/* =============================================================================
 * B06_wf3_ProfileCross_UI_Cross_Design.ts
 * 측점 표준횡단 설계 지정 컨트롤(지반유형·단면유형·측구위치)과 설계선 오버레이.
 *
 * 카드 헤더 아래에 세그먼트 버튼을 배치하고, 지반유형·단면유형이 모두 선택되면
 * onChange로 계산을 요청한다. 계산 결과(section.design)는 상위에서 다시 렌더될 때
 * 절·성토 단면적 표시와 설계선 오버레이로 반영된다. 편절편성은 측구위치가 자동
 * 결정되어 컨트롤을 숨기고, 양절·양성에서만 배수 방향 선택을 노출한다.
 * ========================================================================== */

import { currentLanguageIndex, ui_locales } from "@ui/ui_template_locale";
import type {
  CrossDesign,
  CrossSection,
  DitchSide,
  GroundType,
  SectionMode,
} from "./B06_wf3_ProfileCross_Api_Fetch";

const SVG_NS = "http://www.w3.org/2000/svg";

function L(key: keyof typeof ui_locales): string {
  return ui_locales[key][currentLanguageIndex];
}

const GROUND_OPTIONS: Array<[GroundType, keyof typeof ui_locales]> = [
  ["soil", "B06_Design_Ground_Soil"],
  ["ripping_rock", "B06_Design_Ground_Ripping"],
  ["blasting_rock", "B06_Design_Ground_Blasting"],
];
const MODE_OPTIONS: Array<[SectionMode, keyof typeof ui_locales]> = [
  ["left_cut", "B06_Design_Mode_LeftCut"],
  ["right_cut", "B06_Design_Mode_RightCut"],
  ["both_cut", "B06_Design_Mode_BothCut"],
  ["both_fill", "B06_Design_Mode_BothFill"],
];
const DITCH_OPTIONS: Array<[DitchSide, keyof typeof ui_locales]> = [
  ["left", "B06_Design_Ditch_Left"],
  ["right", "B06_Design_Ditch_Right"],
];

export interface CrossDesignChange {
  ground_type: GroundType;
  section_mode: SectionMode;
  ditch_side: DitchSide | null;
}

function segment<T extends string>(
  legend: string,
  options: Array<[T, keyof typeof ui_locales]>,
  selected: T | null,
  onPick: (value: T) => void,
): HTMLElement {
  const wrap = document.createElement("div");
  wrap.className = "b06-design__seg";
  const legendEl = document.createElement("span");
  legendEl.className = "b06-design__seg-legend";
  legendEl.textContent = legend;
  wrap.append(legendEl);
  const group = document.createElement("div");
  group.className = "b06-design__seg-buttons";
  for (const [value, labelKey] of options) {
    const button = document.createElement("button");
    button.type = "button";
    button.className = `b06-design__btn${value === selected ? " b06-design__btn--active" : ""}`;
    button.textContent = L(labelKey);
    button.setAttribute("aria-pressed", value === selected ? "true" : "false");
    button.addEventListener("click", () => onPick(value));
    group.append(button);
  }
  wrap.append(group);
  return wrap;
}

/** 카드 헤더용 설계 지정 컨트롤 바를 만든다. */
export function buildDesignControls(
  section: CrossSection,
  onChange: (chainageM: number, change: CrossDesignChange) => void,
): HTMLElement {
  const design = section.design;
  // 기본값: 토사(soil) + 좌절토(left_cut). 미지정 측점은 확정 시 이 기본값으로 채워진다.
  const state: { ground: GroundType; mode: SectionMode; ditch: DitchSide | null } = {
    ground: design?.ground_type ?? "soil",
    mode: design?.section_mode ?? "left_cut",
    ditch: design?.ditch_side ?? null,
  };
  const bar = document.createElement("div");
  bar.className = "b06-design";
  // 컨트롤 상호작용이 카드 선택 클릭으로 전파되지 않게 한다.
  bar.addEventListener("click", (event) => event.stopPropagation());

  const needsDitch = (): boolean => state.mode === "both_cut" || state.mode === "both_fill";
  const emit = (): void => {
    if (!state.ground || !state.mode) return;
    onChange(section.chainage_m, {
      ground_type: state.ground,
      section_mode: state.mode,
      ditch_side: needsDitch() ? (state.ditch ?? "left") : null,
    });
  };

  bar.append(
    segment(L("B06_Design_Ground_Legend"), GROUND_OPTIONS, state.ground, (value) => {
      state.ground = value;
      emit();
    }),
    segment(L("B06_Design_Mode_Legend"), MODE_OPTIONS, state.mode, (value) => {
      state.mode = value;
      emit();
    }),
  );
  if (needsDitch()) {
    bar.append(
      segment(L("B06_Design_Ditch_Legend"), DITCH_OPTIONS, state.ditch, (value) => {
        state.ditch = value;
        emit();
      }),
    );
  }

  const readout = document.createElement("div");
  readout.className = "b06-design__areas";
  if (design) {
    const cut = document.createElement("span");
    cut.className = "b06-design__area b06-design__area--cut";
    cut.textContent = `${L("B06_Design_Cut_Area")} ${design.cut_area_m2.toFixed(2)}㎡`;
    const fill = document.createElement("span");
    fill.className = "b06-design__area b06-design__area--fill";
    fill.textContent = `${L("B06_Design_Fill_Area")} ${design.fill_area_m2.toFixed(2)}㎡`;
    readout.append(cut, fill);
  } else {
    const unset = document.createElement("span");
    unset.className = "b06-design__area b06-design__area--unset";
    unset.textContent = L("B06_Design_Unset");
    readout.append(unset);
  }
  bar.append(readout);
  return bar;
}

/** 횡단 SVG에 표준단면 설계선을 겹쳐 그린다. */
export function appendCrossDesignOverlay(
  svg: SVGSVGElement,
  design: CrossDesign,
  x: (offset: number) => number,
  toDisplayY: (elevation: number) => number,
): void {
  const line = design.design_line;
  if (!line || line.length < 2) return;
  const points = line.map((point) => `${x(point.offset_m)},${toDisplayY(point.elevation_m)}`);
  const polyline = document.createElementNS(SVG_NS, "polyline");
  polyline.setAttribute("points", points.join(" "));
  polyline.setAttribute("class", "b06-chart__design-cross");
  svg.append(polyline);
}