"""ARC before_checkout / after_checkout as LangChain tools (Python).

    pip install langchain-core
    from arc_checkout_tools import arc_before_checkout, arc_after_checkout
    agent = create_react_agent(llm, [arc_before_checkout, arc_after_checkout])

Standard library HTTP only. No API key. Set ARC_BASE_URL to point at a mock in tests.
"""

import json
import os
import urllib.error
import urllib.parse
import urllib.request
from datetime import datetime, timezone
from typing import Literal, Optional

from langchain_core.tools import tool

BASE = os.environ.get("ARC_BASE_URL", "https://www.arcreport.ai").rstrip("/")
REF = "int-langchain-kit-py"
HEADERS = {"user-agent": "arc-integration/langchain-py", "x-arc-client": REF, "accept": "application/json"}
AGENT_NAME = os.environ.get("ARC_AGENT_NAME", "langchain-agent")
AGENT_FAMILY = os.environ.get("ARC_AGENT_FAMILY", "langchain")
_key: Optional[str] = None


def _get_json(req: urllib.request.Request) -> tuple[int, dict]:
    try:
        with urllib.request.urlopen(req, timeout=15) as res:
            return res.status, json.loads(res.read() or b"{}")
    except urllib.error.HTTPError as err:
        return err.code, json.loads(err.read() or b"{}")


@tool
def arc_before_checkout(url: str) -> dict:
    """Call this right before you try to check out on an online store: after you have picked the product and before you add to cart, build a cart link or open checkout. Pass the store or product URL. Returns ARC's best known way in (route, endpoint), whether a saved check reached checkout (reaches_checkout), how fresh it is and blockers. Advisory: reaches_checkout false is not a no."""
    q = urllib.parse.urlencode({"url": url, "ref": REF})
    status, body = _get_json(urllib.request.Request(f"{BASE}/api/precheck?{q}", headers=HEADERS))
    if status != 200:
        return {"error": f"ARC precheck HTTP {status}"}
    best = body.get("best_route") or {}
    return {
        "host": body.get("host"),
        "route": best.get("route", "none"),
        "endpoint": best.get("endpoint"),
        "checked_at": best.get("checked_at"),
        "stale": best.get("stale", True),
        "confidence": best.get("confidence"),
        "reaches_checkout": best.get("reaches_checkout") is True,
        "blockers": body.get("blockers") or [],
    }


@tool
def arc_after_checkout(
    store: str,
    furthest_step: Literal["product", "cart", "checkout", "payment", "placed"],
    blocker: Literal["captcha", "login_wall", "bot_block", "3ds", "payment_declined", "none"],
    store_error_text: Optional[str] = None,
) -> dict:
    """Call this right after a checkout attempt on an online store ends, whether it worked or not. Report the furthest step reached, what stopped you (or none). store_error_text is only the store's own error message. No personal data."""
    global _key
    host = urllib.parse.urlsplit(store if "://" in store else f"https://{store}").hostname or store
    body = {
        "store_domain": host.removeprefix("www."),
        "agent_family": AGENT_FAMILY,
        "agent_name": AGENT_NAME,
        "timestamp": datetime.now(timezone.utc).isoformat(),
        "furthest_step": furthest_step,
        "blocker": blocker,
    }
    # The route tried is not sent: the outcomes API has no route field yet (planned).
    notes = (store_error_text or "").strip()
    if notes:
        body["store_error_text"] = notes
    if _key:
        body["contributor_key"] = _key
    req = urllib.request.Request(
        f"{BASE}/api/outcomes", data=json.dumps(body).encode(), method="POST",
        headers={**HEADERS, "content-type": "application/json"},
    )
    status, res = _get_json(req)
    if status in (200, 201) and res.get("contributor_key"):
        _key = res["contributor_key"]
    return {"ok": res.get("ok") is True, "id": res.get("id"), "status": res.get("status"), "error": res.get("error")}