/* =============================================================================
 * M02_DF_RoundRow.ts
 * 끝수 고르기 줄 — 소수 몇 자리 · 반올림/올림/버림 · 단위 표준에서 자리 제안(적용 단추)
 * 모양은 M02_DF_Model 의 CfRound · 칸 · 단추는 공용 작은 크기 · 글 [한, 영] 짝은 아래 TEXT
 * ========================================================================== */

import { currentLanguageIndex } from "@ui/ui_template_locale";
import { createButton, el } from "@ui/ui_template_elements";
import type { CfRound } from "./M02_DF_Model";

const TEXT = {
  Label: ["끝수", "Rounding"],
  None: ["안 씀", "none"],
  Places: ["소수 {n}자리", "{n} decimals"],
  Suggest: ["표준 제안: 소수 {n}자리", "Standard suggests {n} decimals"],
  Apply: ["적용", "Apply"],
  PlacesAria: ["소수자리", "Decimal places"],
  ModeAria: ["방법", "Method"],
} as const;

const METHODS: CfRound["method"][] = ["반올림", "올림", "버림"];

const tr = (key: keyof typeof TEXT, n?: number): string =>
  TEXT[key][currentLanguageIndex === 1 ? 1 : 0].replace("{n}", String(n ?? ""));

export interface RoundRowOptions {
  /** 지금 끝수 — 없으면 undefined */
  round: CfRound | undefined;
  /** 단위 표준이 제안한 소수자리 */
  suggest: number | null;
  readOnly?: boolean;
  /** null = 끝수 벗김 */
  onApply(round: CfRound | null): void;
}

export function createRoundRow(opts: RoundRowOptions): HTMLElement {
  const now = opts.round ?? null;
  const places = el("select", {
    className: "ui-select ui-select--sm",
    attrs: { "aria-label": tr("PlacesAria") },
  });
  places.append(el("option", { attrs: { value: "" }, text: tr("None") }));
  for (let n = 0; n <= 6; n++) {
    places.append(el("option", { attrs: { value: String(n) }, text: tr("Places", n) }));
  }
  places.value = now ? String(now.places) : "";
  const method = el("select", {
    className: "ui-select ui-select--sm",
    attrs: { "aria-label": tr("ModeAria") },
  });
  for (const m of METHODS) method.append(el("option", { attrs: { value: m }, text: m }));
  method.value = now?.method ?? "반올림";
  if (opts.readOnly) places.disabled = method.disabled = true;
  const emit = (): void =>
    opts.onApply(
      places.value === ""
        ? null
        : { places: Number(places.value), method: method.value as CfRound["method"] },
    );
  places.addEventListener("change", emit);
  method.addEventListener("change", () => places.value !== "" && emit());
  const row = el("div", {
    className: "m02-dfpanel-row",
    children: [el("span", { className: "m02-dfpanel-label", text: tr("Label") }), places, method],
  });
  if (opts.suggest !== null && !now && !opts.readOnly) {
    row.append(
      el("span", { className: "m02-dfpanel-note", text: tr("Suggest", opts.suggest) }),
      createButton({
        label: tr("Apply"),
        variant: "ghost",
        size: "sm",
        onClick: () => opts.onApply({ places: opts.suggest!, method: "반올림" }),
      }),
    );
  }
  return row;
}