/* =============================================================================
 * spreadsheet_grid_heads.ts
 * 격자 머리 — 행 · 열 머리 칸(보이는 것만 · 폭 · 높이 끌기) · 숨긴 자리 표시 · 묶음 윤곽 +/- 단추.
 * `spreadsheet_grid.ts` 가 판을 그릴 때 부름 — 머리 칸 모양 · 끌기는 `spreadsheet_headers.ts`.
 * ========================================================================== */

import { colName } from "./spreadsheet_address";
import {
  commitColWidth,
  commitRowHeight,
  isExplicitHidden,
  makeColHeaderCell,
  makeRowHeaderCell,
  startDragResize,
  type OutlineRun,
} from "./spreadsheet_headers";
import { poolSweep, type CellPool, type GridView } from "./spreadsheet_grid_cells";
import type { Sheet } from "./spreadsheet_types";
import type { SpreadsheetContext } from "./spreadsheet_view_types";

export const HEAD_ROW_H_BASE = 24;
export const HEAD_COL_W_BASE = 46;

/** 머리 안쪽 층 넷 — 틀고정 쪽 · 스크롤 쪽. */
export interface HeadLayers {
  colFrozen: HTMLElement;
  colScroll: HTMLElement;
  rowFrozen: HTMLElement;
  rowScroll: HTMLElement;
}

export function createHeads(ctx: SpreadsheetContext, view: GridView, layers: HeadLayers) {
  const {
    colFrozen: colHeadInnerFrozen,
    colScroll: colHeadInnerScroll,
    rowFrozen: rowHeadInnerFrozen,
    rowScroll: rowHeadInnerScroll,
  } = layers;

  /** 건너뛴 자리(prev+1..cur-1) 안에 사용자 숨김 · 필터 걸러짐이 있나(묶음 접힘은 빼고 — 화면 표시가 다름). */
  function colHiddenGap(sheet: Sheet, prev: number, cur: number): boolean {
    for (let i = prev + 1; i < cur; i += 1)
      if (isExplicitHidden(sheet.열?.[colName(i)])) return true;
    return false;
  }
  function rowHiddenGap(sheet: Sheet, prev: number, cur: number): boolean {
    for (let i = prev + 1; i < cur; i += 1)
      if (isExplicitHidden(sheet.행?.[String(i + 1)])) return true;
    return false;
  }

  function layoutColHeaders(
    cols: number[],
    pool: CellPool,
    container: HTMLElement,
    base: number,
  ): void {
    const sheet = ctx.sheet();
    const keep = new Set<string>();
    const top = view.colGutterH();
    const height = Math.round(HEAD_ROW_H_BASE * view.zoom);
    cols.forEach((c, i) => {
      const key = String(c);
      keep.add(key);
      const prev = i > 0 ? cols[i - 1] : c - 1;
      const hiddenBefore = c - prev > 1 && colHiddenGap(sheet, prev, c);
      let cellEl = pool.used.get(key);
      if (!cellEl) {
        const built = makeColHeaderCell(c, 0, 0, hiddenBefore);
        cellEl = built.el;
        pool.used.set(key, cellEl);
        container.append(cellEl);
        const handle = cellEl.querySelector<HTMLElement>(".aislo-grid__resize--col")!;
        startDragResize({
          handle,
          axis: "col",
          currentPx: () => view.colGeo.size(c),
          onPreview: (px) => {
            cellEl!.style.width = `${px}px`;
          },
          onCommit: (px) => commitColWidth(ctx, c, px),
        });
      }
      cellEl.style.left = `${view.colGeo.offset(c) - base}px`;
      cellEl.style.top = `${top}px`;
      cellEl.style.width = `${view.colGeo.size(c)}px`;
      cellEl.style.height = `${height}px`;
      cellEl.classList.toggle("aislo-grid__colhead--hidden-before", hiddenBefore);
    });
    poolSweep(pool, keep);
  }

  function layoutRowHeaders(
    rows: number[],
    pool: CellPool,
    container: HTMLElement,
    base: number,
  ): void {
    const sheet = ctx.sheet();
    const keep = new Set<string>();
    const left = view.rowGutterW();
    const width = Math.round(HEAD_COL_W_BASE * view.zoom);
    rows.forEach((r, i) => {
      const key = String(r);
      keep.add(key);
      const prev = i > 0 ? rows[i - 1] : r - 1;
      const hiddenBefore = r - prev > 1 && rowHiddenGap(sheet, prev, r);
      let cellEl = pool.used.get(key);
      if (!cellEl) {
        const built = makeRowHeaderCell(r, 0, 0, hiddenBefore);
        cellEl = built.el;
        pool.used.set(key, cellEl);
        container.append(cellEl);
        const handle = cellEl.querySelector<HTMLElement>(".aislo-grid__resize--row")!;
        startDragResize({
          handle,
          axis: "row",
          currentPx: () => view.rowGeo.size(r),
          onPreview: (px) => {
            cellEl!.style.height = `${px}px`;
          },
          onCommit: (px) => commitRowHeight(ctx, r, px),
        });
      }
      cellEl.style.top = `${view.rowGeo.offset(r) - base}px`;
      cellEl.style.left = `${left}px`;
      cellEl.style.height = `${view.rowGeo.size(r)}px`;
      cellEl.style.width = `${width}px`;
      cellEl.classList.toggle("aislo-grid__rowhead--hidden-before", hiddenBefore);
    });
    poolSweep(pool, keep);
  }

  /** 묶음 접힘 뒤집기(같은 묶음 자리 모두) → `묶음설정` dispatch. */
  function outlineToggle(axis: "행" | "열", run: OutlineRun): void {
    const idx: number[] = [];
    for (let i = run.from; i <= run.to; i += 1) idx.push(i);
    ctx.dispatch({
      종류: "묶음설정",
      시트: ctx.sheet().id,
      축: axis,
      번호: idx,
      묶음: { 층: 1, 접힘: !run.collapsed },
    });
  }

  /** 윤곽 +/- 단추 — 행 묶음 마지막 다음 자리(머리 왼쪽 띠) · 열 묶음도 같은 이치(머리 위 띠).
   * 여러 층(중첩)은 1단계 다음(지금은 늘 층 1). */
  function renderRowOutline(): void {
    rowHeadInnerFrozen.querySelectorAll(".aislo-grid__outline-btn").forEach((n) => n.remove());
    rowHeadInnerScroll.querySelectorAll(".aislo-grid__outline-btn").forEach((n) => n.remove());
    if (!view.rowOutlineRuns.length) return;
    const gw = view.rowGutterW();
    for (const run of view.rowOutlineRuns) {
      const btnRow = Math.min(run.to + 1, view.extent.rows - 1);
      const container = btnRow < view.frozenRows ? rowHeadInnerFrozen : rowHeadInnerScroll;
      const base = btnRow < view.frozenRows ? 0 : view.rowGeo.offset(view.frozenRows);
      const btn = document.createElement("button");
      btn.type = "button";
      btn.className = "aislo-grid__outline-btn";
      btn.textContent = run.collapsed ? "+" : "−";
      btn.style.top = `${view.rowGeo.offset(btnRow) - base}px`;
      btn.style.left = "0";
      btn.style.width = `${gw}px`;
      btn.style.height = `${view.rowGeo.size(btnRow) || Math.round(HEAD_ROW_H_BASE * view.zoom)}px`;
      btn.addEventListener("click", (ev) => {
        ev.stopPropagation();
        outlineToggle("행", run);
      });
      container.append(btn);
    }
  }

  function renderColOutline(): void {
    colHeadInnerFrozen.querySelectorAll(".aislo-grid__outline-btn").forEach((n) => n.remove());
    colHeadInnerScroll.querySelectorAll(".aislo-grid__outline-btn").forEach((n) => n.remove());
    if (!view.colOutlineRuns.length) return;
    const gh = view.colGutterH();
    for (const run of view.colOutlineRuns) {
      const btnCol = Math.min(run.to + 1, view.extent.cols - 1);
      const container = btnCol < view.frozenCols ? colHeadInnerFrozen : colHeadInnerScroll;
      const base = btnCol < view.frozenCols ? 0 : view.colGeo.offset(view.frozenCols);
      const btn = document.createElement("button");
      btn.type = "button";
      btn.className = "aislo-grid__outline-btn";
      btn.textContent = run.collapsed ? "+" : "−";
      btn.style.left = `${view.colGeo.offset(btnCol) - base}px`;
      btn.style.top = "0";
      btn.style.width = `${view.colGeo.size(btnCol) || Math.round(HEAD_COL_W_BASE * view.zoom)}px`;
      btn.style.height = `${gh}px`;
      btn.addEventListener("click", (ev) => {
        ev.stopPropagation();
        outlineToggle("열", run);
      });
      container.append(btn);
    }
  }

  return { layoutColHeaders, layoutRowHeaders, renderRowOutline, renderColOutline };
}