//
// Copyright © 2020 Anticrm Platform Contributors.
//
// Licensed under the Eclipse Public License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License. You may
// obtain a copy of the License at https://www.eclipse.org/legal/epl-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
//
// See the License for the specific language governing permissions and
// limitations under the License.
//

import clientPlugin from '@hcengineering/client'
import type { ClientFactoryOptions } from '@hcengineering/client/src'
import core, {
  AccountClient,
  LoadModelResponse,
  Tx,
  TxHandler,
  TxPersistenceStore,
  TxWorkspaceEvent,
  WorkspaceEvent,
  concatLink,
  createClient,
  fillConfiguration,
  pluginFilterTx,
  type Class,
  type ClientConnection,
  type Doc,
  type ModelFilter,
  type PluginConfiguration,
  type Ref,
  type TxCUD
} from '@hcengineering/core'
import platform, { Severity, Status, getMetadata, getPlugins, setPlatformStatus } from '@hcengineering/platform'
import { connect } from './connection'

export { connect }

let dbRequest: IDBOpenDBRequest | undefined
let dbPromise: Promise<IDBDatabase | undefined> = Promise.resolve(undefined)

if (typeof localStorage !== 'undefined') {
  const st = Date.now()
  dbPromise = new Promise<IDBDatabase>((resolve) => {
    dbRequest = indexedDB.open('model.db.persistence', 2)

    dbRequest.onupgradeneeded = function () {
      const db = (dbRequest as IDBOpenDBRequest).result
      if (!db.objectStoreNames.contains('model')) {
        db.createObjectStore('model', { keyPath: 'id' })
      }
    }
    dbRequest.onsuccess = function () {
      const db = (dbRequest as IDBOpenDBRequest).result
      console.log('init DB complete', Date.now() - st)
      resolve(db)
    }
  })
}

/**
 * @public
 */
function decodeTokenPayload (token: string): any {
  try {
    return JSON.parse(atob(token.split('.')[1]))
  } catch (err: any) {
    console.error(err)
    return {}
  }
}

// eslint-disable-next-line @typescript-eslint/explicit-function-return-type
export default async () => {
  return {
    function: {
      GetClient: async (token: string, endpoint: string, opt?: ClientFactoryOptions): Promise<AccountClient> => {
        const filterModel = getMetadata(clientPlugin.metadata.FilterModel) ?? 'none'

        const handler = async (handler: TxHandler): Promise<ClientConnection> => {
          const url = concatLink(endpoint, `/${token}`)

          const upgradeHandler: TxHandler = (...txes: Tx[]) => {
            for (const tx of txes) {
              if (tx?._class === core.class.TxModelUpgrade) {
                opt?.onUpgrade?.()
                return
              }
              if (tx?._class === core.class.TxWorkspaceEvent) {
                const event = tx as TxWorkspaceEvent
                if (event.event === WorkspaceEvent.MaintenanceNotification) {
                  void setPlatformStatus(
                    new Status(Severity.WARNING, platform.status.MaintenanceWarning, {
                      time: event.params.timeMinutes
                    })
                  )
                }
              }
            }
            handler(...txes)
          }
          const tokenPayload: { workspace: string, email: string } = decodeTokenPayload(token)

          const newOpt = { ...opt }
          const connectTimeout = opt?.connectionTimeout ?? getMetadata(clientPlugin.metadata.ConnectionTimeout)
          let connectPromise: Promise<void> | undefined
          if ((connectTimeout ?? 0) > 0) {
            connectPromise = new Promise<void>((resolve, reject) => {
              const connectTO = setTimeout(() => {
                if (!clientConnection.isConnected()) {
                  newOpt.onConnect = undefined
                  void clientConnection?.close()
                  void opt?.onDialTimeout?.()
                  reject(new Error(`Connection timeout, and no connection established to ${endpoint}`))
                }
              }, connectTimeout)
              newOpt.onConnect = async (event, data) => {
                // Any event is fine, it means server is alive.
                clearTimeout(connectTO)
                await opt?.onConnect?.(event, data)
                resolve()
              }
            })
          }
          const clientConnection = connect(url, upgradeHandler, tokenPayload.workspace, tokenPayload.email, newOpt)
          if (connectPromise !== undefined) {
            await connectPromise
          }
          return await Promise.resolve(clientConnection)
        }

        const modelFilter: ModelFilter = async (txes) => {
          if (filterModel === 'client') {
            return returnClientTxes(txes)
          }
          if (filterModel === 'ui') {
            return returnUITxes(txes)
          }
          return txes
        }

        const client = createClient(handler, modelFilter, createModelPersistence(getWSFromToken(token)), opt?.ctx)
        return await client
      }
    }
  }
}
function returnUITxes (txes: Tx[]): Tx[] {
  const configs = new Map<Ref<PluginConfiguration>, PluginConfiguration>()
  fillConfiguration(txes, configs)

  const allowedPlugins = [...getPlugins(), ...(getMetadata(clientPlugin.metadata.ExtraPlugins) ?? [])]
  const excludedPlugins = Array.from(configs.values()).filter(
    (it) => !it.enabled || !allowedPlugins.includes(it.pluginId)
  )
  return pluginFilterTx(excludedPlugins, configs, txes)
}

function returnClientTxes (txes: Tx[]): Tx[] {
  const configs = new Map<Ref<PluginConfiguration>, PluginConfiguration>()
  fillConfiguration(txes, configs)
  const excludedPlugins = Array.from(configs.values()).filter((it) => !it.enabled || it.pluginId.startsWith('server-'))

  const toExclude = new Set([
    'workbench:class:Application' as Ref<Class<Doc>>,
    'presentation:class:ComponentPointExtension' as Ref<Class<Doc>>,
    'presentation:class:ObjectSearchCategory' as Ref<Class<Doc>>,
    'notification:class:NotificationGroup' as Ref<Class<Doc>>,
    'notification:class:NotificationType' as Ref<Class<Doc>>,
    'view:class:Action' as Ref<Class<Doc>>,
    'view:class:Viewlet' as Ref<Class<Doc>>,
    'text-editor:class:TextEditorAction' as Ref<Class<Doc>>,
    'templates:class:TemplateField' as Ref<Class<Doc>>,
    'activity:class:DocUpdateMessageViewlet' as Ref<Class<Doc>>,
    'core:class:PluginConfiguration' as Ref<Class<Doc>>,
    'core:class:DomainIndexConfiguration' as Ref<Class<Doc>>
  ])

  const result = pluginFilterTx(excludedPlugins, configs, txes).filter((tx) => {
    // Exclude all matched UI plugins
    if (
      tx?._class === core.class.TxCreateDoc ||
      tx?._class === core.class.TxUpdateDoc ||
      tx?._class === core.class.TxRemoveDoc
    ) {
      const cud = tx as TxCUD<Doc>
      if (toExclude.has(cud.objectClass)) {
        return false
      }
    }
    return true
  })
  return result
}

function createModelPersistence (workspace: string): TxPersistenceStore | undefined {
  const overrideStore = getMetadata(clientPlugin.metadata.OverridePersistenceStore)
  if (overrideStore !== undefined) {
    return overrideStore
  }

  return {
    load: async () => {
      const db = await dbPromise
      if (db !== undefined) {
        try {
          const transaction = db.transaction('model', 'readwrite') // (1)
          const models = transaction.objectStore('model') // (2)
          const model = await new Promise<{ id: string, model: LoadModelResponse } | undefined>((resolve) => {
            const storedValue: IDBRequest<{ id: string, model: LoadModelResponse }> = models.get(workspace)
            storedValue.onsuccess = function () {
              resolve(storedValue.result)
            }
            storedValue.onerror = function () {
              resolve(undefined)
            }
          })

          if (model == null) {
            return {
              full: false,
              transactions: [],
              hash: ''
            }
          }
          return model.model
        } catch (err: any) {
          // Assume no model is stored.
        }
      }
      return {
        full: true,
        transactions: [],
        hash: ''
      }
    },
    store: async (model) => {
      const db = await dbPromise
      if (db !== undefined) {
        const transaction = db.transaction('model', 'readwrite') // (1)
        const models = transaction.objectStore('model') // (2)
        models.put({ id: workspace, model })
      }
    }
  }
}

function getWSFromToken (token: string): string {
  const parts = token.split('.')

  const payload = parts[1]

  const decodedPayload = atob(payload)

  const parsedPayload = JSON.parse(decodedPayload)

  return parsedPayload.workspace
}