/**
 * Services Store
 */

import { ref, computed, readonly } from 'vue'
import { defineStore } from 'pinia'
import { serviceService } from '../services'
import { ServiceObject } from '../models/service'
import type {
  SourceSelector,
  ServiceInterface,
} from '../types'

export const useServicesStore = defineStore('documentsServicesStore', () => {
  // State
  const _services = ref<Record<string, ServiceObject>>({})
  const transceiving = ref(false)

  /**
   * Get count of services in store
   */
  const count = computed(() => Object.keys(_services.value).length)

  /**
   * Check if any services are present in store
   */
  const has = computed(() => count.value > 0)

  /**
   * Get all services present in store
   */
  const services = computed(() => Object.values(_services.value))

  /**
   * Get all services present in store grouped by provider
   */
  const servicesByProvider = computed(() => {
    const groups: Record<string, ServiceObject[]> = {}
    
    Object.values(_services.value).forEach((service) => {
      const providerServices = (groups[service.provider] ??= [])
      providerServices.push(service)
    })
    
    return groups
  })

  /**
   * Get a specific service from store, with optional retrieval
   * 
   * @param provider - provider identifier
   * @param identifier - service identifier
   * @param retrieve - Retrieve behavior: true = fetch if missing or refresh, false = cache only
   * 
   * @returns Service object or null
   */
  function service(provider: string, identifier: string | number, retrieve: boolean = false): ServiceObject | null {
    const key = identifierKey(provider, identifier)
    if (retrieve === true && !_services.value[key]) {
      console.debug(`[Documents Manager][Store] - Force fetching service "${key}"`)
      fetch(provider, identifier)
    }
    
    return _services.value[key] || null
  }

  /**
   * Unique key for a service
   */
  function identifierKey(provider: string, identifier: string | number | null): string {
    return `${provider}:${identifier ?? ''}`
  }

  // Actions
  
  /**
   * Retrieve all or specific services, optionally filtered by source selector
   * 
   * @param sources - optional source selector
   * 
   * @returns Promise with service object list keyed by provider and service identifier
   */
  async function list(sources?: SourceSelector): Promise<Record<string, ServiceObject>> {
    transceiving.value = true
    try {
      const response = await serviceService.list({ sources })

      // Flatten nested structure: provider-id: { service-id: object } -> "provider-id:service-id": object
      const services: Record<string, ServiceObject> = {}
      Object.entries(response).forEach(([_providerId, providerServices]) => {
        Object.entries(providerServices).forEach(([_serviceId, serviceObj]) => {
          const key = identifierKey(serviceObj.provider, serviceObj.identifier)
          services[key] = serviceObj
        })
      })

      // Merge retrieved services into state
      _services.value = { ..._services.value, ...services }

      console.debug('[Documents Manager][Store] - Successfully retrieved', Object.keys(services).length, 'services')
      return services
    } catch (error: any) {
      console.error('[Documents Manager][Store] - Failed to retrieve services:', error)
      throw error
    } finally {
      transceiving.value = false
    }
  }
  
  /**
   * Retrieve a specific service by provider and identifier
   * 
   * @param provider - provider identifier
   * @param identifier - service identifier
   * 
   * @returns Promise with service object
   */
  async function fetch(provider: string, identifier: string | number): Promise<ServiceObject> {
    transceiving.value = true
    try {
      const service = await serviceService.fetch({ provider, identifier })
      
      // Merge fetched service into state
      const key = identifierKey(service.provider, service.identifier)
      _services.value[key] = service

      console.debug('[Documents Manager][Store] - Successfully fetched service:', key)
      return service
    } catch (error: any) {
      console.error('[Documents Manager][Store] - Failed to fetch service:', error)
      throw error
    } finally {
      transceiving.value = false
    }
  }

  /**
   * Retrieve service availability status for a given source selector
   * 
   * @param sources - source selector to check availability for
   * 
   * @returns Promise with service availability status
   */
  async function extant(sources: SourceSelector) {
    transceiving.value = true
    try {
      const response = await serviceService.extant({ sources })
      
      console.debug('[Documents Manager][Store] - Successfully checked', sources ? Object.keys(sources).length : 0, 'services')
      return response
    } catch (error: any) {
      console.error('[Documents Manager][Store] - Failed to check services:', error)
      throw error
    } finally {
      transceiving.value = false
    }
  }

  /**
   * Create a new service with given provider and data
   * 
   * @param provider - provider identifier for the new service
   * @param data - partial service data for creation
   * 
   * @returns Promise with created service object
   */
  async function create(provider: string, data: Partial<ServiceInterface>): Promise<ServiceObject> {
    transceiving.value = true
    try {
      const service = await serviceService.create({ provider, data })
      
      // Merge created service into state
      const key = identifierKey(service.provider, service.identifier)
      _services.value[key] = service
      
      console.debug('[Documents Manager][Store] - Successfully created service:', key)
      return service
    } catch (error: any) {
      console.error('[Documents Manager][Store] - Failed to create service:', error)
      throw error
    } finally {
      transceiving.value = false
    }
  }

  /**
   * Update an existing service with given provider, identifier, and data
   * 
   * @param provider - provider identifier for the service to update
   * @param identifier - service identifier for the service to update
   * @param data - partial service data for update
   * 
   * @returns Promise with updated service object
   */
  async function update(provider: string, identifier: string | number, data: Partial<ServiceInterface>): Promise<ServiceObject> {
    transceiving.value = true
    try {
      const service = await serviceService.update({ provider, identifier, data })
      
      // Merge updated service into state
      const key = identifierKey(service.provider, service.identifier)
      _services.value[key] = service
      
      console.debug('[Documents Manager][Store] - Successfully updated service:', key)
      return service
    } catch (error: any) {
      console.error('[Documents Manager][Store] - Failed to update service:', error)
      throw error
    } finally {
      transceiving.value = false
    }
  }

  /**
   * Delete a service by provider and identifier
   * 
   * @param provider - provider identifier for the service to delete
   * @param identifier - service identifier for the service to delete
   * 
   * @returns Promise with deletion result
   */
  async function remove(provider: string, identifier: string | number): Promise<any> {
    transceiving.value = true
    try {
      await serviceService.delete({ provider, identifier })
      
      // Remove deleted service from state
      const key = identifierKey(provider, identifier)
      delete _services.value[key]

      console.debug('[Documents Manager][Store] - Successfully deleted service:', key)
    } catch (error: any) {
      console.error('[Documents Manager][Store] - Failed to delete service:', error)
      throw error
    } finally {
      transceiving.value = false
    }
  }

  // Return public API
  return {
    // State (readonly)
    transceiving: readonly(transceiving),
    // Getters
    count,
    has,
    services,
    servicesByProvider,
    
    // Actions
    service,
    list,
    fetch,
    extant,
    create,
    update,
    delete: remove,
  }
})