import { nextTick, unref } from 'vue'
import {
  createSlashCommandApplyPlan,
  createSlashCommandEditorEffectPlan,
  getSlashCommandFocusTarget,
  getSlashCommandTextareaSelection,
  parseSlashInput,
  resolveSlashCommand
} from '../lib/markdown-slash-commands.js'

/**
 * 관리자 Markdown 에디터의 슬래시 명령 적용 실행을 관리한다.
 * @param {Object} options - 슬래시 명령 실행 옵션
 * @param {import('vue').Ref<string>} options.activeMode - 현재 에디터 모드
 * @param {import('vue').Ref<string>} options.markdownValue - 마크다운 본문
 * @param {import('vue').Ref<number|null>} options.liveSlashSourceLine - 슬래시 입력 줄
 * @param {import('vue').Ref<string>} options.liveSlashQuery - 슬래시 검색어
 * @param {import('vue').Ref<number|null>} options.liveSlashInsertLine - 미디어 삽입 대기 줄
 * @param {() => void} options.clearLiveSlashState - 슬래시 상태 초기화 함수
 * @param {(line: number) => void} options.releaseLiveSlashLine - 슬래시 억제 해제 함수
 * @param {(line: number, lineValue?: string) => void} options.suppressLiveSlashLine - 슬래시 억제 함수
 * @param {(startLine: number, endLine: number, replacementLines: string[], focusEditor?: boolean) => void} options.replaceLineRange - 줄 교체 함수
 * @param {(mediaKind: 'image'|'gallery'|'video'|'audio'|'file') => void} options.openMediaPicker - 미디어 모달 열기 함수
 * @param {(start: number, end: number) => void} options.setTextareaSelection - textarea 선택 복원 함수
 * @param {(line: number, column?: number, position?: string, offset?: number) => void} options.focusPreviewEditableAtLine - 미리보기 줄 포커스 함수
 * @param {boolean} [options.isClient] - 클라이언트 실행 여부
 * @returns {{
 *   applyLiveSlashCommand: (command: import('../lib/markdown-slash-commands.js').MarkdownSlashCommand) => void,
 *   cancelLiveSlashCommand: () => void,
 *   focusPreviewAfterSlashCommand: (line: number, replacementLines: string[]) => void,
 *   focusTextareaAfterSlashCommand: (line: number, replacementLines: string[]) => void,
 *   onLiveSlashApply: (payload?: { sourceLine?: number, value?: string }) => void,
 *   onLiveSlashEnd: (payload?: { sourceLine?: number }) => void
 * }} 슬래시 명령 실행 액션
 */
export const useAdminMarkdownSlashCommandActions = (options) => {
  const isClient = options.isClient ?? import.meta.client

  /**
   * 슬래시 명령 입력을 종료한다.
   * @param {{ sourceLine?: number }} [payload] - 종료 대상 줄
   * @returns {void}
   */
  const onLiveSlashEnd = (payload) => {
    if (typeof payload?.sourceLine === 'number') {
      options.releaseLiveSlashLine(payload.sourceLine)
    }

    options.clearLiveSlashState()
  }

  /**
   * 슬래시 명령 입력을 취소한다(줄 내용은 유지, 메뉴만 닫음).
   * @returns {void}
   */
  const cancelLiveSlashCommand = () => {
    const line = options.liveSlashSourceLine.value

    if (line !== null) {
      const lines = String(unref(options.markdownValue) ?? '').split('\n')
      options.suppressLiveSlashLine(line, lines[line] ?? '')
    }

    options.clearLiveSlashState()
  }

  /**
   * 슬래시 명령 적용 후 미리보기 인라인 편집에 포커스를 복원한다.
   * @param {number} line - 줄 번호(0-based)
   * @param {string[]} replacementLines - 삽입된 줄
   * @returns {void}
   */
  const focusPreviewAfterSlashCommand = (line, replacementLines) => {
    if (!isClient) {
      return
    }

    const { line: focusLine, offset } = getSlashCommandFocusTarget(line, replacementLines)
    const requestFrame = globalThis.requestAnimationFrame ?? ((callback) => globalThis.setTimeout(callback, 0))

    nextTick(() => {
      nextTick(() => {
        requestFrame(() => {
          requestFrame(() => {
            options.focusPreviewEditableAtLine(focusLine, 0, 'end', offset)
          })
        })
      })
    })
  }

  /**
   * 소스 모드 textarea에 슬래시 명령 적용 후 커서를 복원한다.
   * @param {number} line - 줄 번호(0-based)
   * @param {string[]} replacementLines - 삽입된 줄
   * @returns {void}
   */
  const focusTextareaAfterSlashCommand = (line, replacementLines) => {
    const selection = getSlashCommandTextareaSelection({
      markdown: unref(options.markdownValue) ?? '',
      startLine: line,
      lines: replacementLines
    })
    options.setTextareaSelection(selection.start, selection.end)
  }

  /**
   * 슬래시 명령을 적용한다.
   * @param {import('../lib/markdown-slash-commands.js').MarkdownSlashCommand} command - 명령
   * @returns {void}
   */
  const applyLiveSlashCommand = (command) => {
    const plan = createSlashCommandApplyPlan({
      command,
      sourceLine: options.liveSlashSourceLine.value
    })
    const effectPlan = createSlashCommandEditorEffectPlan({
      plan,
      activeMode: options.activeMode.value
    })

    if (effectPlan.kind === 'none') {
      return
    }

    if (effectPlan.kind === 'media') {
      options.liveSlashInsertLine.value = effectPlan.line
      options.replaceLineRange(effectPlan.line, effectPlan.line, [], false)
      onLiveSlashEnd()
      options.openMediaPicker(effectPlan.mediaKind)
      return
    }

    if (effectPlan.kind === 'lines') {
      options.releaseLiveSlashLine(effectPlan.line)
      options.replaceLineRange(effectPlan.line, effectPlan.line, effectPlan.lines, false)
      options.clearLiveSlashState()

      if (effectPlan.focusTarget === 'textarea') {
        focusTextareaAfterSlashCommand(effectPlan.line, effectPlan.lines)
      } else {
        focusPreviewAfterSlashCommand(effectPlan.line, effectPlan.lines)
      }
    }
  }

  /**
   * 슬래시 명령 Enter 적용.
   * @param {{ sourceLine?: number, value?: string }} [payload] - 줄·입력 값
   * @returns {void}
   */
  const onLiveSlashApply = (payload) => {
    const parsed = parseSlashInput(payload?.value)
    const command = resolveSlashCommand(parsed?.query ?? options.liveSlashQuery.value)

    if (!command) {
      onLiveSlashEnd({ sourceLine: payload?.sourceLine })
      return
    }

    applyLiveSlashCommand(command)
  }

  return {
    applyLiveSlashCommand,
    cancelLiveSlashCommand,
    focusPreviewAfterSlashCommand,
    focusTextareaAfterSlashCommand,
    onLiveSlashApply,
    onLiveSlashEnd
  }
}