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

const TIER_LABEL: Record<Tier, string> = { free: "Free", starter: "Starter", growth: "Growth", pro: "Pro" };

const FEATURES: Record<Tier, string[]> = {
  free: ["1 location", "Shipping / Local Delivery / Pickup", "Date/time picker widget", "Blackout dates", "All-plan checkout enforcement"],
  starter: ["Everything in Free", "Cut-off & prep-time windows", "Up to 3 locations", "Dispatch dashboard"],
  growth: ["Everything in Starter", "Unlimited locations", "Delivery zones & rates", "Distance auto-assignment"],
  pro: ["Everything in Growth", "Priority support"],
};

const isTest = process.env.NODE_ENV !== "production";

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

  const { appSubscriptions } = await billing.check({ isTest });
  const activeSubscription = appSubscriptions[0];
  // Reconcile our cached Shop.tier against Shopify's own live billing state
  // on every visit to this page — the app_subscriptions/update webhook is
  // the durable sync path, but this catches drift immediately rather than
  // waiting on webhook delivery.
  const liveTier = activeSubscription ? tierFromPlanName(activeSubscription.name) : "free";
  await setShopTier(session.shop, liveTier);

  return { tier: liveTier, subscription: activeSubscription ?? null };
};

export const action = async ({ request }: ActionFunctionArgs) => {
  const { session, billing } = await authenticate.admin(request);
  const formData = await request.formData();
  const intent = formData.get("intent");
  const returnUrl = `${new URL(request.url).origin}/app/billing`;

  if (intent === "downgrade") {
    const { appSubscriptions } = await billing.check({ isTest });
    if (appSubscriptions[0]) {
      await billing.cancel({ subscriptionId: appSubscriptions[0].id, isTest, prorate: true });
    }
    await setShopTier(session.shop, "free");
    return data({ ok: true });
  }

  const plan = PLAN_PRICING.find((p) => p.tier === intent);
  if (!plan) return data({ ok: false }, { status: 400 });

  // billing.request() redirects to Shopify's confirmation page; it never
  // returns normally (typed Promise<never>).
  return billing.request({ plan: plan.name, isTest, returnUrl });
};

export default function Billing() {
  const { tier, subscription } = useLoaderData<typeof loader>();
  const navigation = useNavigation();
  const isSubmitting = navigation.state === "submitting";

  return (
    <Page>
      <TitleBar title="Billing" />
      <BlockStack gap="500">
        <Layout>
          <Layout.Section>
            <Card>
              <BlockStack gap="200">
                <InlineStack gap="200" blockAlign="center">
                  <Text as="h2" variant="headingMd">
                    Current plan: {TIER_LABEL[tier]}
                  </Text>
                  {subscription && <Badge tone="success">Active</Badge>}
                </InlineStack>
                {subscription && (
                  <Text as="p" tone="subdued">
                    Renews {new Date(subscription.currentPeriodEnd).toLocaleDateString()}.
                  </Text>
                )}
              </BlockStack>
            </Card>
          </Layout.Section>
          <Layout.Section>
            <InlineStack gap="400" wrap>
              {(["free", "starter", "growth", "pro"] as const).map((planTier) => (
                <div key={planTier} style={{ minWidth: 220, flex: "1 1 220px" }}>
                  <Card>
                    <BlockStack gap="300">
                      <InlineStack align="space-between" blockAlign="center">
                        <Text as="h3" variant="headingSm">
                          {TIER_LABEL[planTier]}
                        </Text>
                        {planTier === tier && <Badge>Current</Badge>}
                      </InlineStack>
                      <Text as="p" variant="bodySm" tone="subdued">
                        {planTier === "free"
                          ? "$0"
                          : `$${PLAN_PRICING.find((p) => p.tier === planTier)!.amount}/mo`}
                      </Text>
                      <BlockStack gap="100">
                        {FEATURES[planTier].map((feature) => (
                          <Text as="p" variant="bodySm" key={feature}>
                            • {feature}
                          </Text>
                        ))}
                      </BlockStack>
                      {planTier !== tier && (
                        <Form method="post">
                          <input type="hidden" name="intent" value={planTier === "free" ? "downgrade" : planTier} />
                          <Button submit fullWidth loading={isSubmitting}>
                            {planTier === "free" ? "Downgrade to Free" : `Switch to ${TIER_LABEL[planTier]}`}
                          </Button>
                        </Form>
                      )}
                    </BlockStack>
                  </Card>
                </div>
              ))}
            </InlineStack>
          </Layout.Section>
        </Layout>
      </BlockStack>
    </Page>
  );
}