/**
 *
 * @param {import("@/types").SidebarItem[]} sidebarItems - The items to add numbers to their titles
 * @param {number[]} numbering - The current numbering level
 * @returns {import("@/types").SidebarItem[]} The modified sidebar items
 */
export default function numberSidebarItems(sidebarItems, numbering = [1]) {
  if (!numbering.length) {
    numbering.push(1)
  }
  const isTopItems = numbering.length === 1
  /** @type {import("@/types").SidebarItem[]} */
  const numberedItems = []
  /** @type {import("@/types").SidebarItem | undefined} */
  let parentItem
  sidebarItems.forEach((item, index) => {
    if (item.type === "separator") {
      ;(parentItem?.children || numberedItems).push(item)
      return
    }

    // append current number to the item's title
    item.number = `${numbering.join(".")}.`
    item.chapterTitle = `${item.number} ${
      item.chapterTitle?.trim() || item.title?.trim()
    }`
    item.title = item.title.trim()

    if (isTopItems) {
      // Add chapter category
      numberedItems.push(
        item.type === "category"
          ? item
          : {
              type: "category",
              title: item.chapterTitle,
              children: [],
              loaded: true,
              initialOpen: false,
            }
      )

      parentItem = numberedItems[numberedItems.length - 1]
    }

    if (item.children) {
      item.children = numberSidebarItems(item.children, [...numbering, 1])
    }

    if (item.type !== "category" || !isTopItems) {
      ;(parentItem?.children || numberedItems).push(item)
    }

    numbering[numbering.length - 1]++
  })

  return numberedItems
}