import type { CatalogPlaceholderGroupView, TechStepPlaceholderView } from "@batch-cooking/shared";
import { useCallback, useEffect, useRef, useState } from "react";
import { useTranslation } from "react-i18next";
import { adminApiClient } from "../../../api/admin-client";
import "../admin-page.scss";
import "./catalog-page.scss";
import { type CatalogTab, formatDate, reviewedParam, splitSpellings } from "./catalog";

type IngredientState =
  | { status: "loading" }
  | { status: "loaded"; groups: CatalogPlaceholderGroupView[] }
  | { status: "error" };

type TechStepState =
  | { status: "loading" }
  | { status: "loaded"; rows: TechStepPlaceholderView[] }
  | { status: "error" };

/** Which catalogue gap the page is reviewing — off-catalog ingredients, or techniques users proposed while correcting a step (issue #130). */
type CatalogKind = "ingredients" | "techSteps";

/**
 * Off-catalog review. Two lists a maintainer works through to see what the
 * seeded catalog is missing: the free-text **ingredients** users typed on a
 * recipe line (grouped by normalized name), and the free-text **techniques**
 * users proposed while correcting a step (issue #130, a flat list — that's
 * rarer). Actions are deliberately minimal: mark a gap as handled (and, for
 * ingredients, purge rows no recipe references any more). Adding the real
 * catalog entry stays a manual edit of `reference-seed-data.ts` + the locale
 * files.
 */
export function CatalogPage() {
  const { t } = useTranslation();
  const [kind, setKind] = useState<CatalogKind>("ingredients");
  const [tab, setTab] = useState<CatalogTab>("pending");

  return (
    <div className="admin-page">
      <h1 className="admin-page__title">{t("admin.catalog.title")}</h1>
      <p className="admin-page__lead">{t("admin.catalog.lead")}</p>

      <div className="catalog-kinds" role="tablist">
        {(["ingredients", "techSteps"] as const).map((value) => (
          <button
            key={value}
            type="button"
            role="tab"
            aria-selected={kind === value}
            className={kind === value ? "active" : undefined}
            onClick={() => setKind(value)}
          >
            {t(`admin.catalog.kind.${value}`)}
          </button>
        ))}
      </div>

      <div className="catalog-tabs" role="tablist">
        {(["pending", "reviewed"] as const).map((value) => (
          <button
            key={value}
            type="button"
            role="tab"
            aria-selected={tab === value}
            className={tab === value ? "active" : undefined}
            onClick={() => setTab(value)}
          >
            {t(`admin.catalog.tab.${value}`)}
          </button>
        ))}
      </div>

      {kind === "ingredients" ? (
        <IngredientPlaceholders tab={tab} />
      ) : (
        <TechStepPlaceholders tab={tab} />
      )}
    </div>
  );
}

/** The off-catalog ingredient list — grouped by normalized name, with a prune-orphans action. */
function IngredientPlaceholders({ tab }: { tab: CatalogTab }) {
  const { t } = useTranslation();
  const [state, setState] = useState<IngredientState>({ status: "loading" });
  const [pendingIds, setPendingIds] = useState<number[] | null>(null);
  const [pruneMessage, setPruneMessage] = useState<string | null>(null);
  const [isPruning, setIsPruning] = useState(false);

  // Monotonic id of the most recent `load()` call — a response from an
  // earlier one (switching tabs fast, or React 18 StrictMode's double-mount
  // firing the effect twice) must not clobber the current tab's data.
  const requestSeq = useRef(0);

  const load = useCallback((forTab: CatalogTab) => {
    const seq = ++requestSeq.current;
    setState({ status: "loading" });
    adminApiClient
      .getPlaceholders(reviewedParam(forTab))
      .then((groups) => {
        if (seq === requestSeq.current) setState({ status: "loaded", groups });
      })
      .catch(() => {
        if (seq === requestSeq.current) setState({ status: "error" });
      });
  }, []);

  useEffect(() => {
    load(tab);
  }, [tab, load]);

  function markReviewed(group: CatalogPlaceholderGroupView) {
    setPendingIds(group.ingredientIds);
    adminApiClient
      .markPlaceholdersReviewed({ ingredientIds: group.ingredientIds })
      .then(() => load(tab))
      .catch(() => load(tab))
      .finally(() => setPendingIds(null));
  }

  function pruneOrphans() {
    setIsPruning(true);
    setPruneMessage(null);
    adminApiClient
      .pruneOrphanPlaceholders()
      .then(({ deleted }) => {
        setPruneMessage(
          deleted === 0
            ? t("admin.catalog.prunedNone")
            : t("admin.catalog.pruned", { count: deleted }),
        );
        load(tab);
      })
      .catch(() => setPruneMessage(t("admin.common.loadError")))
      .finally(() => setIsPruning(false));
  }

  return (
    <>
      <div className="catalog-toolbar">
        <button type="button" onClick={pruneOrphans} disabled={isPruning}>
          {isPruning ? t("admin.catalog.pruning") : t("admin.catalog.pruneOrphans")}
        </button>
      </div>
      {pruneMessage && <p className="catalog-prune-message">{pruneMessage}</p>}

      {state.status === "loading" && (
        <p className="admin-page__placeholder">{t("admin.common.loading")}</p>
      )}
      {state.status === "error" && (
        <p className="admin-page__placeholder">{t("admin.common.loadError")}</p>
      )}
      {state.status === "loaded" &&
        (state.groups.length === 0 ? (
          <p className="admin-page__placeholder">{t("admin.catalog.empty")}</p>
        ) : (
          <ul className="catalog-list">
            {state.groups.map((group) => (
              <PlaceholderGroupCard
                key={group.normalizedName}
                group={group}
                busy={pendingIds === group.ingredientIds}
                onMarkReviewed={() => markReviewed(group)}
              />
            ))}
          </ul>
        ))}
    </>
  );
}

/** The proposed-technique list (issue #130) — a flat list, each row markable as reviewed. */
function TechStepPlaceholders({ tab }: { tab: CatalogTab }) {
  const { t } = useTranslation();
  const [state, setState] = useState<TechStepState>({ status: "loading" });
  const [busyId, setBusyId] = useState<number | null>(null);
  const requestSeq = useRef(0);

  const load = useCallback((forTab: CatalogTab) => {
    const seq = ++requestSeq.current;
    setState({ status: "loading" });
    adminApiClient
      .getTechStepPlaceholders(reviewedParam(forTab))
      .then((rows) => {
        if (seq === requestSeq.current) setState({ status: "loaded", rows });
      })
      .catch(() => {
        if (seq === requestSeq.current) setState({ status: "error" });
      });
  }, []);

  useEffect(() => {
    load(tab);
  }, [tab, load]);

  function markReviewed(id: number) {
    setBusyId(id);
    adminApiClient
      .markTechStepPlaceholdersReviewed({ techStepIds: [id] })
      .then(() => load(tab))
      .catch(() => load(tab))
      .finally(() => setBusyId(null));
  }

  if (state.status === "loading") {
    return <p className="admin-page__placeholder">{t("admin.common.loading")}</p>;
  }
  if (state.status === "error") {
    return <p className="admin-page__placeholder">{t("admin.common.loadError")}</p>;
  }
  if (state.rows.length === 0) {
    return <p className="admin-page__placeholder">{t("admin.catalog.techStepEmpty")}</p>;
  }
  return (
    <ul className="catalog-list">
      {state.rows.map((row) => {
        const firstSeen = formatDate(row.createdAt);
        return (
          <li key={row.id} className="catalog-card">
            <div className="catalog-card__head">
              <h2 className="catalog-card__name">{row.displayName}</h2>
              <span className="catalog-card__count">
                {t("admin.catalog.recipeCount", { count: row.recipeCount })}
              </span>
            </div>
            {row.sampleRecipes.length > 0 && (
              <p className="catalog-card__recipes">
                {t("admin.catalog.seenIn")}{" "}
                {row.sampleRecipes.map((recipe) => recipe.name).join(", ")}
              </p>
            )}
            <div className="catalog-card__foot">
              {firstSeen && (
                <span className="catalog-card__seen">
                  {t("admin.catalog.firstSeen", { date: firstSeen })}
                </span>
              )}
              {row.reviewedAt === null && (
                <button
                  type="button"
                  onClick={() => markReviewed(row.id)}
                  disabled={busyId === row.id}
                >
                  {busyId === row.id ? t("admin.catalog.marking") : t("admin.catalog.markReviewed")}
                </button>
              )}
            </div>
          </li>
        );
      })}
    </ul>
  );
}

function PlaceholderGroupCard({
  group,
  busy,
  onMarkReviewed,
}: {
  group: CatalogPlaceholderGroupView;
  busy: boolean;
  onMarkReviewed: () => void;
}) {
  const { t } = useTranslation();
  const { headline, variants } = splitSpellings(group);
  const firstSeen = formatDate(group.firstSeenAt);

  return (
    <li className="catalog-card">
      <div className="catalog-card__head">
        <h2 className="catalog-card__name">{headline}</h2>
        <span className="catalog-card__count">
          {t("admin.catalog.recipeCount", { count: group.recipeCount })}
        </span>
      </div>

      {variants.length > 0 && (
        <p className="catalog-card__variants">
          {t("admin.catalog.alsoWritten", { variants: variants.join(" · ") })}
        </p>
      )}

      {group.sampleRecipes.length > 0 && (
        <p className="catalog-card__recipes">
          {t("admin.catalog.seenIn")} {group.sampleRecipes.map((recipe) => recipe.name).join(", ")}
        </p>
      )}

      <div className="catalog-card__foot">
        {firstSeen && (
          <span className="catalog-card__seen">
            {t("admin.catalog.firstSeen", { date: firstSeen })}
          </span>
        )}
        {!group.allReviewed && (
          <button type="button" onClick={onMarkReviewed} disabled={busy}>
            {busy ? t("admin.catalog.marking") : t("admin.catalog.markReviewed")}
          </button>
        )}
      </div>
    </li>
  );
}