export function bareLink(badgeUrl, link, title = '') {
  return badgeUrl
}

export function html(badgeUrl, link, title) {
  // To be more robust, this should escape the title.
  const img = `<img alt="${title}" src="${badgeUrl}">`
  if (link) {
    return `<a href=${link}>${img}</a>`
  } else {
    return img
  }
}

export function markdown(badgeUrl, link, title) {
  const withoutLink = `![${title || ''}](${badgeUrl})`
  if (link) {
    return `[${withoutLink}](${link})`
  } else {
    return withoutLink
  }
}

export function reStructuredText(badgeUrl, link, title) {
  let result = `.. image:: ${badgeUrl}`
  if (title) {
    result += `   :alt: ${title}`
  }
  if (link) {
    result += `   :target: ${link}`
  }
  return result
}

function quoteAsciiDocAttribute(attr) {
  if (typeof attr === 'string') {
    const withQuotesEscaped = attr.replace(/"/g, '\\"')
    return `"${withQuotesEscaped}"`
  } else if (attr == null) {
    return 'None'
  } else {
    return attr
  }
}

// lodash.mapvalues is huge!
function mapValues(obj, iteratee) {
  const result = {}
  for (const k in obj) {
    result[k] = iteratee(obj[k])
  }
  return result
}

export function renderAsciiDocAttributes(positional, named) {
  // http://asciidoc.org/userguide.html#X21
  const needsQuoting =
    positional.some(attr => attr.includes(',')) || Object.keys(named).length > 0

  if (needsQuoting) {
    positional = positional.map(attr => quoteAsciiDocAttribute(attr))
    named = mapValues(named, attr => quoteAsciiDocAttribute(attr))
  }

  const items = positional.concat(
    Object.entries(named).map(([k, v]) => `${k}=${v}`)
  )

  if (items.length) {
    return `[${items.join(',')}]`
  } else {
    return ''
  }
}

export function asciiDoc(badgeUrl, link, title) {
  const positional = title ? [title] : []
  const named = link ? { link } : {}
  const attrs = renderAsciiDocAttributes(positional, named)
  return `image:${badgeUrl}${attrs}`
}

export default function generateAllMarkup(badgeUrl, link, title) {
  // This is a wee bit "clever". It runs each of the three functions on the
  // parameters provided, and returns the result in an object.
  return mapValues({ markdown, reStructuredText, asciiDoc }, fn =>
    fn(badgeUrl, link, title)
  )
}

export function generateMarkup({ badgeUrl, link, title, markupFormat }) {
  const generatorFn = {
    markdown,
    rst: reStructuredText,
    asciidoc: asciiDoc,
    link: bareLink,
    html,
  }[markupFormat]
  return generatorFn(badgeUrl, link, title)
}