// Publishes the compiled configuration to Shopify (brief §11.1, §11.5, §12):
//  ONE automatic app discount per shop (function "bundle-discount") carrying $app:configuration and
//  $app:function-vars, plus the app-data metafield bundle_offers.storefront read by the theme extension.
import db from "../db.server";
import { compile, settingsOf, type CompileResult } from "./compile";
import { gql, ensureShop, type AdminLike } from "./shop.server";

export const FUNCTION_HANDLE = "bundle-discount";
export const DISCOUNT_TITLE = "Bundle Offers";
export const STOREFRONT_NAMESPACE = "bundle_offers";

const CREATE = `#graphql
  mutation BundleOffersCreateDiscount($d: DiscountAutomaticAppInput!) {
    discountAutomaticAppCreate(automaticAppDiscount: $d) {
      automaticAppDiscount { discountId }
      userErrors { field message }
    }
  }`;

const UPDATE = `#graphql
  mutation BundleOffersUpdateDiscount($id: ID!, $d: DiscountAutomaticAppInput!) {
    discountAutomaticAppUpdate(id: $id, automaticAppDiscount: $d) {
      automaticAppDiscount { discountId }
      userErrors { field message }
    }
  }`;

const NODE = `#graphql
  query BundleOffersDiscountNode($id: ID!) {
    discountNode(id: $id) { id discount { ... on DiscountAutomaticApp { status } } }
  }`;

const SET_METAFIELDS = `#graphql
  mutation BundleOffersSetMetafields($m: [MetafieldsSetInput!]!) {
    metafieldsSet(metafields: $m) { userErrors { field message code } }
  }`;

const DELETE_DISCOUNT = `#graphql
  mutation BundleOffersDeleteDiscount($id: ID!) {
    discountAutomaticDelete(id: $id) { deletedAutomaticDiscountId userErrors { field message } }
  }`;

const DELETE_METAFIELDS = `#graphql
  mutation BundleOffersDeleteMetafields($m: [MetafieldIdentifierInput!]!) {
    metafieldsDelete(metafields: $m) { userErrors { field message } }
  }`;

function combinesWith(settingsRaw: unknown) {
  const s = settingsOf(settingsRaw);
  return { productDiscounts: s.combineProduct, orderDiscounts: s.combineOrder, shippingDiscounts: s.combineShipping };
}

function userErrorText(errors: { message: string }[] | undefined) {
  return errors?.length ? errors.map((e) => e.message).join("; ") : null;
}

async function loadOffers(shopId: string) {
  return db.offer.findMany({ where: { shopId }, include: { lines: { orderBy: { sequence: "asc" } }, scopes: true } });
}

export async function compileShop(shopId: string, now = new Date()): Promise<CompileResult> {
  const shop = await db.shop.findUniqueOrThrow({ where: { id: shopId } });
  const offers = await loadOffers(shopId);
  return compile(
    { planCode: shop.planCode, currency: shop.currency, timezone: shop.timezone, settings: shop.settings, monthOrders: currentMonthOrders(shop) },
    offers.map((o) => ({ ...o, lines: o.lines, scopes: o.scopes })),
    now,
  );
}

export function monthKey(d = new Date()) {
  return d.toISOString().slice(0, 7);
}

export function currentMonthOrders(shop: { monthKey: string | null; monthOrders: number }) {
  return shop.monthKey === monthKey() ? shop.monthOrders : 0;
}

/** Creates the shop's single automatic discount if it is missing; returns its id. */
async function ensureDiscount(admin: AdminLike, shop: { id: string; discountNodeId: string | null; settings: unknown }, metafields: object[]) {
  if (shop.discountNodeId) {
    const node = await gql(admin, NODE, { id: shop.discountNodeId });
    if (node.discountNode) return { id: shop.discountNodeId, created: false };
  }
  const data = await gql(admin, CREATE, {
    d: {
      title: DISCOUNT_TITLE,
      functionHandle: FUNCTION_HANDLE,
      discountClasses: ["PRODUCT"],
      startsAt: new Date().toISOString(),
      endsAt: null,
      combinesWith: combinesWith(shop.settings),
      metafields,
    },
  });
  const err = userErrorText(data.discountAutomaticAppCreate.userErrors);
  if (err) throw new Error(`Could not create the Bundle Offers discount: ${err}`);
  const id = data.discountAutomaticAppCreate.automaticAppDiscount.discountId as string;
  await db.shop.update({ where: { id: shop.id }, data: { discountNodeId: id } });
  return { id, created: true };
}

export interface PublishOutcome {
  ok: boolean;
  error: string | null;
  result: CompileResult;
}

/** Compiles and pushes everything to Shopify. Safe to call any time (idempotent). */
export async function publishShop(admin: AdminLike, domain: string, now = new Date()): Promise<PublishOutcome> {
  const shop = await ensureShop(admin, domain);
  const result = await compileShop(shop.id, now);

  if (result.error) {
    await db.shop.update({ where: { id: shop.id }, data: { publishError: result.error, nextSyncAt: result.nextSyncAt } });
    return { ok: false, error: result.error, result };
  }

  const configMetafields = [
    { namespace: "$app", key: "configuration", type: "json", value: JSON.stringify(result.config) },
    { namespace: "$app", key: "function-vars", type: "json", value: JSON.stringify(result.vars) },
  ];
  try {
    const discount = await ensureDiscount(admin, shop, configMetafields);
    const metafields: object[] = [
      { ownerId: shop.appInstallationId, namespace: STOREFRONT_NAMESPACE, key: "storefront", type: "json", value: JSON.stringify(result.storefront) },
    ];
    if (!discount.created) metafields.push(...configMetafields.map((m) => ({ ...m, ownerId: discount.id })));
    const set = await gql(admin, SET_METAFIELDS, { m: metafields });
    const err = userErrorText(set.metafieldsSet.userErrors);
    if (err) throw new Error(err);

    await db.shop.update({
      where: { id: shop.id },
      data: {
        publishError: null,
        lastPublishedAt: now,
        nextSyncAt: result.nextSyncAt,
        configBytes: result.configBytes,
        storefrontBytes: result.storefrontBytes,
      },
    });
    return { ok: true, error: null, result };
  } catch (e) {
    const error = e instanceof Error ? e.message : String(e);
    // retry in a minute
    await db.shop.update({ where: { id: shop.id }, data: { publishError: error, nextSyncAt: new Date(Date.now() + 60_000) } });
    return { ok: false, error, result };
  }
}

/** Applies the combine settings to the discount node. */
export async function updateCombinations(admin: AdminLike, domain: string) {
  const shop = await ensureShop(admin, domain);
  if (!shop.discountNodeId) return publishShop(admin, domain);
  const data = await gql(admin, UPDATE, { id: shop.discountNodeId, d: { combinesWith: combinesWith(shop.settings) } });
  const err = userErrorText(data.discountAutomaticAppUpdate.userErrors);
  if (err) throw new Error(err);
  return publishShop(admin, domain);
}

/** Removes the discount and the storefront metafield (uninstall from inside the app, or plan cleanup). */
export async function removeShopifyData(admin: AdminLike, shop: { discountNodeId: string | null; appInstallationId: string | null }) {
  if (shop.discountNodeId) await gql(admin, DELETE_DISCOUNT, { id: shop.discountNodeId }).catch(() => null);
  if (shop.appInstallationId) {
    await gql(admin, DELETE_METAFIELDS, {
      m: [{ ownerId: shop.appInstallationId, namespace: STOREFRONT_NAMESPACE, key: "storefront" }],
    }).catch(() => null);
  }
}