// Canvas size data access and pagination helpers.

const { fetchPagedRows } = require('./utils');
const MAX_CANVAS_SIZE_DIMENSION = 16384;

async function fetchCanvasSizesData(pool) {
  const [canvasSizes] = await pool.query('SELECT id, name, width, height, created_at, modified_at, created_by, modified_by FROM c_canvas_sizes ORDER BY width ASC, height ASC, name ASC');
  return { canvasSizes };
}

async function fetchCanvasSizesPage(pool, page, pageSize, searchTerm, sortKey, sortDirection) {
  const paged = await fetchPagedRows(pool, {
    selectSql: 'SELECT id, name, width, height, created_at, modified_at, created_by, modified_by FROM c_canvas_sizes ORDER BY width ASC, height ASC, name ASC',
    countSql: 'SELECT COUNT(*) AS count FROM c_canvas_sizes',
    searchColumns: ['name', 'width', 'height'],
    searchTerm: searchTerm,
    sortColumns: {
      name: 'name',
      dimensions: ['width', 'height', 'name'],
      created: 'created_at',
      modified: 'modified_at'
    },
    sortKey: sortKey,
    sortDirection: sortDirection,
    page: page,
    pageSize: pageSize
  });

  return Object.assign({ canvasSizes: paged.rows }, paged);
}

async function fetchCanvasSizeById(pool, id) {
  const [rows] = await pool.query('SELECT id, name, width, height, created_at, modified_at, created_by, modified_by FROM c_canvas_sizes WHERE id = ?', [id]);
  return rows[0] || null;
}

function readCanvasDimension(rawValue, fallbackValue, fieldName) {
  const sourceValue = rawValue !== undefined && rawValue !== null && String(rawValue).trim() !== ''
    ? rawValue
    : fallbackValue;
  const numericValue = Number(sourceValue);

  if (!Number.isFinite(numericValue)) {
    const error = new Error('Canvas size ' + fieldName + ' must be a number.');
    error.statusCode = 400;
    throw error;
  }

  if (numericValue > MAX_CANVAS_SIZE_DIMENSION) {
    const error = new Error('Canvas size dimensions must be 16384 or less.');
    error.statusCode = 400;
    throw error;
  }

  return Math.max(1, numericValue);
}

function buildCanvasSizePayload(req, existingCanvasSize) {
  const name = String(req.body.name || '').trim();
  const width = readCanvasDimension(req.body.width, existingCanvasSize && existingCanvasSize.width, 'width');
  const height = readCanvasDimension(req.body.height, existingCanvasSize && existingCanvasSize.height, 'height');

  if (!name) {
    const error = new Error('Canvas size name is required.');
    error.statusCode = 400;
    throw error;
  }

  return {
    name,
    width,
    height
  };
}

module.exports = {
  fetchCanvasSizesData,
  fetchCanvasSizesPage,
  fetchCanvasSizeById,
  buildCanvasSizePayload,
  MAX_CANVAS_SIZE_DIMENSION
};