"""Front-tab detection: decide whether the current page is an enabled site's
capturable target (a LinkedIn profile, to start).

Strategy:
  1. Try to read the browser URL natively (fast, exact; macOS reliably, others
     best-effort).
  2. If no URL, capture one screenshot and let the AI read the address bar /
     recognise the site visually (portable, screen-only).
  3. Ask the recipe registry whether any enabled recipe matches.
"""
from __future__ import annotations

from typing import Optional

from agent import screenshot
from agent.platform import get_active_tab_url
from ai import recipes
from core.models import DetectionResult, PageContext


def detect(use_ai_fallback: bool = True) -> DetectionResult:
    url = get_active_tab_url()
    ctx = PageContext(url=url)
    method = "url" if url else ""

    hit = recipes.match(ctx)

    if hit is None and url is None and use_ai_fallback:
        # No native URL and nothing matched — read the screen visually.
        try:
            shot = screenshot.capture(prefix="detect")
            from ai import extractor

            info = extractor.classify_page(shot)
            ctx.ai_site = info.get("site")
            ctx.ai_page_type = info.get("page_type")
            ctx.ai_url_text = info.get("address_bar_url")
            method = "visual"
            hit = recipes.match(ctx)
        except Exception as e:
            return DetectionResult(ok=False, reason=f"detection failed: {e}")

    if hit is None:
        where = ctx.best_url or "the current tab"
        return DetectionResult(
            ok=False,
            reason=f"Front tab is not a supported site ({where}).",
            url=ctx.best_url,
            method=method,
        )

    recipe, pm = hit
    if not pm.is_target:
        return DetectionResult(
            ok=False,
            reason=(f"Front tab is {recipe.display_name} but not a "
                    f"{recipe.target_page_type} page (got '{pm.page_type}')."),
            recipe_id=recipe.site_id,
            page_type=pm.page_type,
            url=ctx.best_url,
            method=method,
        )

    return DetectionResult(
        ok=True,
        recipe_id=recipe.site_id,
        page_type=pm.page_type,
        url=ctx.best_url,
        method=method,
    )