/* importer.js — parse OpenSCAD ECHO / CSV / JSON / parametric generator.
 *
 * All parsers return an array of {id, x, y} in millimetres.
 * Generator formulas are 1:1 mirrors of `get_hex_center_points_*` from
 * Addy's hex_cell.scad (see CLAUDE.md for the cheat sheet).
 */

const Importer = (() => {
  const COS30 = Math.cos(Math.PI / 6);

  /** Parse OpenSCAD ECHO lines or loose `Cell N: x = …, y = …`. */
  function parsePaste(text) {
    const out = [];
    const re = /Cell\s*(\d+)\s*:\s*x\s*=\s*(-?\d+(?:\.\d+)?(?:[eE][-+]?\d+)?)\s*,\s*y\s*=\s*(-?\d+(?:\.\d+)?(?:[eE][-+]?\d+)?)/g;
    let m;
    while ((m = re.exec(text)) !== null) {
      out.push({ id: parseInt(m[1], 10), x: parseFloat(m[2]), y: parseFloat(m[3]) });
    }
    if (out.length) return out;

    // Fallback: lines of form `index x y` or `index, x, y` (any separator).
    const lines = text.split(/\r?\n/);
    let auto = 1;
    for (const line of lines) {
      const nums = line.match(/-?\d+(?:\.\d+)?(?:[eE][-+]?\d+)?/g);
      if (!nums) continue;
      if (nums.length >= 3) {
        out.push({ id: parseInt(nums[0], 10), x: parseFloat(nums[1]), y: parseFloat(nums[2]) });
      } else if (nums.length === 2) {
        out.push({ id: auto++, x: parseFloat(nums[0]), y: parseFloat(nums[1]) });
      }
    }
    return out;
  }

  /** CSV with optional header. Columns: index,x,y  OR  x,y. */
  function parseCSV(text) {
    const out = [];
    const lines = text.trim().split(/\r?\n/).filter(Boolean);
    let auto = 1;
    for (const raw of lines) {
      const cols = raw.split(/[,;\t]/).map((s) => s.trim());
      // Skip header rows that don't parse as numbers.
      if (cols.length >= 2 && isNaN(parseFloat(cols[0])) && isNaN(parseFloat(cols[1]))) continue;
      if (cols.length >= 3) {
        const id = parseInt(cols[0], 10);
        const x = parseFloat(cols[1]);
        const y = parseFloat(cols[2]);
        if (!isNaN(x) && !isNaN(y)) out.push({ id: isNaN(id) ? auto++ : id, x, y });
      } else if (cols.length === 2) {
        const x = parseFloat(cols[0]);
        const y = parseFloat(cols[1]);
        if (!isNaN(x) && !isNaN(y)) out.push({ id: auto++, x, y });
      }
    }
    return out;
  }

  /** JSON: array of objects {id,x,y} OR array of [x,y]. */
  function parseJSON(text) {
    const j = JSON.parse(text);
    if (!Array.isArray(j)) throw new Error("JSON must be a top-level array");
    return j.map((item, i) => {
      if (Array.isArray(item)) {
        return { id: i + 1, x: +item[0], y: +item[1] };
      }
      return {
        id: item.id != null ? +item.id : i + 1,
        x: +item.x,
        y: +item.y,
      };
    });
  }

  /** Generator — mirrors get_hex_center_points_{rect,para,tria} from hex_cell.scad. */
  function generate({ cellDia, wall, rows, cols, style }) {
    const hex_w = cellDia + 2 * wall;
    const hex_pt = (hex_w / 2) / COS30;
    const rowY = (r) => r * 1.5 * hex_pt;
    const out = [];
    let id = 1;

    if (style === "rect") {
      for (let r = 0; r < rows; r++) {
        for (let c = 0; c < cols; c++) {
          const x = (r % 2 === 0) ? hex_w * c : 0.5 * hex_w + hex_w * c;
          out.push({ id: id++, x, y: rowY(r) });
        }
      }
    } else if (style === "para") {
      for (let r = 0; r < rows; r++) {
        for (let c = 0; c < cols; c++) {
          const x = r * 0.5 * hex_w + hex_w * c;
          out.push({ id: id++, x, y: rowY(r) });
        }
      }
    } else if (style === "tria") {
      for (let r = 0; r < rows; r++) {
        for (let c = 0; c <= r; c++) {
          const x = r * 0.5 * hex_w - hex_w * c;
          out.push({ id: id++, x, y: rowY(r) });
        }
      }
    } else {
      throw new Error(`unknown style: ${style}`);
    }
    return out;
  }

  return { parsePaste, parseCSV, parseJSON, generate };
})();