import { data, type ActionFunctionArgs, type LoaderFunctionArgs } from "@remix-run/node";
import { Form, useLoaderData, useNavigation } from "@remix-run/react";
import { Page, Layout, Text, Card, BlockStack, EmptyState, InlineStack, Badge, Button } from "@shopify/polaris";
import { TitleBar } from "@shopify/app-bridge-react";
import { authenticate } from "../shopify.server";
import db from "../db.server";
import { getShopTier } from "../services/billing.server";
import { tierAtLeast } from "../lib/billing-plans";

interface OnboardingSettings {
  onboarding?: { widgetDone?: boolean };
}

export const loader = async ({ request }: LoaderFunctionArgs) => {
  const { session } = await authenticate.admin(request);

  const [locations, shop, tier] = await Promise.all([
    db.location.findMany({
      where: { shopDomain: session.shop },
      include: { _count: { select: { slotTemplates: true } } },
    }),
    db.shop.findUnique({ where: { shopDomain: session.shop }, select: { settings: true } }),
    getShopTier(session.shop),
  ]);

  const zonesEligible = tierAtLeast(tier, "growth");
  const zonesCount = zonesEligible ? await db.zone.count({ where: { shopDomain: session.shop } }) : 0;
  const settings = (shop?.settings as OnboardingSettings | null) ?? {};

  return {
    locations,
    tier,
    checklist: {
      hasLocation: locations.length > 0,
      hasSlots: locations.some((l) => l._count.slotTemplates > 0),
      widgetDone: settings.onboarding?.widgetDone ?? false,
      zonesEligible,
      hasZones: zonesCount > 0,
    },
  };
};

// Only the widget step needs an action — every other checklist item is
// "done" once its own underlying data exists (a Location, a SlotTemplate,
// a Zone), which those pages already create. Theme customization isn't
// something this app's data can detect, so it's a manual acknowledgment
// stored in Shop.settings.onboarding, the same JSON field templates.server.ts
// already uses for widgetCopy.
export const action = async ({ request }: ActionFunctionArgs) => {
  const { session } = await authenticate.admin(request);
  const formData = await request.formData();

  if (formData.get("intent") === "ack-widget") {
    const shop = await db.shop.findUnique({ where: { shopDomain: session.shop }, select: { settings: true } });
    const settings = (shop?.settings as OnboardingSettings | null) ?? {};
    const nextSettings = { ...settings, onboarding: { ...settings.onboarding, widgetDone: true } };
    await db.shop.upsert({
      where: { shopDomain: session.shop },
      create: { shopDomain: session.shop, settings: nextSettings },
      update: { settings: nextSettings },
    });
    return data({ ok: true });
  }

  return data({ ok: false }, { status: 400 });
};

interface ChecklistStep {
  title: string;
  description: string;
  done: boolean;
  action: { label: string; url: string } | { label: string; formIntent: string } | null;
}

export default function Index() {
  const { locations, checklist } = useLoaderData<typeof loader>();
  const navigation = useNavigation();
  const isSubmitting = navigation.state === "submitting";

  const steps: ChecklistStep[] = [
    {
      title: "Add a location",
      description: "A fulfillment point — a store, warehouse, or kitchen — that ships, delivers, or hands off orders.",
      done: checklist.hasLocation,
      action: { label: "Add location", url: "/app/locations/new" },
    },
    {
      title: "Configure weekly slots",
      description: "Set the days and time windows each location is open for Shipping, Local Delivery, or Pickup.",
      done: checklist.hasSlots,
      action: { label: "Set up slots", url: "/app/slots" },
    },
    {
      title: "Enable the widget on your storefront",
      description:
        'Add the "Date & time picker" app block to your product or cart page from Online Store > Themes > Customize.',
      done: checklist.widgetDone,
      action: { label: "Mark as done", formIntent: "ack-widget" },
    },
    ...(checklist.zonesEligible
      ? [
          {
            title: "Set up delivery zones (optional)",
            description: "Route Local Delivery orders to the nearest location by postal code or radius.",
            done: checklist.hasZones,
            action: { label: "Set up zones", url: "/app/zones" },
          },
        ]
      : []),
  ];
  const completedCount = steps.filter((s) => s.done).length;

  return (
    <Page>
      <TitleBar title="Delivery Date & Time" />
      <BlockStack gap="500">
        <Layout>
          {completedCount < steps.length && (
            <Layout.Section>
              <Card>
                <BlockStack gap="300">
                  <InlineStack align="space-between" blockAlign="center">
                    <Text as="h2" variant="headingMd">
                      Get set up
                    </Text>
                    <Badge tone={completedCount === steps.length ? "success" : "info"}>
                      {`${completedCount}/${steps.length} done`}
                    </Badge>
                  </InlineStack>
                  <BlockStack gap="200">
                    {steps.map((step) => (
                      <InlineStack key={step.title} align="space-between" blockAlign="center" wrap={false}>
                        <BlockStack gap="050">
                          <InlineStack gap="150" blockAlign="center">
                            <Badge tone={step.done ? "success" : undefined}>{step.done ? "Done" : "To do"}</Badge>
                            <Text as="span" fontWeight="semibold">
                              {step.title}
                            </Text>
                          </InlineStack>
                          <Text as="span" tone="subdued" variant="bodySm">
                            {step.description}
                          </Text>
                        </BlockStack>
                        {!step.done && step.action && (
                          "url" in step.action ? (
                            <Button url={step.action.url}>{step.action.label}</Button>
                          ) : (
                            <Form method="post">
                              <input type="hidden" name="intent" value={step.action.formIntent} />
                              <Button submit loading={isSubmitting}>
                                {step.action.label}
                              </Button>
                            </Form>
                          )
                        )}
                      </InlineStack>
                    ))}
                  </BlockStack>
                </BlockStack>
              </Card>
            </Layout.Section>
          )}
          <Layout.Section>
            <Card>
              {locations.length === 0 ? (
                <EmptyState
                  heading="No locations configured yet"
                  action={{ content: "Add a location", url: "/app/locations" }}
                  image="https://cdn.shopify.com/s/files/1/0757/9955/files/empty-state.svg"
                >
                  <Text as="p" variant="bodyMd">
                    Set up a fulfillment location and its weekly slots to start
                    taking scheduled Shipping, Local Delivery, or Pickup orders.
                  </Text>
                </EmptyState>
              ) : (
                <BlockStack gap="300">
                  <Text as="h2" variant="headingMd">
                    {locations.length} location{locations.length === 1 ? "" : "s"} configured
                  </Text>
                  {locations.map((location) => (
                    <InlineStack key={location.id} align="space-between">
                      <Text as="span">{location.name}</Text>
                      <Badge>{`${location._count.slotTemplates} slot templates`}</Badge>
                    </InlineStack>
                  ))}
                </BlockStack>
              )}
            </Card>
          </Layout.Section>
        </Layout>
      </BlockStack>
    </Page>
  );
}