/* =============================================================================
 * map_legend.ts
 * 공용 지도 범례(PLAN 569-2 · 622-2 · 624-2 · 요구 530) — 켠 겹 범례 칸 하나(줄마다 `createLegend`) + 페이지가 붙이는 덧 줄.
 *   조각 겹 범례(산사태위험 · 국유림 임도 · 경제림 · 생태자연도) = 받을 자료 없음 → 켬끔만 보고 여기서 만듦(`tileLegendRows`).
 *   받은 자료 범례 줄(수 · 넓이 · 급경사 범위 · 624-3 D03 에서 옮김) = `legendRows(on, data)` — 받은 자료 꼴은 `LegendData`
 *     (D03 옛 캔버스 자료 · B05 GL 자료 둘 다 맞음 · 받는 일은 페이지 몫).
 *   쓰는 법 = `const legend = createMapLegend("d03-plan__legend")` → `legend.show(rows, [덧 줄])` · 줄 · 덧 없으면 숨김.
 * ========================================================================== */

import { createLegend, type LegendItem } from "@ui/ui_template_flow_legend";
import { forestLegendRows } from "./map_forest_layers";
import type {
  PlanBand,
  PlanForestRoads,
  PlanLandslideZones,
  PlanRaster,
  PlanSoils,
  PlanZones,
} from "./map_layer_api";
import { hectare } from "./map_layer_data";
import {
  LANDSLIDE_LEGEND,
  LINE_KEYS,
  LINE_LAYERS,
  ZONE_COLORS,
  type MapLayerKey,
} from "./map_layer_list";
import { SLOPE_MAX_PCT, bandRatios, pctToDeg, type SlopeBand } from "./logic/map_slope_bands";

/** 지물 수만 보는 겹(옛 캔버스 자료 · GeoJSON 둘 다). */
interface Counted {
  features?: ArrayLike<unknown>;
}

/** 범례가 읽는 받은 자료 — 받은 겹만. */
export interface LegendData {
  slope: { raster: PlanRaster; bands: SlopeBand[] };
  landslideZones: { info: PlanLandslideZones };
  zones: { summary: PlanZones["summary"] };
  /** 토양형(코드 차례) 색 값 · 요약. */
  soils: { kinds: Array<{ color: string }>; summary: PlanSoils["summary"] };
  bands: { info: { stream: PlanBand; road: PlanBand } };
  water: Counted;
  building: Counted;
  road: { small: Counted };
  forestRoadFile: { info: PlanForestRoads };
  faults: { count: number; length_m: number };
  lineaments: { count: number; length_m: number };
  zeroOrder: { count: number; length_m: number };
}

export interface MapLegend {
  root: HTMLElement;
  show: (rows: LegendItem[][], tail?: HTMLElement[]) => void;
}

/** 켠 조각 겹 범례 — 산사태위험 다음 산림 셋. */
export const tileLegendRows = (on: Record<MapLayerKey, boolean>): LegendItem[][] => [
  ...(on.landslide ? [LANDSLIDE_LEGEND] : []),
  ...forestLegendRows(on),
];

/** `className` = 자리 · 꼴(페이지 CSS). */
export function createMapLegend(className: string): MapLegend {
  const root = document.createElement("div");
  root.className = className;
  root.title = "켠 겹 범례 — 받은 지형 범위 안 수 · 넓이";
  return {
    root,
    show(rows, tail = []) {
      root.replaceChildren(...rows.map((row) => createLegend(row)), ...tail);
      root.hidden = !rows.length && !tail.length;
    },
  };
}

const km = (m: number): string => `${(m / 1000).toFixed(2)} km`;

/** 급경사 범례 — 범위마다 「아래~위 %(°) · 비율」(위 = 끝 = 「↑」). */
function slopeRow({ raster, bands }: LegendData["slope"]): LegendItem[] {
  const ratios = bandRatios(raster.counts ?? [], bands);
  const deg = (pct: number): string => pctToDeg(pct).toFixed(0);
  return bands.map((band, i) => {
    const open = band.high >= SLOPE_MAX_PCT;
    const range = open
      ? `${band.low} %↑(${deg(band.low)}°↑)`
      : `${band.low}~${band.high} %(${deg(band.low)}~${deg(band.high)}°)`;
    return { label: `${range} · ${(ratios[i] * 100).toFixed(1)} %`, color: `var(${band.color})` };
  });
}

/** 산사태취약지역 범례 — 점 · 필지 · 위치 없는 시도 · 표 없는 시도 · 지적 못 받음. */
function landslideZoneRow({ info }: LegendData["landslideZones"]): LegendItem[] {
  const color = "var(--draw-map-landslide-zone)";
  const items: LegendItem[] = [
    {
      label: `산사태취약지역 점 ${info.points.length}곳`,
      color,
      kind: "dot",
      off: !info.points.length,
    },
    {
      label: `지번 맞는 필지 ${info.parcels.features?.length ?? 0}곳(테두리)`,
      color,
      kind: "dash",
      off: !info.parcels.features?.length,
    },
  ];
  for (const sido of info.sidos)
    if (!sido.located) items.push({ label: `${sido.name} 위치 없음 — 필지만`, color, off: true });
  for (const name of info.missing)
    items.push({ label: `${name} — 이 시도 자료 없음`, color: "transparent", off: true });
  if (!info.cadastral)
    items.push({ label: "지적도 못 받음 — 필지 테두리 없음", color: "transparent", off: true });
  return items;
}

/** 켠 겹의 받은 자료 범례 줄(급경사 · 조각 겹 · 산사태취약 · 보호구역 · 토양 · 띠 · 선 겹 · 물 면 · 건물 · 임도). */
export function legendRows(
  on: Record<MapLayerKey, boolean>,
  data: Partial<LegendData>,
): LegendItem[][] {
  const rows: LegendItem[][] = [];
  if (on.slope && data.slope) rows.push(slopeRow(data.slope));
  rows.push(...tileLegendRows(on)); // 조각 겹 = 받기 없음(622-2 · 공용 범례)
  if (on.landslideZones && data.landslideZones) rows.push(landslideZoneRow(data.landslideZones));
  if (on.zones && data.zones) {
    const items = Object.entries(data.zones.summary)
      .filter(([, kind]) => kind.count || kind.failed)
      .map(([key, kind]) => ({
        label: kind.failed
          ? `${kind.label} 받지 못함`
          : `${kind.label} ${kind.count}곳 ${hectare(kind.area_m2)}`,
        color: `var(${ZONE_COLORS[key]})`,
        off: !!kind.failed,
      }));
    rows.push(
      items.length
        ? items
        : [{ label: "보호 · 규제 구역 없음(받은 범위 안)", color: "transparent", off: true }],
    );
  }
  if (on.soils && data.soils) {
    const { kinds, summary } = data.soils;
    rows.push(
      summary.length
        ? summary.map((soil, i) => ({
            label: `${soil.name} ${hectare(soil.area_m2)}`,
            color: `var(${kinds[i].color})`,
          }))
        : [{ label: "산림입지도 없음(받은 범위 안)", color: "transparent", off: true }],
    );
  }
  if (on.bands && data.bands) {
    const { stream, road } = data.bands.info;
    rows.push([
      {
        label: `계류 ${stream.dist_m} m 띠 ${hectare(stream.area_m2)} (${(stream.ratio * 100).toFixed(1)} %)`,
        color: "var(--draw-map-band-stream)",
      },
      {
        label: `도로 ${road.dist_m} m 띠 ${hectare(road.area_m2)} (${(road.ratio * 100).toFixed(1)} %)`,
        color: "var(--draw-map-band-road)",
      },
    ]);
  }
  const lines = LINE_KEYS.flatMap((key) => {
    const got = on[key] && data[key];
    if (!got) return [];
    const { label, color, dash } = LINE_LAYERS[key];
    return [
      {
        label: `${label} ${got.count}가닥 ${km(got.length_m)}`,
        color: `var(${color})`,
        kind: dash.length ? ("dash" as const) : ("line" as const),
        off: !got.count,
      },
    ];
  });
  if (lines.length) rows.push(lines);
  const tail: LegendItem[] = [];
  if (on.water && data.water)
    tail.push({
      label: `물 면 ${data.water.features?.length ?? 0}곳`,
      color: "var(--draw-map-water)",
    });
  if (on.building && data.building)
    tail.push({
      label: `건물 ${(data.building.features?.length ?? 0).toLocaleString()}동`,
      color: "var(--draw-map-building)",
    });
  if (on.forestRoad && data.road)
    tail.push({
      label: `임도 짐작 ${data.road.small.features?.length ?? 0}가닥`,
      color: "var(--draw-map-forest-road)",
      kind: "dash",
    });
  if (on.forestRoadFile && data.forestRoadFile)
    tail.push({
      label: `올린 임도망도 ${data.forestRoadFile.info.count}가닥 ${km(data.forestRoadFile.info.length_m)}`,
      color: "var(--draw-map-forest-road-file)",
      kind: "line",
    });
  if (tail.length) rows.push(tail);
  return rows;
}