import tinygradient from "tinygradient"

// An internal function to help with easily creating SVG elements with an object of attributes
export const svgElem = (type, attrs) => {
  const elem = document.createElementNS("http://www.w3.org/2000/svg", type),
    attributes = Object.keys(attrs)

  for (let i = 0; i < attributes.length; i++) {
    const attr = attributes[i]

    elem.setAttribute(attr, attrs[attr])
  }

  return elem
}

// An internal function to help with the repetition of adding fill, stroke, and stroke-width attributes
export const styleAttrs = (
  fill,
  stroke,
  strokeWidth,
  progress,
  animation
) => {
  const determineColor = (type, progress) =>
    typeof type === "string" ? type : tinygradient(type).rgbAt(progress)

  const attrs = {}

  if (stroke) {
    attrs["stroke"] = determineColor(stroke, progress)
    attrs["stroke-width"] = strokeWidth
  }

  if (fill) {
    attrs["fill"] = determineColor(fill, progress)
  }

  if (animation?.name) {
    // TODO: add animation-direction support
    
    const duration = animation.duration || 5
    
    attrs["style"] = `
      animation-name: ${animation?.name}; 
      animation-delay: ${progress * duration - duration}s;
      animation-duration: ${duration}s; 
      animation-iteration-count: infinite; 
      animation-timing-function: linear;`
  }

  return attrs
}

// An internal function to convert any array of samples into a "d" attribute to be passed to an SVG path
export const segmentToD = (samples) => {
  let d = ""

  for (let i = 0; i < samples.length; i++) {
    const { x, y } = samples[i],
      prevSample = i === 0 ? null : samples[i - 1]

    if (i === 0 && i !== samples.length - 1) {
      d += `M${x},${y}`
    } else if (x !== prevSample.x && y !== prevSample.y) {
      d += `L${x},${y}`
    } else if (x !== prevSample.x) {
      d += `H${x}`
    } else if (y !== prevSample.y) {
      d += `V${y}`
    }

    if (i === samples.length - 1) {
      d += "Z"
    }
  }

  return d
}

// An internal function for getting the colors of a segment, we need to get middle most sample (sorted by progress along the path)
export const getMiddleSample = (samples) => {
  const sortedSamples = [...samples].sort((a, b) => a.progress - b.progress)

  return sortedSamples[(sortedSamples.length / 2) | 0]
}

// An internal function for converting any D3 selection or DOM-like element into a DOM node
export const convertPathToNode = (path) =>
  path instanceof Element || path instanceof HTMLDocument ? path : path.node()