import { Box2 } from 'vecks'
import type { Transform, TransformResult } from '../types'

/**
 * Transform the bounding box and the SVG element by the given
 * transforms. The <g> element are created in reverse transform
 * order and the bounding box in the given order.
 */
export default function transformBoundingBoxAndElement(
  bbox: Box2,
  element: string,
  transforms: Transform[]
): TransformResult {
  let transformedElement = ''
  const matrices = transforms.map((transform) => {
    // Create the transformation matrix
    const tx = transform.x || 0
    const ty = transform.y || 0
    const sx = transform.scaleX || 1
    const sy = transform.scaleY || 1
    const angle = ((transform.rotation || 0) / 180) * Math.PI
    const { cos, sin } = Math
    let a, b, c, d, e, f
    // In DXF an extrusionZ value of -1 denote a tranform around the Y axis.
    if (transform.extrusionZ === -1) {
      a = -sx * cos(angle)
      b = sx * sin(angle)
      c = sy * sin(angle)
      d = sy * cos(angle)
      e = -tx
      f = ty
    } else {
      a = sx * cos(angle)
      b = sx * sin(angle)
      c = -sy * sin(angle)
      d = sy * cos(angle)
      e = tx
      f = ty
    }
    return [a, b, c, d, e, f]
  })

  // Only transform the bounding box is it is valid (i.e. not Infinity)
  let transformedBBox = new Box2()
  if (bbox.valid) {
    let bboxPoints = [
      { x: bbox.min.x, y: bbox.min.y },
      { x: bbox.max.x, y: bbox.min.y },
      { x: bbox.max.x, y: bbox.max.y },
      { x: bbox.min.x, y: bbox.max.y },
    ]
    for (const [a, b, c, d, e, f] of matrices) {
      bboxPoints = bboxPoints.map((point) => ({
        x: point.x * a + point.y * c + e,
        y: point.x * b + point.y * d + f,
      }))
    }
    transformedBBox = bboxPoints.reduce((acc, point) => {
      return acc.expandByPoint(point)
    }, new Box2())
  }

  matrices.reverse()
  for (const [a, b, c, d, e, f] of matrices) {
    transformedElement += `<g transform="matrix(${a} ${b} ${c} ${d} ${e} ${f})">`
  }
  transformedElement += element
  // eslint-disable-next-line @typescript-eslint/no-unused-vars
  for (const _ of matrices) {
    transformedElement += '</g>'
  }

  return { bbox: transformedBBox, element: transformedElement }
}