import type { PageMapItem } from 'nextra/dist/types'

export type PageMetadata = {
  route: string
  title: string
  frontMatter: Record<string, any>

  path: {
    title: string
    route?: string
  }[]
}

const _fromMap = (
  path: PageMetadata['path'],
  list: PageMapItem[],
): PageMetadata[] => {
  const meta = list.find((item) => item.kind === 'Meta') as Extract<
    PageMapItem,
    { kind: 'Meta' }
  >

  const pages = list.filter((item) => item.kind === 'MdxPage') as Extract<
    PageMapItem,
    { kind: 'MdxPage' }
  >[]
  const folders = list.filter((item) => item.kind === 'Folder') as Extract<
    PageMapItem,
    { kind: 'Folder' }
  >[]

  const findTitle = (item: PageMapItem) => {
    if (item.kind === 'Meta') return ''

    const name = item.name
    const metadata = meta.data[name]
    if (!metadata && item.kind === 'Folder') return name
    if (!metadata && item.kind === 'MdxPage') return ''

    return typeof metadata === 'string' ? metadata : metadata?.title || ''
  }

  return [
    ...pages.map(
      (page) =>
        ({
          route: page.route,
          title: findTitle(page) || '',
          frontMatter: page.frontMatter || {},
          path: [
            ...path,
            {
              title: findTitle(page),
              route: page.route,
            },
          ],
        }) as PageMetadata,
    ),
    ...folders.flatMap((folder: any) => {
      return _fromMap(
        [...path, { title: findTitle(folder), route: folder.route }],
        folder.children,
      )
    }),
  ]
}

export class PagesMetadata {
  data: Record<string, any> = {}

  constructor() {}

  get = (route: string) => this.data[route]

  toJson = () => ({
    data: this.data,
  })

  fromJson = (data: any) => {
    this.data = data?.data || {}

    return this
  }

  static fromPageMap(list: PageMapItem[]) {
    const data = _fromMap([], list)
    const instance = new PagesMetadata()
    instance.data = Object.fromEntries(data.map((item) => [item.route, item]))

    return instance
  }
}