// @flow

type PaddingProps = {
  height: ?number,
  labelHalfHeight: number,
  multiline?: ?boolean,
  dense: ?boolean,
  topPosition: number,
  fontSize: number,
  label: ?string,
  scale: number,
  offset: number,
  isAndroid: boolean,
  styles: { paddingTop: number, paddingBottom: number },
};

type AdjProps = PaddingProps & {
  pad: number,
};

type Padding = { paddingTop: number, paddingBottom: number };

export const calculateLabelTopPosition = (
  labelHeight: number,
  height: number = 0,
  optionalPadding: number = 0
): number => {
  const customHeight = height > 0 ? height : 0;

  return Math.floor((customHeight - labelHeight) / 2 + optionalPadding);
};

export const calculateInputHeight = (
  labelHeight: number,
  height: any = 0,
  minHeight: number
): number => {
  const finalHeight = height > 0 ? height : labelHeight;

  if (height > 0) return height;
  return finalHeight < minHeight ? minHeight : finalHeight;
};

export const calculatePadding = (props: PaddingProps): number => {
  const { height, multiline = false } = props;

  let result = 0;

  if (multiline) {
    if (height && multiline) {
      result = calculateTextAreaPadding(props);
    } else {
      result = calculateInputPadding(props);
    }
  }

  return Math.max(0, result);
};

const calculateTextAreaPadding = props => {
  const { dense } = props;

  return dense ? 10 : 20;
};

const calculateInputPadding = ({
  topPosition,
  fontSize,
  multiline,
  scale,
  dense,
  offset,
  isAndroid,
}): number => {
  const refFontSize = scale * fontSize;
  let result = Math.floor(topPosition / 2);

  result =
    result +
    Math.floor((refFontSize - fontSize) / 2) -
    (scale < 1 ? offset / 2 : 0);

  if (multiline && isAndroid)
    result = Math.min(dense ? offset / 2 : offset, result);

  return result;
};

export const adjustPaddingOut = ({
  pad,
  multiline,
  label,
  scale,
  height,
  fontSize,
  dense,
  offset,
  isAndroid,
}: AdjProps): Padding => {
  const refFontSize = scale * fontSize;
  let result = pad;

  if (height) {
    return {
      paddingTop: Math.max(0, (height - fontSize) / 2),
      paddingBottom: Math.max(0, (height - fontSize) / 2),
    };
  }
  if (!isAndroid && multiline) {
    if (dense) {
      if (label) {
        result += scale < 1 ? Math.min(offset, (refFontSize / 2) * scale) : 0;
      } else {
        result += 0;
      }
    }
    if (!dense) {
      if (label) {
        result +=
          scale < 1
            ? Math.min(offset, refFontSize * scale)
            : Math.min(offset / 2, refFontSize * scale);
      } else {
        result += scale < 1 ? Math.min(offset / 2, refFontSize * scale) : 0;
      }
    }
    result = Math.floor(result);
  }
  return { paddingTop: result, paddingBottom: result };
};

export const adjustPaddingFlat = ({
  pad,
  scale,
  multiline,
  label,
  height,
  offset,
  dense,
  fontSize,
  isAndroid,
  styles,
}: AdjProps): Padding => {
  let result = pad;
  let topResult = result;
  let bottomResult = result;
  const { paddingTop, paddingBottom } = styles;
  const refFontSize = scale * fontSize;

  if (!multiline) {
    // do not modify padding if input is not multiline
    if (label) {
      // return const style for flat input with label
      return { paddingTop, paddingBottom };
    }
    // return pad for flat input without label
    return { paddingTop: result, paddingBottom: result };
  }

  if (label) {
    // add paddings passed from styles
    topResult = paddingTop;
    bottomResult = paddingBottom;

    // adjust top padding for iOS
    if (!isAndroid) {
      if (dense) {
        topResult +=
          scale < 1
            ? Math.min(result, refFontSize * scale) - result / 2
            : Math.min(result, refFontSize * scale) - result / 2;
      }
      if (!dense) {
        topResult +=
          scale < 1
            ? Math.min(offset / 2, refFontSize * scale)
            : Math.min(result, refFontSize * scale) - offset / 2;
      }
    }
    topResult = Math.floor(topResult);
  } else {
    if (height) {
      // center text when height is passed
      return {
        paddingTop: Math.max(0, (height - fontSize) / 2),
        paddingBottom: Math.max(0, (height - fontSize) / 2),
      };
    }
    // adjust paddings for iOS if no label
    if (!isAndroid) {
      if (dense) {
        result +=
          scale < 1
            ? Math.min(offset / 2, (fontSize / 2) * scale)
            : Math.min(offset / 2, scale);
      }
      if (!dense) {
        result +=
          scale < 1
            ? Math.min(offset, fontSize * scale)
            : Math.min(fontSize, (offset / 2) * scale);
      }

      result = Math.floor(result);
      topResult = result;
      bottomResult = result;
    }
  }

  return {
    paddingTop: Math.max(0, topResult),
    paddingBottom: Math.max(0, bottomResult),
  };
};