export const ASSISTANT_SCOPE_ACTION_SWITCH = 'switch_assistant_session'

export const ASSISTANT_SCOPE_SESSION_APPLICATION = 'application'
export const ASSISTANT_SCOPE_SESSION_EXPENSE = 'expense'
export const ASSISTANT_SCOPE_SESSION_APPROVAL = 'approval'
export const ASSISTANT_SCOPE_SESSION_KNOWLEDGE = 'knowledge'

const SESSION_SCOPE_CONFIG = {
  [ASSISTANT_SCOPE_SESSION_APPLICATION]: {
    label: '申请助手',
    icon: 'mdi mdi-file-plus-outline',
    scope: '费用申请、事前审批、申请材料清单、申请单状态查询'
  },
  [ASSISTANT_SCOPE_SESSION_EXPENSE]: {
    label: '报销助手',
    icon: 'mdi mdi-receipt-text-plus-outline',
    scope: '发起报销、票据识别、草稿归集、报销单状态查询和报销信息核对'
  },
  [ASSISTANT_SCOPE_SESSION_APPROVAL]: {
    label: '审核助手',
    icon: 'mdi mdi-clipboard-check-outline',
    scope: '待审单据查询、审批动作、风险解释和审核意见草稿'
  },
  [ASSISTANT_SCOPE_SESSION_KNOWLEDGE]: {
    label: '财务知识助手',
    icon: 'mdi mdi-book-open-page-variant-outline',
    scope: '财务制度、报销标准、票据要求、流程规则和政策口径解释'
  }
}

const SESSION_SCOPE_TYPES = Object.keys(SESSION_SCOPE_CONFIG)

const APPLICATION_PATTERN =
  /费用申请|发起申请|申请单|事前申请|事前审批|前置审批|出差申请|采购申请|用款申请|预算申请|申请材料|材料清单|先申请|立项申请/
const EXPENSE_PATTERN =
  /报销|报销单|票据|发票|火车票|高铁票|机票|飞机票|的士票|出租车|网约车|酒店票|住宿票|住宿单据|保存草稿|草稿|费用明细|归集|上传.*票|关联单据|继续下一步/
const APPROVAL_PATTERN =
  /待我审核|待审|审核|审批|审核意见|审批意见|审批通过|审批驳回|驳回|退回|审核中心|审批中心|领导审批|财务审核|处理意见/
const KNOWLEDGE_PATTERN =
  /制度|政策|标准|规则|规定|流程|口径|依据|上限|额度|补贴|住宿标准|差旅标准|报销标准|票据要求|可不可以|能不能|怎么规定|如何计算|怎么算/
const EXPENSE_OPERATION_PATTERN = /发起报销|报销单|票据|发票|火车票|高铁票|机票|的士票|草稿|归集|上传|关联单据|继续下一步/
const CURRENT_CLAIM_RISK_PATTERN = /这张|当前|本单|该单|单据|风险|超标|异常|重复|待补/

function normalizeSessionType(sessionType) {
  const normalized = String(sessionType || '').trim()
  return SESSION_SCOPE_TYPES.includes(normalized) ? normalized : ASSISTANT_SCOPE_SESSION_EXPENSE
}

function normalizeText(rawText) {
  return String(rawText || '')
    .replace(/\s+/g, '')
    .toLowerCase()
}

function resolveScopeConfig(sessionType) {
  return SESSION_SCOPE_CONFIG[normalizeSessionType(sessionType)] || SESSION_SCOPE_CONFIG[ASSISTANT_SCOPE_SESSION_EXPENSE]
}

export function inferAssistantScopeTarget(rawText, options = {}) {
  const text = normalizeText(rawText)
  if (!text) {
    return ''
  }

  const applicationMatched = APPLICATION_PATTERN.test(text)
  const expenseMatched = EXPENSE_PATTERN.test(text)
  const approvalMatched = APPROVAL_PATTERN.test(text)
  const knowledgeMatched = KNOWLEDGE_PATTERN.test(text)

  if (approvalMatched && /(待我审核|待审|审核意见|审批意见|审批通过|审批驳回|驳回|退回|审核中心|审批中心|处理意见)/.test(text)) {
    return ASSISTANT_SCOPE_SESSION_APPROVAL
  }

  if (knowledgeMatched && !options.hasActiveReviewPayload && !EXPENSE_OPERATION_PATTERN.test(text)) {
    return ASSISTANT_SCOPE_SESSION_KNOWLEDGE
  }

  if (expenseMatched && !applicationMatched) {
    return ASSISTANT_SCOPE_SESSION_EXPENSE
  }

  if (applicationMatched && !expenseMatched) {
    return ASSISTANT_SCOPE_SESSION_APPLICATION
  }

  if (knowledgeMatched && !expenseMatched && !approvalMatched && !applicationMatched) {
    return ASSISTANT_SCOPE_SESSION_KNOWLEDGE
  }

  if (knowledgeMatched && !options.hasActiveReviewPayload) {
    return ASSISTANT_SCOPE_SESSION_KNOWLEDGE
  }

  if (approvalMatched) {
    return ASSISTANT_SCOPE_SESSION_APPROVAL
  }

  if (expenseMatched) {
    return ASSISTANT_SCOPE_SESSION_EXPENSE
  }

  if (applicationMatched) {
    return ASSISTANT_SCOPE_SESSION_APPLICATION
  }

  return ''
}

function shouldAllowCurrentExpensePolicyQuestion(rawText, currentSessionType, targetSessionType, options = {}) {
  if (
    normalizeSessionType(currentSessionType) !== ASSISTANT_SCOPE_SESSION_EXPENSE ||
    targetSessionType !== ASSISTANT_SCOPE_SESSION_KNOWLEDGE ||
    !options.hasActiveReviewPayload
  ) {
    return false
  }

  return CURRENT_CLAIM_RISK_PATTERN.test(normalizeText(rawText))
}

function buildScopeSwitchAction(targetSessionType, rawText, options = {}) {
  const target = resolveScopeConfig(targetSessionType)
  const carryText = String(rawText || '').trim()

  return {
    label: `切换到${target.label}`,
    description: `带着这条内容进入${target.label}继续处理`,
    icon: target.icon,
    action_type: ASSISTANT_SCOPE_ACTION_SWITCH,
    payload: {
      session_type: normalizeSessionType(targetSessionType),
      carry_text: carryText,
      carry_files: Boolean(options.attachmentCount)
    }
  }
}

function buildScopeBoundaryText(currentSessionType, targetSessionType) {
  const current = resolveScopeConfig(currentSessionType)
  const target = resolveScopeConfig(targetSessionType)

  return [
    `我先暂停在「${current.label}」里继续处理这条消息。`,
    '',
    `当前助手的业务范围是：${current.scope}。`,
    '',
    `您这条内容更适合交给「${target.label}」处理；它的业务范围是：${target.scope}。`,
    '',
    `建议切换到「${target.label}」后继续，我会尽量把这条内容带过去，避免在错误的会话里把流程跑偏。`
  ].join('\n')
}

export function resolveAssistantScopeGuard(rawText, currentSessionType, options = {}) {
  const normalizedCurrent = normalizeSessionType(currentSessionType)
  const targetSessionType = inferAssistantScopeTarget(rawText, options)
  if (!targetSessionType || targetSessionType === normalizedCurrent) {
    return null
  }

  if (shouldAllowCurrentExpensePolicyQuestion(rawText, normalizedCurrent, targetSessionType, options)) {
    return null
  }

  const target = resolveScopeConfig(targetSessionType)

  return {
    targetSessionType,
    targetLabel: target.label,
    text: buildScopeBoundaryText(normalizedCurrent, targetSessionType),
    meta: [`建议切换至${target.label}`],
    suggestedActions: [buildScopeSwitchAction(targetSessionType, rawText, options)]
  }
}