import {
  spacingFixers,
} from '../../utilities';

const hasLineBreak = (direction, colon, context) => {
  const sourceCode = context.getSourceCode();

  if (direction === 'before') {
    return colon.loc.start.line !== sourceCode.getTokenBefore(colon).loc.end.line;
  }

  return sourceCode.getTokenAfter(colon).loc.start.line !== colon.loc.end.line;
};

const getSpaces = (direction, colon, context) => {
  const sourceCode = context.getSourceCode();

  if (direction === 'before') {
    return colon.range[0] - sourceCode.getTokenBefore(colon).range[1];
  }

  return sourceCode.getTokenAfter(colon).range[0] - colon.range[1];
};

export default (direction, context, { always, allowLineBreak }) => ({
  colon, node, name = '', type = 'type annotation',
}) => {
  let lineBreak;
  let spaces;

  // Support optional names
  // type X = { [string]: a }
  // type X = string => string
  if (!colon || colon.value !== ':') {
    return;
  }

  const data = {
    direction,
    name,
    type,
  };

  if (hasLineBreak(direction, colon, context)) {
    if (allowLineBreak) {
      spaces = 1;
    } else {
      lineBreak = true;
      spaces = getSpaces(direction, colon, context);
    }
  } else {
    spaces = getSpaces(direction, colon, context);
  }

  if (always && lineBreak) {
    context.report({
      data,
      fix: spacingFixers.replaceWithSpace(direction, colon, spaces),
      message: 'There must not be a line break {{direction}} {{name}}{{type}} colon.',
      node,
    });
  } else if (always && spaces > 1) {
    context.report({
      data,
      fix: spacingFixers.stripSpaces(direction, colon, spaces - 1),
      message: 'There must be 1 space {{direction}} {{name}}{{type}} colon.',
      node,
    });
  } else if (always && spaces === 0) {
    context.report({
      data,
      fix: spacingFixers.addSpace(direction, colon),
      message: 'There must be a space {{direction}} {{name}}{{type}} colon.',
      node,
    });
  } else if (!always && spaces > 0) {
    context.report({
      data,
      fix: spacingFixers.stripSpaces(direction, colon, spaces),
      message: 'There must be no space {{direction}} {{name}}{{type}} colon.',
      node,
    });
  }
};