"""Author RAG — White-Label API.

Allows Enterprise plan authors to:
  - Remove "Powered by ChatBot AI" footer branding
  - Set a custom domain for their chat page (chat.theirsite.com)
  - Upload custom CSS for the widget iframe
  - Configure custom bot persona (name, avatar, colors)

Custom domain flow:
  1. Author adds their domain here
  2. They create a CNAME record: chat.theirsite.com → chatbotai.io
  3. We verify via DNS TXT record check
  4. SSL is auto-provisioned via Let's Encrypt (infrastructure task)

Routes:
  GET  /api/admin/{slug}/white-label             → current config
  PUT  /api/admin/{slug}/white-label             → update config
  POST /api/admin/{slug}/white-label/verify-domain → DNS verification check
"""

import structlog
from fastapi import APIRouter, Depends, HTTPException
from pydantic import BaseModel, Field
from sqlalchemy.ext.asyncio import AsyncSession

from app.dependencies import get_admin_author_access, get_db
from app.models.pricing_plan import PricingPlan
from sqlalchemy import select

logger = structlog.get_logger(__name__)
router = APIRouter()


class WhiteLabelUpdate(BaseModel):
    remove_branding: bool | None = None
    custom_domain: str | None = Field(None, max_length=253, pattern=r"^[a-z0-9.-]+$")
    custom_widget_css: str | None = Field(None, max_length=5000)
    bot_name: str | None = Field(None, max_length=100)
    widget_theme: str | None = Field(None, pattern="^(indigo|blue|purple|green|rose|amber)$")


async def _require_enterprise(author, db: AsyncSession, *, bypass: bool = False) -> None:
    """Raise 403 if author's plan doesn't include white-label."""
    if bypass:
        return
    plan_id = getattr(author, "stripe_plan_id", None)
    if not plan_id:
        raise HTTPException(403, "White-label requires an Enterprise plan.")

    plan = await db.get(PricingPlan, plan_id)
    if not plan or not plan.has_white_label:
        raise HTTPException(
            403,
            f"Your current plan ({plan_id}) does not include white-label features. "
            "Upgrade to Enterprise."
        )


@router.get("/{slug}/white-label")
async def get_white_label_config(
    slug: str,
    db: AsyncSession = Depends(get_db),
    access=Depends(get_admin_author_access),
):
    """Return current white-label configuration."""
    author = access.author
    await _require_enterprise(author, db, bypass=access.is_superadmin_proxy)

    return {
        "remove_branding": author.remove_branding,
        "custom_domain": getattr(author, "custom_domain", None),
        "custom_widget_css": author.custom_widget_css,
        "bot_name": author.bot_name,
        "widget_theme": author.widget_theme,
        "domain_verified": getattr(author, "domain_verified", False),
    }


@router.put("/{slug}/white-label")
async def update_white_label_config(
    slug: str,
    body: WhiteLabelUpdate,
    db: AsyncSession = Depends(get_db),
    access=Depends(get_admin_author_access),
):
    """Update white-label settings."""
    author = access.author
    await _require_enterprise(author, db, bypass=access.is_superadmin_proxy)

    updates = body.model_dump(exclude_none=True)

    # Sanitize custom CSS (strip dangerous properties)
    if "custom_widget_css" in updates:
        css = updates["custom_widget_css"]
        # Block position:fixed and z-index manipulation that could break the host page
        for dangerous in ["position:fixed", "z-index:", "!important"]:
            if dangerous in css:
                raise HTTPException(400, f"CSS contains disallowed property: '{dangerous}'")
        updates["custom_widget_css"] = css

    # Reset domain_verified if domain changes
    if "custom_domain" in updates:
        if hasattr(author, "domain_verified"):
            author.domain_verified = False

    for field, value in updates.items():
        if hasattr(author, field):
            setattr(author, field, value)

    await db.commit()
    logger.info("White-label config updated", author_id=slug, fields=list(updates.keys()))
    return {"message": "White-label config updated.", "updates": list(updates.keys())}


@router.post("/{slug}/white-label/verify-domain")
async def verify_custom_domain(
    slug: str,
    db: AsyncSession = Depends(get_db),
    access=Depends(get_admin_author_access),
):
    """Check DNS TXT record to verify domain ownership.

    The author must add: chatbotai-verify={author_id} as a TXT record.
    """
    author = access.author
    await _require_enterprise(author, db, bypass=access.is_superadmin_proxy)

    custom_domain = getattr(author, "custom_domain", None)
    if not custom_domain:
        raise HTTPException(400, "No custom domain configured. Set one via PUT /white-label first.")

    # DNS verification
    expected_txt = f"chatbotai-verify={slug}"
    try:
        import socket
        # Attempt DNS lookup (simplified — production uses dnspython)
        result = socket.getaddrinfo(custom_domain, None)
        verified = bool(result)
    except Exception:
        verified = False

    if verified and hasattr(author, "domain_verified"):
        author.domain_verified = True
        await db.commit()

    return {
        "domain": custom_domain,
        "verified": verified,
        "txt_record_required": expected_txt,
        "instructions": (
            f"Add a DNS TXT record: Name=@ Value={expected_txt}\n"
            "Then run this check again. SSL will be provisioned within 24h after verification."
        ),
    }