// Transforms tests/README.md into a Docusaurus-ready markdown page and writes
// it to tests/.docs-dist/. CI publishes that directory to the
// `server-testing-docs` branch, which the docs site (opencloud-eu/docs) pulls
// into docs/dev/server/testing via git-batch (.batchfile).
//
// Run locally with: node tests/scripts/generate-docs.mjs

import { mkdir, readFile, rm, writeFile } from 'node:fs/promises'
import path from 'node:path'
import { fileURLToPath } from 'node:url'

const HERE = path.dirname(fileURLToPath(import.meta.url))
const TESTS_DIR = path.resolve(HERE, '..')
const REPO_ROOT = path.resolve(TESTS_DIR, '..')
const INPUT = path.join(TESTS_DIR, 'README.md')
const OUT_DIR = path.join(TESTS_DIR, '.docs-dist')

// tests, relative to the repo root, used to resolve README-relative links.
const TESTS_REL = path.relative(REPO_ROOT, TESTS_DIR).split(path.sep).join('/')
const GH_BLOB = 'https://github.com/opencloud-eu/opencloud/blob/main'

const FRONT_MATTER = `---
title: 'Acceptance Testing'
sidebar_position: 1
id: acceptance-testing
---
`

const CATEGORY = {
  label: 'Testing',
  position: 4
}

// GitHub alert syntax -> Docusaurus admonitions.
const ALERT_TYPES = {
  NOTE: 'note',
  TIP: 'tip',
  IMPORTANT: 'info',
  WARNING: 'warning',
  CAUTION: 'danger'
}

function stripTitleAndToc(md) {
  // Docusaurus renders the title from front matter, so drop the leading H1.
  md = md.replace(/^#\s+.*\r?\n+/, '')
  // Drop the hand-maintained "Table of Contents" section (auto-generated by Docusaurus).
  md = md.replace(/^##\s+Table of Contents\s*\r?\n[\s\S]*?(?=^##\s)/m, '')
  return md
}

function stripHugoShortcodes(md) {
  // Hugo shortcodes ({{< ref "x" >}}) are not valid in Docusaurus MDX and raw
  // "{{ }}" would break the build. Keep the link text, drop the broken target.
  md = md.replace(/\[([^\]]+)\]\(\s*\{\{[<%][\s\S]*?[%>]\}\}\s*\)/g, '$1')
  // Remove any remaining bare shortcodes.
  md = md.replace(/\{\{[<%][\s\S]*?[%>]\}\}/g, '')
  return md
}

function convertAlerts(md) {
  const lines = md.split('\n')
  const out = []
  for (let i = 0; i < lines.length; i++) {
    const match = lines[i].match(/^>\s*\[!(NOTE|TIP|IMPORTANT|WARNING|CAUTION)\]\s*$/)
    if (!match) {
      out.push(lines[i])
      continue
    }
    const type = ALERT_TYPES[match[1]]
    const body = []
    while (i + 1 < lines.length && lines[i + 1].startsWith('>')) {
      i++
      body.push(lines[i].replace(/^>\s?/, ''))
    }
    out.push(`:::${type}`, ...body, ':::')
  }
  return out.join('\n')
}

function rewriteRelativeLinks(md) {
  // ](./foo) or ](../foo) -> absolute GitHub blob URL, resolved against tests/.
  return md.replace(/\]\((\.{1,2}\/[^)]+)\)/g, (_full, rel) => {
    const repoRelative = path.posix.join(TESTS_REL, rel)
    return `](${GH_BLOB}/${repoRelative})`
  })
}

async function main() {
  const readme = await readFile(INPUT, 'utf8')
  const body = rewriteRelativeLinks(
    convertAlerts(stripHugoShortcodes(stripTitleAndToc(readme)))
  )
  const page = `${FRONT_MATTER}\n${body.replace(/^\n+/, '')}`

  if (page.includes('{{')) {
    console.warn('Warning: unresolved "{{" remains in the output; Docusaurus MDX may fail.')
  }

  await rm(OUT_DIR, { recursive: true, force: true })
  await mkdir(OUT_DIR, { recursive: true })
  await writeFile(path.join(OUT_DIR, 'index.md'), page, 'utf8')
  await writeFile(path.join(OUT_DIR, '_category_.json'), JSON.stringify(CATEGORY, null, 2) + '\n', 'utf8')
  console.log(`Wrote ${path.relative(REPO_ROOT, OUT_DIR)}/{index.md,_category_.json}`)
}

main().catch((err) => {
  console.error(err)
  process.exit(1)
})