import type { GraphQLError } from 'graphql'
import type { JSONValue, FieldMeta } from '../../types'
import type { DataGetter } from './dataGetter'
import { getRootGraphQLFieldsFromFieldController } from './getRootGraphQLFieldsFromFieldController'

export type ItemData = { id: string, [key: string]: any }

export type DeserializedValue = Record<
  string,
  | { kind: 'error', errors: readonly [GraphQLError, ...GraphQLError[]] }
  | { kind: 'value', value: any }
>

export function deserializeValue (
  fields: Record<string, FieldMeta>,
  itemGetter: DataGetter<ItemData>
) {
  const value: DeserializedValue = {}
  Object.keys(fields).forEach(fieldKey => {
    const field = fields[fieldKey]
    const itemForField: Record<string, any> = {}
    const errors = new Set<GraphQLError>()
    for (const graphqlField of getRootGraphQLFieldsFromFieldController(field.controller)) {
      const fieldGetter = itemGetter.get(graphqlField)
      if (fieldGetter.errors) {
        fieldGetter.errors.forEach(error => {
          errors.add(error)
        })
      }
      itemForField[graphqlField] = fieldGetter.data
    }
    if (errors.size) {
      value[fieldKey] = { kind: 'error', errors: [...errors] as any }
    } else {
      value[fieldKey] = { kind: 'value', value: field.controller.deserialize(itemForField) }
    }
  })
  return value
}

export function serializeValueToObjByFieldKey (
  fields: Record<string, FieldMeta>,
  value: DeserializedValue
) {
  const obj: Record<string, Record<string, JSONValue>> = {}
  Object.keys(fields).map(fieldKey => {
    const val = value[fieldKey]
    if (val.kind === 'value') {
      obj[fieldKey] = fields[fieldKey].controller.serialize(val.value)
    }
  })
  return obj
}