import { SVGPathData } from './SVGPathData.js';
import type { SVGCommand } from './types.js';

// Encode SVG PathData
// http://www.w3.org/TR/SVG/paths.html#PathDataBNF

// Private consts : Char groups
const WSP = ' ';

export function encodeSVGPath(commands: SVGCommand | SVGCommand[]) {
  let str = '';

  if (!Array.isArray(commands)) {
    commands = [commands];
  }
  for (let i = 0; i < commands.length; i++) {
    const command = commands[i];
    if (command.type === SVGPathData.CLOSE_PATH) {
      str += 'z';
    } else if (command.type === SVGPathData.HORIZ_LINE_TO) {
      str += (command.relative ? 'h' : 'H') + command.x;
    } else if (command.type === SVGPathData.VERT_LINE_TO) {
      str += (command.relative ? 'v' : 'V') + command.y;
    } else if (command.type === SVGPathData.MOVE_TO) {
      str += (command.relative ? 'm' : 'M') + command.x + WSP + command.y;
    } else if (command.type === SVGPathData.LINE_TO) {
      str += (command.relative ? 'l' : 'L') + command.x + WSP + command.y;
    } else if (command.type === SVGPathData.CURVE_TO) {
      str +=
        (command.relative ? 'c' : 'C') +
        command.x1 +
        WSP +
        command.y1 +
        WSP +
        command.x2 +
        WSP +
        command.y2 +
        WSP +
        command.x +
        WSP +
        command.y;
    } else if (command.type === SVGPathData.SMOOTH_CURVE_TO) {
      str +=
        (command.relative ? 's' : 'S') +
        command.x2 +
        WSP +
        command.y2 +
        WSP +
        command.x +
        WSP +
        command.y;
    } else if (command.type === SVGPathData.QUAD_TO) {
      str +=
        (command.relative ? 'q' : 'Q') +
        command.x1 +
        WSP +
        command.y1 +
        WSP +
        command.x +
        WSP +
        command.y;
    } else if (command.type === SVGPathData.SMOOTH_QUAD_TO) {
      str += (command.relative ? 't' : 'T') + command.x + WSP + command.y;
    } else if (command.type === SVGPathData.ARC) {
      str +=
        (command.relative ? 'a' : 'A') +
        command.rX +
        WSP +
        command.rY +
        WSP +
        command.xRot +
        WSP +
        +command.lArcFlag +
        WSP +
        +command.sweepFlag +
        WSP +
        command.x +
        WSP +
        command.y;
    } else {
      // Unknown command
      throw new Error(
        `Unexpected command type "${(command as SVGCommand)?.type}" at index ${i}.`,
      );
    }
  }

  return str;
}