import { reactive, computed } from 'vue'
import { knowledgeApi } from '../api'
import type {
  KnowledgeRecord,
  KnowledgeDetailPayload,
  KnowledgeEventRecord,
  CreateKnowledgeInput,
  UpdateKnowledgeInput,
  KnowledgeConfig,
} from '../api/types'

// ── 全局响应式状态（单例） ──

const state = reactive({
  items: [] as KnowledgeRecord[],
  candidates: [] as KnowledgeRecord[],
  config: null as KnowledgeConfig | null,
  loading: false,
  error: null as string | null,
})

// ── 异步竞态保护(请求序号,类似 ai.ts messages 的 switch token 模式) ──
// 快速连点(切换筛选/连续检索/重连)时,旧响应晚到会覆盖新响应。序号自增,
// 请求发起时捕获序号,响应回时比对:非最新请求的响应直接丢弃,只取最新。
// items 序号覆盖 loadList/loadCandidates/search;candidates 与 items 共用同一队列
// (loadList/search 写 items,loadCandidates 写 candidates),故 items 序号也兜底 candidates。
let _itemsReqSeq = 0
let _configReqSeq = 0

// 7 种知识类型(snake_case,与后端 KnowledgeKind 对齐)
// 仅存 key + icon;展示文案(label)走 i18n: $t('knowledge.kind.<key>')
export const KNOWLEDGE_KINDS = [
  { key: 'review_rule', icon: '🔍' },
  { key: 'prompt_template', icon: '💬' },
  { key: 'pitfall', icon: '⚠️' },
  { key: 'architecture_pattern', icon: '🏛️' },
  { key: 'diagnosis', icon: '🩺' },
  { key: 'deployment_note', icon: '🚀' },
  { key: 'workflow_optimization', icon: '⚡' },
] as const

/** 解析 tags JSON 字符串为 string[] */
export function parseTags(tags: string | null): string[] {
  if (!tags) return []
  try {
    const arr = JSON.parse(tags)
    return Array.isArray(arr) ? arr : []
  } catch {
    return []
  }
}

export function useKnowledgeStore() {
  // ── 加载列表(默认排除 archived) ──
  async function loadList(status?: string) {
    const seq = ++_itemsReqSeq
    state.loading = true
    state.error = null
    try {
      const result = await knowledgeApi.list(status ?? null)
      if (seq !== _itemsReqSeq) return // 旧响应丢弃,只取最新
      state.items = result
    } catch (e: any) {
      if (seq !== _itemsReqSeq) return // 旧请求的失败不污染当前视图
      state.error = e?.toString() ?? '加载知识库失败'
    } finally {
      if (seq === _itemsReqSeq) state.loading = false
    }
  }

  // ── 加载审核收件箱(候选列表) ──
  async function loadCandidates() {
    const seq = ++_itemsReqSeq
    try {
      const result = await knowledgeApi.listCandidates()
      if (seq !== _itemsReqSeq) return // 旧响应丢弃,只取最新
      state.candidates = result
    } catch (e: any) {
      if (seq !== _itemsReqSeq) return
      state.error = e?.toString() ?? '加载收件箱失败'
    }
  }

  async function search(query: string, kind?: string) {
    const seq = ++_itemsReqSeq
    state.loading = true
    state.error = null
    try {
      const result = await knowledgeApi.search({ query, kind })
      if (seq !== _itemsReqSeq) return // 旧响应丢弃,只取最新
      state.items = result
    } catch (e: any) {
      if (seq !== _itemsReqSeq) return
      state.error = e?.toString() ?? '检索失败'
    } finally {
      if (seq === _itemsReqSeq) state.loading = false
    }
  }

  async function create(input: CreateKnowledgeInput) {
    try {
      const record = await knowledgeApi.create(input)
      // 手动录入默认 candidate,刷新收件箱。
      // create 已成功返回 record,刷新失败不应污染成功语义 —— 直接走原始 API + 非阻塞 console.warn,
      // 不经 loadCandidates(后者会写 state.error,污染 create 成功语义)。
      try {
        state.candidates = await knowledgeApi.listCandidates()
      } catch (e: any) {
        console.warn('create 后刷新收件箱失败(非阻塞)', e?.toString?.() ?? e)
      }
      return record
    } catch (e: any) {
      state.error = e?.toString() ?? '创建知识失败'
      return null
    }
  }

  async function updateStatus(id: string, status: string) {
    try {
      await knowledgeApi.updateStatus(id, status)
      // 从 items 和 candidates 中同步移除
      state.items = state.items.filter(k => k.id !== id)
      state.candidates = state.candidates.filter(k => k.id !== id)
    } catch (e: any) {
      state.error = e?.toString() ?? '更新状态失败'
    }
  }

  async function archive(id: string) {
    try {
      await knowledgeApi.archive(id)
      state.items = state.items.filter(k => k.id !== id)
      state.candidates = state.candidates.filter(k => k.id !== id)
    } catch (e: any) {
      state.error = e?.toString() ?? '归档失败'
    }
  }

  // ── 配置 ──
  async function loadConfig() {
    const seq = ++_configReqSeq
    try {
      const result = await knowledgeApi.getConfig()
      if (seq !== _configReqSeq) return // 旧响应丢弃,只取最新
      state.config = result
    } catch (e: any) {
      if (seq !== _configReqSeq) return
      state.error = e?.toString() ?? '加载配置失败'
    }
  }

  async function saveConfig(config: KnowledgeConfig) {
    try {
      await knowledgeApi.saveConfig(config)
      state.config = config
    } catch (e: any) {
      state.error = e?.toString() ?? '保存配置失败'
    }
  }

  async function extractNow() {
    try {
      await knowledgeApi.extractNow()
      await loadCandidates()
    } catch (e: any) {
      state.error = e?.toString() ?? '立即抽取失败'
    }
  }

  // ── 生命线:详情 / 编辑 / 事件查询(按需调用,不入全局 state) ──
  async function getDetail(id: string): Promise<KnowledgeDetailPayload> {
    return knowledgeApi.getDetail(id)
  }

  async function update(id: string, input: UpdateKnowledgeInput): Promise<KnowledgeRecord> {
    const updated = await knowledgeApi.update(id, input)
    // 同步刷新内存中的列表/收件箱条目
    const patch = (arr: KnowledgeRecord[]) => {
      const idx = arr.findIndex(k => k.id === id)
      if (idx >= 0) arr[idx] = { ...arr[idx], ...updated }
    }
    patch(state.items)
    patch(state.candidates)
    return updated
  }

  async function getEvents(knowledgeId: string, eventType?: string, limit?: number): Promise<KnowledgeEventRecord[]> {
    return knowledgeApi.events(knowledgeId, eventType, limit)
  }

  // 候选数量(供侧栏 badge 用)
  const candidateCount = computed(() => state.candidates.length)

  // 清除错误条(供 Knowledge.vue error-banner 关闭按钮调用)
  function clearError() {
    state.error = null
  }

  return reactive({
    // 状态用 getter 实时读 state(防快照不跟随,同 project store 模式)
    get items() { return state.items },
    get candidates() { return state.candidates },
    get config() { return state.config },
    get loading() { return state.loading },
    get error() { return state.error },
    candidateCount,
    // actions
    loadList, loadCandidates, search, create, updateStatus, archive,
    loadConfig, saveConfig, extractNow,
    getDetail, update, getEvents,
    clearError,
  })
}