const SelectionMixin = { // eslint-disable-line no-unused-vars
  computed: {
    selectedSectionID: {
      get() {
        return this.$store.getters.SELECTED_SECTION_ID
      },
      set(value) {
        this.$store.dispatch('SET_SELECTED_SECTION_ID', value)
      }
    },
    selectedFamilyID: {
      get() {
        return this.$store.getters.SELECTED_FAMILY_ID
      },
      set(value) {
        this.$store.dispatch('SET_SELECTED_FAMILY_ID', value)
      }
    },
    selectedModelID: {
      get() {
        return this.$store.getters.SELECTED_MODEL_ID
      },
      set(value) {
        this.$store.dispatch('SET_SELECTED_MODEL_ID', value)
      }
    },
    selectedMaterial: {
      get() {
        return this.$store.getters.SELECTED_MATERIAL_ID
      },
      set(value) {
        this.$store.dispatch('SET_SELECTED_MATERIAL_ID', value)
      }
    },
  },
  methods: {
    selectSection: function(id) {
      this.selectedSectionID = id
      // this.selectedFamilyID = null
      // this.selectedModelID = null
      // this.selectedMaterial = null
    },
    selectFamily: function(id) {
      this.selectedFamilyID = id
      // this.selectedModelID = null
      // this.selectedMaterial = null
    },
    selectModel: function(id) {
      this.selectedModelID = id
      // this.selectedFamilyID = null
      // this.selectedMaterial = null
    },
    selectMaterial: function(id) {
      this.selectedMaterial = id
    },
    selectedFamilies: function() {
      let section = this.$store.getters.CAT_SECTION(this.selectedSectionID)
      let ids = this.sectionIDs(section)
      let materials = this.findMaterials(ids)
      return this.makeFamilies(materials)
    },
    selectedFamily: function() {
      let families = this.selectedFamilies()
      return families.find(s => s.id === this.selectedFamilyID)
    },
    sectionIDs: function(section) {
      let ids = []

      if (section) {
        for (let page of section.pages) {
          for (let block of page) {
            ids.push(...block.ids)
          }
        }
      }

      return ids
    },
    findMaterials: function(ids) {
      return ids.map(id => this.$store.getters.MATERIAL(id))
    },
    makeFamilies: function(materials) {
      let families = []

      for (let mat of materials) {
        let family = families.length > 0 ? families[families.length - 1] : null

        if (family === null || family.id !== mat.family) {
          // new family
          family = { id: mat.family,
                     name: mat.name, // TODO where does this come from?
                     models: [mat.model],
                     materials: [mat.id] }
          families.push(family)
        } else {
          // add to existing
          family.materials.push(mat.id)
          family.models.push(mat.model)
          family.models = this.uniquify(family.models)
        }
      }

      return families
    },
    uniquify: function(arr) {
      return [...new Set(arr)]
    },
  }
}

export default SelectionMixin