/* eslint-disable max-depth, complexity
function nestLists(blocks, mode = 'html') {
  const tree = []
  let currentList

  for (let i = 0; i < blocks.length; i++) {
    const block = blocks[i]
    if (!isListBlock(block)) {
      tree.push(block)
      currentList = null
      continue
    }

    // Start of a new list?
    if (!currentList) {
      currentList = listFromBlock(block)
      tree.push(currentList)
      continue
    }

    // New list item within same list?
    if (blockMatchesList(block, currentList)) {
      currentList.children.push(block)
      continue
    }

    // Different list props, are we going deeper?
    if (block.level > currentList.level) {
      const newList = listFromBlock(block)

      if (mode === 'html') {
        // Because HTML is kinda weird, nested lists needs to be nested within list items
        // So while you would think that we could populate the parent list with a new sub-list,
        // We actually have to target the last list element (child) of the parent.
        // However, at this point we need to be very careful - simply pushing to the list of children
        // will mutate the input, and we don't want to blindly clone the entire tree.

        // Clone the last child while adding our new list as the last child of it
        const lastListItem = lastChild(currentList)
        const newLastChild = objectAssign({}, lastListItem, {
          children: lastListItem.children.concat(newList)
        })

        // Swap the last child
        currentList.children[currentList.children.length - 1] = newLastChild
      } else {
        currentList.children.push(newList)
      }

      // Set the newly created, deeper list as the current
      currentList = newList
      continue
    }

    // Different list props, are we going back up the tree?
    if (block.level < currentList.level) {
      // Current list has ended, and we need to hook up with a parent of the same level and type
      const match = findListMatching(tree[tree.length - 1], block)
      if (match) {
        currentList = match
        currentList.children.push(block)
        continue
      }

      // Similar parent can't be found, assume new list
      currentList = listFromBlock(block)
      tree.push(currentList)
      continue
    }

    // Different list props, different list style?
    if (block.listItem !== currentList.listItem) {
      const match = findListMatching(tree[tree.length - 1], {level: block.level})
      if (match && match.listItem === block.listItem) {
        currentList = match
        currentList.children.push(block)
        continue
      } else {
        currentList = listFromBlock(block)
        tree.push(currentList)
        continue
      }
    }

    // eslint-disable-next-line no-console
    console.warn('Unknown state encountered for block', block)
    tree.push(block)
  }

  return tree
}