---
import DocsCard from './DocsCard.astro'
import docs from '@data/docs.json'
import Icon from '@ui/Icon.astro'
import { getDocsChildren } from '@shared/lib/docs-children'
import type { DocsChildPage } from '@shared/lib/docs-children'

interface MenuLeaf {
  title: string
  url: string
}

interface MenuNode {
  title: string
  url?: string
  children?: MenuNode[]
}

interface Props {
  /** Page URL in the docs namespace (equivalent of page.url), e.g. "/ui/components/alert/". */
  url: string
}

const { url } = Astro.props

const children = getDocsChildren(url)

type Pagination = {
  prev: MenuLeaf | null
  next: MenuLeaf | null
  found: boolean
}

function findPage(nodes: MenuNode[]): Pagination | null {
  const index = nodes.findIndex((item) => item.url === url)

  if (index !== -1) {
    const previousNode = index > 0 ? nodes[index - 1] : null
    const nextNode = index < nodes.length - 1 ? nodes[index + 1] : null

    return {
      prev: previousNode?.url ? { title: previousNode.title, url: previousNode.url } : null,
      next: nextNode?.url ? { title: nextNode.title, url: nextNode.url } : null,
      found: true,
    }
  }

  for (const node of nodes) {
    const result = node.children ? findPage(node.children) : null
    if (result) return result
  }

  return null
}

const { prev, next, found } = findPage(docs.menu as MenuNode[]) ?? {
  prev: null,
  next: null,
  found: false,
}
---

<!-- BEGIN DOCS PAGINATION -->{
  children.length > 0 && (
    <div class="mt-6 pt-6">
      <div class="row row-deck row-cards">
        {children.map((child: DocsChildPage) => (
          <DocsCard href={child.url} title={child.title} description={child.description} icon={child.icon} />
        ))}
      </div>
    </div>
  )
}

{
  children.length === 0 && found && (
    <div class="mt-6 pt-6">
      <ul class="pagination">
        {prev && (
          <li class="page-item page-prev">
            <a class="page-link" href={prev.url}>
              <div class="row align-items-center">
                <div class="col-auto">
                  <Icon name="chevron-left" />
                </div>
                <div class="col">
                  <div class="page-item-subtitle">previous</div>
                  <div class="page-item-title">{prev.title}</div>
                </div>
              </div>
            </a>
          </li>
        )}
        {next && (
          <li class="page-item page-next">
            <a class="page-link" href={next.url}>
              <div class="row align-items-center">
                <div class="col">
                  <div class="page-item-subtitle">next</div>
                  <div class="page-item-title">{next.title}</div>
                </div>
                <div class="col-auto">
                  <Icon name="chevron-right" />
                </div>
              </div>
            </a>
          </li>
        )}
      </ul>
    </div>
  )
}
<!-- END DOCS PAGINATION -->