/**
 * Selection & Navigation — cell selection, range extension, scrolling, visual highlights.
 *
 * Extracted from main.ts for decomposition.
 */

import { cellId, parseRef } from './formulas.js';
import { normalizeRange } from './selection-utils.js';

// ── Types ───────────────────────────────────────────────────

export interface SelectionNavigationDeps {
  grid: HTMLElement;
  cellAddressInput: HTMLInputElement;
  sheetContainer: HTMLElement | null;
  getActiveSheet: () => any;
  getSelectedCell: () => { col: number; row: number };
  setSelectedCell: (cell: { col: number; row: number }) => void;
  getSelectionRange: () => any;
  setSelectionRange: (range: any) => void;
  getCells: () => any;
  getColWidth: (col: number) => number;
  getRowHeight: (row: number) => number;
  updateFormulaBar: () => void;
  updateStatusBar: () => void;
  updateMergeButtonState: () => void;
  updateWrapButtonState: () => void;
  updateBoldButtonState: () => void;
  updateItalicButtonState: () => void;
  updateUnderlineButtonState: () => void;
  updateStrikethroughButtonState: () => void;
  updateFontSizeSelect: () => void;
  updateFontFamilySelect: () => void;
  updateVerticalAlignButton: () => void;
  updateColorPickerState: () => void;
  ROW_HEADER_WIDTH: number;
  DEFAULT_COLS: number;
  DEFAULT_ROWS: number;
}

// ── Selection classes (shared with main.ts for clearPrevSelection) ──

export const selectionClasses = ['selected', 'in-range', 'range-top', 'range-bottom', 'range-left', 'range-right', 'col-selected', 'row-selected', 'has-fill-handle', 'fill-preview'] as const;

// ── State managed by this module ────────────────────────────

let prevSelectionEls: Element[] = [];

// ── Functions ───────────────────────────────────────────────

export function clearPrevSelection(): void {
  for (const el of prevSelectionEls) {
    el.classList.remove(...selectionClasses);
    el.removeAttribute('aria-selected');
  }
  prevSelectionEls = [];
}

export function getCellEl(grid: HTMLElement, col: number, row: number): Element | null {
  return grid.querySelector(`td[data-col="${col}"][data-row="${row}"]`);
}

export function moveSelection(deps: SelectionNavigationDeps, dCol: number, dRow: number): void {
  const sheet = deps.getActiveSheet();
  const maxCol = sheet.get('colCount') || deps.DEFAULT_COLS;
  const maxRow = sheet.get('rowCount') || deps.DEFAULT_ROWS;
  const selected = deps.getSelectedCell();
  const newCol = Math.max(1, Math.min(maxCol, selected.col + dCol));
  const newRow = Math.max(1, Math.min(maxRow, selected.row + dRow));
  deps.setSelectedCell({ col: newCol, row: newRow });
  deps.setSelectionRange({ startCol: newCol, startRow: newRow, endCol: newCol, endRow: newRow });
  updateSelectionVisuals(deps);
  deps.updateFormulaBar();
  deps.updateMergeButtonState();
  deps.updateWrapButtonState();
  deps.updateBoldButtonState();
  deps.updateItalicButtonState();
  deps.updateUnderlineButtonState();
  deps.updateStrikethroughButtonState();
  deps.updateFontSizeSelect();
  deps.updateFontFamilySelect();
  deps.updateVerticalAlignButton();
  deps.updateColorPickerState();
  scrollCellIntoView(deps, newCol, newRow);
}

export function extendSelection(deps: SelectionNavigationDeps, dCol: number, dRow: number): void {
  const sheet = deps.getActiveSheet();
  const maxCol = sheet.get('colCount') || deps.DEFAULT_COLS;
  const maxRow = sheet.get('rowCount') || deps.DEFAULT_ROWS;
  let range = deps.getSelectionRange();
  if (!range) {
    const selected = deps.getSelectedCell();
    range = { startCol: selected.col, startRow: selected.row, endCol: selected.col, endRow: selected.row };
  }
  range.endCol = Math.max(1, Math.min(maxCol, range.endCol + dCol));
  range.endRow = Math.max(1, Math.min(maxRow, range.endRow + dRow));
  deps.setSelectionRange(range);
  updateSelectionVisuals(deps);
  scrollCellIntoView(deps, range.endCol, range.endRow);
}

export function moveSelectionTo(deps: SelectionNavigationDeps, col: number, row: number): void {
  deps.setSelectedCell({ col, row });
  deps.setSelectionRange({ startCol: col, startRow: row, endCol: col, endRow: row });
  updateSelectionVisuals(deps);
  deps.updateFormulaBar();
  deps.updateBoldButtonState();
  deps.updateItalicButtonState();
  deps.updateUnderlineButtonState();
  deps.updateStrikethroughButtonState();
  deps.updateFontSizeSelect();
  deps.updateFontFamilySelect();
  deps.updateColorPickerState();
  scrollCellIntoView(deps, col, row);
}

export function getDataExtent(deps: SelectionNavigationDeps): { col: number; row: number } {
  let maxRow = 1, maxCol = 1;
  const cells = deps.getCells();
  cells.forEach((_: any, id: string) => {
    const ref = parseRef(id);
    if (ref) {
      if (ref.row + 1 > maxRow) maxRow = ref.row + 1;
      if (ref.col + 1 > maxCol) maxCol = ref.col + 1;
    }
  });
  return { col: maxCol, row: maxRow };
}

export function scrollCellIntoView(deps: SelectionNavigationDeps, col: number, row: number): void {
  const td = deps.grid.querySelector('td[data-col="' + col + '"][data-row="' + row + '"]');
  if (td) {
    td.scrollIntoView({ block: 'nearest', inline: 'nearest' });
    return;
  }
  // Cell not in DOM (outside virtual range) — scroll to estimated position
  if (!deps.sheetContainer) return;
  let targetTop = 0;
  for (let r = 1; r < row; r++) targetTop += deps.getRowHeight(r);
  let targetLeft = deps.ROW_HEADER_WIDTH;
  for (let c = 1; c < col; c++) targetLeft += deps.getColWidth(c);
  deps.sheetContainer.scrollTop = Math.max(0, targetTop - deps.sheetContainer.clientHeight / 3);
  deps.sheetContainer.scrollLeft = Math.max(0, targetLeft - deps.sheetContainer.clientWidth / 3);
}

export function updateSelectionVisuals(deps: SelectionNavigationDeps): void {
  clearPrevSelection();

  const selectedCell = deps.getSelectedCell();
  const selectionRange = deps.getSelectionRange();

  const currentTd = getCellEl(deps.grid, selectedCell.col, selectedCell.row);
  if (currentTd) {
    currentTd.classList.add('selected');
    currentTd.setAttribute('aria-selected', 'true');
    prevSelectionEls.push(currentTd);
  }

  if (selectionRange) {
    const { startCol, startRow, endCol, endRow } = normalizeRange(selectionRange);
    const isMultiCell = startCol !== endCol || startRow !== endRow;
    for (let r = startRow; r <= endRow; r++) {
      for (let c = startCol; c <= endCol; c++) {
        const td = getCellEl(deps.grid, c, r);
        if (!td) continue;
        td.setAttribute('aria-selected', 'true');
        if (!(c === selectedCell.col && r === selectedCell.row)) td.classList.add('in-range');
        if (isMultiCell) {
          if (r === startRow) td.classList.add('range-top');
          if (r === endRow) td.classList.add('range-bottom');
          if (c === startCol) td.classList.add('range-left');
          if (c === endCol) td.classList.add('range-right');
        }
        prevSelectionEls.push(td);
      }
    }
    for (let c = startCol; c <= endCol; c++) {
      const th = deps.grid.querySelector('thead th[data-col="' + c + '"]');
      if (th) { th.classList.add('col-selected'); prevSelectionEls.push(th); }
    }
    for (let r = startRow; r <= endRow; r++) {
      const th = deps.grid.querySelector('th.row-header[data-row="' + r + '"]');
      if (th) { th.classList.add('row-selected'); prevSelectionEls.push(th); }
    }
    if (isMultiCell) {
      deps.cellAddressInput.value = cellId(startCol, startRow) + ':' + cellId(endCol, endRow);
    }
  }
  // Render fill handle on bottom-right cell of selection
  const existingHandle = deps.grid.querySelector('.fill-handle');
  if (existingHandle) existingHandle.remove();
  if (selectionRange) {
    const { endCol: brCol, endRow: brRow } = normalizeRange(selectionRange);
    const brTd = getCellEl(deps.grid, brCol, brRow);
    if (brTd) {
      brTd.classList.add('has-fill-handle');
      const handle = document.createElement('div');
      handle.className = 'fill-handle';
      (brTd as HTMLElement).appendChild(handle);
    }
  } else {
    const curTd = getCellEl(deps.grid, selectedCell.col, selectedCell.row);
    if (curTd) {
      curTd.classList.add('has-fill-handle');
      const handle = document.createElement('div');
      handle.className = 'fill-handle';
      (curTd as HTMLElement).appendChild(handle);
    }
  }

  deps.updateStatusBar();
}