(username)
    if not names:
        return ""
    cookie_val = request.cookies.get(_LAST_PERSONA_COOKIE, "")
    if cookie_val in names:
        return cookie_val
    return names[0]


@router.get("/help", include_in_schema=False)
async def help_page(request: Request, persona: str = ""):
    username = _get_session_user(request)
    if not username:
        return RedirectResponse("/login", status_code=302)

    personas = list_user_personas(username)
    # Use persona from query param if valid, else prefer last-visited from cookie
    if persona and persona in personas:
        back_persona = persona
    else:
        back_persona = _preferred_persona(request, username)
    back_href = f"/{username}/{back_persona}" if back_persona else "/"

    html = (_STATIC / "help.html").read_text()
    config_tag = (
        f'<script>window.HELP_CONFIG = '
        f'{{user: "{username}", persona: "{back_persona}", backHref: "{back_href}"}};</script>'
    )
    html = html.replace("</head>", f"{config_tag}\n</head>", 1)
    nav = '<a href="/settings/integrations" class="nav-link">Integrations</a>' \
        if _read_auth(username).get("role", "user") == "admin" else ""
    html = html.replace("{{ integrations_nav }}", nav)
    return HTMLResponse(html)