import type { App } from 'vuepress/core'
import { createPage } from 'vuepress/core'
import type { PageFrontmatter } from 'vuepress/shared'
import { getTitleFromFilename } from './getTitleFromFilename.js'
import { logger } from './logger.js'
import type { CatalogPluginOptions } from './options.js'

export const generateCatalogPage = async (
  app: App,
  {
    component = 'Catalog',
    exclude = [],
    frontmatter = (): PageFrontmatter => ({}),
    level = 3,
    index = false,
  }: CatalogPluginOptions,
): Promise<void> => {
  const {
    env: { isDebug },
    pages,
  } = app

  const pathToBeGenerated = new Set<string>()
  const content = `\
<${component}${[1, 2].includes(level) ? ` :level="${level}"` : ''}${
    index ? ' index' : ''
  }/>
`

  pages.forEach(({ path: pagePath, pathLocale }) => {
    let catalogPath = pagePath

    // not 404 page
    if (pagePath !== '/404.html')
      while (catalogPath !== pathLocale) {
        catalogPath = catalogPath.replace(/\/(?:[^/]+\/?)$/, '/')

        if (
          // not discovered yet
          !pathToBeGenerated.has(catalogPath) &&
          // not being excluded
          exclude.every((pattern) => !catalogPath.match(pattern)) &&
          // path not found
          pages.every(({ path }) => path !== catalogPath)
        ) {
          if (isDebug) logger.info(`Generating catalog ${catalogPath}`)

          pathToBeGenerated.add(catalogPath)
        }
      }
  })

  await Promise.all(
    Array.from(pathToBeGenerated)
      .map((path) => decodeURI(path))
      .map((path) => {
        const [, basename = ''] = /\/([^/]+)\/?$/.exec(path) || []
        const title = getTitleFromFilename(basename)

        return createPage(app, {
          frontmatter: {
            title,
            ...(frontmatter(path) || {}),
          },
          content,
          path,
        })
      }),
  ).then((pages) => {
    app.pages.push(...pages)
  })
}