import { defineStore } from 'pinia'
import { ref, computed } from 'vue'

export interface RegionConfig {
  country_code: string
  name: string
  currency: string
  default_vat_rate: number
  locale_code: string
  timezone: string
  is_active: boolean
}

export const useRegionStore = defineStore('region', () => {
  // ── State ──────────────────────────────────────────────────────────
  const regions = ref<RegionConfig[]>([])
  const activeRegion = ref<RegionConfig | null>(null)
  const isLoading = ref(false)
  const error = ref<string | null>(null)

  // ── Getters ────────────────────────────────────────────────────────
  const defaultRegion = computed(() => {
    return regions.value.find(r => r.country_code === 'DEFAULT') || null
  })

  const regionMap = computed(() => {
    const map = new Map<string, RegionConfig>()
    for (const r of regions.value) {
      map.set(r.country_code, r)
    }
    return map
  })

  const activeCurrency = computed(() => {
    return activeRegion.value?.currency || defaultRegion.value?.currency || 'EUR'
  })

  const activeLocale = computed(() => {
    return activeRegion.value?.locale_code || defaultRegion.value?.locale_code || 'en-EU'
  })

  const activeVatRate = computed(() => {
    return activeRegion.value?.default_vat_rate ?? defaultRegion.value?.default_vat_rate ?? 0
  })

  const activeTimezone = computed(() => {
    return activeRegion.value?.timezone || defaultRegion.value?.timezone || 'Europe/Brussels'
  })

  // ── Actions ────────────────────────────────────────────────────────

  /**
   * Fetch all active regions from the public API endpoint.
   * Called once on app initialization.
   */
  async function fetchRegions() {
    if (regions.value.length > 0) return // already loaded
    isLoading.value = true
    error.value = null

    try {
      const data = await $fetch<RegionConfig[]>('/api/v1/system/regions')
      regions.value = data || []
    } catch (err: any) {
      error.value = err?.data?.detail || err?.message || 'Failed to load regions'
      console.error('[RegionStore] Fetch error:', err)
    } finally {
      isLoading.value = false
    }
  }

  /**
   * Set the active region by country_code.
   * Falls back to DEFAULT if the code is not found.
   */
  function setActiveRegion(countryCode: string) {
    const found = regions.value.find(r => r.country_code === countryCode)
    activeRegion.value = found || defaultRegion.value
  }

  /**
   * Get a region config by country_code.
   */
  function getRegion(countryCode: string): RegionConfig | undefined {
    return regionMap.value.get(countryCode)
  }

  return {
    // State
    regions,
    activeRegion,
    isLoading,
    error,

    // Getters
    defaultRegion,
    regionMap,
    activeCurrency,
    activeLocale,
    activeVatRate,
    activeTimezone,

    // Actions
    fetchRegions,
    setActiveRegion,
    getRegion,
  }
})