import type { Page } from '@/lib/schema/page'

export type ExtrasOverrides = {
  robotsText?: string
  manifest?: Partial<{
    name: string
    short_name: string
    start_url: string
    display: string
    theme_color: string
  }>
  sheetsMode?: 'auto' | 'include' | 'exclude'
}

function toBytes(s: string): Uint8Array {
  return new TextEncoder().encode(s)
}

function buildRobots(base?: string): string {
  if (base && base.trim().length > 0) {
    const s = base.trim()
    if (/^User-agent:/i.test(s)) return s
    const lines = s.split(/\n+/).map((l) => l.trim()).filter((l) => l.length > 0)
    if (lines.length === 0) return 'User-agent: *\n'
    const disallowLines = lines.map((l) => (l.startsWith('Disallow:') ? l : `Disallow: ${l}`))
    return `User-agent: *\n${disallowLines.join('\n')}`
  }
  return 'User-agent: *\n'
}

function deriveManifest(page: Page) {
  const name = page.title || 'Landing'
  const short_name = name.length > 12 ? name.slice(0, 12) : name
  const start_url = '/'
  const display = 'standalone'
  const theme_color = page.theme?.primaryColor || '#0ea5e9'
  return { name, short_name, start_url, display, theme_color }
}

export function buildExtrasForPage(page: Page, overrides?: ExtrasOverrides): Record<string, Uint8Array> {
  const out: Record<string, Uint8Array> = {}

  // robots.txt
  const robotsText = buildRobots(overrides?.robotsText)
  out['robots.txt'] = toBytes(robotsText)

  // site.webmanifest (auto-enrich and safe-merge)
  const manifestBase = deriveManifest(page)
  const ov = overrides?.manifest || {}
  const name = ov.name && ov.name.trim().length > 0 ? ov.name : manifestBase.name
  const short_name = ov.short_name && ov.short_name.trim().length > 0
    ? ov.short_name
    : (name.length > 12 ? name.slice(0, 12) : name)
  const start_url = ov.start_url && ov.start_url.trim().length > 0 ? ov.start_url : manifestBase.start_url
  const display = ov.display && ov.display.trim().length > 0 ? ov.display : manifestBase.display
  const hexOk = ov.theme_color ? /^#([0-9a-fA-F]{3}){1,2}$/.test(ov.theme_color) : false
  const theme_color = hexOk ? (ov.theme_color as string) : manifestBase.theme_color
  const manifestMerged = { name, short_name, start_url, display, theme_color }
  const manifestJson = JSON.stringify(manifestMerged, null, 2)
  out['site.webmanifest'] = toBytes(manifestJson)

  // Google Sheets 템플릿: 기본 auto. overrides.sheetsMode로 강제 포함/제외 가능
  const mode = overrides?.sheetsMode ?? 'auto'
  const action = page.form?.actionUrl?.trim()
  const hasAction = !!(action && action.length > 0)
  const shouldInclude = mode === 'include' || (mode === 'auto' && !hasAction)
  if (shouldInclude) {
    const code = `/**
 * Google Apps Script Web App for form submissions
 * - Deploy as Web App and set URL as form action if needed.
 */
function doPost(e){
  // TODO: handle submission to Google Sheets
  return ContentService.createTextOutput('OK')
}
`
    const readme = `Google Sheets Apps Script Template\n\n1) Apps Script에서 새 프로젝트를 만들고 아래 Code.gs를 붙여넣으세요.\n2) 배포 > 웹 앱으로 배포 후 URL을 복사해 사용하세요.`
    out['sheets/Code.gs'] = toBytes(code)
    out['sheets/README.txt'] = toBytes(readme)
  }

  return out
}