import {
  useId,
  useState,
  type AnchorHTMLAttributes,
  type ButtonHTMLAttributes,
  type ReactNode,
} from "react";
import ArrowLink from "../../components/ArrowLink.tsx";
import type { OrgKind } from "../../lib/hrefs.ts";
import type { OrganizationListItem } from "../../lib/useContent.ts";
import {
  areasSentence,
  initialsFor,
  orgPath,
  useOrganizations,
} from "../../data/organizations.js";

/* ═══════════════════════════════════════════════════════════════
   ORGANIZATION LIST — VERTICAL

   A stack of organizations, each collapsed to a line and
   expandable for the rest. Every row carries two ways out: an
   arrow through to that organization's page on this site, and a
   labelled button out to its own site when it has one.

   Nothing here is region-specific. It asks for a kind and renders
   what comes back, so the same section lists partners or chapters
   by changing one prop:

     <OrgListVertical kind="partner" title="Our Partners" />

     <OrgListVertical
       kind="region"
       groups={[
         { key: "domestic",      title: "US Unity Regions" },
         { key: "international", title: "International Unity Regions" },
       ]}
       groupBy={org => org.details?.scope}
     />

   Kind-specific extras (the areas a region covers, the chapters
   inside it) come from `details` and render only when present, so
   a partner row simply doesn't have them.
   ═══════════════════════════════════════════════════════════════ */

const LOGO_BASE = "/org-logos/";

const MUTED = "#7a9299";
const RULE = "#cfe3e7";
const INK = "#2c4a50";
const FALLBACK_COLOR = "#4a6b72";

/* ── Row button ───────────────────────────────────────────────
   Deliberately a sibling of the summary button rather than inside
   it — a link nested in a button is invalid, and a screen reader
   announces the whole row as one confused control.
   ───────────────────────────────────────────────────────────── */
type RowButtonProps = {
  as?: "a" | "button";
  color: string;
  children: ReactNode;
} & AnchorHTMLAttributes<HTMLAnchorElement> &
  ButtonHTMLAttributes<HTMLButtonElement>;

function RowButton({ as: As = "button", color, children, ...rest }: RowButtonProps) {
  return (
    <As
      className="shrink-0 whitespace-nowrap py-2 px-4 rounded-xl font-700 text-sm transition-transform duration-200 hover:scale-105"
      style={{ border: `1px solid ${color}`, color }}
      {...rest}
    >
      {children}
    </As>
  );
}

function OrgMark({
  org,
  color,
}: {
  org: Pick<OrganizationListItem, "logo" | "color" | "name">;
  color: string;
}) {
  const [failed, setFailed] = useState(false);

  if (org.logo && !failed) {
    return (
      <img
        src={`${LOGO_BASE}${org.logo}`}
        alt=""
        onError={() => setFailed(true)}
        className="h-8 w-8 object-contain shrink-0"
      />
    );
  }

  if (org.color) {
    return (
      <span
        className="h-3 w-3 rounded-full shrink-0"
        style={{ background: color }}
        aria-hidden="true"
      />
    );
  }

  return (
    <span
      className="h-8 w-8 rounded-lg shrink-0 flex items-center justify-center text-xs font-800"
      style={{ border: `1px solid ${color}`, color }}
      aria-hidden="true"
    >
      {initialsFor(org.name)}
    </span>
  );
}

type RowLabels = { pageLabel: string; siteLabel: string };

function OrgRow({ org, pageLabel, siteLabel }: RowLabels & { org: OrganizationListItem }) {
  const [open, setOpen] = useState(false);
  const panelId = useId();

  const color = org.color || FALLBACK_COLOR;
  const path = orgPath(org);

  // Region extras. Absent for every other kind, and the JSX below
  // skips them rather than rendering empty headings.
  const areas = areasSentence(org.details?.areas ?? []);
  const chapterCount = (org.details?.chapters ?? []).length;
  const note = org.details?.map_note;

  /* Collapsed, a row says who it is and nothing else — the areas
     sentence runs long and lives in the panel, where it appears
     exactly once rather than in both places. */
  const summary = org.tagline;

  // Something has to be behind the chevron or opening it does nothing.
  const hasPanel =
    org.description?.length > 0 || areas || note || org.links?.length > 0;

  return (
    <div className="py-3" style={{ borderTop: `1px solid ${RULE}` }}>
      <div className="flex flex-wrap items-center gap-3">
        <button
          onClick={() => setOpen(v => !v)}
          aria-expanded={open}
          aria-controls={panelId}
          className="flex-1 min-w-0 flex items-center gap-3 text-left py-1"
        >
          <svg
            viewBox="0 0 24 24"
            className="ol-chevron h-4 w-4 shrink-0"
            style={{ color, transform: open ? "rotate(90deg)" : "none" }}
            fill="none"
            stroke="currentColor"
            strokeWidth="2.5"
            strokeLinecap="round"
            strokeLinejoin="round"
            aria-hidden="true"
          >
            <path d="M9 6l6 6-6 6" />
          </svg>

          <OrgMark org={org} color={color} />

          <span className="min-w-0">
            <span className="block font-800 text-lg leading-tight" style={{ color }}>
              {org.name}
            </span>
            {summary && (
              <span className="block text-sm leading-snug" style={{ color: MUTED }}>
                {summary}
              </span>
            )}
          </span>

          {chapterCount > 0 && (
            <span
              className="ml-auto text-sm shrink-0"
              style={{ color: MUTED }}
              title={`${chapterCount} chapter${chapterCount > 1 ? "s" : ""}`}
            >
              {chapterCount}
            </span>
          )}
        </button>

        <div className="flex items-center gap-2">
          {org.website && (
            <RowButton
              as="a"
              href={org.website}
              target="_blank"
              rel="noopener noreferrer"
              color={color}
            >
              {siteLabel} ↗
            </RowButton>
          )}

          {/* Last in the row, so the arrow lines up down the right
              edge whether or not a row has an outbound site. */}
          {path && (
            <ArrowLink
              to={path}
              label={`${org.name} — ${pageLabel}`}
              color={color}
            />
          )}
        </div>
      </div>

      {/* 0fr → 1fr animates to the panel's real height, so nobody
          has to guess a max-height that's wrong the moment a
          description grows. */}
      <div
        id={panelId}
        className="ol-panel"
        style={{ gridTemplateRows: open ? "1fr" : "0fr" }}
      >
        <div className="overflow-hidden">
          <div className="pt-2 pb-3 pl-10 pr-2 flex flex-col gap-3">
            {org.description?.map((text, i) => (
              <p key={i} className="leading-relaxed" style={{ color: INK }}>
                {text}
              </p>
            ))}

            {areas && (
              <p className="text-sm" style={{ color: MUTED }}>
                <span className="font-700">Covers</span> {areas}
              </p>
            )}

            {note && (
              <p className="text-sm" style={{ color: MUTED }}>
                {note}
              </p>
            )}

            {!hasPanel && (
              <p className="text-sm" style={{ color: MUTED }}>
                More about this region soon.
              </p>
            )}

            {org.links?.length > 0 && (
              <div className="flex flex-wrap gap-2 pt-1">
                {org.links.map(link => (
                  <RowButton
                    key={link.url}
                    as="a"
                    href={link.url}
                    target="_blank"
                    rel="noopener noreferrer"
                    color={color}
                  >
                    {link.label}
                  </RowButton>
                ))}
              </div>
            )}
          </div>
        </div>
      </div>
    </div>
  );
}

function Block({
  title,
  orgs,
  pageLabel,
  siteLabel,
}: RowLabels & { title?: string; orgs: OrganizationListItem[] }) {
  if (orgs.length === 0) return null;

  return (
    <section className="mb-10">
      {title && (
        <h3 className="text-xl font-800 mb-1" style={{ color: FALLBACK_COLOR }}>
          {title}
        </h3>
      )}
      {orgs.map(org => (
        <OrgRow key={org.id} org={org} pageLabel={pageLabel} siteLabel={siteLabel} />
      ))}
    </section>
  );
}

const byName = (a: OrganizationListItem, b: OrganizationListItem) =>
  a.name.localeCompare(b.name);

/* One heading's worth of the list. Labels override the list's own. */
type OrgGroup = {
  key: string;
  title: string;
  pageLabel?: string;
  siteLabel?: string;
};

type OrgListVerticalProps = {
  kind?: OrgKind;
  title?: string;
  groups?: OrgGroup[];
  /** Which group key an organization files under. */
  groupBy?: (org: OrganizationListItem) => string | null | undefined;
  accent?: string;
  pageLabel?: string;
  siteLabel?: string;
  /** Null keeps the API's order. */
  sort?: ((a: OrganizationListItem, b: OrganizationListItem) => number) | null;
  empty?: string;
};

export default function OrgListVertical({
  kind,
  title,
  groups,
  groupBy,
  accent = FALLBACK_COLOR,
  pageLabel = "Region page",
  siteLabel = "Visit site",
  sort = byName,
  empty = "· Nothing to show here just yet ·",
}: OrgListVerticalProps) {
  const { organizations, loading, error } = useOrganizations(kind);

  const shell = (children: ReactNode) => (
    <div className="mx-auto px-8 md:px-12 max-w-6xl">{children}</div>
  );

  if (loading && organizations.length === 0) {
    return shell(
      <div className="skeleton" role="status" aria-label="Loading organizations" />
    );
  }

  if (error && organizations.length === 0) {
    return shell(
      <p className="font-600" style={{ color: accent }}>
        · This list couldn't be loaded just now — please try again shortly ·
      </p>
    );
  }

  if (organizations.length === 0) {
    return shell(
      <p className="font-600" style={{ color: accent }}>
        {empty}
      </p>
    );
  }

  const sorted = sort ? [...organizations].sort(sort) : organizations;

  // No groups given means one undivided list.
  if (!groups || !groupBy) {
    return shell(
      <Block title={title} orgs={sorted} pageLabel={pageLabel} siteLabel={siteLabel} />
    );
  }

  return shell(
    groups.map(group => (
      <Block
        key={group.key}
        title={group.title}
        orgs={sorted.filter(org => groupBy(org) === group.key)}
        pageLabel={group.pageLabel ?? pageLabel}
        siteLabel={group.siteLabel ?? siteLabel}
      />
    ))
  );
}