import { set, get, cloneDeep, differenceWith, isEqual, flatten } from 'lodash'

export const defaultState = {
  frontends: [],
  loaded: false,
  needsReboot: null,
  config: null,
  modifiedPaths: null,
  descriptions: null,
  draft: null,
  dbConfigEnabled: null
}

export const newUserFlags = {
  ...defaultState.flagStorage
}

const adminSettingsStorage = {
  state: {
    ...cloneDeep(defaultState)
  },
  mutations: {
    setInstanceAdminNoDbConfig (state) {
      state.loaded = false
      state.dbConfigEnabled = false
    },
    setAvailableFrontends (state, { frontends }) {
      state.frontends = frontends.map(f => {
        f.installedRefs = f.installed_refs
        if (f.name === 'pleroma-fe') {
          f.refs = ['master', 'develop']
        } else {
          f.refs = [f.ref]
        }
        return f
      })
    },
    updateAdminSettings (state, { config, modifiedPaths }) {
      state.loaded = true
      state.dbConfigEnabled = true
      state.config = config
      state.modifiedPaths = modifiedPaths
    },
    updateAdminDescriptions (state, { descriptions }) {
      state.descriptions = descriptions
    },
    updateAdminDraft (state, { path, value }) {
      const [group, key, subkey] = path
      const parent = [group, key, subkey]

      set(state.draft, path, value)

      // force-updating grouped draft to trigger refresh of group settings
      if (path.length > parent.length) {
        set(state.draft, parent, cloneDeep(get(state.draft, parent)))
      }
    },
    resetAdminDraft (state) {
      state.draft = cloneDeep(state.config)
    }
  },
  actions: {
    loadFrontendsStuff ({ state, rootState, dispatch, commit }) {
      rootState.api.backendInteractor.fetchAvailableFrontends()
        .then(frontends => commit('setAvailableFrontends', { frontends }))
    },
    loadAdminStuff ({ state, rootState, dispatch, commit }) {
      rootState.api.backendInteractor.fetchInstanceDBConfig()
        .then(backendDbConfig => {
          if (backendDbConfig.error) {
            if (backendDbConfig.error.status === 400) {
              backendDbConfig.error.json().then(errorJson => {
                if (/configurable_from_database/.test(errorJson.error)) {
                  commit('setInstanceAdminNoDbConfig')
                }
              })
            }
          } else {
            dispatch('setInstanceAdminSettings', { backendDbConfig })
          }
        })
      if (state.descriptions === null) {
        rootState.api.backendInteractor.fetchInstanceConfigDescriptions()
          .then(backendDescriptions => dispatch('setInstanceAdminDescriptions', { backendDescriptions }))
      }
    },
    setInstanceAdminSettings ({ state, commit, dispatch }, { backendDbConfig }) {
      const config = state.config || {}
      const modifiedPaths = new Set()
      backendDbConfig.configs.forEach(c => {
        const path = [c.group, c.key]
        if (c.db) {
          // Path elements can contain dot, therefore we use ' -> ' as a separator instead
          // Using strings for modified paths for easier searching
          c.db.forEach(x => modifiedPaths.add([...path, x].join(' -> ')))
        }
        const convert = (value) => {
          if (Array.isArray(value) && value.length > 0 && value[0].tuple) {
            return value.reduce((acc, c) => {
              return { ...acc, [c.tuple[0]]: convert(c.tuple[1]) }
            }, {})
          } else {
            return value
          }
        }
        set(config, path, convert(c.value))
      })
      commit('updateAdminSettings', { config, modifiedPaths })
      commit('resetAdminDraft')
    },
    setInstanceAdminDescriptions ({ state, commit, dispatch }, { backendDescriptions }) {
      const convert = ({ children, description, label, key = '<ROOT>', group, suggestions }, path, acc) => {
        const newPath = group ? [group, key] : [key]
        const obj = { description, label, suggestions }
        if (Array.isArray(children)) {
          children.forEach(c => {
            convert(c, newPath, obj)
          })
        }
        set(acc, newPath, obj)
      }

      const descriptions = {}
      backendDescriptions.forEach(d => convert(d, '', descriptions))
      commit('updateAdminDescriptions', { descriptions })
    },

    // This action takes draft state, diffs it with live config state and then pushes
    // only differences between the two. Difference detection only work up to subkey (third) level.
    pushAdminDraft ({ rootState, state, commit, dispatch }) {
      // TODO cleanup paths in modifiedPaths
      const convert = (value) => {
        if (typeof value !== 'object') {
          return value
        } else if (Array.isArray(value)) {
          return value.map(convert)
        } else {
          return Object.entries(value).map(([k, v]) => ({ tuple: [k, v] }))
        }
      }

      // Getting all group-keys used in config
      const allGroupKeys = flatten(
        Object
          .entries(state.config)
          .map(
            ([group, lv1data]) => Object
              .keys(lv1data)
              .map((key) => ({ group, key }))
          )
      )

      // Only using group-keys where there are changes detected
      const changedGroupKeys = allGroupKeys.filter(({ group, key }) => {
        return !isEqual(state.config[group][key], state.draft[group][key])
      })

      // Here we take all changed group-keys and get all changed subkeys
      const changed = changedGroupKeys.map(({ group, key }) => {
        const config = state.config[group][key]
        const draft = state.draft[group][key]

        // We convert group-key value into entries arrays
        const eConfig = Object.entries(config)
        const eDraft = Object.entries(draft)

        // Then those entries array we diff so only changed subkey entries remain
        // We use the diffed array to reconstruct the object and then shove it into convert()
        return ({ group, key, value: convert(Object.fromEntries(differenceWith(eDraft, eConfig, isEqual))) })
      })

      rootState.api.backendInteractor.pushInstanceDBConfig({
        payload: {
          configs: changed
        }
      })
        .then(() => rootState.api.backendInteractor.fetchInstanceDBConfig())
        .then(backendDbConfig => dispatch('setInstanceAdminSettings', { backendDbConfig }))
    },
    pushAdminSetting ({ rootState, state, commit, dispatch }, { path, value }) {
      const [group, key, ...rest] = Array.isArray(path) ? path : path.split(/\./g)
      const clone = {} // not actually cloning the entire thing to avoid excessive writes
      set(clone, rest, value)

      // TODO cleanup paths in modifiedPaths
      const convert = (value) => {
        if (typeof value !== 'object') {
          return value
        } else if (Array.isArray(value)) {
          return value.map(convert)
        } else {
          return Object.entries(value).map(([k, v]) => ({ tuple: [k, v] }))
        }
      }

      rootState.api.backendInteractor.pushInstanceDBConfig({
        payload: {
          configs: [{
            group,
            key,
            value: convert(clone)
          }]
        }
      })
        .then(() => rootState.api.backendInteractor.fetchInstanceDBConfig())
        .then(backendDbConfig => dispatch('setInstanceAdminSettings', { backendDbConfig }))
    },
    resetAdminSetting ({ rootState, state, commit, dispatch }, { path }) {
      const [group, key, subkey] = path.split(/\./g)

      state.modifiedPaths.delete(path)

      return rootState.api.backendInteractor.pushInstanceDBConfig({
        payload: {
          configs: [{
            group,
            key,
            delete: true,
            subkeys: [subkey]
          }]
        }
      })
        .then(() => rootState.api.backendInteractor.fetchInstanceDBConfig())
        .then(backendDbConfig => dispatch('setInstanceAdminSettings', { backendDbConfig }))
    }
  }
}

export default adminSettingsStorage