import {
  ANALYTICS_ACTIVE_SESSION_TTL_SECONDS,
  ANALYTICS_CHART_MAX_DAYS,
  ANALYTICS_ENGAGED_MIN_SECONDS,
  ANALYTICS_RETENTION_PURGE_INTERVAL_MS,
  ANALYTICS_VISITOR_HASH_RETENTION_DAYS,
  clampAnalyticsDurationSeconds,
  clampAnalyticsScrollRatio,
  createDailyVisitorHash,
  createRealtimeSessionHash,
  getAnalyticsDayBefore,
  getAnalyticsDayKey,
  getNewScrollBucketColumns
} from '../../lib/analytics.js'
import { getPostgresClient } from './postgres-client.js'
import { getRuntimeEnvValue } from '../utils/runtime-env.js'
import { getMemberSession } from '../utils/member-auth.js'

/** @type {number} 마지막 통계 보관 정리 실행 시각 */
let lastAnalyticsRetentionPurgeAt = 0

/**
 * 통계 해시용 시크릿을 반환한다.
 * @returns {string} 시크릿
 */
const getAnalyticsHashSecret = () => {
  return getRuntimeEnvValue(
    'ANALYTICS_HASH_SECRET',
    'analyticsHashSecret',
    getRuntimeEnvValue('MEMBER_SESSION_SECRET', 'memberSessionSecret', 'analytics-fallback-secret')
  ).trim()
}

/**
 * 일별 사이트 통계 행을 보장한다.
 * @param {import('postgres').Sql} sql - DB 클라이언트
 * @param {string} day - YYYY-MM-DD
 * @returns {Promise<void>}
 */
const ensureSiteDailyRow = async (sql, day) => {
  await sql`
    INSERT INTO site_analytics_daily (day)
    VALUES (${day})
    ON CONFLICT (day) DO NOTHING
  `
}

/**
 * 일별 게시물 통계 행을 보장한다.
 * @param {import('postgres').Sql} sql - DB 클라이언트
 * @param {string} day - YYYY-MM-DD
 * @param {string} postId - 게시물 ID
 * @returns {Promise<void>}
 */
const ensurePostDailyRow = async (sql, day, postId) => {
  await sql`
    INSERT INTO post_analytics_daily (day, post_id)
    VALUES (${day}, ${postId})
    ON CONFLICT (day, post_id) DO NOTHING
  `
}

/**
 * 일별 페이지 통계 행을 보장한다.
 * @param {import('postgres').Sql} sql - DB 클라이언트
 * @param {string} day - YYYY-MM-DD
 * @param {string} pageId - 페이지 ID
 * @returns {Promise<void>}
 */
const ensurePageDailyRow = async (sql, day, pageId) => {
  await sql`
    INSERT INTO page_analytics_daily (day, page_id)
    VALUES (${day}, ${pageId})
    ON CONFLICT (day, page_id) DO NOTHING
  `
}

/**
 * 일별 유입 통계 행을 보장한다.
 * @param {import('postgres').Sql} sql - DB 클라이언트
 * @param {string} day - YYYY-MM-DD
 * @param {{ sourceGroup: string, sourceName: string, deviceType: string, osName: string, keyword?: string }} traffic - 유입 분류
 * @returns {Promise<void>}
 */
const ensureTrafficDailyRow = async (sql, day, traffic) => {
  await sql`
    INSERT INTO analytics_traffic_daily (
      day,
      source_group,
      source_name,
      device_type,
      os_name,
      keyword
    )
    VALUES (
      ${day},
      ${traffic.sourceGroup},
      ${traffic.sourceName},
      ${traffic.deviceType},
      ${traffic.osName},
      ${traffic.keyword || ''}
    )
    ON CONFLICT (day, source_group, source_name, device_type, os_name, keyword) DO NOTHING
  `
}

/**
 * 사이트 방문자를 등록하고 신규 방문자면 true를 반환한다.
 * @param {import('postgres').Sql} sql - DB 클라이언트
 * @param {string} day - YYYY-MM-DD
 * @param {string} visitorHash - 방문자 해시
 * @returns {Promise<boolean>} 신규 방문자 여부
 */
const registerSiteVisitor = async (sql, day, visitorHash) => {
  const rows = await sql`
    INSERT INTO analytics_daily_visitors (day, scope, visitor_hash)
    VALUES (${day}, 'site', ${visitorHash})
    ON CONFLICT DO NOTHING
    RETURNING id
  `

  return Boolean(rows[0])
}

/**
 * 게시물 방문자를 등록하고 신규 방문자면 true를 반환한다.
 * @param {import('postgres').Sql} sql - DB 클라이언트
 * @param {string} day - YYYY-MM-DD
 * @param {string} postId - 게시물 ID
 * @param {string} visitorHash - 방문자 해시
 * @returns {Promise<boolean>} 신규 방문자 여부
 */
const registerPostVisitor = async (sql, day, postId, visitorHash) => {
  const rows = await sql`
    INSERT INTO analytics_daily_visitors (day, scope, post_id, visitor_hash)
    VALUES (${day}, 'post', ${postId}, ${visitorHash})
    ON CONFLICT DO NOTHING
    RETURNING id
  `

  return Boolean(rows[0])
}

/**
 * 페이지 방문자를 등록하고 신규 방문자면 true를 반환한다.
 * @param {import('postgres').Sql} sql - DB 클라이언트
 * @param {string} day - YYYY-MM-DD
 * @param {string} pageId - 페이지 ID
 * @param {string} visitorHash - 방문자 해시
 * @returns {Promise<boolean>} 신규 방문자 여부
 */
const registerPageVisitor = async (sql, day, pageId, visitorHash) => {
  const rows = await sql`
    INSERT INTO analytics_daily_visitors (day, scope, page_id, visitor_hash)
    VALUES (${day}, 'page', ${pageId}, ${visitorHash})
    ON CONFLICT DO NOTHING
    RETURNING id
  `

  return Boolean(rows[0])
}

/**
 * 유입 분류별 방문자를 등록하고 신규 방문자면 true를 반환한다.
 * @param {import('postgres').Sql} sql - DB 클라이언트
 * @param {string} day - YYYY-MM-DD
 * @param {string} visitorHash - 방문자 해시
 * @param {{ sourceGroup: string, sourceName: string, deviceType: string, osName: string, keyword?: string }} traffic - 유입 분류
 * @returns {Promise<boolean>} 신규 방문자 여부
 */
const registerTrafficVisitor = async (sql, day, visitorHash, traffic) => {
  const rows = await sql`
    INSERT INTO analytics_daily_visitors (
      day,
      scope,
      visitor_hash,
      source_group,
      source_name,
      device_type,
      os_name,
      keyword
    )
    VALUES (
      ${day},
      'traffic',
      ${visitorHash},
      ${traffic.sourceGroup},
      ${traffic.sourceName},
      ${traffic.deviceType},
      ${traffic.osName},
      ${traffic.keyword || ''}
    )
    ON CONFLICT DO NOTHING
    RETURNING id
  `

  return Boolean(rows[0])
}

/**
 * 유입·디바이스 통계를 기록한다.
 * @param {import('postgres').Sql} sql - DB 클라이언트
 * @param {string} day - YYYY-MM-DD
 * @param {string} visitorHash - 방문자 해시
 * @param {{ sourceGroup: string, sourceName: string, deviceType: string, osName: string, keyword?: string }} traffic - 유입 분류
 * @returns {Promise<void>}
 */
const recordAnalyticsTraffic = async (sql, day, visitorHash, traffic) => {
  await ensureTrafficDailyRow(sql, day, traffic)
  const isNewTrafficVisitor = await registerTrafficVisitor(sql, day, visitorHash, traffic)

  await sql`
    UPDATE analytics_traffic_daily
    SET
      page_views = page_views + 1,
      visitors = visitors + ${isNewTrafficVisitor ? 1 : 0}
    WHERE day = ${day}
      AND source_group = ${traffic.sourceGroup}
      AND source_name = ${traffic.sourceName}
      AND device_type = ${traffic.deviceType}
      AND os_name = ${traffic.osName}
      AND keyword = ${traffic.keyword || ''}
  `
}

/**
 * 페이지뷰·읽음 이벤트를 기록한다.
 * @param {{ visitorHash: string, postId?: string | null, pageId?: string | null, traffic?: { sourceGroup: string, sourceName: string, deviceType: string, osName: string, keyword?: string }, recordSite?: boolean, recordView?: boolean, recordRead?: boolean }} input - 기록 입력
 * @returns {Promise<{ ok: true }>}
 */
export const recordAnalyticsPageview = async (input) => {
  const sql = getPostgresClient()

  if (!sql) {
    return { ok: true }
  }

  const day = getAnalyticsDayKey()
  const visitorHash = input.visitorHash
  const postId = input.postId || null
  const pageId = input.pageId || null
  const recordSite = input.recordSite !== false
  const recordView = Boolean(input.recordView)
  const recordRead = Boolean(input.recordRead)
  const traffic = input.traffic || null

  if (recordSite) {
    await ensureSiteDailyRow(sql, day)

    const isNewSiteVisitor = await registerSiteVisitor(sql, day, visitorHash)

    await sql`
      UPDATE site_analytics_daily
      SET
        page_views = page_views + 1,
        visitors = visitors + ${isNewSiteVisitor ? 1 : 0}
      WHERE day = ${day}
    `

    if (traffic) {
      await recordAnalyticsTraffic(sql, day, visitorHash, traffic)
    }
  }

  if (!postId) {
    if (pageId && recordView) {
      await ensurePageDailyRow(sql, day, pageId)

      const isNewPageVisitor = await registerPageVisitor(sql, day, pageId, visitorHash)

      await sql`
        UPDATE page_analytics_daily
        SET
          views = views + 1,
          visitors = visitors + ${isNewPageVisitor ? 1 : 0}
        WHERE day = ${day}
          AND page_id = ${pageId}
      `
    }

    await purgeAnalyticsRetention(sql)
    return { ok: true }
  }

  await ensurePostDailyRow(sql, day, postId)

  if (recordView) {
    const isNewPostVisitor = await registerPostVisitor(sql, day, postId, visitorHash)

    await sql`
      UPDATE post_analytics_daily
      SET
        views = views + 1,
        visitors = visitors + ${isNewPostVisitor ? 1 : 0}
      WHERE day = ${day}
        AND post_id = ${postId}
    `
  }

  if (recordRead) {
    await sql`
      UPDATE post_analytics_daily
      SET reads = reads + 1
      WHERE day = ${day}
        AND post_id = ${postId}
    `
  }

  await purgeAnalyticsRetention(sql)

  return { ok: true }
}

/**
 * 요청에서 일 단위 방문자 해시를 만든다.
 * @param {import('h3').H3Event} event - H3 이벤트
 * @returns {string} visitor hash
 */
export const createVisitorHashFromEvent = (event) => {
  const day = getAnalyticsDayKey()
  const ip = String(getRequestIP(event, { xForwardedFor: true }) || '')
  const userAgent = String(getRequestHeader(event, 'user-agent') || '')

  return createDailyVisitorHash({
    day,
    ip,
    userAgent,
    secret: getAnalyticsHashSecret()
  })
}

/**
 * heartbeat용 실시간 세션 해시를 만든다.
 * @param {import('h3').H3Event} event - H3 이벤트
 * @param {string} clientSessionId - 탭 단위 클라이언트 세션 ID
 * @returns {string} session hash
 */
export const createSessionHashFromEvent = (event, clientSessionId) => {
  return createRealtimeSessionHash({
    clientSessionId: String(clientSessionId || '').trim(),
    visitorHash: createVisitorHashFromEvent(event),
    secret: getAnalyticsHashSecret()
  })
}

/**
 * 만료된 실시간 세션 행을 정리한다.
 * @param {import('postgres').Sql} sql - DB 클라이언트
 * @returns {Promise<void>}
 */
const purgeStaleActiveSessions = async (sql) => {
  await sql`
    DELETE FROM analytics_active_sessions
    WHERE last_seen_at < now() - (${ANALYTICS_ACTIVE_SESSION_TTL_SECONDS} * interval '1 second')
  `
}

/**
 * 오래된 방문자 해시를 정리한다.
 * @param {import('postgres').Sql} sql - DB 클라이언트
 * @returns {Promise<void>}
 */
const purgeAnalyticsRetention = async (sql) => {
  const now = Date.now()

  if (now - lastAnalyticsRetentionPurgeAt < ANALYTICS_RETENTION_PURGE_INTERVAL_MS) {
    return
  }

  const today = getAnalyticsDayKey()
  const visitorHashCutoffDay = getAnalyticsDayBefore(today, ANALYTICS_VISITOR_HASH_RETENTION_DAYS)

  await sql`
    DELETE FROM analytics_daily_visitors
    WHERE day < ${visitorHashCutoffDay}::date
  `

  lastAnalyticsRetentionPurgeAt = now
}

/**
 * 스크롤 구간 카운터를 증가시킨다.
 * @param {import('postgres').Sql} sql - DB 클라이언트
 * @param {string} day - YYYY-MM-DD
 * @param {string} postId - 게시물 ID
 * @param {Array<'scroll_25' | 'scroll_50' | 'scroll_75' | 'scroll_100'>} columns - 구간 컬럼
 * @returns {Promise<void>}
 */
const incrementPostScrollBuckets = async (sql, day, postId, columns) => {
  if (!columns.length) {
    return
  }

  await ensurePostDailyRow(sql, day, postId)

  for (const column of columns) {
    if (column === 'scroll_25') {
      await sql`
        UPDATE post_analytics_daily
        SET scroll_25 = scroll_25 + 1
        WHERE day = ${day}
          AND post_id = ${postId}
      `
    } else if (column === 'scroll_50') {
      await sql`
        UPDATE post_analytics_daily
        SET scroll_50 = scroll_50 + 1
        WHERE day = ${day}
          AND post_id = ${postId}
      `
    } else if (column === 'scroll_75') {
      await sql`
        UPDATE post_analytics_daily
        SET scroll_75 = scroll_75 + 1
        WHERE day = ${day}
          AND post_id = ${postId}
      `
    } else if (column === 'scroll_100') {
      await sql`
        UPDATE post_analytics_daily
        SET scroll_100 = scroll_100 + 1
        WHERE day = ${day}
          AND post_id = ${postId}
      `
    }
  }
}

/**
 * 페이지 스크롤 구간 카운터를 증가시킨다.
 * @param {import('postgres').Sql} sql - DB 클라이언트
 * @param {string} day - YYYY-MM-DD
 * @param {string} pageId - 페이지 ID
 * @param {Array<'scroll_25' | 'scroll_50' | 'scroll_75' | 'scroll_100'>} columns - 구간 컬럼
 * @returns {Promise<void>}
 */
const incrementPageScrollBuckets = async (sql, day, pageId, columns) => {
  if (!columns.length) {
    return
  }

  await ensurePageDailyRow(sql, day, pageId)

  for (const column of columns) {
    if (column === 'scroll_25') {
      await sql`
        UPDATE page_analytics_daily
        SET scroll_25 = scroll_25 + 1
        WHERE day = ${day}
          AND page_id = ${pageId}
      `
    } else if (column === 'scroll_50') {
      await sql`
        UPDATE page_analytics_daily
        SET scroll_50 = scroll_50 + 1
        WHERE day = ${day}
          AND page_id = ${pageId}
      `
    } else if (column === 'scroll_75') {
      await sql`
        UPDATE page_analytics_daily
        SET scroll_75 = scroll_75 + 1
        WHERE day = ${day}
          AND page_id = ${pageId}
      `
    } else if (column === 'scroll_100') {
      await sql`
        UPDATE page_analytics_daily
        SET scroll_100 = scroll_100 + 1
        WHERE day = ${day}
          AND page_id = ${pageId}
      `
    }
  }
}

/**
 * heartbeat·체류·스크롤·실시간 세션을 기록한다.
 * @param {{ event: import('h3').H3Event, sessionHash: string, path: string, postId?: string | null, postSlug?: string, pageId?: string | null, pageSlug?: string, durationSeconds: number, maxScrollRatio: number }} input - 기록 입력
 * @returns {Promise<{ ok: true }>}
 */
export const recordAnalyticsHeartbeat = async (input) => {
  const sql = getPostgresClient()

  if (!sql) {
    return { ok: true }
  }

  const day = getAnalyticsDayKey()
  const sessionHash = input.sessionHash
  const path = input.path
  const postId = input.postId || null
  const postSlug = input.postSlug || ''
  const pageId = input.pageId || null
  const pageSlug = input.pageSlug || ''
  const durationSeconds = clampAnalyticsDurationSeconds(input.durationSeconds)
  const maxScrollRatio = clampAnalyticsScrollRatio(input.maxScrollRatio)
  const memberSession = getMemberSession(input.event)
  const userId = memberSession?.userId || null

  const previousRows = await sql`
    SELECT duration_seconds, max_scroll_ratio
    FROM analytics_active_sessions
    WHERE session_hash = ${sessionHash}
    LIMIT 1
  `

  const previousDuration = Number(previousRows[0]?.duration_seconds || 0)
  const previousScrollRatio = Number(previousRows[0]?.max_scroll_ratio || 0)
  const durationDelta = Math.max(0, durationSeconds - previousDuration)
  const scrollBuckets = getNewScrollBucketColumns(previousScrollRatio, maxScrollRatio)

  await sql`
    INSERT INTO analytics_active_sessions (
      session_hash,
      user_id,
      path,
      post_id,
      post_slug,
      page_id,
      page_slug,
      duration_seconds,
      max_scroll_ratio
    )
    VALUES (
      ${sessionHash},
      ${userId},
      ${path},
      ${postId},
      ${postSlug},
      ${pageId},
      ${pageSlug},
      ${durationSeconds},
      ${maxScrollRatio}
    )
    ON CONFLICT (session_hash) DO UPDATE
    SET
      user_id = COALESCE(EXCLUDED.user_id, analytics_active_sessions.user_id),
      path = EXCLUDED.path,
      post_id = EXCLUDED.post_id,
      post_slug = EXCLUDED.post_slug,
      page_id = EXCLUDED.page_id,
      page_slug = EXCLUDED.page_slug,
      duration_seconds = GREATEST(analytics_active_sessions.duration_seconds, EXCLUDED.duration_seconds),
      max_scroll_ratio = GREATEST(analytics_active_sessions.max_scroll_ratio, EXCLUDED.max_scroll_ratio),
      last_seen_at = now()
  `

  if (durationDelta > 0) {
    await ensureSiteDailyRow(sql, day)

    await sql`
      UPDATE site_analytics_daily
      SET total_engaged_seconds = total_engaged_seconds + ${durationDelta}
      WHERE day = ${day}
    `

    const wasSiteEngaged = previousDuration >= ANALYTICS_ENGAGED_MIN_SECONDS
    const isSiteEngaged = durationSeconds >= ANALYTICS_ENGAGED_MIN_SECONDS

    if (!wasSiteEngaged && isSiteEngaged) {
      await sql`
        UPDATE site_analytics_daily
        SET engaged_views = engaged_views + 1
        WHERE day = ${day}
      `
    }
  }

  if (postId && (durationDelta > 0 || scrollBuckets.length)) {
    await ensurePostDailyRow(sql, day, postId)

    if (durationDelta > 0) {
      await sql`
        UPDATE post_analytics_daily
        SET total_engaged_seconds = total_engaged_seconds + ${durationDelta}
        WHERE day = ${day}
          AND post_id = ${postId}
      `

      const wasPostEngaged = previousDuration >= ANALYTICS_ENGAGED_MIN_SECONDS
      const isPostEngaged = durationSeconds >= ANALYTICS_ENGAGED_MIN_SECONDS

      if (!wasPostEngaged && isPostEngaged) {
        await sql`
          UPDATE post_analytics_daily
          SET engaged_views = engaged_views + 1
          WHERE day = ${day}
            AND post_id = ${postId}
        `
      }
    }

    await incrementPostScrollBuckets(sql, day, postId, scrollBuckets)
  }

  if (pageId && (durationDelta > 0 || scrollBuckets.length)) {
    await ensurePageDailyRow(sql, day, pageId)

    if (durationDelta > 0) {
      await sql`
        UPDATE page_analytics_daily
        SET total_engaged_seconds = total_engaged_seconds + ${durationDelta}
        WHERE day = ${day}
          AND page_id = ${pageId}
      `

      const wasPageEngaged = previousDuration >= ANALYTICS_ENGAGED_MIN_SECONDS
      const isPageEngaged = durationSeconds >= ANALYTICS_ENGAGED_MIN_SECONDS

      if (!wasPageEngaged && isPageEngaged) {
        await sql`
          UPDATE page_analytics_daily
          SET engaged_views = engaged_views + 1
          WHERE day = ${day}
            AND page_id = ${pageId}
        `
      }
    }

    await incrementPageScrollBuckets(sql, day, pageId, scrollBuckets)
  }

  await purgeStaleActiveSessions(sql)
  await purgeAnalyticsRetention(sql)

  return { ok: true }
}

/**
 * 통계 요약을 조회한다.
 * @param {{ days?: number }} [options] - 조회 옵션
 * @returns {Promise<Object>} 요약 통계
 */
export const getAnalyticsSummary = async (options = {}) => {
  const sql = getPostgresClient()
  const days = Math.min(Math.max(Number(options.days) || 30, 1), ANALYTICS_CHART_MAX_DAYS)

  if (!sql) {
    return {
      todayVisitors: 0,
      todayPageViews: 0,
      todayAvgEngagedSeconds: 0,
      visitorsLast7Days: 0,
      pageViewsLast30Days: 0,
      onlineNow: 0,
      loggedInNow: 0,
      avgEngagedSeconds: 0,
      scroll50Reach: 0,
      trends: [],
      days
    }
  }

  const today = getAnalyticsDayKey()
  const last7StartDay = getAnalyticsDayBefore(today, 6)
  const last30StartDay = getAnalyticsDayBefore(today, 29)
  const rangeStartDay = getAnalyticsDayBefore(today, days - 1)
  await purgeStaleActiveSessions(sql)
  await purgeAnalyticsRetention(sql)

  const todayRows = await sql`
    SELECT visitors, page_views, engaged_views, total_engaged_seconds
    FROM site_analytics_daily
    WHERE day = ${today}::date
    LIMIT 1
  `

  const last7Rows = await sql`
    SELECT COALESCE(SUM(visitors), 0)::int AS visitors
    FROM site_analytics_daily
    WHERE day >= ${last7StartDay}::date
  `

  const pageViewRows = await sql`
    SELECT COALESCE(SUM(page_views), 0)::int AS page_views
    FROM site_analytics_daily
    WHERE day >= ${last30StartDay}::date
  `

  const engagementRows = await sql`
    SELECT
      COALESCE(SUM(total_engaged_seconds), 0)::int AS total_engaged_seconds,
      COALESCE(SUM(engaged_views), 0)::int AS engaged_views
    FROM site_analytics_daily
    WHERE day >= ${rangeStartDay}::date
  `

  const scrollRows = await sql`
    SELECT COALESCE(SUM(scroll_50), 0)::int AS scroll_50
    FROM post_analytics_daily
    WHERE day >= ${rangeStartDay}::date
  `

  const onlineRows = await sql`
    SELECT
      COUNT(*)::int AS online_now,
      COUNT(*) FILTER (WHERE user_id IS NOT NULL)::int AS logged_in_now
    FROM analytics_active_sessions
    WHERE last_seen_at >= now() - (${ANALYTICS_ACTIVE_SESSION_TTL_SECONDS} * interval '1 second')
  `

  const trendRows = await sql`
    WITH days AS (
      SELECT generate_series(${rangeStartDay}::date, ${today}::date, interval '1 day')::date AS day
    ),
    post_daily AS (
      SELECT
        day,
        COALESCE(SUM(scroll_50), 0)::int AS scroll_50
      FROM post_analytics_daily
      WHERE day >= ${rangeStartDay}::date
      GROUP BY day
    )
    SELECT
      days.day,
      COALESCE(site_analytics_daily.visitors, 0)::int AS visitors,
      CASE
        WHEN COALESCE(site_analytics_daily.engaged_views, 0) > 0
          THEN ROUND(site_analytics_daily.total_engaged_seconds::numeric / site_analytics_daily.engaged_views)::int
        ELSE 0
      END AS avg_engaged_seconds,
      COALESCE(post_daily.scroll_50, 0)::int AS scroll_50
    FROM days
    LEFT JOIN site_analytics_daily ON site_analytics_daily.day = days.day
    LEFT JOIN post_daily ON post_daily.day = days.day
    ORDER BY days.day ASC
  `

  const engagedViews = Number(engagementRows[0]?.engaged_views || 0)
  const totalEngagedSeconds = Number(engagementRows[0]?.total_engaged_seconds || 0)
  const todayEngagedViews = Number(todayRows[0]?.engaged_views || 0)
  const todayTotalEngagedSeconds = Number(todayRows[0]?.total_engaged_seconds || 0)

  return {
    todayVisitors: Number(todayRows[0]?.visitors || 0),
    todayPageViews: Number(todayRows[0]?.page_views || 0),
    todayAvgEngagedSeconds: todayEngagedViews > 0
      ? Math.round(todayTotalEngagedSeconds / todayEngagedViews)
      : 0,
    visitorsLast7Days: Number(last7Rows[0]?.visitors || 0),
    pageViewsLast30Days: Number(pageViewRows[0]?.page_views || 0),
    onlineNow: Number(onlineRows[0]?.online_now || 0),
    loggedInNow: Number(onlineRows[0]?.logged_in_now || 0),
    avgEngagedSeconds: engagedViews > 0
      ? Math.round(totalEngagedSeconds / engagedViews)
      : 0,
    scroll50Reach: Number(scrollRows[0]?.scroll_50 || 0),
    trends: trendRows.map((row) => ({
      day: row.day ? new Date(row.day).toISOString().slice(0, 10) : '',
      visitors: Number(row.visitors || 0),
      avgEngagedSeconds: Number(row.avg_engaged_seconds || 0),
      scroll50Reach: Number(row.scroll_50 || 0)
    })),
    days
  }
}

/**
 * 실시간 접속 요약을 조회한다.
 * @returns {Promise<Object>} 실시간 요약
 */
export const getAnalyticsRealtimeSummary = async () => {
  const sql = getPostgresClient()

  if (!sql) {
    return {
      onlineNow: 0,
      loggedInNow: 0,
      anonymousNow: 0
    }
  }

  await purgeStaleActiveSessions(sql)
  await purgeAnalyticsRetention(sql)

  const rows = await sql`
    SELECT
      COUNT(*)::int AS online_now,
      COUNT(*) FILTER (WHERE user_id IS NOT NULL)::int AS logged_in_now
    FROM analytics_active_sessions
    WHERE last_seen_at >= now() - (${ANALYTICS_ACTIVE_SESSION_TTL_SECONDS} * interval '1 second')
  `

  const onlineNow = Number(rows[0]?.online_now || 0)
  const loggedInNow = Number(rows[0]?.logged_in_now || 0)

  return {
    onlineNow,
    loggedInNow,
    anonymousNow: Math.max(onlineNow - loggedInNow, 0)
  }
}

/**
 * 현재 접속 중인 세션 목록을 조회한다.
 * @param {{ limit?: number }} [options] - 조회 옵션
 * @returns {Promise<Array<Object>>} 접속자 목록
 */
export const getAnalyticsActiveSessions = async (options = {}) => {
  const sql = getPostgresClient()
  const limit = Math.min(Math.max(Number(options.limit) || 20, 1), 50)

  if (!sql) {
    return []
  }

  await purgeStaleActiveSessions(sql)
  await purgeAnalyticsRetention(sql)

  const rows = await sql`
    SELECT
      analytics_active_sessions.session_hash,
      analytics_active_sessions.path,
      analytics_active_sessions.post_slug,
      analytics_active_sessions.page_slug,
      analytics_active_sessions.duration_seconds,
      analytics_active_sessions.max_scroll_ratio,
      analytics_active_sessions.last_seen_at,
      posts.title AS post_title,
      pages.title AS page_title,
      users.id AS user_id,
      users.username,
      users.avatar_url
    FROM analytics_active_sessions
    LEFT JOIN posts ON posts.id = analytics_active_sessions.post_id
    LEFT JOIN pages ON pages.id = analytics_active_sessions.page_id
    LEFT JOIN users ON users.id = analytics_active_sessions.user_id
    WHERE analytics_active_sessions.last_seen_at >= now() - (${ANALYTICS_ACTIVE_SESSION_TTL_SECONDS} * interval '1 second')
    ORDER BY analytics_active_sessions.last_seen_at DESC
    LIMIT ${limit}
  `

  return rows.map((row) => ({
    sessionHash: row.session_hash,
    path: row.path,
    postSlug: row.post_slug || '',
    pageSlug: row.page_slug || '',
    postTitle: row.post_title || '',
    pageTitle: row.page_title || '',
    durationSeconds: Number(row.duration_seconds || 0),
    maxScrollRatio: Number(row.max_scroll_ratio || 0),
    lastSeenAt: row.last_seen_at ? new Date(row.last_seen_at).toISOString() : null,
    isLoggedIn: Boolean(row.user_id),
    user: row.user_id
      ? {
          id: row.user_id,
          username: row.username,
          avatarUrl: row.avatar_url || ''
        }
      : null
  }))
}

/**
 * 관리자 유입·디바이스·키워드 통계를 조회한다.
 * @param {{ days?: number }} [options] - 조회 옵션
 * @returns {Promise<{ sources: Array<Object>, devices: Array<Object>, keywords: Array<Object>, days: number }>} 유입 통계
 */
export const getAnalyticsTrafficSummary = async (options = {}) => {
  const sql = getPostgresClient()
  const days = Math.min(Math.max(Number(options.days) || 30, 1), ANALYTICS_CHART_MAX_DAYS)

  if (!sql) {
    return {
      sources: [],
      devices: [],
      keywords: [],
      days
    }
  }

  const today = getAnalyticsDayKey()
  const rangeStartDay = getAnalyticsDayBefore(today, days - 1)
  await purgeAnalyticsRetention(sql)

  const sourceRows = await sql`
    SELECT
      source_group,
      source_name,
      COALESCE(SUM(page_views), 0)::int AS page_views,
      COALESCE(SUM(visitors), 0)::int AS visitors
    FROM analytics_traffic_daily
    WHERE day >= ${rangeStartDay}::date
    GROUP BY source_group, source_name
    ORDER BY page_views DESC, visitors DESC, source_name ASC
  `

  const deviceRows = await sql`
    SELECT
      device_type,
      os_name,
      COALESCE(SUM(page_views), 0)::int AS page_views,
      COALESCE(SUM(visitors), 0)::int AS visitors
    FROM analytics_traffic_daily
    WHERE day >= ${rangeStartDay}::date
    GROUP BY device_type, os_name
    ORDER BY page_views DESC, visitors DESC, device_type ASC, os_name ASC
  `

  const keywordRows = await sql`
    SELECT
      keyword,
      source_name,
      COALESCE(SUM(page_views), 0)::int AS page_views,
      COALESCE(SUM(visitors), 0)::int AS visitors
    FROM analytics_traffic_daily
    WHERE day >= ${rangeStartDay}::date
      AND keyword <> ''
    GROUP BY keyword, source_name
    ORDER BY page_views DESC, visitors DESC, keyword ASC
    LIMIT 12
  `

  return {
    sources: sourceRows.map((row) => ({
      sourceGroup: row.source_group,
      sourceName: row.source_name,
      pageViews: Number(row.page_views || 0),
      visitors: Number(row.visitors || 0)
    })),
    devices: deviceRows.map((row) => ({
      deviceType: row.device_type,
      osName: row.os_name,
      pageViews: Number(row.page_views || 0),
      visitors: Number(row.visitors || 0)
    })),
    keywords: keywordRows.map((row) => ({
      keyword: row.keyword,
      sourceName: row.source_name,
      pageViews: Number(row.page_views || 0),
      visitors: Number(row.visitors || 0)
    })),
    days
  }
}

/**
 * 인기 게시물 통계를 조회한다.
 * @param {{ days?: number, limit?: number }} [options] - 조회 옵션
 * @returns {Promise<Array<Object>>} 인기 게시물 목록
 */
export const getAnalyticsTopPosts = async (options = {}) => {
  const sql = getPostgresClient()
  const days = Math.min(Math.max(Number(options.days) || 30, 1), ANALYTICS_CHART_MAX_DAYS)
  const limit = Math.min(Math.max(Number(options.limit) || 5, 1), 20)

  if (!sql) {
    return []
  }

  const today = getAnalyticsDayKey()
  const rangeStartDay = getAnalyticsDayBefore(today, days - 1)
  const monthlyStartDay = getAnalyticsDayBefore(today, 29)
  await purgeAnalyticsRetention(sql)

  const rows = await sql`
    SELECT
      posts.id,
      posts.title,
      posts.slug,
      posts.created_at,
      COALESCE(SUM(post_analytics_daily.views), 0)::int AS views,
      COALESCE(SUM(post_analytics_daily.views) FILTER (
        WHERE post_analytics_daily.day >= ${monthlyStartDay}::date
      ), 0)::int AS monthly_views,
      COALESCE(SUM(post_analytics_daily.reads), 0)::int AS reads,
      COALESCE(SUM(post_analytics_daily.visitors), 0)::int AS visitors,
      COALESCE(SUM(post_analytics_daily.engaged_views), 0)::int AS engaged_views,
      COALESCE(SUM(post_analytics_daily.total_engaged_seconds), 0)::int AS total_engaged_seconds,
      COALESCE(SUM(post_analytics_daily.scroll_50), 0)::int AS scroll_50,
      COALESCE(SUM(post_analytics_daily.scroll_75), 0)::int AS scroll_75,
      COALESCE(SUM(post_analytics_daily.scroll_100), 0)::int AS scroll_100
    FROM post_analytics_daily
    INNER JOIN posts ON posts.id = post_analytics_daily.post_id
    WHERE post_analytics_daily.day >= ${rangeStartDay}::date
    GROUP BY posts.id, posts.title, posts.slug, posts.created_at
    ORDER BY views DESC, reads DESC, posts.published_at DESC NULLS LAST
    LIMIT ${limit}
  `

  return rows.map((row) => {
    const engagedViews = Number(row.engaged_views || 0)
    const totalEngagedSeconds = Number(row.total_engaged_seconds || 0)

    return {
      id: row.id,
      title: row.title,
      slug: row.slug,
      createdAt: row.created_at ? new Date(row.created_at).toISOString() : null,
      views: Number(row.views || 0),
      monthlyViews: Number(row.monthly_views || 0),
      reads: Number(row.reads || 0),
      visitors: Number(row.visitors || 0),
      avgEngagedSeconds: engagedViews > 0
        ? Math.round(totalEngagedSeconds / engagedViews)
        : 0,
      scroll50: Number(row.scroll_50 || 0),
      scroll75: Number(row.scroll_75 || 0),
      scroll100: Number(row.scroll_100 || 0)
    }
  })
}

/**
 * 인기 페이지 통계를 조회한다.
 * @param {{ days?: number, limit?: number }} [options] - 조회 옵션
 * @returns {Promise<Array<Object>>} 인기 페이지 목록
 */
export const getAnalyticsTopPages = async (options = {}) => {
  const sql = getPostgresClient()
  const days = Math.min(Math.max(Number(options.days) || 30, 1), ANALYTICS_CHART_MAX_DAYS)
  const limit = Math.min(Math.max(Number(options.limit) || 5, 1), 20)

  if (!sql) {
    return []
  }

  const today = getAnalyticsDayKey()
  const rangeStartDay = getAnalyticsDayBefore(today, days - 1)
  await purgeAnalyticsRetention(sql)

  const rows = await sql`
    SELECT
      pages.id,
      pages.title,
      pages.slug,
      COALESCE(SUM(page_analytics_daily.views), 0)::int AS views,
      COALESCE(SUM(page_analytics_daily.visitors), 0)::int AS visitors,
      COALESCE(SUM(page_analytics_daily.engaged_views), 0)::int AS engaged_views,
      COALESCE(SUM(page_analytics_daily.total_engaged_seconds), 0)::int AS total_engaged_seconds,
      COALESCE(SUM(page_analytics_daily.scroll_50), 0)::int AS scroll_50,
      COALESCE(SUM(page_analytics_daily.scroll_75), 0)::int AS scroll_75,
      COALESCE(SUM(page_analytics_daily.scroll_100), 0)::int AS scroll_100
    FROM page_analytics_daily
    INNER JOIN pages ON pages.id = page_analytics_daily.page_id
    WHERE page_analytics_daily.day >= ${rangeStartDay}::date
    GROUP BY pages.id, pages.title, pages.slug
    ORDER BY views DESC, pages.updated_at DESC NULLS LAST
    LIMIT ${limit}
  `

  return rows.map((row) => {
    const engagedViews = Number(row.engaged_views || 0)
    const totalEngagedSeconds = Number(row.total_engaged_seconds || 0)

    return {
      id: row.id,
      title: row.title,
      slug: row.slug,
      views: Number(row.views || 0),
      visitors: Number(row.visitors || 0),
      avgEngagedSeconds: engagedViews > 0
        ? Math.round(totalEngagedSeconds / engagedViews)
        : 0,
      scroll50: Number(row.scroll_50 || 0),
      scroll75: Number(row.scroll_75 || 0),
      scroll100: Number(row.scroll_100 || 0)
    }
  })
}