// wiki 知識庫的純邏輯：目錄解析與渲染、頁名、驗證。讀寫與 git 在 register.tsx。

export type Entry = { domain: string; topic: string }

export const CACHE_MS = 10 * 60 * 1000

// 指令名稱只能用英數與底線，領域與主題也沿用。
const NAME_RE = /^[A-Za-z0-9_]+$/

export const validName = (s: string): boolean => NAME_RE.test(s)

export const commandName = (e: Entry): string => `${e.domain}-${e.topic}`

export const pageName = (e: Entry): string => `${e.domain}-${e.topic}`

// Home 的格式：「## 領域」章、「- [主題](頁名)」節。
export const parseCatalog = (home: string): Entry[] => {
  const out: Entry[] = []
  let domain = ''
  for (const line of home.split('\n')) {
    const h = /^##\s+(.+?)\s*$/.exec(line)
    if (h) {
      domain = h[1]!
      continue
    }
    const m = /^\s*[-*]\s+\[(.+?)\]\((.+?)\)\s*$/.exec(line)
    if (m && domain) out.push({ domain, topic: m[1]! })
  }
  return out
}

const group = (entries: Entry[]): Map<string, string[]> => {
  const g = new Map<string, string[]>()
  for (const e of entries) g.set(e.domain, [...(g.get(e.domain) ?? []), e.topic])
  return g
}

export const addEntry = (entries: Entry[], e: Entry): Entry[] =>
  entries.some(x => x.domain === e.domain && x.topic === e.topic) ? entries : [...entries, e]

export const renderHome = (entries: Entry[]): string => {
  const lines = ['# 知識庫', '']
  for (const [domain, topics] of group(entries)) {
    lines.push(`## ${domain}`, '')
    for (const t of topics) lines.push(`- [${t}](${pageName({ domain, topic: t })})`)
    lines.push('')
  }
  return lines.join('\n')
}

export const renderSidebar = (entries: Entry[]): string => {
  const lines = ['**[知識庫](Home)**', '']
  for (const [domain, topics] of group(entries)) {
    lines.push(`**${domain}**`, '')
    for (const t of topics) lines.push(`- [${t}](${pageName({ domain, topic: t })})`)
    lines.push('')
  }
  return lines.join('\n')
}

export const renderPage = (e: Entry, body: string, source: string): string =>
  `# ${e.topic}\n\n> 領域：${e.domain}\n\n${body.trim()}\n\n---\n\n出處：${source}\n`

export const commitMessage = (e: Entry, existed: boolean): string =>
  `feat: ${existed ? '更新' : '新增'}知識「${e.domain}／${e.topic}」`

// tea 設定檔（YAML）中，找出網址主機相符的登入的 token。
export const teaToken = (yaml: string, host: string): string | undefined => {
  for (const block of yaml.split(/^\s*-\s+name:/m).slice(1)) {
    const url = /^\s*url:\s*(\S+)/m.exec(block)?.[1]
    const token = /^\s*token:\s*(\S+)/m.exec(block)?.[1]
    if (!url || !token) continue
    try {
      if (new URL(url.replace(/^['"]|['"]$/g, '')).host === host) return token.replace(/^['"]|['"]$/g, '')
    } catch {}
  }
  return undefined
}

export const wikiUrlFromRemote = (remote: string): string | undefined => {
  const base = remote.trim().replace(/\.git$/, '')
  return base ? `${base}.wiki.git` : undefined
}

// 指令參數：第一行「領域 主題 [出處]」，其後為內容。
export const parseWriteArgs = (args: string): { entry: Entry; source: string; body: string } | undefined => {
  const [first = '', ...rest] = args.trim().split('\n')
  const [domain, topic, ...src] = first.trim().split(/\s+/)
  const body = rest.join('\n').trim()
  if (!domain || !topic || !body || !validName(domain) || !validName(topic)) return undefined
  return { entry: { domain, topic }, source: src.join(' ') || '使用者提供', body }
}