export type Unit = 'px' | 'em' | '%' | 'rem' | 'ratio' | 'fr'
export type Length = { unit: Unit; value: number }

export function normalizeStringLength(length: string): Length {
  let parsedUnit = length.match(/px|em|%|rem|ratio|fr/)
  let parsedValue = parseFloat(length)

  const parsedRatio = length?.match(/\s*([\d+.]+)\s*:\s*([\d+.]+)\s*/)
  if (parsedRatio) {
    const ratio = parseFloat(parsedRatio[1]) / parseFloat(parsedRatio[2])
    if (!Number.isNaN(ratio)) {
      return { value: ratio, unit: 'ratio' }
    }
  }

  let unit: Unit = 'px'
  let value: number = 0

  if (parsedUnit) {
    unit = parsedUnit[0] as Unit
  }

  if (!Number.isNaN(parsedValue)) {
    value = parsedValue
  }

  return { value, unit }
}

export function resolveLength(length: Length, base: number) {
  if (length.unit == '%') return (length.value / 100) * base
  return length.value
}

export function stringifyLength(length: Length | number | string, defaultValue = '0px') {
  if (length && typeof length == 'object') {
    // Skip NaNs
    if (parseInt(String(length.value)) !== parseInt(String(length.value))) {
      return defaultValue
    }
    if (length.unit?.match(/%|ratio|em|px|em|rem|fr|vmax|vmin|vw|vh/)) return length.value + length.unit
    return length.value + 'px'
  }
  if (typeof length == 'string' && length.match(/%|ratio|em|px|em|rem|fr|vmax|vmin|vw|vh/)) {
    return length
  }
  if (length == null) {
    return defaultValue
  }
  return length + 'px'
}

export const Length = (length: any): Length => {
  if (typeof length === 'string') {
    return normalizeStringLength(length)
  }

  if (typeof length === 'number') {
    return { value: normalizeStringLength(`${length}px`).value, unit: 'px' }
  }

  if (length && (length.value || length.unit)) {
    return normalizeStringLength(`${length.value}${length.unit}`)
  }

  return { value: 0, unit: 'px' }
}

export const NullLength = (length: any): null => {
  if (length === '' || length == null || length?.value === null) {
    return null
  }
}

export const pickFirst = <T extends unknown>(object: T, value: any): T => {
  if (object === undefined && value !== undefined) {
    return value
  }
  return object
}

export const pickNonEmpty = <T extends unknown>(object: T, value: any): T => {
  if (!(object instanceof Array) || object.length == 0) {
    return value
  }
  return object
}

export function LengthOrPosition<T>(value: any) {
  switch (value) {
    case 'left':
    case 'top':
      var nextValue = '0%'
      break
    case 'right':
    case 'bottom':
      var nextValue = '100%'
      break
    case null:
    case undefined:
    case 'center':
      var nextValue = '50%'
  }
  return Length(nextValue ?? value)
}