import cache from '@/plugins/cache'
import useUserStore from '@/store/modules/user'

// 弹窗编辑草稿自动保存/恢复：
// 打开弹窗时注册唯一业务 key，表单有改动时防抖写入 localStorage，
// 关闭/切页/刷新后再次打开同一弹窗时自动恢复未保存的内容；保存成功后草稿清除。
export default {
  data() {
    return {
      draftStates: {}
    }
  },
  created() {
    this.draftBeforeUnload = () => {
      this.draftFlushAll()
    }
    window.addEventListener('beforeunload', this.draftBeforeUnload)
  },
  beforeUnmount() {
    this.draftFlushAll()
    window.removeEventListener('beforeunload', this.draftBeforeUnload)
  },
  methods: {
    // 打开弹窗、表单填好后调用；有未保存草稿则自动恢复
    // bizKey：全局唯一业务名；formField：表单字段名(如 'form')；recordId：编辑传记录id、新增传上下文；visibleField：弹窗显隐字段(如 'dialogVisible')
    draftRestore(bizKey, formField, recordId, visibleField) {
      const old = this.draftStates[bizKey]
      if (old) {
        this.draftTeardown(old)
      }
      let uid = ''
      try {
        uid = useUserStore().id || ''
      } catch (e) {
      }
      const rid = (recordId === null || recordId === undefined || recordId === '') ? 'new' : recordId
      const state = {
        key: `limsDraft_${uid}_${bizKey}_${rid}`,
        formField,
        visibleField,
        active: true,
        timer: null,
        baseline: ''
      }
      state.unwatchForm = this.$watch(formField, () => this.draftSchedule(state), { deep: true })
      if (visibleField) {
        state.unwatchVisible = this.$watch(visibleField, (val) => {
          if (!val) {
            this.draftStop(bizKey)
          }
        })
      }
      state.baseline = this.draftSnapshot(state)
      this.draftStates[bizKey] = state
      const raw = cache.local.get(state.key)
      if (raw) {
        try {
          const draft = JSON.parse(raw)
          const target = this[formField]
          if (Array.isArray(target) && Array.isArray(draft)) {
            target.splice(0, target.length, ...draft)
          } else if (target && typeof target === 'object') {
            Object.assign(target, draft)
          } else {
            this[formField] = draft
          }
          this.$message({ type: 'info', message: '已恢复上次未保存的编辑内容' })
        } catch (e) {
          cache.local.remove(state.key)
        }
      }
    },
    draftSnapshot(state) {
      try {
        return JSON.stringify(this[state.formField])
      } catch (e) {
        return ''
      }
    },
    draftSchedule(state) {
      if (!state.active) {
        return
      }
      if (state.timer) {
        clearTimeout(state.timer)
      }
      state.timer = setTimeout(() => {
        state.timer = null
        this.draftWrite(state, true)
      }, 300)
    },
    draftWrite(state, checkVisible) {
      if (!state.active) {
        return
      }
      if (checkVisible && state.visibleField && !this[state.visibleField]) {
        return
      }
      const json = this.draftSnapshot(state)
      if (json === '' || json === state.baseline) {
        cache.local.remove(state.key)
      } else {
        cache.local.set(state.key, json)
      }
    },
    // 用户取消/关闭弹窗时调用(必须在清空表单之前)
    draftStop(bizKey) {
      const state = this.draftStates[bizKey]
      if (!state || !state.active) {
        return
      }
      if (state.timer) {
        clearTimeout(state.timer)
        state.timer = null
      }
      this.draftWrite(state, false)
      this.draftTeardown(state)
    },
    // 保存成功后调用
    draftClear(bizKey) {
      const state = this.draftStates[bizKey]
      if (!state) {
        return
      }
      if (state.timer) {
        clearTimeout(state.timer)
        state.timer = null
      }
      cache.local.remove(state.key)
      this.draftTeardown(state)
    },
    draftTeardown(state) {
      state.active = false
      if (state.unwatchForm) {
        state.unwatchForm()
        state.unwatchForm = null
      }
      if (state.unwatchVisible) {
        state.unwatchVisible()
        state.unwatchVisible = null
      }
    },
    draftFlushAll() {
      Object.keys(this.draftStates).forEach((k) => {
        const state = this.draftStates[k]
        if (state && state.active) {
          if (state.timer) {
            clearTimeout(state.timer)
            state.timer = null
          }
          this.draftWrite(state, true)
          this.draftTeardown(state)
        }
      })
    }
  }
}