"""
ShipStation order source (API V2).

Important context (as of ShipStation's current V2 docs): V2 does not
have a dedicated "list orders" endpoint the way the older V1 API did.
The closest equivalent is GET /v2/shipments, where each shipment
carries a store_id and (depending on how the order arrived) an items
array with SKUs. That's what this service pulls from.

Because we're fetching independently of JIRA (no shared internal ID),
we recover the AR-###### ticket number by scanning the whole shipment
payload for the configured pattern, rather than assuming one fixed
field - so this keeps working even before we've confirmed exactly
which field your team puts it in (order notes, a custom field, a tag,
etc). Once that's confirmed, this can be tightened to read that field
directly for speed and reliability.
"""
from __future__ import annotations

import datetime as dt
import json
import re
from typing import List, Optional

import requests

from app import config
from app.companies import parse_mapping, resolve_company_by_store
from app.services.base import OrderService, NormalizedOrder

API_BASE = "https://api.shipstation.com/v2"
PAGE_SIZE = 100
REQUEST_TIMEOUT_SECONDS = 30


class ShipStationServiceError(Exception):
    """Raised for any ShipStation fetch failure, with a message safe to show in the UI."""


class ShipStationService(OrderService):
    name = "shipstation"

    def __init__(self) -> None:
        settings = config.load_settings()
        self.api_key = settings["SHIPSTATION_API_KEY"]
        self.store_map = parse_mapping(settings["SHIPSTATION_STORE_MAP"])
        self.ticket_pattern = re.compile(
            settings["TICKET_NUMBER_REGEX"] or config.DEFAULT_TICKET_NUMBER_REGEX
        )

    def is_configured(self) -> bool:
        return bool(self.api_key and self.store_map)

    def fetch_orders(self) -> List[NormalizedOrder]:
        if not self.is_configured():
            raise ShipStationServiceError(
                "ShipStation is not fully configured yet. Open Settings and fill in "
                "the API Key and the Store ID -> Company mapping."
            )

        shipments = self._fetch_todays_shipments()

        # Only keep shipments belonging to one of our two known stores.
        known_store_ids = set(self.store_map.keys())
        relevant = [s for s in shipments if str(s.get("store_id")) in known_store_ids]

        return [self._to_normalized_order(s) for s in relevant]

    # -- internals -----------------------------------------------------

    def _fetch_todays_shipments(self) -> List[dict]:
        headers = {"API-Key": self.api_key, "Accept": "application/json"}

        today_start = dt.datetime.combine(dt.date.today(), dt.time.min)
        today_end = today_start + dt.timedelta(days=1)

        all_shipments: List[dict] = []
        page = 1

        while True:
            params = {
                "created_at_start": today_start.isoformat() + "Z",
                "created_at_end": today_end.isoformat() + "Z",
                "page": page,
                "page_size": PAGE_SIZE,
                "sort_by": "created_at",
                "sort_dir": "desc",
            }
            try:
                response = requests.get(
                    f"{API_BASE}/shipments",
                    params=params,
                    headers=headers,
                    timeout=REQUEST_TIMEOUT_SECONDS,
                )
            except requests.RequestException as exc:
                raise ShipStationServiceError(f"Could not reach ShipStation: {exc}") from exc

            if response.status_code == 401:
                raise ShipStationServiceError(
                    "ShipStation rejected the API key (401). Check it in Settings."
                )
            if not response.ok:
                raise ShipStationServiceError(
                    f"ShipStation returned an error ({response.status_code}): {response.text[:300]}"
                )

            try:
                data = response.json()
            except ValueError as exc:
                raise ShipStationServiceError(
                    "ShipStation returned a response that wasn't valid JSON."
                ) from exc

            batch = data.get("shipments", [])
            all_shipments.extend(batch)

            total_pages = data.get("pages", 1)
            if page >= total_pages or not batch:
                break
            page += 1

        return all_shipments

    def _extract_ticket_number(self, shipment: dict) -> Optional[str]:
        try:
            blob = json.dumps(shipment)
        except (TypeError, ValueError):
            return None
        match = self.ticket_pattern.search(blob)
        return match.group(0) if match else None

    @staticmethod
    def _extract_skus(shipment: dict) -> List[str]:
        items = shipment.get("items") or []
        skus = [item.get("sku") for item in items if isinstance(item, dict) and item.get("sku")]
        return skus

    def _to_normalized_order(self, shipment: dict) -> NormalizedOrder:
        created_raw = shipment.get("created_at")
        created_at = None
        if created_raw:
            try:
                created_at = dt.datetime.strptime(created_raw[:19], "%Y-%m-%dT%H:%M:%S")
            except ValueError:
                created_at = None

        store_id = str(shipment.get("store_id", ""))
        company = resolve_company_by_store(store_id, self.store_map)
        skus = self._extract_skus(shipment)
        ticket_number = self._extract_ticket_number(shipment)
        external_id = shipment.get("shipment_id", "")

        summary_bits = [b for b in [ticket_number, ", ".join(skus)] if b]
        summary = " - ".join(summary_bits) or external_id

        return NormalizedOrder(
            source="shipstation",
            external_id=external_id,
            ticket_number=ticket_number,
            company=company,
            skus=skus,
            summary=summary,
            status=shipment.get("shipment_status", ""),
            source_created_at=created_at,
            raw_data=shipment,
        )