//
// 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 type {
  Tx,
  Ref,
  Doc,
  Class,
  DocumentQuery,
  FindResult,
  FindOptions
} from '@anticrm/core'
import { getResource } from '@anticrm/platform'
import core, { ModelDb, TxDb, Hierarchy, DOMAIN_TX, DefaultTxFactory } from '@anticrm/core'

import * as txJson from './model.tx.json'

/**
 * @public
 */
export interface ServerStorage {
  findAll: <T extends Doc>(
    _class: Ref<Class<T>>,
    query: DocumentQuery<T>,
    options?: FindOptions<T>
  ) => Promise<FindResult<T>>
  tx: (tx: Tx) => Promise<Tx[]>
}

class DevStorage implements ServerStorage {
  private readonly txFactory: DefaultTxFactory

  constructor (
    private readonly hierarchy: Hierarchy,
    private readonly txdb: TxDb,
    private readonly modeldb: ModelDb
  ) {
    this.txFactory = new DefaultTxFactory(core.account.System)
  }

  async findAll<T extends Doc> (
    _class: Ref<Class<T>>,
    query: DocumentQuery<T>,
    options?: FindOptions<T>
  ): Promise<FindResult<T>> {
    const domain = this.hierarchy.getClass(_class).domain
    if (domain === DOMAIN_TX) return await this.txdb.findAll(_class, query, options)
    return await this.modeldb.findAll(_class, query, options)
  }

  async tx (tx: Tx): Promise<Tx[]> {
    if (tx.objectSpace === core.space.Model) {
      this.hierarchy.tx(tx)
    }
    await Promise.all([this.modeldb.tx(tx), this.txdb.tx(tx)])
    // invoke triggers
    const triggers = this.hierarchy.getClass(tx.objectClass).triggers
    if (triggers !== undefined) {
      const derived: Tx[] = []
      for (const trigger of triggers) {
        const impl = await getResource(trigger)
        const txes = await impl(tx, this.txFactory)
        derived.push(...txes)
        for (const tx of txes) {
          await Promise.all([this.modeldb.tx(tx), this.txdb.tx(tx)])
        }
      }
      return derived
    }
    return []
  }
}

/**
 * @public
 */
export async function createStorage (): Promise<ServerStorage> {
  const txes = txJson as unknown as Tx[]
  const hierarchy = new Hierarchy()
  for (const tx of txes) hierarchy.tx(tx)

  const transactions = new TxDb(hierarchy)
  const model = new ModelDb(hierarchy)
  for (const tx of txes) {
    await Promise.all([transactions.tx(tx), model.tx(tx)])
  }

  return new DevStorage(hierarchy, transactions, model)
}