import type { LoaderFunctionArgs } from "react-router";
import { useLoaderData } from "react-router";
import { useState } from "react";
import prisma from "../db.server";
import { capsFor } from "../engine/capacity";
import { hoursFor } from "../engine/availability";
import { addDays, localParts } from "../engine/time";
import { METHODS } from "../engine/types";
import { adminContext } from "../lib/admin.server";
import { findGuard } from "../lib/guard.server";
import { METHOD_LABEL, niceDate } from "../lib/format";

export const loader = async ({ request }: LoaderFunctionArgs) => {
  const { cfg, features, admin } = await adminContext(request);
  const shopId = cfg.shop.id;
  const today = localParts(Date.now(), cfg.shop.timezone).date;
  const end = addDays(today, 13);
  const [todayCount, weekCount, review, waiting, counters, monthCount, holdsSeen, guard] = await Promise.all([
    prisma.booking.count({ where: { shopId, date: today, status: "confirmed" } }),
    prisma.booking.count({ where: { shopId, date: { gt: today, lte: addDays(today, 7) }, status: "confirmed" } }),
    prisma.booking.count({ where: { shopId, OR: [{ status: "needs_review" }, { status: "confirmed", reviewReason: { not: null } }] } }),
    prisma.waitlistEntry.count({ where: { shopId, offeredAt: null, date: { gte: today } } }),
    prisma.capacityCounter.findMany({ where: { shopId, slot: "*", date: { gte: today, lte: end } } }),
    prisma.booking.count({ where: { shopId, createdAt: { gte: new Date(`${today.slice(0, 7)}-01T00:00:00Z`) } } }),
    // The widget is live once any shopper has held a time (holds are swept, bookings are not).
    prisma.hold.count({ where: { shopId } }).then(async (n) => n + (await prisma.booking.count({ where: { shopId } }))),
    findGuard(admin).catch(() => ({ fn: undefined, validation: undefined })),
  ]);

  const rows = cfg.locations
    .filter((l) => l.enabled)
    .flatMap((l) =>
      METHODS.filter((m) => l.methods[m]?.enabled && m !== "shipping").map((m) => ({
        key: `${l.id}|${m}`,
        label: `${l.name} · ${METHOD_LABEL[m]}`,
        days: Array.from({ length: 14 }, (_, i) => {
          const date = addDays(today, i);
          const open = hoursFor(l, m, date).hours.length > 0;
          const cap = capsFor(l, m, date, "00:00-00:00", features.peakDays ? cfg.peakDays : []).dayCap;
          const used = counters.find((c) => c.locationId === l.id && c.method === m && c.date === date)?.count ?? 0;
          const peak = cfg.peakDays.find((p) => p.dates.includes(date) && (!p.locationIds?.length || p.locationIds.includes(l.id)));
          return { date, open, cap, used, peak: peak?.name ?? null };
        }),
      })),
    );
  const peaks = cfg.peakDays
    .flatMap((p) => p.dates.filter((d) => d >= today).map((d) => ({ name: p.name, date: d, cutoff: p.cutoff })))
    .sort((a, b) => (a.date < b.date ? -1 : 1))
    .slice(0, 3);
  const setup = {
    anyLocation: cfg.locations.some((l) => l.enabled),
    widgetLive: holdsSeen > 0,
    guardOn: !!guard.validation?.enabled,
  };
  return {
    today, todayCount, weekCount, review, waiting, rows, peaks, setup,
    plan: cfg.shop.plan, monthCount, monthlyLimit: features.monthlyBookings,
    // Deep links: handles are the Liquid file names in extensions/datewise-widget/blocks/.
    themeEditor: {
      embed: `https://${cfg.shop.domain}/admin/themes/current/editor?context=apps&activateAppId=${process.env.SHOPIFY_API_KEY}/embed`,
      block: `https://${cfg.shop.domain}/admin/themes/current/editor?template=cart&addAppBlockId=${process.env.SHOPIFY_API_KEY}/scheduler&target=newAppsSection`,
    },
  };
};

export default function Dashboard() {
  const d = useLoaderData<typeof loader>();
  const overLimit = d.monthlyLimit != null && d.monthCount >= d.monthlyLimit;
  return (
    <s-page heading={`Today, ${niceDate(d.today, true)}`}>
      <s-button slot="primary-action" href="/app/bookings">View bookings</s-button>
      <SetupGuide setup={d.setup} themeEditor={d.themeEditor} />
      {overLimit && (
        <s-banner tone="warning" heading="You've reached this month's Starter limit">
          <s-paragraph>
            New orders are still recorded, so no customer is turned away. <s-link href="/app/settings#plan">Upgrade</s-link> to keep reminders and capacity planning running.
          </s-paragraph>
        </s-banner>
      )}
      <s-section>
        <s-grid gridTemplateColumns="repeat(auto-fit, minmax(160px, 1fr))" gap="base">
          <Kpi label="Bookings today" value={d.todayCount} />
          <Kpi label="Next 7 days" value={d.weekCount} />
          <Kpi label="Needs review" value={d.review} href="/app/bookings?status=review" alert={d.review > 0} />
          <Kpi label="On waitlist" value={d.waiting} href="/app/peak" />
        </s-grid>
      </s-section>
      <s-section heading="Capacity, next 14 days">
        {d.rows.length === 0 && <s-paragraph>No pickup or delivery locations are switched on yet.</s-paragraph>}
        {d.rows.map((r) => (
          <s-stack key={r.key} gap="small-200">
            <s-text type="strong">{r.label}</s-text>
            <div style={{ display: "grid", gridTemplateColumns: "repeat(14, minmax(28px, 1fr))", gap: 4, overflowX: "auto", alignItems: "end" }}>
              {r.days.map((x) => {
                const pct = x.cap ? Math.min(100, Math.round((100 * x.used) / x.cap)) : 0;
                const full = x.cap != null && x.used >= x.cap;
                return (
                  <div key={x.date} title={`${niceDate(x.date)}: ${x.open ? `${x.used}${x.cap != null ? ` of ${x.cap}` : ""} booked` : "closed"}${x.peak ? ` · ${x.peak}` : ""}`} style={{ display: "grid", gap: 2, textAlign: "center", fontSize: 11 }}>
                    <div style={{ height: 70, background: "var(--s-color-bg-surface-secondary, #f1f1f1)", borderRadius: 6, position: "relative", overflow: "hidden" }}>
                      {x.open && <div style={{ position: "absolute", bottom: 0, left: 0, right: 0, height: `${x.cap ? pct : Math.min(100, x.used * 8)}%`, background: full ? "#c5280c" : x.peak ? "#b98900" : "#008060" }} />}
                    </div>
                    <span>{x.open ? (x.cap != null ? `${x.used}/${x.cap}` : x.used) : "—"}</span>
                    <span style={{ opacity: 0.7 }}>{x.date.slice(8)}</span>
                  </div>
                );
              })}
            </div>
          </s-stack>
        ))}
      </s-section>
      <s-section heading="Upcoming festivals">
        {d.peaks.length === 0 ? (
          <s-paragraph>
            No peak days set. Add Diwali, Mother's Day or Valentine's in <s-link href="/app/peak">Rush control</s-link> to cap orders, close earlier and open a waitlist.
          </s-paragraph>
        ) : (
          <s-unordered-list>
            {d.peaks.map((p) => (
              <s-list-item key={p.name + p.date}>
                {p.name}, {niceDate(p.date, true)}
                {p.cutoff ? `. Orders close ${p.cutoff.daysBefore} day(s) before at ${p.cutoff.time}.` : "."}
              </s-list-item>
            ))}
          </s-unordered-list>
        )}
      </s-section>
    </s-page>
  );
}

function Kpi({ label, value, href, alert }: { label: string; value: number; href?: string; alert?: boolean }) {
  const body = (
    <s-box padding="base" border="base" borderRadius="base" background="base">
      <s-stack gap="small-200">
        <s-text color="subdued">{label}</s-text>
        <s-heading>
          <span style={{ fontSize: 28, color: alert ? "#c5280c" : undefined }}>{value}</span>
        </s-heading>
      </s-stack>
    </s-box>
  );
  return href ? <s-clickable href={href}>{body}</s-clickable> : body;
}

type Setup = { anyLocation: boolean; widgetLive: boolean; guardOn: boolean };

function SetupGuide({ setup, themeEditor }: { setup: Setup; themeEditor: { embed: string; block: string } }) {
  const steps = [
    {
      id: "location",
      done: setup.anyLocation,
      title: "Turn on a pickup or delivery location",
      body: "Your Shopify locations were imported switched off. Check the opening hours, time slots and capacity, then turn one on.",
      action: { label: "Open Locations & hours", href: "/app/locations" },
      secondary: null,
    },
    {
      id: "widget",
      done: setup.widgetLive,
      title: "Add the scheduler to your cart",
      body: "Add the Delivery date & time block to your cart page, then switch on the Datewise app embed so the scheduler also appears in the cart drawer and checkout buttons wait for a time. Save in the theme editor after each. This step is marked done after the first shopper picks a time.",
      action: { label: "Add block to cart page", href: themeEditor.block, external: true },
      secondary: { label: "Turn on app embed", href: themeEditor.embed },
    },
    {
      id: "guard",
      done: setup.guardOn,
      title: "Require a time at checkout",
      body: "The checkout guard stops orders without a valid date and time, including Buy it now and express checkouts. It works on every Shopify plan.",
      action: { label: "Open Settings", href: "/app/settings" },
      secondary: null,
    },
  ];
  const doneCount = steps.filter((x) => x.done).length;
  const firstOpen = steps.find((x) => !x.done)?.id ?? null;
  const [open, setOpen] = useState<string | null>(firstOpen);
  const [hidden, setHidden] = useState(false);
  if (hidden || doneCount === steps.length) return null;
  return (
    <s-section>
      <s-grid gap="base">
        <s-grid gap="small-200">
          <s-grid gridTemplateColumns="1fr auto" gap="small-300" alignItems="center">
            <s-heading>Set up Datewise</s-heading>
            <s-button accessibilityLabel="Hide setup guide" variant="tertiary" tone="neutral" icon="x" onClick={() => setHidden(true)} />
          </s-grid>
          <s-paragraph>Three steps and your customers can choose a delivery or pickup time.</s-paragraph>
          <s-paragraph color="subdued">
            {doneCount} of {steps.length} steps completed
          </s-paragraph>
        </s-grid>
        <s-box borderRadius="base" border="base" background="base">
          {steps.map((step, i) => (
            <s-box key={step.id}>
              {i > 0 && <s-divider />}
              <s-box padding="small">
                <s-grid gridTemplateColumns="auto 1fr auto" gap="small-300" alignItems="center">
                  <s-icon type={step.done ? "check-circle" : "circle"} tone={step.done ? "success" : "neutral"} />
                  <s-text type={open === step.id ? "strong" : undefined}>{step.title}</s-text>
                  <s-button
                    accessibilityLabel={`Toggle details for ${step.title}`}
                    variant="tertiary"
                    icon={open === step.id ? "chevron-up" : "chevron-down"}
                    onClick={() => setOpen(open === step.id ? null : step.id)}
                  />
                </s-grid>
                {open === step.id && (
                  <s-box padding="small" paddingBlockStart="none">
                    <s-stack gap="base">
                      <s-paragraph color="subdued">{step.body}</s-paragraph>
                      {!step.done && (
                        <s-stack direction="inline" gap="small-200">
                          <s-button variant="primary" href={step.action.href} target={step.action.external ? "_blank" : undefined}>
                            {step.action.label}
                          </s-button>
                          {step.secondary && (
                            <s-button href={step.secondary.href} target="_blank">
                              {step.secondary.label}
                            </s-button>
                          )}
                        </s-stack>
                      )}
                    </s-stack>
                  </s-box>
                )}
              </s-box>
            </s-box>
          ))}
        </s-box>
      </s-grid>
    </s-section>
  );
}