import { basename } from 'node:path'
import { createMoonbitLanguageRegistration } from 'moonbit-syntax-highlighter'
import { defineConfig, type DefaultTheme } from 'vitepress'

import { docsData } from './generated/docs-data.mjs'

type ApiDocEntry = {
  file: string
  text: string
  group: string
  category: string
}

const repoSlug = process.env.GITHUB_REPOSITORY?.split('/')[1] ?? 'BitLogger'
const docsBase = process.env.DOCS_BASE ?? (process.env.GITHUB_ACTIONS ? `/${repoSlug}/` : '/')
const repository = 'https://github.com/Nanaloveyuki/BitLogger'

function splitWords(input: string): string[] {
  return input
    .split(/[^A-Za-z0-9]+/)
    .map(part => part.trim())
    .filter(Boolean)
}

function formatWord(word: string): string {
  const lower = word.toLowerCase()
  if (lower === 'api') return 'API'
  if (lower === 'json') return 'JSON'
  if (lower === 'js') return 'JS'
  if (lower === 'wasm') return 'WASM'
  if (lower === 'llvm') return 'LLVM'
  return lower.charAt(0).toUpperCase() + lower.slice(1)
}

function humanize(input: string): string {
  const words = splitWords(input)
  if (words.length === 0) return input
  return words.map(formatWord).join(' ')
}

function readApiDocs(): ApiDocEntry[] {
  return docsData.api.entries.map(entry => ({
    file: entry.file,
    text: entry.title,
    group: entry.group,
    category: entry.category,
  }))
}

function buildApiSidebar(): DefaultTheme.SidebarItem[] {
  const entries = readApiDocs()
  const sidebar: DefaultTheme.SidebarItem[] = [{ text: 'Overview', link: '/api/' }]
  const groups = new Map<string, Map<string, DefaultTheme.SidebarItem[]>>()

  for (const entry of entries) {
    if (entry.file === 'index.md') continue
    const group = groups.get(entry.group) ?? new Map<string, DefaultTheme.SidebarItem[]>()
    const categoryItems = group.get(entry.category) ?? []
    categoryItems.push({
      text: entry.text,
      link: `/api/${basename(entry.file, '.md')}`,
    })
    group.set(entry.category, categoryItems)
    groups.set(entry.group, group)
  }

  if (groups.size === 1 && groups.has('api')) {
    const categories = groups.get('api')!
    for (const category of [...categories.keys()].sort((a, b) => humanize(a).localeCompare(humanize(b)))) {
      sidebar.push({
        text: humanize(category),
        collapsed: true,
        items: categories.get(category)!,
      })
    }
    return sidebar
  }

  for (const group of [...groups.keys()].sort((a, b) => humanize(a).localeCompare(humanize(b)))) {
    const categories = groups.get(group)!
    sidebar.push({
      text: humanize(group),
      collapsed: true,
      items: [...categories.keys()]
        .sort((a, b) => humanize(a).localeCompare(humanize(b)))
        .map(category => ({
          text: humanize(category),
          collapsed: true,
          items: categories.get(category)!,
        })),
    })
  }

  return sidebar
}

function buildChangesSidebar(): DefaultTheme.SidebarItem[] {
  return [
    { text: 'Overview', link: '/changes/' },
    {
      text: 'Versions',
      items: docsData.changes.map(item => ({ text: item.version, link: item.link })),
    },
  ]
}

export default defineConfig({
  title: 'BitLogger',
  description: 'Structured logging library docs for MoonBit.',
  base: docsBase,
  cleanUrls: true,
  srcExclude: ['dev/**'],
  lastUpdated: true,
  markdown: {
    languages: [createMoonbitLanguageRegistration()],
  },
  themeConfig: {
    siteTitle: 'BitLogger',
    nav: [
      { text: 'Home', link: '/' },
      { text: 'API', link: '/api/' },
      { text: 'Changes', link: '/changes/' },
      { text: 'Mooncake', link: 'https://mooncakes.io/docs/Nanaloveyuki/BitLogger' },
    ],
    search: {
      provider: 'local',
    },
    socialLinks: [{ icon: 'github', link: repository }],
    editLink: {
      pattern: `${repository}/edit/main/docs/:path`,
      text: 'Edit this page on GitHub',
    },
    sidebar: {
      '/api/': buildApiSidebar(),
      '/changes/': buildChangesSidebar(),
    },
    footer: {
      message: 'Published from the repository docs folder with VitePress.',
      copyright: 'MIT',
    },
  },
})