import { defineStore } from 'pinia'
import { ref, computed } from 'vue'
import * as alertsApi from '@/api/alerts'
import { detectNewCriticalAlerts } from '@/composables/criticalAlertDetect'

export const useAlertStore = defineStore('alerts', () => {
  const alerts = ref([])
  const loading = ref(false)
  const statusFilter = ref(null)
  const lastSeenAlertIds = ref([])
  const bannerAlerts = ref([])
  const pollSeeded = ref(false)

  const openAlerts = computed(() => alerts.value.filter(a => a.status === 'OPEN'))
  const criticalAlerts = computed(() => alerts.value.filter(a => a.severity === 'CRITICAL'))

  function mergeBannerAlerts(newAlerts) {
    const existingIds = new Set(bannerAlerts.value.map(alert => alert.id))
    const merged = [...bannerAlerts.value]
    for (const alert of newAlerts) {
      if (!existingIds.has(alert.id)) merged.push(alert)
    }
    bannerAlerts.value = merged
  }

  function applyPollResults(items) {
    const { newAlerts, nextSeenIds, seeded } = detectNewCriticalAlerts(
      items,
      lastSeenAlertIds.value,
      pollSeeded.value,
    )
    lastSeenAlertIds.value = nextSeenIds
    pollSeeded.value = seeded
    if (newAlerts.length > 0) {
      mergeBannerAlerts(newAlerts)
    }
    return newAlerts
  }

  async function loadAlerts(encounterId, status) {
    loading.value = true
    try {
      const filter = status ?? statusFilter.value
      const data = await alertsApi.fetchAlerts(encounterId, filter)
      alerts.value = data.items
    } catch (e) {
      console.error('Failed to load alerts', e)
    } finally {
      loading.value = false
    }
  }

  async function loadGlobalAlerts(status = 'OPEN') {
    loading.value = true
    try {
      const data = await alertsApi.fetchAllAlerts(status)
      alerts.value = data.items
    } catch (e) {
      console.error('Failed to load alerts', e)
    } finally {
      loading.value = false
    }
  }

  async function pollOpenAlerts() {
    try {
      const items = await alertsApi.fetchAllOpenAlerts()
      alerts.value = items
      return applyPollResults(items)
    } catch (e) {
      console.error('Failed to poll alerts', e)
      return []
    }
  }

  function dismissBannerAlert(alertId) {
    bannerAlerts.value = bannerAlerts.value.filter(alert => alert.id !== alertId)
  }

  function dismissAllBannerAlerts() {
    bannerAlerts.value = []
  }

  async function acknowledge(alertId, note) {
    const updated = await alertsApi.acknowledgeAlert(alertId, note || undefined)
    const alert = alerts.value.find(a => a.id === alertId)
    if (alert) {
      alert.status = updated.status ?? 'ACKNOWLEDGED'
      alert.acknowledgedBy = updated.acknowledgedBy ?? alert.acknowledgedBy
      alert.acknowledgedAt = updated.acknowledgedAt ?? alert.acknowledgedAt
    }
    dismissBannerAlert(alertId)
    return updated
  }

  async function resolve(alertId) {
    await alertsApi.resolveAlert(alertId)
    const alert = alerts.value.find(a => a.id === alertId)
    if (alert) alert.status = 'RESOLVED'
    dismissBannerAlert(alertId)
  }

  return {
    alerts,
    loading,
    statusFilter,
    lastSeenAlertIds,
    bannerAlerts,
    pollSeeded,
    openAlerts,
    criticalAlerts,
    loadAlerts,
    loadGlobalAlerts,
    pollOpenAlerts,
    dismissBannerAlert,
    dismissAllBannerAlerts,
    acknowledge,
    resolve,
    applyPollResults,
  }
})