import type {Position} from './@types'

export type TransformMatrix = [
  number,
  number,
  number,
  number,
  number,
  number,
  number,
  number,
  number,
]

// These are affine transforms. See explanation of every cell here:
// https://en.wikipedia.org/wiki/Transformation_matrix#/media/File:2D_affine_transformation_matrix.svg

export function createTransform(): TransformMatrix {
  'worklet'
  return [1, 0, 0, 0, 1, 0, 0, 0, 1]
}

export function applyRounding(t: TransformMatrix) {
  'worklet'
  t[2] = Math.round(t[2])
  t[5] = Math.round(t[5])
  // For example: 0.985, 0.99, 0.995, then 1:
  t[0] = Math.round(t[0] * 200) / 200
  t[4] = Math.round(t[0] * 200) / 200
}

// We're using a limited subset (always scaling and translating while keeping aspect ratio) so
// we can assume the transform doesn't encode have skew, rotation, or non-uniform stretching.

// All write operations are applied in-place to avoid unnecessary allocations.

export function readTransform(t: TransformMatrix): [number, number, number] {
  'worklet'
  const scale = t[0]
  const translateX = t[2]
  const translateY = t[5]
  return [translateX, translateY, scale]
}

export function prependTranslate(t: TransformMatrix, x: number, y: number) {
  'worklet'
  t[2] += t[0] * x + t[1] * y
  t[5] += t[3] * x + t[4] * y
}

export function prependScale(t: TransformMatrix, value: number) {
  'worklet'
  t[0] *= value
  t[1] *= value
  t[3] *= value
  t[4] *= value
}

export function prependTransform(ta: TransformMatrix, tb: TransformMatrix) {
  'worklet'
  // In-place matrix multiplication.
  const a00 = ta[0],
    a01 = ta[1],
    a02 = ta[2]
  const a10 = ta[3],
    a11 = ta[4],
    a12 = ta[5]
  const a20 = ta[6],
    a21 = ta[7],
    a22 = ta[8]
  ta[0] = a00 * tb[0] + a01 * tb[3] + a02 * tb[6]
  ta[1] = a00 * tb[1] + a01 * tb[4] + a02 * tb[7]
  ta[2] = a00 * tb[2] + a01 * tb[5] + a02 * tb[8]
  ta[3] = a10 * tb[0] + a11 * tb[3] + a12 * tb[6]
  ta[4] = a10 * tb[1] + a11 * tb[4] + a12 * tb[7]
  ta[5] = a10 * tb[2] + a11 * tb[5] + a12 * tb[8]
  ta[6] = a20 * tb[0] + a21 * tb[3] + a22 * tb[6]
  ta[7] = a20 * tb[1] + a21 * tb[4] + a22 * tb[7]
  ta[8] = a20 * tb[2] + a21 * tb[5] + a22 * tb[8]
}

export function prependPan(t: TransformMatrix, translation: Position) {
  'worklet'
  prependTranslate(t, translation.x, translation.y)
}

export function prependPinch(
  t: TransformMatrix,
  scale: number,
  origin: Position,
  translation: Position,
) {
  'worklet'
  prependTranslate(t, translation.x, translation.y)
  prependTranslate(t, origin.x, origin.y)
  prependScale(t, scale)
  prependTranslate(t, -origin.x, -origin.y)
}