import { fetchExpenseClaims } from '../../services/reimbursements.js'
import {
  applyAiExpenseAnswer,
  buildAiExpenseStepPrompt,
  buildAiExpenseSummary,
  createAiExpenseDraft,
  isAiExpenseDraftComplete
} from '../../utils/aiExpenseDraftModel.js'
import {
  buildExpenseSceneSelectionMessage,
  SESSION_TYPE_EXPENSE
} from '../../views/scripts/travelReimbursementConversationModel.js'
import { buildExpenseSceneSelectionActions } from '../../utils/expenseAssistantActions.js'
import {
  buildRequiredApplicationActions,
  buildRequiredApplicationMissingText,
  buildRequiredApplicationSelectionText,
  filterRequiredApplicationCandidates
} from '../../views/scripts/travelReimbursementApplicationLinkModel.js'

export { SESSION_TYPE_EXPENSE }

export function useWorkbenchAiExpenseFlow({
  activateInlineConversation,
  aiExpenseDraft,
  assistantDraft,
  clearAiModeFiles,
  closeWorkbenchDatePicker,
  conversationMessages,
  conversationStarted,
  createInlineMessage,
  currentUser,
  persistCurrentConversation,
  pushInlineUserMessage,
  removeWorkbenchDateTag,
  resolveLatestInlineUserPrompt,
  scrollInlineConversationToBottom,
  startAiApplicationPreview
}) {
  function pushInlineExpenseSceneSelectionPrompt(originalMessage, selectedLabel = '') {
    const sourceText = String(originalMessage || '我要报销').trim()
    if (!conversationStarted.value) {
      activateInlineConversation({
        title: String(selectedLabel || sourceText || '报销').trim().slice(0, 18) || '报销'
      })
    }
    assistantDraft.value = ''
    removeWorkbenchDateTag()
    closeWorkbenchDatePicker()
    conversationMessages.value.push(createInlineMessage('user', String(selectedLabel || sourceText).trim()))
    conversationMessages.value.push(createInlineMessage('assistant', buildExpenseSceneSelectionMessage(sourceText), {
      suggestedActions: buildExpenseSceneSelectionActions(sourceText)
    }))
    persistCurrentConversation()
    scrollInlineConversationToBottom()
  }

  function startAiApplicationPreviewFromAction(payload = {}, fallbackLabel = '') {
    const expenseType = String(payload.expense_type || '').trim()
    const expenseTypeLabel = String(payload.expense_type_label || fallbackLabel || '').trim()
    return startAiApplicationPreview(
      expenseType,
      expenseTypeLabel,
      payload.carry_text || resolveLatestInlineUserPrompt()
    )
  }

  function startAiExpenseDraft(expenseType, expenseTypeLabel, requiresApplicationBeforeReimbursement) {
    if (!conversationStarted.value) {
      activateInlineConversation({ title: String(expenseTypeLabel || '报销').trim().slice(0, 18) || '报销' })
    }
    assistantDraft.value = ''
    removeWorkbenchDateTag()
    closeWorkbenchDatePicker()
    clearAiModeFiles()
    pushInlineUserMessage(`选择${expenseTypeLabel || expenseType || '报销'}`)

    if (requiresApplicationBeforeReimbursement) {
      void resolveAiExpenseApplicationLink(expenseType, expenseTypeLabel)
      return
    }

    const draft = createAiExpenseDraft(expenseType, expenseTypeLabel)
    aiExpenseDraft.value = draft
    conversationMessages.value.push(createInlineMessage('assistant', buildAiExpenseStepPrompt(draft)))
    persistCurrentConversation()
    scrollInlineConversationToBottom()
  }

  function advanceAiExpenseDraft(answer, files = []) {
    const fileNames = Array.from(files || [])
    pushInlineUserMessage(answer || (fileNames.length ? `上传 ${fileNames.length} 份附件` : ''))
    assistantDraft.value = ''
    clearAiModeFiles()

    const next = applyAiExpenseAnswer(aiExpenseDraft.value, answer, fileNames)
    aiExpenseDraft.value = next

    if (isAiExpenseDraftComplete(next)) {
      conversationMessages.value.push(createInlineMessage('assistant', `${buildAiExpenseSummary(next)}\n\n如果哪一项需要修改，直接告诉我；确认无误后我再帮你生成报销草稿。`))
      aiExpenseDraft.value = null
    } else {
      conversationMessages.value.push(createInlineMessage('assistant', buildAiExpenseStepPrompt(next)))
    }
    persistCurrentConversation()
    scrollInlineConversationToBottom()
  }

  async function resolveAiExpenseApplicationLink(expenseType, expenseTypeLabel) {
    let claims = null
    try {
      claims = await fetchExpenseClaims()
    } catch {
      aiExpenseDraft.value = null
      conversationMessages.value.push(createInlineMessage('assistant', '查询可关联申请单时出现异常，请稍后再试，我先暂停这次报销流程。'))
      persistCurrentConversation()
      scrollInlineConversationToBottom()
      return
    }

    const candidates = filterRequiredApplicationCandidates(claims, expenseType, currentUser.value || {})
    aiExpenseDraft.value = createAiExpenseDraft(expenseType, expenseTypeLabel)

    if (!candidates.length) {
      conversationMessages.value.push(createInlineMessage('assistant', buildRequiredApplicationMissingText(expenseType), {
        suggestedActions: [{
          label: '确认发起出差申请',
          description: '生成完整申请表，并预填已识别的时间、地点和事由',
          icon: 'mdi mdi-file-plus-outline',
          action_type: 'ai_application_start_inline',
          payload: {
            expense_type: expenseType,
            expense_type_label: expenseTypeLabel
          }
        }]
      }))
      persistCurrentConversation()
      scrollInlineConversationToBottom()
      return
    }

    conversationMessages.value.push(createInlineMessage('assistant', buildRequiredApplicationSelectionText(expenseType, candidates), {
      suggestedActions: buildRequiredApplicationActions(candidates, 'select_required_application')
    }))
    persistCurrentConversation()
    scrollInlineConversationToBottom()
  }

  function linkAiExpenseApplication(application = {}) {
    const draft = aiExpenseDraft.value
    if (!draft) {
      return
    }
    const claimNo = String(application.application_claim_no || '').trim()
    pushInlineUserMessage(`关联申请单 ${claimNo}`.trim())

    const linked = {
      ...draft,
      applicationClaim: application,
      values: {
        ...draft.values,
        reason: String(application.application_reason || '').trim(),
        location: String(application.application_location || '').trim(),
        time_range: String(application.application_business_time || '').trim(),
        amount: String(application.application_amount_label || application.application_amount || '').trim()
      },
      stepKey: 'attachments'
    }
    aiExpenseDraft.value = linked
    conversationMessages.value.push(createInlineMessage('assistant', [
      `已关联申请单${claimNo ? ` ${claimNo}` : ''}，事由、时间、地点、金额我先用申请单的内容预填了。`,
      '',
      '再确认一下票据：可以现在上传，或回复“稍后上传”。'
    ].join('\n')))
    persistCurrentConversation()
    scrollInlineConversationToBottom()
  }

  return {
    advanceAiExpenseDraft,
    linkAiExpenseApplication,
    pushInlineExpenseSceneSelectionPrompt,
    startAiApplicationPreviewFromAction,
    startAiExpenseDraft
  }
}