/* =============================================================================
 * ui_template_item_picker.ts
 * 항목 고르기 모달 — 구조물집계표 항목(SS 한 줄)을 마스터 · 회사 · 개인 세 그룹 나무에서 고름.
 * 키(SS · UA …)는 앞에 내세우지 않고 이름으로 보임 · 키는 마우스를 올리면(PLAN.md 21-0).
 *
 *   const result = await openItemPicker({ current, canCopy });
 *   result.action = "apply"(result.item = 21-1 `summary_item`) | "clear" | "cancel"
 * ========================================================================== */

import "./ui_template_item_picker.css";
import { API_BASE_URL } from "@config/config_frontend";
import { createButton, createInputField, el, showToast } from "./ui_template_elements";
import {
  buildTree,
  filterRows,
  folderLines,
  isCurrent,
  itemName,
  layerOf,
  ownerOf,
  pathIds,
  rowId,
  rowTip,
  shown,
  toSummary,
  type FolderKind,
  type PickNode,
  type PickerLayer,
  type PickerRow,
  type SummaryItem,
  type TreeLabels,
} from "./ui_template_item_picker_data";
import { t } from "./ui_template_locale";
import { openModal } from "./ui_template_modal";
import { createTreeRow, renderTree, type TreeNode } from "./ui_template_tree";

export type { SummaryItem } from "./ui_template_item_picker_data";

export interface ItemPickerOptions {
  /** 지금 지정된 항목 — 없으면 null */
  current: SummaryItem | null;
  /** [개인용으로 복사]를 쓸 수 있나 — 개인 층에 쓸 수 있을 때(회사 등록 뒤) */
  canCopy: boolean;
}

export type ItemPickerResult =
  { action: "apply"; item: SummaryItem } | { action: "clear" } | { action: "cancel" };

const MANAGE_HASH = "#/m02-master-template?layer=personal";

const FOLDER_LABEL: Record<FolderKind, () => string> = {
  drawing: () => t("M02_PickerDrawing"),
  area: () => t("M02_PickerArea"),
  material: () => t("M02_PickerMaterial"),
  combo: () => t("M02_PickerCombo"),
  unitPrice: () => t("M02_PickerUnitPrice"),
};

const labels = (): TreeLabels => ({
  layers: {
    system: t("M02_PickerSystem"),
    company: t("M02_PickerCompany"),
    personal: t("M02_PickerPersonal"),
  },
  unclassified: t("M02_PickerNoClass"),
});

/** 서버가 막은 까닭 그대로 */
function reasonOf(body: unknown, status: number): string {
  const detail = (body as { detail?: unknown } | null)?.detail;
  return typeof detail === "string" && detail ? detail : `HTTP ${status}`;
}

/** `GET /api/m02/items?all=1` = `[{layer, owner, items}]` — 줄마다 `layer` · `owner` 를 붙여 하나로 폄 */
async function loadRows(): Promise<PickerRow[]> {
  const response = await fetch(`${API_BASE_URL}/m02/items?all=1`, { credentials: "include" });
  const body = (await response.json().catch(() => null)) as
    | { layer: PickerLayer; owner: string | null; items: PickerRow[] }[]
    | { detail?: unknown }
    | null;
  if (!response.ok || !Array.isArray(body)) throw new Error(reasonOf(body, response.status));
  return body.flatMap((group) =>
    group.items.map((item) => ({ ...item, layer: group.layer, owner: group.owner })),
  );
}

/** 개인용으로 복사 — 새로 생긴 줄의 키를 돌려줌(서버가 안 주면 null) */
async function copyToPersonal(row: PickerRow): Promise<string | null> {
  const response = await fetch(`${API_BASE_URL}/m02/layers/personal/items/copy`, {
    method: "POST",
    credentials: "include",
    headers: { "Content-Type": "application/json" },
    body: JSON.stringify({ from_layer: layerOf(row), from_owner: ownerOf(row), key: row.key }),
  });
  const body = (await response.json().catch(() => null)) as { key?: string } | null;
  if (!response.ok) throw new Error(reasonOf(body, response.status));
  return body?.key ?? null;
}

const message = (error: unknown): string =>
  error instanceof Error ? error.message : String(error);

export function openItemPicker(opts: ItemPickerOptions): Promise<ItemPickerResult> {
  return new Promise((resolve) => {
    let rows: PickerRow[] = [];
    let chosen: PickerRow | null = null;
    /** 접었다 펼친 것을 다시 그려도 남기려고 펼친 줄 id 를 기억 */
    const opened = new Set<string>();
    const leafButtons = new Map<string, HTMLElement>();

    const search = createInputField({ placeholder: t("M02_PickerSearch"), compact: true });
    const treeHost = el("div", { className: "ui-item-picker__tree" });
    const detail = el("div", { className: "ui-item-picker__detail" });
    const applyButton = createButton({ label: t("M02_PickerApply"), variant: "filled" });
    const clearButton = createButton({ label: t("M02_PickerClear"), variant: "ghost" });
    const copyButton = createButton({ label: t("M02_PickerCopy"), variant: "ghost" });
    const manageButton = createButton({ label: t("M02_PickerManage"), variant: "ghost" });
    let close = (): void => {};

    const finish = (result: ItemPickerResult): void => {
      resolve(result);
      close();
    };

    const hint = (text: string): HTMLElement =>
      el("p", { className: "ui-item-picker__hint", text });

    const paintDetail = (): void => {
      if (!chosen) {
        detail.replaceChildren(hint(t("M02_PickerHint")));
      } else {
        const where = [labels().layers[layerOf(chosen)], shown(chosen.종류), shown(chosen.분류1)]
          .filter(Boolean)
          .join(" › ");
        const small = (text: string): HTMLElement =>
          el("p", { className: "ui-item-picker__where", text });
        detail.replaceChildren(
          el("h4", {
            className: "ui-item-picker__name",
            text: itemName(chosen),
            attrs: { title: rowTip(chosen, labels()) },
          }),
          small(where),
          ...(chosen.단위 ? [small(`${t("M02_PickerUnit")} ${chosen.단위}`)] : []),
          el("ul", {
            className: "ui-item-picker__folder",
            children: folderLines(chosen).map((line) =>
              el("li", {
                attrs: line.name && line.key ? { title: line.key } : {},
                children: [
                  el("span", {
                    className: "ui-item-picker__folder-label",
                    text: FOLDER_LABEL[line.kind](),
                  }),
                  // 이름이 있으면 이름(키는 툴팁) · 없으면 키를 작은 글로 · 둘 다 없으면 「없음」
                  el("span", {
                    className: line.name
                      ? ""
                      : line.key
                        ? "ui-item-picker__key"
                        : "ui-item-picker__none",
                    text: line.name || line.key || t("M02_PickerNone"),
                  }),
                ],
              }),
            ),
          }),
        );
      }
      const layer = chosen ? layerOf(chosen) : null;
      applyButton.disabled = !chosen;
      clearButton.disabled = !opts.current;
      copyButton.hidden = !(chosen && layer !== "personal" && opts.canCopy);
      manageButton.hidden = !(chosen && layer === "personal");
    };

    const choose = (row: PickerRow): void => {
      chosen = row;
      for (const [id, button] of leafButtons)
        button.classList.toggle("is-active", id === rowId(row));
      paintDetail();
    };

    const toTree = (node: PickNode, searching: boolean): TreeNode => ({
      id: node.id,
      label: node.label,
      count: node.count,
      tip: node.tip,
      open: searching || opened.has(node.id),
      run: node.row ? () => choose(node.row as PickerRow) : undefined,
      children: node.children?.map((child) => toTree(child, searching)),
    });

    const paintTree = (): void => {
      leafButtons.clear();
      const text = search.input.value;
      const searching = text.trim() !== "";
      const groups = buildTree(filterRows(rows, text), labels())
        // 찾는 중에는 결과가 없는 그룹을 감춤
        .filter((group) => !searching || (group.count ?? 0) > 0)
        .map((group) => toTree(group, searching));
      if (!groups.length) {
        treeHost.replaceChildren(hint(t("M02_PickerNoMatch")));
        return;
      }
      treeHost.replaceChildren(
        ...renderTree(groups, (node, caret, depth, onClick) => {
          const button = createTreeRow(node, caret, depth, () => {
            onClick();
            if (!node.children?.length) return;
            if (button.querySelector(".ui-tree__caret")?.textContent === "▾") opened.add(node.id);
            else opened.delete(node.id);
          });
          if (node.run) {
            leafButtons.set(node.id, button);
            if (chosen && node.id === rowId(chosen)) button.classList.add("is-active");
          }
          return button;
        }),
      );
    };

    const load = async (pickKey: string | null): Promise<void> => {
      treeHost.replaceChildren(hint(t("M02_PickerLoading")));
      try {
        rows = await loadRows();
      } catch (error) {
        treeHost.replaceChildren(
          hint(t("M02_PickerLoadFailed").replace("{value}", message(error))),
        );
        return;
      }
      const start = pickKey
        ? rows.find((row) => layerOf(row) === "personal" && row.key === pickKey)
        : rows.find((row) => isCurrent(opts.current, row));
      if (start) {
        for (const id of pathIds(start, labels())) opened.add(id);
        chosen = start;
      } else {
        opened.add("system"); // 지정된 게 없으면 첫 그룹만 펼침
      }
      paintTree();
      paintDetail();
      treeHost.querySelector(".is-active")?.scrollIntoView({ block: "nearest" });
    };

    search.input.addEventListener("input", paintTree);
    applyButton.addEventListener(
      "click",
      () => chosen && finish({ action: "apply", item: toSummary(chosen) }),
    );
    clearButton.addEventListener("click", () => finish({ action: "clear" }));
    manageButton.addEventListener("click", () => {
      finish({ action: "cancel" });
      location.hash = MANAGE_HASH;
    });
    copyButton.addEventListener("click", async () => {
      if (!chosen) return;
      copyButton.disabled = true;
      try {
        const key = await copyToPersonal(chosen);
        showToast(t("M02_PickerCopied"), "success");
        await load(key);
      } catch (error) {
        showToast(t("M02_PickerCopyFailed").replace("{value}", message(error)), "error");
      } finally {
        copyButton.disabled = false;
      }
    });

    close = openModal({
      title: t("M02_PickerTitle"),
      closeLabel: t("M02_Close"),
      dialogClass: "ui-item-picker",
      // 닫기 단추 · Esc · 바깥 누르기 = 취소
      beforeClose: () => {
        resolve({ action: "cancel" });
        return true;
      },
      mount: (body) => {
        body.append(
          el("div", {
            className: "ui-item-picker__cols",
            children: [
              el("div", { className: "ui-item-picker__left", children: [search.root, treeHost] }),
              detail,
            ],
          }),
          el("div", {
            className: "ui-item-picker__actions",
            children: [copyButton, manageButton, clearButton, applyButton],
          }),
        );
        paintDetail();
        void load(null);
      },
    }).close;
  });
}