"use client";

import { useQuery } from "@tanstack/react-query";
import { fetchColonies } from "@/lib/colonies/api";
import { colonyOptionLabel } from "@/lib/colonies/labels";
import { isLivingColony } from "@/lib/colonies/status";
import type { Colony } from "@/lib/colonies/types";
import { useCurrentUserId } from "@/lib/auth/auth-context";
import {
  OFFLINE_PACKS_QUERY_KEY,
  listPacks,
  livingColoniesFromPacks,
} from "@/lib/apiaries/offline-pack";
import { isNetworkError } from "@/lib/http/fetch-with-timeout";
import { Field } from "@/components/form/field";
import { RecordSelect } from "@/components/form/record-select";

const PLACEHOLDER = "Volk wählen";
const LOADING_PLACEHOLDER = "Völker werden geladen…";
const LOAD_ERROR_HINT = "Völker konnten nicht geladen werden – bitte die Seite neu laden.";
const OFFLINE_PACK_HINT = "Offline: nur Völker der geladenen Stände.";
const OFFLINE_NOT_LOADED_HINT = "Kein Netz. Lade den Stand vorher mit „Für offline laden“.";

/** What a colony choice needs - a server colony or one from an offline pack. */
type ColonyChoice = Pick<Colony, "id" | "code" | "status" | "apiaryId">;

function useColonies() {
  return useQuery({ queryKey: ["colonies"], queryFn: () => fetchColonies() });
}

type ChoicesHint = "load-error" | "offline-not-loaded" | "from-packs";

const HINT_TEXTS: Record<ChoicesHint, string> = {
  "load-error": LOAD_ERROR_HINT,
  "offline-not-loaded": OFFLINE_NOT_LOADED_HINT,
  "from-packs": OFFLINE_PACK_HINT,
};

interface LivingColonyChoices {
  colonies: readonly ColonyChoice[] | undefined;
  isLoading: boolean;
  hint: ChoicesHint | null;
}

/**
 * Every colony from the shared ["colonies"] query - one request for every
 * colony list on the page. Only when that failed for lack of network (never
 * on a server refusal) the living colonies of the user's offline packs step
 * in, from their own query: pack colonies are partial records and never go
 * into the shared cache.
 */
function useLivingColonyChoices(): LivingColonyChoices {
  const userId = useCurrentUserId();
  const server = useColonies();
  // failureReason: offline the retry pauses, so `error` stays unset.
  const isOffline =
    server.data === undefined && isNetworkError(server.error ?? server.failureReason);
  const packs = useQuery({
    queryKey: [...OFFLINE_PACKS_QUERY_KEY, userId, "living-colonies"],
    queryFn: async () => livingColoniesFromPacks(await listPacks(userId ?? "")),
    enabled: isOffline && userId !== null,
    // Reads this device's storage, never the network.
    networkMode: "always",
  });

  if (!isOffline) {
    return {
      colonies: server.data,
      isLoading: server.isLoading,
      hint: server.isError && server.data === undefined ? "load-error" : null,
    };
  }
  const packColonies = packs.data && packs.data.length > 0 ? packs.data : undefined;
  let hint: ChoicesHint | null = "offline-not-loaded";
  if (packColonies) {
    hint = "from-packs";
  } else if (packs.isLoading) {
    hint = null;
  }
  return { colonies: packColonies, isLoading: packs.isLoading, hint };
}

interface ColonyChoicesProps {
  id: string;
  value: string;
  onChange: (colonyId: string) => void;
  /** The colonies on offer; `undefined` while loading. */
  options: readonly ColonyChoice[] | undefined;
  /** Every known colony, so a chosen one is named even if it is not offered. */
  colonies: readonly ColonyChoice[] | undefined;
  isLoading: boolean;
  dataField?: string;
  describedBy?: string;
  invalid?: boolean;
}

/** The colony select: a RecordSelect named by code and status ("V-03 (Weisellos)"). */
function ColonyChoices({ colonies, options, isLoading, ...props }: ColonyChoicesProps) {
  return (
    <RecordSelect
      {...props}
      items={options}
      labelItems={colonies}
      getLabel={colonyOptionLabel}
      placeholder={isLoading ? LOADING_PLACEHOLDER : PLACEHOLDER}
    />
  );
}

interface LivingColonySelectFieldProps {
  /** Id of the select trigger, used to focus it on a validation error. */
  triggerId: string;
  value: string;
  onChange: (colonyId: string) => void;
  error?: string | null;
  label?: string;
  /** A colony that must not be offered, e.g. the one another is merged into. */
  excludeId?: string;
  /** Shown when there is nothing to choose from. */
  emptyHint?: string;
  /** `data-field` of the trigger; the capture forms focus "colonyId" on errors. */
  dataField?: string;
}

/**
 * Picks a colony that still lives in the apiary: the one a new record
 * (inspection, varroa count, feeding, treatment, swarm control check) is filed
 * under, the colony a queen moves into, the colony merged into another.
 * Weak, conspicuous and queenless colonies are included - they need the most
 * attention - and none that has ended. A colony handed in by a link that has
 * ended since is still named, just not offered.
 *
 * Without network it offers the living colonies of the apiaries loaded for
 * offline use ("Für offline laden") and says so.
 */
export function LivingColonySelectField({
  triggerId,
  value,
  onChange,
  error,
  label = "Volk",
  excludeId,
  emptyHint = "Noch keine aktiven Völker – zuerst unter „Völker“ eines anlegen.",
  dataField = "colonyId",
}: LivingColonySelectFieldProps) {
  const { colonies, isLoading, hint: choicesHint } = useLivingColonyChoices();
  const living = colonies?.filter(
    (colony) => isLivingColony(colony) && colony.id !== excludeId,
  );

  function hint(): string | undefined {
    if (choicesHint) {
      return HINT_TEXTS[choicesHint];
    }
    return living?.length === 0 ? emptyHint : undefined;
  }

  return (
    <Field
      id={triggerId}
      label={label}
      required
      error={error}
      hint={hint()}
    >
      {({ id, describedBy, invalid }) => (
        <ColonyChoices
          id={id}
          value={value}
          onChange={onChange}
          options={living}
          colonies={colonies}
          isLoading={isLoading}
          dataField={dataField}
          describedBy={describedBy}
          invalid={invalid}
        />
      )}
    </Field>
  );
}

interface ColonySelectFieldProps {
  id: string;
  value: string;
  onChange: (colonyId: string) => void;
  label?: string;
  error?: string | null;
  dataField?: string;
}

/**
 * Picks the colony a record belongs to. Every colony-scoped record
 * (inspection, treatment, feeding, varroa measurement, swarm control check)
 * can be re-filed under a different colony after the fact, because filing one
 * against the wrong colony is a data-entry error rather than a fact of
 * beekeeping - and the only alternative repair would be deleting the record.
 *
 * Ended colonies stay in the list: a record already filed against one has
 * to remain visible and selectable, otherwise opening the form would silently
 * re-file it somewhere else.
 */
export function ColonySelectField({
  id: triggerId,
  value,
  onChange,
  label = "Volk",
  error,
  dataField,
}: ColonySelectFieldProps) {
  const { data: colonies, isLoading, isError } = useColonies();

  return (
    <Field
      id={triggerId}
      label={label}
      required
      error={error}
      hint={isError ? LOAD_ERROR_HINT : undefined}
    >
      {({ id, describedBy, invalid }) => (
        <ColonyChoices
          id={id}
          value={value}
          onChange={onChange}
          options={colonies}
          colonies={colonies}
          isLoading={isLoading}
          dataField={dataField}
          describedBy={describedBy}
          invalid={invalid}
        />
      )}
    </Field>
  );
}