//
// Copyright © 2022 Hardcore Engineering Inc.
//
// 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 {
  Class,
  Doc,
  DocumentQuery,
  DocumentUpdate,
  Domain,
  FindOptions,
  FindResult,
  Hierarchy,
  IndexingConfiguration,
  ModelDb,
  Ref,
  StorageIterator,
  toFindResult,
  Tx,
  TxResult,
  WorkspaceId
} from '@hcengineering/core'
import { MinioService } from '@hcengineering/minio'

/**
 * @public
 */
export interface DbAdapter {
  /**
   * Method called after hierarchy is ready to use.
   */
  init: (model: Tx[]) => Promise<void>

  createIndexes: (domain: Domain, config: Pick<IndexingConfiguration<Doc>, 'indexes'>) => Promise<void>

  close: () => Promise<void>
  findAll: <T extends Doc>(
    _class: Ref<Class<T>>,
    query: DocumentQuery<T>,
    options?: FindOptions<T>
  ) => Promise<FindResult<T>>
  tx: (...tx: Tx[]) => Promise<TxResult>

  find: (domain: Domain) => StorageIterator

  load: (domain: Domain, docs: Ref<Doc>[]) => Promise<Doc[]>
  upload: (domain: Domain, docs: Doc[]) => Promise<void>
  clean: (domain: Domain, docs: Ref<Doc>[]) => Promise<void>

  // Bulk update operations
  update: (domain: Domain, operations: Map<Ref<Doc>, DocumentUpdate<Doc>>) => Promise<void>
}

/**
 * @public
 */
export interface TxAdapter extends DbAdapter {
  getModel: () => Promise<Tx[]>
}

/**
 * @public
 */
export type DbAdapterFactory = (
  hierarchy: Hierarchy,
  url: string,
  workspaceId: WorkspaceId,
  modelDb: ModelDb,
  storage?: MinioService
) => Promise<DbAdapter>

/**
 * @public
 */
export interface DbAdapterConfiguration {
  factory: DbAdapterFactory
  url: string
}

/**
 * @public
 */
export class DummyDbAdapter implements DbAdapter {
  async init (model: Tx[]): Promise<void> {}
  async findAll<T extends Doc>(
    _class: Ref<Class<T>>,
    query: DocumentQuery<T>,
    options?: FindOptions<T> | undefined
  ): Promise<FindResult<T>> {
    return toFindResult([])
  }

  async createIndexes (domain: Domain, config: Pick<IndexingConfiguration<Doc>, 'indexes'>): Promise<void> {}

  async tx (...tx: Tx[]): Promise<TxResult> {
    return {}
  }

  async close (): Promise<void> {}

  find (domain: Domain): StorageIterator {
    return {
      next: async () => undefined,
      close: async () => {}
    }
  }

  async load (domain: Domain, docs: Ref<Doc>[]): Promise<Doc[]> {
    return []
  }

  async upload (domain: Domain, docs: Doc[]): Promise<void> {}

  async clean (domain: Domain, docs: Ref<Doc>[]): Promise<void> {}

  async update (domain: Domain, operations: Map<Ref<Doc>, DocumentUpdate<Doc>>): Promise<void> {}
}

class InMemoryAdapter extends DummyDbAdapter implements DbAdapter {
  private readonly modeldb: ModelDb

  constructor (hierarchy: Hierarchy) {
    super()
    this.modeldb = new ModelDb(hierarchy)
  }

  async findAll<T extends Doc>(
    _class: Ref<Class<T>>,
    query: DocumentQuery<T>,
    options?: FindOptions<T>
  ): Promise<FindResult<T>> {
    return await this.modeldb.findAll(_class, query, options)
  }

  async tx (...tx: Tx[]): Promise<TxResult> {
    return await this.modeldb.tx(...tx)
  }

  async init (model: Tx[]): Promise<void> {
    for (const tx of model) {
      try {
        await this.modeldb.tx(tx)
      } catch (err: any) {
        console.error('skip broken TX', err)
      }
    }
  }
}

/**
 * @public
 */
export async function createInMemoryAdapter (
  hierarchy: Hierarchy,
  url: string,
  workspaceId: WorkspaceId
): Promise<DbAdapter> {
  return new InMemoryAdapter(hierarchy)
}