import type { AdfNode } from '../../adf/document.ts'
import type { BlockNodeModel } from '../../adf/block-nodes.ts'
import { attributeNestingMessage, nodeAttrs, nodeMarks } from '../../adf/document.ts'
import { blockArgument, markValues, marksAttribute } from '../block-directive.ts'
import { failure, success, type ConvertErrorPath, type Result } from '../../result.ts'
import { isBareToken, spellAttributes, spellDirectiveOpener, spellJsonAttribute, spellVocabulary } from '../directive-syntax.ts'
import { overNested } from '../../json-value.ts'
import { spellEmptyKeys } from '../empty-keys.ts'
import { vocabularyPairs } from '../../adf/attribute-vocabulary.ts'

export function spellBlockDirectiveOpener(node: AdfNode, model: BlockNodeModel, path: ConvertErrorPath, spelledByBody: readonly string[] = []): Result<string> | undefined {
  const argumentAttribute = blockArgument(node.type)
  const slot = bareArgument(node, argumentAttribute)
  if (slot === undefined) return undefined
  const spelled = argumentAttribute === undefined ? spelledByBody : [argumentAttribute, ...spelledByBody]
  const pairs = vocabularyPairs(nodeAttrs(node), model.attributes, spelled)
  if (pairs === undefined) return undefined
  const spelledPairs = [...spellVocabulary(pairs), ...spellEmptyKeys(node)]
  const marks = nodeMarks(node)
  if (marks.length > 0) {
    const values = markValues(marks)
    if (overNested(values)) return failure('unsupported-nesting-depth', attributeNestingMessage(marksAttribute, node.type), path)
    spelledPairs.push([marksAttribute, spellJsonAttribute(values)])
  }
  return success(spellDirectiveOpener(node.type, slot.argument, spellAttributes(spelledPairs)))
}

// `undefined` where the argument slot holds a value no bare token spells.
function bareArgument(node: AdfNode, argumentAttribute: string | undefined): { argument: string | undefined } | undefined {
  const value = argumentAttribute === undefined ? undefined : nodeAttrs(node)[argumentAttribute]
  if (value === undefined) return { argument: undefined }
  return typeof value === 'string' && isBareToken(value) ? { argument: value } : undefined
}