/**
 * @typedef {import('hast').Element} Element
 * @typedef {import('hast').ElementContent} ElementContent
 * @typedef {import('hast').Properties} Properties
 * @typedef {import('mdast').ListItem} ListItem
 * @typedef {import('mdast').Parents} Parents
 * @typedef {import('../state.js').State} State
 */

// Make VS Code show references to the above types.
''

/**
 * Turn an mdast `listItem` node into hast.
 *
 * @param {State} state
 *   Info passed around.
 * @param {ListItem} node
 *   mdast node.
 * @param {Parents | undefined} parent
 *   Parent of `node`.
 * @returns {Element}
 *   hast node.
 */
export function listItem(state, node, parent) {
  const results = state.all(node)
  const loose = parent ? listLoose(parent) : listItemLoose(node)
  /** @type {Properties} */
  const properties = {}
  /** @type {Array<ElementContent>} */
  const children = []

  if (typeof node.checked === 'boolean') {
    const head = results[0]
    /** @type {Element} */
    let paragraph

    if (head && head.type === 'element' && head.tagName === 'p') {
      paragraph = head
    } else {
      paragraph = {type: 'element', tagName: 'p', properties: {}, children: []}
      results.unshift(paragraph)
    }

    if (paragraph.children.length > 0) {
      paragraph.children.unshift({type: 'text', value: ' '})
    }

    paragraph.children.unshift({
      type: 'element',
      tagName: 'input',
      properties: {type: 'checkbox', checked: node.checked, disabled: true},
      children: []
    })

    // According to github-markdown-css, this class hides bullet.
    // See: <https://github.com/sindresorhus/github-markdown-css>.
    properties.className = ['task-list-item']
  }

  let index = -1

  while (++index < results.length) {
    const child = results[index]

    // Add eols before nodes, except if this is a loose, first paragraph.
    if (
      loose ||
      index !== 0 ||
      child.type !== 'element' ||
      child.tagName !== 'p'
    ) {
      children.push({type: 'text', value: '\n'})
    }

    if (child.type === 'element' && child.tagName === 'p' && !loose) {
      children.push(...child.children)
    } else {
      children.push(child)
    }
  }

  const tail = results[results.length - 1]

  // Add a final eol.
  if (tail && (loose || tail.type !== 'element' || tail.tagName !== 'p')) {
    children.push({type: 'text', value: '\n'})
  }

  /** @type {Element} */
  const result = {type: 'element', tagName: 'li', properties, children}
  state.patch(node, result)
  return state.applyData(node, result)
}

/**
 * @param {Parents} node
 * @return {Boolean}
 */
function listLoose(node) {
  let loose = false
  if (node.type === 'list') {
    loose = node.spread || false
    const children = node.children
    let index = -1

    while (!loose && ++index < children.length) {
      loose = listItemLoose(children[index])
    }
  }

  return loose
}

/**
 * @param {ListItem} node
 * @return {Boolean}
 */
function listItemLoose(node) {
  const spread = node.spread

  return spread === null || spread === undefined
    ? node.children.length > 1
    : spread
}