1 files changed, 194 insertions, 0 deletions
diff --git a/web/src/js/ducks/utils/store.js b/web/src/js/ducks/utils/store.js
new file mode 100644
index 00000000..3252d697
--- /dev/null
+++ b/web/src/js/ducks/utils/store.js
@@ -0,0 +1,194 @@
+export const SET_FILTER = 'LIST_SET_FILTER'
+export const SET_SORT = 'LIST_SET_SORT'
+export const ADD = 'LIST_ADD'
+export const UPDATE = 'LIST_UPDATE'
+export const REMOVE = 'LIST_REMOVE'
+export const RECEIVE = 'LIST_RECEIVE'
+
+const defaultState = {
+    byId: {},
+    list: [],
+    listIndex: {},
+    view: [],
+    viewIndex: {},
+}
+
+export default function reduce(state = defaultState, action) {
+
+    let { byId, list, listIndex, view, viewIndex } = state
+
+    switch (action.type) {
+        case SET_FILTER:
+            view = list.filter(action.filter).sort(action.sort)
+            viewIndex = {}
+            view.forEach((item, index) => {
+                viewIndex[item.id] = index
+            })
+            break
+
+        case SET_SORT:
+            view = [...view].sort(action.sort)
+            viewIndex = {}
+            view.forEach((item, index) => {
+                viewIndex[item.id] = index
+            })
+            break
+
+        case ADD:
+            if (action.item.id in byId) {
+                // we already had that.
+                break
+            }
+            byId = { ...byId, [action.item.id]: action.item }
+            listIndex = { ...listIndex, [action.item.id]: list.length }
+            list = [...list, action.item]
+            if (action.filter(action.item)) {
+                ({ view, viewIndex } = sortedInsert(state, action.item, action.sort))
+            }
+            break
+
+        case UPDATE:
+            byId = { ...byId, [action.item.id]: action.item }
+            list = [...list]
+            list[listIndex[action.item.id]] = action.item
+
+            let hasOldItem = action.item.id in viewIndex
+            let hasNewItem = action.filter(action.item)
+            if (hasNewItem && !hasOldItem) {
+                ({view, viewIndex} = sortedInsert(state, action.item, action.sort))
+            }
+            else if (!hasNewItem && hasOldItem) {
+                ({data: view, dataIndex: viewIndex} = removeData(view, viewIndex, action.item.id))
+            }
+            else if (hasNewItem && hasOldItem) {
+                ({view, viewIndex} = sortedUpdate(state, action.item, action.sort))
+            }
+            break
+
+        case REMOVE:
+            if (!(action.id in byId)) {
+                break
+            }
+            delete byId[action.id];
+            ({data: list, dataIndex: listIndex} = removeData(list, listIndex, action.id))
+
+            if (action.id in viewIndex) {
+                ({data: view, dataIndex: viewIndex} = removeData(view, viewIndex, action.id))
+            }
+            break
+
+        case RECEIVE:
+            list = action.list
+            listIndex = {}
+            byId = {}
+            list.forEach((item, i) => {
+                byId[item.id] = item
+                listIndex[item.id] = i
+            })
+            view = list.filter(action.filter).sort(action.sort)
+            viewIndex = {}
+            view.forEach((item, index) => {
+                viewIndex[item.id] = index
+            })
+            break
+    }
+    return { byId, list, listIndex, view, viewIndex }
+}
+
+
+export function setFilter(filter = defaultFilter, sort = defaultSort) {
+    return { type: SET_FILTER, filter, sort }
+}
+
+export function setSort(sort = defaultSort) {
+    return { type: SET_SORT, sort }
+}
+
+export function add(item, filter = defaultFilter, sort = defaultSort) {
+    return { type: ADD, item, filter, sort }
+}
+
+export function update(item, filter = defaultFilter, sort = defaultSort) {
+    return { type: UPDATE, item, filter, sort }
+}
+
+export function remove(id) {
+    return { type: REMOVE, id }
+}
+
+export function receive(list, filter = defaultFilter, sort = defaultSort) {
+    return { type: RECEIVE, list, filter, sort }
+}
+
+function sortedInsert(state, item, sort) {
+    const index = sortedIndex(state.view, item, sort)
+    const view = [...state.view]
+    const viewIndex = { ...state.viewIndex }
+
+    view.splice(index, 0, item)
+    for (let i = view.length - 1; i >= index; i--) {
+        viewIndex[view[i].id] = i
+    }
+
+    return { view, viewIndex }
+}
+
+function removeData(currentData, currentDataIndex, id) {
+    const index = currentDataIndex[id]
+    const data = [...currentData]
+    const dataIndex = { ...currentDataIndex }
+    delete dataIndex[id];
+
+    data.splice(index, 1)
+    for (let i = data.length - 1; i >= index; i--) {
+        dataIndex[data[i].id] = i
+    }
+
+    return { data, dataIndex }
+}
+
+function sortedUpdate(state, item, sort) {
+    let view = [...state.view]
+    let viewIndex = { ...state.viewIndex }
+    let index = viewIndex[item.id]
+    view[index] = item
+    while (index + 1 < view.length && sort(view[index], view[index + 1]) > 0) {
+        view[index] = view[index + 1]
+        view[index + 1] = item
+        viewIndex[item.id] = index + 1
+        viewIndex[view[index].id] = index
+        ++index
+    }
+    while (index > 0 && sort(view[index], view[index - 1]) < 0) {
+        view[index] = view[index - 1]
+        view[index - 1] = item
+        viewIndex[item.id] = index - 1
+        viewIndex[view[index].id] = index
+        --index
+    }
+    return { view, viewIndex }
+}
+
+function sortedIndex(list, item, sort) {
+    let low = 0
+    let high = list.length
+
+    while (low < high) {
+        const middle = (low + high) >>> 1
+        if (sort(item, list[middle]) >= 0) {
+            low = middle + 1
+        } else {
+            high = middle
+        }
+    }
+
+    return low
+}
+
+function defaultFilter() {
+    return true
+}
+
+function defaultSort(a, b) {
+    return 0
+}