/* ============================================================================
   ACTIVITIES AND INITIATIVES - the section index
   ----------------------------------------------------------------------------
   URL   /en/activities-and-initiatives  ·  /ar/activities-and-initiatives
   Route id "activities" (see app/routes.ts)

   Laid out to the 2026 redesign draft ("Activities-and-Initiatives"): an
   ambient hero, a "filter by partner" pill row, and the five activity streams
   as a numbered disclosure list - each row carrying its implementing partner
   and opening onto the stream's description and the activities filed under it.

   The five streams are the approved draft copy
   (docs/SHARPER_Website_Draft_Section_EN_AR.docx, section 3): their headings,
   descriptions and implementing partners are project structure and live in
   ./activities.content, while the activities themselves come from Strapi.

   THE DISCLOSURE IS A NATIVE <details>, NOT THE PAGE KIT'S <Accordion>.
   That component renders a markdown answer and nothing else; these panels
   carry a grid of links to the activities in the stream, and those links have
   to stay in the served HTML whether the panel is open or shut, or the only
   route a crawler has to an activity page disappears. `<details>` keeps them
   there and needs no JavaScript to work.

   THE FIGURES BAND IS NOT BUILT. The draft draws three counters reading "TBD"
   over a note saying the numbers must be confirmed before publication; the
   approved copy says the same ("[XX+] activities completed · [XX+] CSOs
   engaged · [X] regions covered - placeholder only"). Neither the figures nor
   the placeholder is rendered (CLAUDE.md rule 5), and there is no
   `activities-page` single type in the CMS to read a confirmed figure from.

   THE FIELD NAMES BELOW ARE THE CMS'S OWN
   apps/cms/src/api/activity/content-types/activity/schema.json:
   `activityStream` (not `stream`), `activityStatus`, `coverImage` (not
   `cover`), `implementingPartners` and `regions` as RELATIONS, and NO dates
   or `location` string. Sorting or filtering on a field the content type does
   not have is a 400 from Strapi, so nothing here is guessed.
   ========================================================================= */

import { useSearchParams } from "react-router";

import { Card } from "~/components/ui/Card";
import { getMessages, sectionPath, useTranslation } from "~/i18n";
import { DEFAULT_LOCALE, isLocale, type Locale } from "~/i18n/config";
import { buildBreadcrumbJsonLd, buildMeta } from "~/lib/seo";
import {
  getMany,
  isStrapiError,
  mediaAlt,
  mediaUrl,
  type StrapiEntity,
  type StrapiMedia,
} from "~/lib/strapi";

import {
  ACTIVITY_STREAMS,
  ACTIVITY_STREAM_KEYS,
  activitiesIndexPath,
  activityPath,
  getIndexCopy,
  getStreamCopy,
  groupActivitiesByStream,
  isActivityStatus,
  readRootMeta,
  streamAnchorId,
  toActivityStreamKey,
  type ActivityStreamKey,
  type ActivitySummary,
} from "./activities.content";
import { getRouteCopy } from "./_events-opportunities/copy";
import { FilterPills, ListingHero, PageShell } from "./_shared/listing-ui";
import { getListingChrome } from "./_shared/page-copy";

import type { Route } from "./+types/activities-and-initiatives";

import "./_page-kit/motion.css";

/* ---------------------------------------------------------------------------
   CMS SHAPES
   ------------------------------------------------------------------------ */

/** A related entry that only contributes its display name. */
interface NamedEntity {
  readonly name?: string | null;
  readonly slug?: string | null;
}

/** `api::activity.activity` - one activity or initiative. */
interface ActivityEntity extends StrapiEntity {
  readonly title: string;
  readonly slug: string;
  readonly activityStream?: string | null;
  readonly activityStatus?: string | null;
  readonly summary?: string | null;
  readonly regions?: readonly NamedEntity[] | null;
  readonly implementingPartners?: readonly NamedEntity[] | null;
  readonly coverImage?: StrapiMedia | null;
}

/** The fields one listing request asks for. All of them exist on the type. */
const ACTIVITY_FIELDS = [
  "title",
  "slug",
  "activityStream",
  "activityStatus",
  "summary",
] as const;

const ACTIVITY_POPULATE = {
  coverImage: { fields: ["url", "alternativeText"] },
  regions: { fields: ["name", "slug"] },
  implementingPartners: { fields: ["name", "slug"] },
} as const;

/**
 * An activity carries no date in the CMS, so the newest CMS entry leads.
 * `publishedAt` is a system field and is always sortable.
 */
const ACTIVITY_SORT = ["publishedAt:desc", "title:asc"] as const;

/** Names of a relation list, joined - or null when the relation is empty. */
function namesOf(entries: readonly NamedEntity[] | null | undefined): string | null {
  const names = (entries ?? [])
    .map((entry) => entry?.name?.trim())
    .filter((name): name is string => Boolean(name));

  return names.length > 0 ? names.join(", ") : null;
}

/** How many activities one request pulls. Well above the project's volume. */
const ACTIVITY_PAGE_SIZE = 100;

/* ---------------------------------------------------------------------------
   THE PARTNER FILTER
   ----------------------------------------------------------------------------
   The draft's pill row. The three consortium members are proper names, not
   translatable copy - they are written the same way in the English and the
   Arabic draft - and which stream each one implements is read off the approved
   stream copy rather than restated here, so the filter cannot drift from the
   line the panel shows.
   ------------------------------------------------------------------------ */

const PARTNER_FILTERS = ["acted", "uec", "sbe"] as const;
type PartnerFilter = (typeof PARTNER_FILTERS)[number];

const PARTNER_LABELS: Readonly<Record<PartnerFilter, string>> = {
  acted: "Acted",
  uec: "UEC",
  sbe: "SBE",
};

function isPartnerFilter(value: unknown): value is PartnerFilter {
  return (
    typeof value === "string" &&
    (PARTNER_FILTERS as readonly string[]).includes(value)
  );
}

/** True when the stream's approved partner line names this organisation. */
function streamHasPartner(
  stream: ActivityStreamKey,
  partner: PartnerFilter,
): boolean {
  return ACTIVITY_STREAMS[DEFAULT_LOCALE][stream].partners
    .toLowerCase()
    .includes(partner);
}

/* ---------------------------------------------------------------------------
   LOADER
   ------------------------------------------------------------------------ */

/**
 * A CMS read that must never take the page down with it. An unreachable or
 * not-yet-modelled Strapi degrades to the empty state - the five stream
 * descriptions are still worth serving - and the reason is logged server-side.
 * Anything that is not a Strapi transport/HTTP error is rethrown untouched.
 */
async function readFromCms<T>(
  label: string,
  read: () => Promise<T>,
  fallback: T,
): Promise<T> {
  try {
    return await read();
  } catch (error) {
    if (isStrapiError(error)) {
      console.error(`[activities] ${label} unavailable: ${error.message}`);
      return fallback;
    }
    throw error;
  }
}

function toSummary(entity: ActivityEntity): ActivitySummary {
  return {
    id: entity.documentId,
    slug: entity.slug,
    title: entity.title,
    stream: toActivityStreamKey(entity.activityStream),
    summary: entity.summary ?? null,
    // Resolved here rather than in the component: mediaUrl() reads STRAPI_URL
    // from the server environment, which never reaches the browser bundle.
    imageUrl: mediaUrl(entity.coverImage?.url) ?? null,
    imageAlt: mediaAlt(entity.coverImage),
    location: namesOf(entity.regions),
    implementingPartner: namesOf(entity.implementingPartners),
    status: isActivityStatus(entity.activityStatus)
      ? entity.activityStatus
      : null,
  };
}

export async function loader({ params }: Route.LoaderArgs) {
  // The ":lang" layout has already validated the segment; the guard is here so
  // the locale is a `Locale` by inference rather than by assertion.
  const locale: Locale = isLocale(params.lang) ? params.lang : DEFAULT_LOCALE;

  const activities = await readFromCms(
    "activities",
    async () => {
      const response = await getMany<ActivityEntity>("activities", {
        locale,
        sort: [...ACTIVITY_SORT],
        fields: [...ACTIVITY_FIELDS],
        populate: ACTIVITY_POPULATE,
        pagination: { pageSize: ACTIVITY_PAGE_SIZE, withCount: false },
      });
      return response.data;
    },
    [] as ActivityEntity[],
  );

  return {
    locale,
    activities: activities
      .filter((entity) => Boolean(entity.slug && entity.title))
      .map(toSummary),
  };
}

/* ---------------------------------------------------------------------------
   META
   The canonical link and the en / ar / x-default hreflang alternates are
   emitted for every route by the shell (root.tsx `Layout`), because a leaf
   `meta` replaces its parents' wholesale - so `alternates` stays false here on
   purpose. Passing it would duplicate every one of those tags.
   ------------------------------------------------------------------------ */

export function meta({ matches }: Route.MetaArgs) {
  const root = readRootMeta(matches, activitiesIndexPath(DEFAULT_LOCALE));
  const { locale, pathname, siteUrl } = root;
  const copy = getIndexCopy(locale);
  const { sections } = getMessages(locale).nav;

  return buildMeta({
    locale,
    pathname,
    siteUrl,
    title: sections.activities,
    description: copy.metaDescription,
    jsonLd: buildBreadcrumbJsonLd(siteUrl, [
      { name: sections.home, pathname: sectionPath("home", locale) },
      { name: sections.activities, pathname: activitiesIndexPath(locale) },
    ]),
  });
}

/* ---------------------------------------------------------------------------
   VIEW
   ------------------------------------------------------------------------ */

export default function ActivitiesAndInitiatives({
  loaderData,
}: Route.ComponentProps) {
  const { activities } = loaderData;
  const { locale, t } = useTranslation();
  const [searchParams] = useSearchParams();

  const copy = getIndexCopy(locale);
  const chrome = getListingChrome(locale).activities;
  const routeCopy = getRouteCopy(locale);
  const grouped = groupActivitiesByStream(activities);
  const hasActivities = activities.length > 0;

  const pathname = activitiesIndexPath(locale);
  const requested = searchParams.get("partner");
  const partner = isPartnerFilter(requested) ? requested : null;

  const streams = ACTIVITY_STREAM_KEYS.filter(
    (stream) => partner === null || streamHasPartner(stream, partner),
  );

  const pills = [
    {
      id: "all",
      label: chrome.allPartners,
      href: pathname,
      isCurrent: partner === null,
    },
    ...PARTNER_FILTERS.map((value) => ({
      id: value,
      label: PARTNER_LABELS[value],
      href: `${pathname}?partner=${value}`,
      isCurrent: partner === value,
    })),
  ];

  return (
    <>
      <ListingHero
        eyebrow={copy.eyebrow}
        heading={copy.headline}
        intro={copy.lede}
        ambient={[{ top: -250, from: "start", offset: "12%", width: 740, height: 580, durationSeconds: 21 }]}
      />

      <PageShell>
        {/* The draft reveals the filter row as it enters, like every other
            band on the page. */}
        <div className="sh-reveal">
          <FilterPills label={chrome.partnerFilterLabel} pills={pills} />
        </div>

        {hasActivities ? null : (
          <section
            aria-labelledby="activities-empty"
            className="flex flex-col items-start gap-md rounded-card border border-dashed border-border-default p-xl"
          >
            <h2 id="activities-empty" className="body-lg-bold text-text-primary">
              {copy.emptyTitle}
            </h2>
            <p className="body-md max-w-[var(--layout-prose-max)] text-text-secondary">
              {copy.emptyBody}
            </p>
          </section>
        )}

        <section aria-label={copy.streamsNavLabel} className="flex flex-col">
          <h2 className="sr-only">{copy.streamsNavLabel}</h2>

          <div className="border-t border-border-default">
            {streams.map((stream, index) => (
              <StreamDisclosure
                key={stream}
                stream={stream}
                ordinal={index + 1}
                open={index === 0}
                activities={grouped[stream]}
                hasActivities={hasActivities}
                locale={locale}
                viewDetailsLabel={t("actions.viewDetails")}
                streamEmptyLabel={copy.streamEmpty}
                streamListLabel={copy.streamListLabel}
              />
            ))}
          </div>
        </section>

        {/* Where to go next - the draft's two closing cards. Both blurbs are
            the approved standfirsts of sections 4 and 8, not new copy. */}
        <nav aria-label={chrome.nextStepsLabel}>
          <h2 className="sr-only">{chrome.nextStepsLabel}</h2>
          <ul className="grid gap-lg sm:grid-cols-2">
            <Card.Content
              as="li"
              titleAs="h3"
              className="sh-reveal sh-reveal--in"
              href={sectionPath("events", locale)}
              eyebrow={chrome.nextEventsEyebrow}
              title={routeCopy.events.heading}
              excerpt={routeCopy.events.intro}
              actionLabel={t("actions.viewUpcomingSessions")}
            />
            <Card.Content
              as="li"
              titleAs="h3"
              className="sh-reveal sh-reveal--in"
              href={sectionPath("applications", locale)}
              eyebrow={chrome.nextApplicationsEyebrow}
              title={routeCopy.opportunities.heading}
              excerpt={routeCopy.opportunities.intro}
              actionLabel={t("actions.seeCurrentCalls")}
            />
          </ul>
        </nav>
      </PageShell>
    </>
  );
}

/* ---------------------------------------------------------------------------
   ONE STREAM
   ------------------------------------------------------------------------ */

/** The +/- mark, drawn the way the page kit's accordion draws it. */
function ToggleMark() {
  return (
    <span
      aria-hidden="true"
      className={[
        "flex size-8 shrink-0 items-center justify-center rounded-pill border",
        "border-border-default text-text-accent transition-colors",
        "duration-[var(--motion-duration-base)]",
        "group-open:border-border-accent group-open:bg-surface-accent-subtle",
      ].join(" ")}
    >
      <svg width="14" height="14" viewBox="0 0 14 14" fill="none" aria-hidden="true">
        <path d="M1 7h12" stroke="currentColor" strokeWidth="1.6" strokeLinecap="round" />
        <path
          d="M7 1v12"
          stroke="currentColor"
          strokeWidth="1.6"
          strokeLinecap="round"
          className="origin-center transition-transform duration-[var(--motion-duration-base)] group-open:scale-y-0"
        />
      </svg>
    </span>
  );
}

function StreamDisclosure({
  stream,
  ordinal,
  open,
  activities,
  hasActivities,
  locale,
  viewDetailsLabel,
  streamEmptyLabel,
  streamListLabel,
}: {
  stream: ActivityStreamKey;
  ordinal: number;
  open: boolean;
  activities: readonly ActivitySummary[];
  hasActivities: boolean;
  locale: Locale;
  viewDetailsLabel: string;
  streamEmptyLabel: string;
  streamListLabel: string;
}) {
  const copy = getStreamCopy(stream, locale);
  const anchor = streamAnchorId(stream);
  const number = new Intl.NumberFormat(`${locale}-u-nu-latn`, {
    minimumIntegerDigits: 2,
    useGrouping: false,
  }).format(ordinal);

  return (
    <details
      id={anchor}
      open={open}
      className="sh-reveal sh-lift group scroll-mt-2xl border-b border-border-default hover:bg-surface-raised"
    >
      <summary
        className={[
          "flex cursor-pointer list-none items-center gap-lg py-lg",
          "text-start text-text-primary transition-colors",
          "duration-[var(--motion-duration-base)] hover:text-text-accent",
          "[&::-webkit-details-marker]:hidden",
        ].join(" ")}
      >
        <span aria-hidden="true" className="label-md min-w-8 text-text-tertiary">
          {number}
        </span>

        <h3 className="flex-1 heading-h3">{copy.title}</h3>

        <span className="hidden shrink-0 rounded-chip bg-surface-accent-subtle px-xs py-2xs label-md uppercase text-text-accent sm:inline-block">
          {copy.partners}
        </span>

        <ToggleMark />
      </summary>

      {/* The animation is attached by the `open` state, so it plays when the
          reader opens the row rather than once on first paint. */}
      <div className="flex flex-col gap-lg pb-xl ps-2xl group-open:[animation:sh-answer_var(--motion-duration-base)_var(--motion-ease-entrance)_both]">
        <div className="flex max-w-[var(--layout-prose-max)] flex-col gap-xs">
          <p className="body-md text-text-secondary">{copy.description}</p>
          <p className="body-sm text-text-tertiary">
            <span className="body-sm-bold text-text-secondary">
              {copy.partnerLabel}:
            </span>{" "}
            {copy.partners}
          </p>
        </div>

        {activities.length > 0 ? (
          <>
            <h4 className="sr-only">{streamListLabel}</h4>
            <ul className="grid list-none grid-cols-1 gap-lg sm:grid-cols-2 lg:grid-cols-3">
              {activities.map((activity) => (
                <Card.Content
                  as="li"
                  key={activity.id}
                  titleAs="h4"
                  href={activityPath(activity.slug, locale)}
                  title={activity.title}
                  eyebrow={activity.location ?? undefined}
                  excerpt={activity.summary ?? undefined}
                  actionLabel={viewDetailsLabel}
                  image={
                    activity.imageUrl
                      ? { src: activity.imageUrl, alt: activity.imageAlt }
                      : undefined
                  }
                />
              ))}
            </ul>
          </>
        ) : hasActivities ? (
          <p className="body-sm text-text-tertiary">{streamEmptyLabel}</p>
        ) : null}
      </div>
    </details>
  );
}