import { graphql } from '../..'
import { allowAll } from '../../access'
import type { InitialisedField } from './initialise-lists'

export type ListForValidation = { listKey: string, fields: Record<string, InitialisedField> }

export function assertFieldsValid (list: ListForValidation) {
  assertNoConflictingExtraOutputFields(list)
  assertIdFieldGraphQLTypesCorrect(list)
  assertNoFieldKeysThatConflictWithFilterCombinators(list)
  assertUniqueWhereInputsValid(list)
  assertFieldsIsNonNullAllowed(list)
}

function assertFieldsIsNonNullAllowed (list: ListForValidation) {
  for (const [fieldKey, field] of Object.entries(list.fields)) {
    if (field.access.read !== allowAll) {
      if (field.graphql.isNonNull.read) {
        throw new Error(
          `The field at ${list.listKey}.${fieldKey} sets graphql.isNonNull.read: true, and has 'read' field access control, this is not allowed.\n` +
            `Either disable graphql.read.isNonNull, or disable 'read' field access control.`
        )
      }
    }
  }
}

function assertUniqueWhereInputsValid (list: ListForValidation) {
  for (const [fieldKey, { dbField, input }] of Object.entries(list.fields)) {
    if (input?.uniqueWhere) {
      if (dbField.kind !== 'scalar' && dbField.kind !== 'enum' && dbField.kind !== 'relation') {
        throw new Error(
          `Only scalar db fields can provide a uniqueWhere input currently but the field at ${list.listKey}.${fieldKey} specifies a uniqueWhere input`
        )
      }

      if (dbField.kind !== 'relation' && dbField.index !== 'unique' && fieldKey !== 'id') {
        throw new Error(
          `Fields must have a unique index or be the idField to specify a uniqueWhere input but the field at ${list.listKey}.${fieldKey} specifies a uniqueWhere input without a unique index`
        )
      }
    }
  }
}

function assertNoFieldKeysThatConflictWithFilterCombinators (list: ListForValidation) {
  for (const fieldKey of Object.keys(list.fields)) {
    if (fieldKey === 'AND' || fieldKey === 'OR' || fieldKey === 'NOT') {
      throw new Error(
        `Fields cannot be named ${fieldKey} but there is a field named ${fieldKey} on ${list.listKey}`
      )
    }
  }
}

function assertNoConflictingExtraOutputFields (list: ListForValidation) {
  const fieldKeys = new Set(Object.keys(list.fields))
  const alreadyFoundFields: Record<string, string> = {}
  for (const [fieldKey, field] of Object.entries(list.fields)) {
    if (field.extraOutputFields) {
      for (const outputTypeFieldName of Object.keys(field.extraOutputFields)) {
        // note that this and the case handled below are fundamentally the same thing but i want different errors for each of them
        if (fieldKeys.has(outputTypeFieldName)) {
          throw new Error(
            `The field ${fieldKey} on the ${list.listKey} list defines an extra GraphQL output field named ${outputTypeFieldName} which conflicts with the Keystone field type named ${outputTypeFieldName} on the same list`
          )
        }
        const alreadyFoundField = alreadyFoundFields[outputTypeFieldName]
        if (alreadyFoundField !== undefined) {
          throw new Error(
            `The field ${fieldKey} on the ${list.listKey} list defines an extra GraphQL output field named ${outputTypeFieldName} which conflicts with the Keystone field type named ${alreadyFoundField} which also defines an extra GraphQL output field named ${outputTypeFieldName}`
          )
        }
        alreadyFoundFields[outputTypeFieldName] = fieldKey
      }
    }
  }
}

function assertIdFieldGraphQLTypesCorrect (list: ListForValidation) {
  const idField = list.fields.id
  if (idField.input?.uniqueWhere === undefined) {
    throw new Error(
      `The idField on a list must define a uniqueWhere GraphQL input with the ID GraphQL scalar type but the idField for ${list.listKey} does not define one`
    )
  }
  if (idField.input.uniqueWhere.arg.type !== graphql.ID) {
    throw new Error(
      `The idField on a list must define a uniqueWhere GraphQL input with the ID GraphQL scalar type but the idField for ${
        list.listKey
      } defines the type ${idField.input.uniqueWhere.arg.type.graphQLType.toString()}`
    )
  }
  // we may want to loosen these constraints in the future
  if (idField.input.create !== undefined) {
    throw new Error(
      `The idField on a list must not define a create GraphQL input but the idField for ${list.listKey} does define one`
    )
  }
  if (idField.input.update !== undefined) {
    throw new Error(
      `The idField on a list must not define an update GraphQL input but the idField for ${list.listKey} does define one`
    )
  }
  if (idField.graphql.isEnabled.read === false) {
    throw new Error(
      `The idField on a list must not have graphql.isEnabled.read be set to false but ${list.listKey} does`
    )
  }
  if (idField.output.type.kind !== 'non-null' || idField.output.type.of !== graphql.ID) {
    throw new Error(
      `The idField on a list must define a GraphQL output field with a non-nullable ID GraphQL scalar type but the idField for ${
        list.listKey
      } defines the type ${idField.output.type.graphQLType.toString()}`
    )
  }
}