import { z } from 'zod'
import {
  isBotUserAgent,
  isTrackableAnalyticsPath,
  normalizePageSlugForAnalytics,
  normalizePostSlugForAnalytics
} from '../../lib/analytics.js'
import { getPageBySlug, getPostBySlug } from '../repositories/content-repository.js'
import {
  createSessionHashFromEvent,
  recordAnalyticsHeartbeat
} from '../repositories/analytics-repository.js'

const heartbeatInputSchema = z.object({
  path: z.string().trim().min(1).max(500),
  postSlug: z.string().trim().max(200).optional().default(''),
  pageSlug: z.string().trim().max(200).optional().default(''),
  clientSessionId: z.string().trim().min(8).max(120),
  durationSeconds: z.number().int().min(0).max(1800),
  maxScrollRatio: z.number().min(0).max(1)
})

/**
 * heartbeat 추적 요청을 처리한다.
 * @param {import('h3').H3Event} event - H3 이벤트
 * @returns {Promise<{ ok: true }>}
 */
export const handleAnalyticsHeartbeat = async (event) => {
  const parsedBody = heartbeatInputSchema.safeParse(await readBody(event))

  if (!parsedBody.success) {
    throw createError({
      statusCode: 400,
      message: '통계 heartbeat 형식이 올바르지 않습니다.'
    })
  }

  const body = parsedBody.data
  const userAgent = String(getRequestHeader(event, 'user-agent') || '')

  if (isBotUserAgent(userAgent)) {
    return { ok: true }
  }

  if (!isTrackableAnalyticsPath(body.path)) {
    return { ok: true }
  }

  const postSlug = normalizePostSlugForAnalytics(body.postSlug)
  const pageSlug = normalizePageSlugForAnalytics(body.pageSlug)
  let postId = null
  let pageId = null

  if (postSlug) {
    const post = await getPostBySlug(postSlug)
    if (!post) {
      return { ok: true }
    }
    postId = post.id
  }

  if (!postId && pageSlug) {
    const page = await getPageBySlug(pageSlug)
    if (!page) {
      return { ok: true }
    }
    pageId = page.id
  }

  const sessionHash = createSessionHashFromEvent(event, body.clientSessionId)

  await recordAnalyticsHeartbeat({
    event,
    sessionHash,
    path: body.path,
    postId,
    postSlug,
    pageId,
    pageSlug,
    durationSeconds: body.durationSeconds,
    maxScrollRatio: body.maxScrollRatio
  })

  return { ok: true }
}