/* =============================================================================
 * D03_PlanAnalysis_UI_Layers.ts
 * D03 평면 바탕 겹 켜고 끔(PLAN 569-2 · 요구 395-2) — 지도 왼쪽 위 아이콘 한 줄(도구줄과 따로).
 *
 *   겹 = 위성 · 도엽 등고선(계곡선 25 m 굵게 · 수치) · 세류선(가는 파랑) · 하천(굵은 파랑) · 지적도 ·
 *        기존 도로(도엽 도로중심선) · 급경사 색(15° · 35° · 40° · 범례 작은 칸).
 *   처음 켬 = 위성 · 등고선 · 세류 · 고른 값 = 화면 취향(`aislo:pref:d03.layers`) 기억.
 *   받기 = 켤 때만(한 번 받으면 다시 안 받음) · 지형을 안 받았으면 단추를 막음.
 *   그리기 차례(아래 → 위) = 위성(`scene.image`) → 급경사 → 지적 → 등고선 → 도로 → 세류 → 그은 선.
 * ========================================================================== */

import { createIconButton } from "@ui/ui_template_button";
import { showToast } from "@ui/ui_template_elements";
import { createLegend } from "@ui/ui_template_flow_legend";
import type { IconName } from "@ui/ui_template_icons";
import { themeColor } from "@ui/ui_template_palette";
import { createToolbar } from "@ui/ui_template_toolbar";
import { fetchCachedSheetLayer } from "../A00_Common/b_asset_cache";
import { readByKey, writeByKey } from "../A00_Common/b_page_state";
import {
  fetchVWorldMeta,
  getVWorldMapUrl,
  type VWorldMeta,
} from "../B04_PreProcess/B04_PreProcess_Api_Fetch";
import {
  createNormalizer,
  drawPreparedLabels,
  drawPreparedLayer,
  pickLevelStep,
  type GeoJsonCollection,
  type PreparedLayer,
} from "../B04_PreProcess/B04_PreProcess_UI_MapRender";
import { prepareLayer } from "../B04_PreProcess/logic/B04_PreProcess_UI_MapRender_Prepare";
import {
  fetchPlanCadastral,
  fetchPlanRaster,
  fetchPlanSheetLayer,
  type PlanRaster,
} from "./D03_PlanAnalysis_Api";
import type { PlanMap, PlanMapLayer, ScreenMap } from "./D03_PlanAnalysis_UI_Map";
import type { Vertex } from "./logic/D03_PlanAnalysis_Plan";

export type PlanLayerKey = "satellite" | "contour" | "stream" | "cadastral" | "road" | "slope";

interface LayerDef {
  key: PlanLayerKey;
  icon: IconName;
  title: string;
  on: boolean;
}

const LAYERS: readonly LayerDef[] = [
  { key: "satellite", icon: "satellite", title: "위성사진", on: true },
  { key: "contour", icon: "mountain", title: "도엽 등고선(굵은 선 = 계곡선 25 m)", on: true },
  { key: "stream", icon: "droplet", title: "세류선(가는 파랑) · 하천(굵은 파랑)", on: true },
  { key: "cadastral", icon: "borderAll", title: "지적도(참고용 · 법적 효력 없음)", on: false },
  { key: "road", icon: "road", title: "기존 도로(도엽 도로중심선)", on: false },
  { key: "slope", icon: "angle", title: "급경사 색(15° · 35° · 40° 이상)", on: false },
];
const PREF_KEY = "aislo:pref:d03.layers";
/** 등고선을 받아 올 그은 선 둘레(m). */
const CONTOUR_PAD_M = 600;

interface Prepared {
  contour: PreparedLayer;
  /** 세류 · 하천(소하천 · 지방하천 · 연결선). */
  stream: [PreparedLayer, PreparedLayer];
  cadastral: PreparedLayer;
  road: PreparedLayer;
  slope: { raster: PlanRaster; image: HTMLImageElement };
}

export interface PlanLayers {
  bar: HTMLElement;
  legend: HTMLElement;
  /** 바탕 겹(아래 → 위 · 위성 뺌) — 그은 선 겹 아래에 둠. */
  layers: PlanMapLayer[];
  /** 지형(위성 틀)을 다시 읽음 — 처음 · 지형 받은 뒤. */
  load: () => Promise<void>;
  /** 검증 창구 — 켬끔 · 받은 겹. */
  state: () => { on: Record<PlanLayerKey, boolean>; loaded: PlanLayerKey[] };
}

function readPref(): Record<PlanLayerKey, boolean> {
  const on = Object.fromEntries(LAYERS.map((def) => [def.key, def.on])) as Record<
    PlanLayerKey,
    boolean
  >;
  try {
    const saved = JSON.parse(readByKey(PREF_KEY) ?? "{}") as Partial<Record<PlanLayerKey, unknown>>;
    for (const def of LAYERS)
      if (typeof saved[def.key] === "boolean") on[def.key] = saved[def.key] as boolean;
  } catch {
    // 깨진 값 = 처음 값
  }
  return on;
}

const loadImage = (src: string): Promise<HTMLImageElement> =>
  new Promise((done, fail) => {
    const image = new Image();
    image.onload = () => done(image);
    image.onerror = () => fail(new Error("그림을 읽지 못했습니다"));
    image.src = src;
  });

export function createPlanLayers(opts: {
  projectId: string;
  map: PlanMap;
  /** 등고선 받을 범위를 정할 점(시점 · 종점 · 그은 선). */
  points: () => Vertex[];
}): PlanLayers {
  const { projectId, map } = opts;
  const on = readPref();
  const data: Partial<Prepared> = {};
  const pending = new Map<PlanLayerKey, Promise<void>>();
  let meta: VWorldMeta | null = null;
  let satellite: HTMLImageElement | null = null;

  const buttons = new Map<PlanLayerKey, HTMLButtonElement>();
  for (const def of LAYERS) {
    const button = createIconButton({
      icon: def.icon,
      title: def.title,
      pressed: on[def.key],
      onClick: () => toggle(def.key),
    });
    button.dataset.layer = def.key;
    buttons.set(def.key, button);
  }
  const bar = createToolbar({
    glass: true,
    size: 32,
    label: "지도 겹",
    items: [...buttons.values()],
  });
  bar.classList.add("d03-plan__layers");
  const legend = document.createElement("div");
  legend.className = "d03-plan__legend";
  legend.title = "급경사 색 — 단계 · 받은 지형 안 넓이 비율";

  function sync(): void {
    for (const def of LAYERS) {
      const button = buttons.get(def.key)!;
      button.setAttribute("aria-pressed", String(on[def.key]));
      button.disabled = !meta;
      const title = meta ? def.title : `${def.title} — 지형 받기 뒤 보임`;
      button.title = title;
      button.setAttribute("aria-label", title);
    }
    legend.hidden = !meta || !on.slope || !data.slope;
  }

  sync();

  function toggle(key: PlanLayerKey): void {
    on[key] = !on[key];
    writeByKey(PREF_KEY, JSON.stringify(on));
    void ensure(key);
    showSatellite();
    sync();
    map.redraw();
  }

  function showSatellite(): void {
    map.update({ image: on.satellite ? satellite : null });
  }

  /** 켜진 겹의 자료를 받음(한 번). */
  function ensure(key: PlanLayerKey): Promise<void> {
    if (!meta || !on[key] || (key === "satellite" ? satellite : data[key as keyof Prepared]))
      return Promise.resolve();
    const running = pending.get(key);
    if (running) return running;
    const at = meta;
    const job = fetchLayer(key, at)
      .then(() => {
        if (meta !== at) return;
        showSatellite();
        sync();
        map.redraw();
      })
      .catch((error: unknown) => {
        const text = error instanceof Error ? error.message : String(error);
        showToast(`${LAYERS.find((def) => def.key === key)!.title} 받지 못함 — ${text}`, "error");
      })
      .finally(() => pending.delete(key));
    pending.set(key, job);
    return job;
  }

  async function fetchLayer(key: PlanLayerKey, at: VWorldMeta): Promise<void> {
    const normalizer = createNormalizer(at);
    const prepare = (collection: GeoJsonCollection, labels?: string[]): PreparedLayer =>
      prepareLayer(collection, normalizer, labels);
    if (key === "satellite") {
      // 범위가 넓어지면 주소가 바뀌어 옛 그림을 안 씀
      const v = `${at.x_min}_${at.x_max}_${at.y_min}_${at.y_max}`;
      satellite = await loadImage(`${getVWorldMapUrl(projectId, "satellite")}&v=${v}`);
    } else if (key === "contour") {
      const points = opts.points();
      const xs = points.map(([x]) => x);
      const ys = points.map(([, y]) => y);
      const bbox = [
        Math.min(...xs) - CONTOUR_PAD_M,
        Math.min(...ys) - CONTOUR_PAD_M,
        Math.max(...xs) + CONTOUR_PAD_M,
        Math.max(...ys) + CONTOUR_PAD_M,
      ].map((v) => v.toFixed(0));
      const collection = await fetchCachedSheetLayer<GeoJsonCollection>(
        projectId,
        "도엽_등고선",
        "route",
        bbox.join(","),
      );
      data.contour = prepare(collection, ["등고수치"]);
    } else if (key === "stream") {
      const collection = await fetchCachedSheetLayer<GeoJsonCollection>(
        projectId,
        "도엽_하천중심선",
      );
      const pick = (small: boolean): GeoJsonCollection => ({
        ...collection,
        features: (collection.features ?? []).filter(
          (feature) => (feature.properties?.["구분"] === "세류") === small,
        ),
      });
      data.stream = [prepare(pick(true)), prepare(pick(false))];
    } else if (key === "cadastral") {
      data.cadastral = prepare(await fetchPlanCadastral(projectId));
    } else if (key === "road") {
      data.road = prepare(await fetchPlanSheetLayer(projectId, "도로중심선"));
    } else {
      const raster = await fetchPlanRaster(projectId, "slope");
      data.slope = { raster, image: await loadImage(raster.image) };
      // 범례 = 서버 단계 색 그대로(색 한 곳)
      legend.replaceChildren(
        createLegend(
          raster.bands.map((band) => ({
            label: `${band.min_deg}${band.max_deg < 90 ? `~${band.max_deg}°` : "°↑"} ${(band.ratio * 100).toFixed(1)} %`,
            color: band.color,
          })),
        ),
      );
    }
  }

  const stroke = (
    context: CanvasRenderingContext2D,
    map: ScreenMap,
    layer: PreparedLayer,
    color: string,
    width: number,
    everyM?: number,
  ): void => {
    context.strokeStyle = color;
    context.lineWidth = width;
    drawPreparedLayer(context, layer, map.view, "dot", everyM);
  };

  const layers: PlanMapLayer[] = [
    {
      draw: (context, map) => {
        const slope = on.slope && data.slope;
        if (!slope) return;
        const [x0, y0, x1, y1] = slope.raster.box_m;
        const [left, top] = map.toScreen([x0, y1]);
        const [right, bottom] = map.toScreen([x1, y0]);
        context.globalAlpha = 0.55;
        context.drawImage(slope.image, left, top, right - left, bottom - top);
      },
    },
    {
      draw: (context, map) => {
        if (!on.cadastral || !data.cadastral) return;
        context.globalAlpha = 0.8;
        stroke(context, map, data.cadastral, themeColor("--draw-map-parcel", "#f0abfc"), 0.8);
      },
    },
    {
      draw: (context, map) => {
        const contour = on.contour && data.contour;
        if (!contour) return;
        const color = themeColor("--draw-map-contour", "#ffd68c");
        context.globalAlpha = 0.7;
        stroke(context, map, contour, color, 0.8, pickLevelStep(contour, map.view, 5));
        stroke(context, map, contour, color, 1.6, 25); // 계곡선
        context.globalAlpha = 1;
        context.font = "10px system-ui, sans-serif";
        context.textAlign = "center";
        context.textBaseline = "middle";
        drawPreparedLabels(
          context,
          contour,
          map.view,
          color,
          25,
          map.uprightRad,
          "rgba(0, 0, 0, 0.6)",
        );
      },
    },
    {
      draw: (context, map) => {
        if (!on.road || !data.road) return;
        stroke(context, map, data.road, "rgba(0, 0, 0, 0.55)", 3.2);
        stroke(context, map, data.road, themeColor("--draw-map-road", "#f8fafc"), 1.6);
      },
    },
    {
      draw: (context, map) => {
        if (!on.stream || !data.stream) return;
        const color = themeColor("--draw-map-stream", "#38bdf8");
        stroke(context, map, data.stream[0], color, 1);
        stroke(context, map, data.stream[1], color, 2.4);
      },
    },
  ];

  async function load(): Promise<void> {
    const next = await fetchVWorldMeta(projectId, "satellite").catch(() => null);
    const changed =
      JSON.stringify(next && [next.x_min, next.x_max, next.y_min, next.y_max]) !==
      JSON.stringify(meta && [meta.x_min, meta.x_max, meta.y_min, meta.y_max]);
    meta = next;
    if (changed) {
      satellite = null;
      for (const key of Object.keys(data)) delete data[key as keyof Prepared];
    }
    map.update({ meta });
    showSatellite();
    sync();
    await Promise.all(LAYERS.map((def) => ensure(def.key)));
  }

  return {
    bar,
    legend,
    layers,
    load,
    state: () => ({
      on: { ...on },
      loaded: [
        ...(satellite ? (["satellite"] as PlanLayerKey[]) : []),
        ...(Object.keys(data) as PlanLayerKey[]),
      ],
    }),
  };
}