/* =============================================================================
 * M02_MasterTemplete_TreePanel.ts
 * 관리 화면(마스터 · 회사 · 개인 공용) 좌측 「항목 나무」 — 폴더 → … → 항목(깊이 자유) · 찾기.
 * 항목을 누르면 표에서 그 열이 골라짐(카드 넷은 표가 엶) · 표에서 열을 고르면 `select` 로 나무도 그 항목.
 * 오른쪽 클릭 · 키보드(F2 · Delete)로 폴더 · 항목 더하기 · 이름 바꾸기 · 옮기기 · 지우기 —
 * `POST /api/m02/layers/{층}/tree`(PLAN 26-1). 읽기만 층은 메뉴 · 키 없음. 나무 자료는 `_Model`.
 * ========================================================================== */

import "./M02_MasterTemplete_TreePanel.css";
import { createInputField, el, showConfirmDialog, showToast } from "@ui/ui_template_elements";
import { t as L } from "@ui/ui_template_locale";
import {
  createTreeRow,
  openTreeMenu,
  renderTree,
  type MakeRow,
  type TreeMenuItem,
  type TreeNode,
} from "@ui/ui_template_tree";
import {
  StaleError,
  editTree,
  fetchTree,
  type Layer,
  type TreeEdit,
  type TreeItem,
  type TreeNote,
  type TreeView,
} from "./M02_MasterTemplete_Api_Fetch";
import { askFolder, askText } from "./M02_MasterTemplete_TreePanel_Dialogs";
import {
  ancestorsOf,
  buildFolders,
  countItems,
  folderIdOf,
  folderOf,
  isUnder,
  itemIdOf,
  leafName,
  listFolders,
  samePath,
  type FolderNode,
} from "./M02_MasterTemplete_TreePanel_Model";

export interface TreePanelOptions {
  layer: Layer;
  /** 이 층을 고칠 수 있나 — 아니면 메뉴 · 키 없음 */
  canEdit: boolean;
  /** 항목을 누름 — 표에서 그 열을 고름 */
  onPick: (item: TreeItem) => void;
  /** 고치기 전에 저장 안 한 표 고침을 처리 — 취소면 false · 저장했으면 "changed" */
  settle: () => Promise<false | "clean" | "changed">;
  /** 나무가 바뀜 — 표를 다시 읽고 그 열(`colId`)을 고름 */
  onChanged: (colId: string | null) => Promise<void>;
}

export interface TreePanelHandle {
  root: HTMLElement;
  refresh: () => Promise<void>;
  /** 표에서 고른 열을 나무에 표시(null = 지움) */
  select: (colId: string | null) => void;
}

type Target = { kind: "folder"; path: string[] } | { kind: "item"; item: TreeItem };

const why = (error: unknown): string => (error instanceof Error ? error.message : "");
const hint = (text: string): HTMLElement => el("p", { className: "m02-tree__hint", text });

export function createTreePanel(opt: TreePanelOptions): TreePanelHandle {
  const layerLabel = L(
    opt.layer === "company"
      ? "M02_PickerCompany"
      : opt.layer === "personal"
        ? "M02_PickerPersonal"
        : "M02_PickerSystem",
  );
  let view: TreeView | null = null;
  let text = "";
  let activeCol: string | null = null;
  let seq = 0;
  let busy = false;
  const open = new Set<string>([folderIdOf([])]);
  const targets = new Map<string, Target>();

  const search = createInputField({ placeholder: L("M02_TreeSearch"), compact: true });
  const body = el("div", { className: "m02-tree__body", attrs: { tabindex: "-1" } });
  const root = el("div", { className: "m02-tree", children: [search.root, body] });

  /* --- 그리기 --- */
  const menuOf = (target: Target): TreeMenuItem[] => {
    const isTop = target.kind === "folder" && !target.path.length;
    return [
      ...(target.kind === "folder"
        ? [
            { label: L("M02_TreeAddFolder"), run: () => void addFolder(target.path) },
            { label: L("M02_TreeAddItem"), run: () => void addItem(target.path) },
          ]
        : []),
      ...(isTop
        ? []
        : [
            { label: L("M02_TreeRename"), run: () => void rename(target) },
            { label: L("M02_TreeMove"), run: () => void move(target) },
            { label: L("M02_Delete"), run: () => void remove(target) },
          ]),
    ];
  };

  function node(target: Target, base: Omit<TreeNode, "id" | "menu">, id: string): TreeNode {
    targets.set(id, target);
    return { ...base, id, ...(opt.canEdit ? { menu: () => menuOf(target) } : {}) };
  }

  function folderNode(folder: FolderNode, searching: boolean): TreeNode {
    const id = folderIdOf(folder.path);
    const kids = [
      ...folder.folders.map((one) => folderNode(one, searching)),
      ...folder.items.map((item) =>
        node(
          { kind: "item", item },
          {
            label: leafName(item),
            count: null,
            tip: `${item.이름} · ${item.key}`,
            run: () => opt.onPick(item),
          },
          itemIdOf(item),
        ),
      ),
    ];
    return node(
      { kind: "folder", path: folder.path },
      {
        label: folder.path.length ? folder.path[folder.path.length - 1] : layerLabel,
        count: countItems(folder),
        children: kids,
        open: searching || open.has(id),
        run: () => void (open.has(id) ? open.delete(id) : open.add(id)),
      },
      id,
    );
  }

  const make: MakeRow = (one, caret, depth, onClick) => {
    const button = createTreeRow(one, caret, depth, onClick);
    button.dataset.node = one.id;
    button.classList.toggle("is-active", !!activeCol && one.id === `i|${activeCol}`);
    return button;
  };

  function paint(): void {
    const focused = (document.activeElement as HTMLElement | null)?.dataset?.node;
    targets.clear();
    if (!view) return body.replaceChildren(hint(L("M02_PickerLoading")));
    const searching = text.trim() !== "";
    const tree = buildFolders(view, text);
    const none = countItems(tree) === 0 && (searching || !tree.folders.length);
    body.replaceChildren(
      ...renderTree([folderNode(tree, searching)], make),
      ...(none
        ? [
            hint(
              L(searching ? "M02_TreeNoHit" : opt.canEdit ? "M02_TreeEmptyEdit" : "M02_TreeEmpty"),
            ),
          ]
        : []),
    );
    if (focused) rowOf(focused)?.focus({ preventScroll: true });
  }

  const rowOf = (id: string): HTMLElement | null =>
    [...body.querySelectorAll<HTMLElement>("[data-node]")].find((b) => b.dataset.node === id) ??
    null;

  async function refresh(): Promise<void> {
    const mine = ++seq;
    try {
      const got = await fetchTree(opt.layer);
      if (mine !== seq) return;
      view = got;
    } catch (error) {
      if (mine !== seq) return;
      view = null;
      body.replaceChildren(hint(L("M02_PickerLoadFailed").replace("{value}", why(error))));
      return;
    }
    paint();
  }

  function select(colId: string | null): void {
    activeCol = colId;
    const need =
      view && colId ? ancestorsOf(view, colId).filter((p) => !open.has(folderIdOf(p))) : [];
    if (need.length) {
      need.forEach((p) => open.add(folderIdOf(p)));
      paint();
    } else {
      body
        .querySelectorAll<HTMLElement>("[data-node]")
        .forEach((b) =>
          b.classList.toggle("is-active", !!colId && b.dataset.node === `i|${colId}`),
        );
    }
    if (colId) rowOf(`i|${colId}`)?.scrollIntoView({ block: "nearest" });
  }

  /* --- 고치기 --- */
  /** 저장 안 한 표 고침 처리 → (바뀌었으면 나무 다시 읽음) → 참이면 계속 */
  async function ready(): Promise<boolean> {
    const settled = await opt.settle();
    if (!settled) return false;
    if (settled === "changed") await refresh();
    return true;
  }

  async function edit(body_: TreeEdit, keepCol: string | null = activeCol): Promise<void> {
    if (!view || busy) return;
    busy = true;
    try {
      const got = await editTree(opt.layer, body_, view.판);
      view = got;
      const note: TreeNote | undefined = got.알림;
      // 새 항목은 그 열을 고름 · 지운 항목이면 고름 풀림 · 나머지는 지금 고른 열 그대로
      const gone = note?.지운항목 ?? [];
      const col = note?.열 ?? (keepCol && !gone.includes(keepCol) ? keepCol : null);
      activeCol = col;
      const parent = note?.경로 ? note.경로.slice(0, -1) : [];
      parent.forEach((_, i) => open.add(folderIdOf(parent.slice(0, i + 1))));
      if (note?.op === "add-folder" || note?.op === "rename" || note?.op === "move") {
        if (note.경로) open.add(folderIdOf(note.경로));
      }
      paint();
      showToast(L("M02_TreeDone"), "success");
      await opt.onChanged(col);
    } catch (error) {
      // 409 = 판 다름(서버 detail 이 객체 → 「HTTP 409」) 또는 같은 이름(글 까닭 — 그대로 보임)
      if (error instanceof StaleError && error.message === "HTTP 409") {
        await refresh();
        showToast(L("M02_TreeStale"), "error");
      } else {
        showToast(L("M02_ActionFailed").replace("{value}", why(error)), "error");
      }
    } finally {
      busy = false;
    }
  }

  const nameOf = (target: Target): string =>
    target.kind === "item" ? leafName(target.item) : target.path[target.path.length - 1];

  async function addFolder(parent: string[]): Promise<void> {
    if (!(await ready())) return;
    const got = await askText(L("M02_TreeAddFolder"), [
      { key: "name", label: L("M02_TreeFolderName") },
    ]);
    if (got) await edit({ op: "add-folder", 경로: parent, 이름: got.name });
  }

  async function addItem(parent: string[]): Promise<void> {
    if (!(await ready())) return;
    const got = await askText(L("M02_TreeAddItem"), [
      { key: "name", label: L("M02_TreeItemName") },
      { key: "unit", label: L("M02_TreeUnit") },
    ]);
    if (got) {
      await edit({
        op: "add-item",
        경로: parent,
        이름: got.name,
        ...(got.unit ? { 단위: got.unit } : {}),
      });
    }
  }

  async function rename(target: Target): Promise<void> {
    if (!(await ready())) return;
    const got = await askText(L("M02_TreeRename"), [
      {
        key: "name",
        label: L(target.kind === "item" ? "M02_TreeItemName" : "M02_TreeFolderName"),
        value: nameOf(target),
      },
    ]);
    if (!got || got.name === nameOf(target)) return;
    await edit(
      target.kind === "item"
        ? { op: "rename", 경로: folderOf(target.item), 키: target.item.key, 이름: got.name }
        : { op: "rename", 경로: target.path, 이름: got.name },
    );
  }

  async function move(target: Target): Promise<void> {
    if (!(await ready()) || !view) return;
    const from = target.kind === "item" ? folderOf(target.item) : target.path.slice(0, -1);
    const to = await askFolder(
      L("M02_TreeMove"),
      listFolders(buildFolders(view)),
      (path) => target.kind === "folder" && isUnder(path, target.path),
      from,
    );
    if (!to || samePath(to, from)) return;
    await edit(
      target.kind === "item"
        ? { op: "move", 경로: from, 키: target.item.key, 새경로: to }
        : { op: "move", 경로: target.path, 새경로: to },
    );
  }

  async function remove(target: Target): Promise<void> {
    if (!(await ready()) || !view) return;
    const folder =
      target.kind === "folder" ? findFolder(buildFolders(view), target.path) : undefined;
    const message =
      target.kind === "item"
        ? L("M02_TreeDeleteItem").replace("{value}", leafName(target.item))
        : L("M02_TreeDeleteFolder")
            .replace("{value}", nameOf(target))
            .replace("{n}", String(folder ? countItems(folder) : 0));
    if (!(await showConfirmDialog(message, L("M02_Delete")))) return;
    await edit(
      target.kind === "item"
        ? { op: "delete", 경로: folderOf(target.item), 키: target.item.key }
        : { op: "delete", 경로: target.path },
    );
  }

  const findFolder = (from: FolderNode, path: string[]): FolderNode | undefined =>
    samePath(from.path, path)
      ? from
      : from.folders.map((one) => findFolder(one, path)).find(Boolean);

  /* --- 이음 --- */
  search.input.addEventListener("input", () => {
    text = search.input.value;
    paint();
  });

  // 빈 자리 오른쪽 클릭 = 맨 위 메뉴(폴더 · 항목 더하기)
  body.addEventListener("contextmenu", (event) => {
    if (!opt.canEdit || (event.target as HTMLElement).closest("[data-node]")) return;
    event.preventDefault();
    openTreeMenu(event, menuOf({ kind: "folder", path: [] }).slice(0, 2));
  });

  body.addEventListener("keydown", (event) => {
    const row = (event.target as HTMLElement).closest<HTMLElement>("[data-node]");
    if (!row) return;
    const rows = [...body.querySelectorAll<HTMLElement>("[data-node]")].filter(
      (b) => !b.closest("[hidden]"),
    );
    const at = rows.indexOf(row);
    const caret = row.querySelector(".ui-tree__caret")?.textContent;
    const target = targets.get(row.dataset.node ?? "");
    if (event.key === "ArrowDown" || event.key === "ArrowUp") {
      event.preventDefault();
      rows[at + (event.key === "ArrowDown" ? 1 : -1)]?.focus();
    } else if (
      (event.key === "ArrowRight" && caret === "▸") ||
      (event.key === "ArrowLeft" && caret === "▾")
    ) {
      event.preventDefault();
      row.click();
    } else if (opt.canEdit && target && event.key === "F2") {
      event.preventDefault();
      if (!(target.kind === "folder" && !target.path.length)) void rename(target);
    } else if (opt.canEdit && target && event.key === "Delete") {
      event.preventDefault();
      if (!(target.kind === "folder" && !target.path.length)) void remove(target);
    }
  });

  return { root, refresh, select };
}