/**
 * 集成工具生成 - 3 步流程状态机
 *
 * 流程：
 *   步骤① 发现资源 → POST /discover
 *   步骤② 预览工具 → POST /preview + GET /tools（冲突比对）→ POST /generate
 *   步骤③ 生成草稿 → POST /integration-tools（持久化，事务型）
 *
 * 数据流：
 *   discover 返回 resources → preview 返回 tools → generate 返回 draft.tool_configs
 *   前端按步骤②勾选项过滤草稿，persist 仅持久化勾选项
 *
 * 冲突处理：
 *   后端 override_existing 硬编码 False，冲突 slug 仅能跳过
 *   前端比对 GET /tools 已有 slug，冲突项禁用勾选
 */
import { ref, reactive, computed } from 'vue'
import {
  getIntegrationToolListApi,
  discoverIntegrationToolsApi,
  previewIntegrationToolsApi,
  generateIntegrationToolsApi,
  persistIntegrationToolsApi
} from '@/apis/external-systems/integration_generator_api'
import { getSystemListApi } from '@/apis/external-systems/system_api'
import { getEnvironmentListApi } from '@/apis/external-systems/environment_api'
import { getToolListApi, deleteToolApi } from '@/apis/external-systems/tool_api'
import { getVendorSourceTypesApi } from '@/apis/external-systems/vendor_integration_api'
import { unwrap } from './utils'

// 步骤常量
const STEP_DISCOVER = 0
const STEP_PREVIEW = 1
const STEP_GENERATE = 2

export function useIntegrationGenerator() {
  // ===== 列表状态（已持久化的集成工具） =====
  const toolList = ref([])
  const listLoading = ref(false)
  const listTotal = ref(0)

  // ===== 弹窗与步骤 =====
  const modalVisible = ref(false)
  const currentStep = ref(STEP_DISCOVER)

  // ===== 表单状态 =====
  const form = reactive({
    system_id: null,
    env_key: undefined,
    source_type: undefined,
    discovery_options: {}
  })
  const discoveryOptionsStr = ref('{}')

  // ===== 选项数据 =====
  const systemOptions = ref([])
  const environmentOptions = ref([])
  const sourceTypeOptions = ref([])
  const existingToolSlugs = ref(new Set())

  // ===== 流程结果 =====
  const discoverResult = ref(null)
  const previewResult = ref(null)
  const draftResult = ref(null)

  // ===== 选中的工具 slug 列表 =====
  const selectedToolSlugs = ref([])

  // ===== 加载状态 =====
  const discoverLoading = ref(false)
  const previewLoading = ref(false)
  const generateLoading = ref(false)
  const persistLoading = ref(false)
  const deleteLoading = ref(false)
  const optionsLoading = ref(false)

  // ===== 错误状态（组件 watch 后显示 message.error） =====
  const error = ref(null)

  // ===== 计算属性 =====

  /**
   * 预览工具列表（带冲突标记）
   * 冲突定义：preview 返回的 slug 已存在于 GET /tools 结果中
   */
  const previewTools = computed(() => {
    const tools = previewResult.value?.tools || []
    return tools.map((tool) => ({
      ...tool,
      is_conflict: existingToolSlugs.value.has(tool.slug)
    }))
  })

  const previewStats = computed(() => {
    const total = previewTools.value.length
    const conflictCount = previewTools.value.filter((t) => t.is_conflict).length
    const newCount = total - conflictCount
    return { total, newCount, conflictCount }
  })

  /**
   * 草稿列表（按步骤②勾选过滤）
   *
   * 后端 GenerateToolsDraftOutput 结构：
   *   { system_id, source_type, draft: { tool_configs, override_existing } }
   * 前端按勾选项过滤草稿后展示与持久化
   */
  const draftTools = computed(() => {
    const configs = draftResult.value?.draft?.tool_configs || []
    return configs.filter((config) => selectedToolSlugs.value.includes(config.slug))
  })

  const hasUnpersistedDrafts = computed(
    () => currentStep.value === STEP_GENERATE && draftTools.value.length > 0
  )

  // ===== 列表加载 =====

  async function fetchToolList(params = {}) {
    listLoading.value = true
    error.value = null
    try {
      const data = unwrap(await getIntegrationToolListApi(params))
      toolList.value = data?.items || data || []
      listTotal.value = data?.total || toolList.value.length
    } catch (e) {
      error.value = e
    } finally {
      listLoading.value = false
    }
  }

  // ===== 选项加载 =====

  async function loadInitData() {
    optionsLoading.value = true
    error.value = null
    try {
      const [systemsRes, sourceTypesRes] = await Promise.all([
        getSystemListApi({ limit: 500 }),
        getVendorSourceTypesApi()
      ])
      const systemsData = unwrap(systemsRes)
      systemOptions.value = systemsData?.items || systemsData || []
      // 后端返回 { items: [{ source_type, operations }], total }，
      // a-select options 需要 { label, value } 格式
      const sourceTypesData = unwrap(sourceTypesRes)
      const sourceTypeItems = sourceTypesData?.items || []
      sourceTypeOptions.value = sourceTypeItems.map((item) => ({
        label: item.source_type,
        value: item.source_type
      }))
    } catch (e) {
      error.value = e
    } finally {
      optionsLoading.value = false
    }
  }

  async function loadEnvironments(systemId) {
    if (!systemId) {
      environmentOptions.value = []
      return
    }
    error.value = null
    try {
      const data = unwrap(await getEnvironmentListApi({ system_id: systemId, limit: 100 }))
      environmentOptions.value = data?.items || data || []
    } catch (e) {
      error.value = e
    }
  }

  async function loadExistingToolSlugs(systemId) {
    if (!systemId) {
      existingToolSlugs.value = new Set()
      return
    }
    error.value = null
    try {
      const data = unwrap(await getToolListApi({ system_id: systemId, limit: 500 }))
      const tools = data?.items || data || []
      existingToolSlugs.value = new Set(tools.map((t) => t.slug))
    } catch (e) {
      error.value = e
    }
  }

  async function handleSystemChange(systemId) {
    form.env_key = undefined
    await Promise.all([loadEnvironments(systemId), loadExistingToolSlugs(systemId)])
  }

  // ===== 流程请求构造 =====

  function parseDiscoveryOptions() {
    const raw = discoveryOptionsStr.value?.trim()
    if (!raw) {
      form.discovery_options = null
      return true
    }
    try {
      form.discovery_options = JSON.parse(raw)
      return true
    } catch {
      error.value = new Error('发现选项必须为合法 JSON')
      return false
    }
  }

  function buildFlowRequest() {
    return {
      system_id: form.system_id,
      // 使用 ?? 而非 ||，避免空字符串/0 被误转 null；
      // discovery_options 为空对象 {} 时应保留（语义为"无特殊选项"），不应转 null
      source_type: form.source_type ?? null,
      env_key: form.env_key ?? null,
      discovery_options: form.discovery_options ?? null
    }
  }

  // 字段校验规则（对齐后端 ExternalToolItemRequest 约束）
  const SLUG_PATTERN = /^[a-zA-Z_][a-zA-Z0-9_-]{0,127}$/

  /**
   * 持久化前字段级校验（对齐后端 ExternalToolItemRequest 约束）
   * - slug: 正则 ^[a-zA-Z_][a-zA-Z0-9_-]{0,127}$，长度 1-128
   * - name: 长度 1-128
   * - timeout: 1-300
   *
   * @returns {string|null} 首个错误信息，null 表示通过
   */
  function validateToolsBeforePersist(tools) {
    for (const tool of tools) {
      if (!tool.slug || !SLUG_PATTERN.test(tool.slug)) {
        return `工具 slug 格式不合法：${tool.slug || '(空)'}（需匹配 ^[a-zA-Z_][a-zA-Z0-9_-]{0,127}$）`
      }
      if (!tool.name || tool.name.length > 128) {
        return `工具 name 长度需在 1-128 之间：${tool.name || '(空)'}`
      }
      if (tool.timeout === undefined || tool.timeout === null || tool.timeout < 1 || tool.timeout > 300) {
        return `工具 timeout 需在 1-300 之间：${tool.timeout}`
      }
    }
    return null
  }

  // ===== 3 步流程方法 =====

  /**
   * 步骤①：发现资源
   * 成功且有资源 → 自动进入步骤②并加载预览
   * 成功但无资源 → 停留步骤①展示空状态
   */
  async function discover() {
    if (!form.system_id) {
      error.value = new Error('请选择系统')
      return false
    }
    if (!parseDiscoveryOptions()) return false

    discoverLoading.value = true
    error.value = null
    try {
      discoverResult.value = unwrap(await discoverIntegrationToolsApi(buildFlowRequest()))
      const resources = discoverResult.value?.resources || []
      if (resources.length === 0) {
        // 无资源，停留步骤①
        return false
      }
      // 进入步骤②，加载预览工具列表
      // 先加载预览，成功后再推进步骤，避免 preview 失败时步骤已推进
      const previewOk = await preview()
      if (previewOk) {
        currentStep.value = STEP_PREVIEW
      }
      return previewOk
    } catch (e) {
      error.value = e
      return false
    } finally {
      discoverLoading.value = false
    }
  }

  /**
   * 步骤②：预览工具列表
   * 调用 POST /preview 获取工具列表
   * 默认勾选所有「新增」项，冲突项不可勾选
   *
   * @returns {boolean} 是否成功
   */
  async function preview() {
    previewLoading.value = true
    error.value = null
    try {
      previewResult.value = unwrap(await previewIntegrationToolsApi(buildFlowRequest()))
      // 默认勾选所有非冲突项
      const tools = previewResult.value?.tools || []
      const existing = existingToolSlugs.value
      selectedToolSlugs.value = tools.filter((t) => !existing.has(t.slug)).map((t) => t.slug)
      return true
    } catch (e) {
      error.value = e
      return false
    } finally {
      previewLoading.value = false
    }
  }

  /**
   * 步骤② → 步骤③：生成草稿
   * 调用 POST /generate 生成全量草稿（不持久化）
   * 前端按步骤②勾选项过滤草稿列表
   */
  async function generate() {
    if (selectedToolSlugs.value.length === 0) {
      error.value = new Error('请至少选择 1 个工具')
      return false
    }
    generateLoading.value = true
    error.value = null
    try {
      draftResult.value = unwrap(await generateIntegrationToolsApi(buildFlowRequest()))
      currentStep.value = STEP_GENERATE
      return true
    } catch (e) {
      error.value = e
      return false
    } finally {
      generateLoading.value = false
    }
  }

  /**
   * 步骤③：持久化草稿（事务型全量成功/失败）
   * 调用 POST /integration-tools，body 含 system_id + 过滤后的 tools 列表
   * 成功 → 关闭弹窗 + 刷新列表，返回后端实际持久化数量（affected）
   * 失败 → 错误提示，支持重试
   *
   * 后端 PersistGeneratedToolsOutput：{ persisted: [...], affected: int }
   */
  async function persist() {
    if (draftTools.value.length === 0) {
      error.value = new Error('持久化工具列表不能为空')
      return false
    }
    // 字段级校验前置（对齐后端 ExternalToolItemRequest 约束）
    const validateError = validateToolsBeforePersist(draftTools.value)
    if (validateError) {
      error.value = new Error(validateError)
      return false
    }
    persistLoading.value = true
    error.value = null
    try {
      const response = await persistIntegrationToolsApi({
        system_id: form.system_id,
        tools: draftTools.value
      })
      // 使用后端返回的 affected 字段，而非前端计算的 length
      const data = unwrap(response)
      const affected = data?.affected ?? draftTools.value.length
      resetFlow()
      modalVisible.value = false
      await fetchToolList()
      return affected
    } catch (e) {
      error.value = e
      return false
    } finally {
      persistLoading.value = false
    }
  }

  /**
   * 删除已持久化的工具
   * 调用 DELETE /tools/{tool_id}，system_id 为可选 query
   * 成功 → 返回后端响应，由组件刷新列表
   * 失败 → 设置 error，返回 false
   */
  async function deleteTool(toolId) {
    deleteLoading.value = true
    error.value = null
    try {
      const result = unwrap(await deleteToolApi(toolId))
      return result
    } catch (e) {
      error.value = e
      return false
    } finally {
      deleteLoading.value = false
    }
  }

  // ===== 弹窗控制 =====

  function openModal() {
    resetFlow()
    modalVisible.value = true
    loadInitData()
  }

  /**
   * 关闭弹窗：若有未持久化草稿，返回 false 由组件触发二次确认
   */
  function closeModal() {
    if (hasUnpersistedDrafts.value) {
      return false
    }
    modalVisible.value = false
    resetFlow()
    return true
  }

  function forceClose() {
    modalVisible.value = false
    resetFlow()
  }

  function back() {
    if (currentStep.value > STEP_DISCOVER) {
      currentStep.value--
    }
  }

  // ===== 重置 =====

  function resetFlow() {
    currentStep.value = STEP_DISCOVER
    form.system_id = null
    form.env_key = undefined
    form.source_type = undefined
    form.discovery_options = {}
    discoveryOptionsStr.value = '{}'
    discoverResult.value = null
    previewResult.value = null
    draftResult.value = null
    selectedToolSlugs.value = []
    environmentOptions.value = []
    existingToolSlugs.value = new Set()
  }

  return {
    // 列表
    toolList,
    listLoading,
    listTotal,
    fetchToolList,
    // 弹窗与步骤
    modalVisible,
    currentStep,
    // 表单
    form,
    discoveryOptionsStr,
    // 选项
    systemOptions,
    environmentOptions,
    sourceTypeOptions,
    existingToolSlugs,
    optionsLoading,
    // 流程结果
    discoverResult,
    previewResult,
    draftResult,
    previewTools,
    previewStats,
    draftTools,
    hasUnpersistedDrafts,
    // 选中
    selectedToolSlugs,
    // 加载状态
    discoverLoading,
    previewLoading,
    generateLoading,
    persistLoading,
    deleteLoading,
    // 错误
    error,
    // 方法
    loadInitData,
    handleSystemChange,
    discover,
    preview,
    generate,
    persist,
    deleteTool,
    openModal,
    closeModal,
    forceClose,
    back,
    resetFlow
  }
}