import { deepEqual } from 'fast-equals'
import { DocumentUpdate, Hierarchy, MixinData, MixinUpdate, ModelDb, toFindResult } from '.'
import type {
  Account,
  AnyAttribute,
  AttachedData,
  AttachedDoc,
  Class,
  Data,
  Doc,
  Mixin,
  Ref,
  Space,
  Timestamp
} from './classes'
import { Client } from './client'
import core from './component'
import type { DocumentQuery, FindOptions, FindResult, TxResult, WithLookup } from './storage'
import { DocumentClassQuery, Tx, TxCUD, TxFactory, TxProcessor } from './tx'

/**
 * @public
 *
 * High Level operations with client, will create low level transactions.
 *
 * `notify` is not supported by TxOperations.
 */
export class TxOperations implements Omit<Client, 'notify'> {
  readonly txFactory: TxFactory

  constructor (readonly client: Client, readonly user: Ref<Account>, readonly isDerived: boolean = false) {
    this.txFactory = new TxFactory(user, isDerived)
  }

  getHierarchy (): Hierarchy {
    return this.client.getHierarchy()
  }

  getModel (): ModelDb {
    return this.client.getModel()
  }

  async close (): Promise<void> {
    return await this.client.close()
  }

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

  findOne<T extends Doc>(
    _class: Ref<Class<T>>,
    query: DocumentQuery<T>,
    options?: FindOptions<T> | undefined
  ): Promise<WithLookup<T> | undefined> {
    return this.client.findOne(_class, query, options)
  }

  tx (tx: Tx): Promise<TxResult> {
    return this.client.tx(tx)
  }

  async createDoc<T extends Doc>(
    _class: Ref<Class<T>>,
    space: Ref<Space>,
    attributes: Data<T>,
    id?: Ref<T>,
    modifiedOn?: Timestamp,
    modifiedBy?: Ref<Account>
  ): Promise<Ref<T>> {
    const hierarchy = this.client.getHierarchy()
    if (hierarchy.isDerived(_class, core.class.AttachedDoc)) {
      throw new Error('createDoc cannot be used for objects inherited from AttachedDoc')
    }
    const tx = this.txFactory.createTxCreateDoc(_class, space, attributes, id, modifiedOn, modifiedBy)
    await this.client.tx(tx)
    return tx.objectId
  }

  async addCollection<T extends Doc, P extends AttachedDoc>(
    _class: Ref<Class<P>>,
    space: Ref<Space>,
    attachedTo: Ref<T>,
    attachedToClass: Ref<Class<T>>,
    collection: string,
    attributes: AttachedData<P>,
    id?: Ref<P>,
    modifiedOn?: Timestamp,
    modifiedBy?: Ref<Account>
  ): Promise<Ref<P>> {
    const tx = this.txFactory.createTxCollectionCUD<T, P>(
      attachedToClass,
      attachedTo,
      space,
      collection,
      this.txFactory.createTxCreateDoc<P>(_class, space, attributes as unknown as Data<P>, id, modifiedOn, modifiedBy),
      modifiedOn,
      modifiedBy
    )
    await this.client.tx(tx)
    return tx.tx.objectId as unknown as Ref<P>
  }

  async updateCollection<T extends Doc, P extends AttachedDoc>(
    _class: Ref<Class<P>>,
    space: Ref<Space>,
    objectId: Ref<P>,
    attachedTo: Ref<T>,
    attachedToClass: Ref<Class<T>>,
    collection: string,
    operations: DocumentUpdate<P>,
    retrieve?: boolean,
    modifiedOn?: Timestamp,
    modifiedBy?: Ref<Account>
  ): Promise<Ref<T>> {
    const tx = this.txFactory.createTxCollectionCUD(
      attachedToClass,
      attachedTo,
      space,
      collection,
      this.txFactory.createTxUpdateDoc(_class, space, objectId, operations, retrieve, modifiedOn, modifiedBy),
      modifiedOn,
      modifiedBy
    )
    await this.client.tx(tx)
    return tx.objectId
  }

  async removeCollection<T extends Doc, P extends AttachedDoc>(
    _class: Ref<Class<P>>,
    space: Ref<Space>,
    objectId: Ref<P>,
    attachedTo: Ref<T>,
    attachedToClass: Ref<Class<T>>,
    collection: string,
    modifiedOn?: Timestamp,
    modifiedBy?: Ref<Account>
  ): Promise<Ref<T>> {
    const tx = this.txFactory.createTxCollectionCUD(
      attachedToClass,
      attachedTo,
      space,
      collection,
      this.txFactory.createTxRemoveDoc(_class, space, objectId, modifiedOn, modifiedBy),
      modifiedOn,
      modifiedBy
    )
    await this.client.tx(tx)
    return tx.objectId
  }

  updateDoc<T extends Doc>(
    _class: Ref<Class<T>>,
    space: Ref<Space>,
    objectId: Ref<T>,
    operations: DocumentUpdate<T>,
    retrieve?: boolean,
    modifiedOn?: Timestamp,
    modifiedBy?: Ref<Account>
  ): Promise<TxResult> {
    const tx = this.txFactory.createTxUpdateDoc(_class, space, objectId, operations, retrieve, modifiedOn, modifiedBy)
    return this.client.tx(tx)
  }

  removeDoc<T extends Doc>(
    _class: Ref<Class<T>>,
    space: Ref<Space>,
    objectId: Ref<T>,
    modifiedOn?: Timestamp,
    modifiedBy?: Ref<Account>
  ): Promise<TxResult> {
    const tx = this.txFactory.createTxRemoveDoc(_class, space, objectId, modifiedOn, modifiedBy)
    return this.client.tx(tx)
  }

  createMixin<D extends Doc, M extends D>(
    objectId: Ref<D>,
    objectClass: Ref<Class<D>>,
    objectSpace: Ref<Space>,
    mixin: Ref<Mixin<M>>,
    attributes: MixinData<D, M>,
    modifiedOn?: Timestamp,
    modifiedBy?: Ref<Account>
  ): Promise<TxResult> {
    const tx = this.txFactory.createTxMixin(
      objectId,
      objectClass,
      objectSpace,
      mixin,
      attributes,
      modifiedOn,
      modifiedBy
    )
    return this.client.tx(tx)
  }

  updateMixin<D extends Doc, M extends D>(
    objectId: Ref<D>,
    objectClass: Ref<Class<D>>,
    objectSpace: Ref<Space>,
    mixin: Ref<Mixin<M>>,
    attributes: MixinUpdate<D, M>,
    modifiedOn?: Timestamp,
    modifiedBy?: Ref<Account>
  ): Promise<TxResult> {
    const tx = this.txFactory.createTxMixin(
      objectId,
      objectClass,
      objectSpace,
      mixin,
      attributes,
      modifiedOn,
      modifiedBy
    )
    return this.client.tx(tx)
  }

  async update<T extends Doc>(
    doc: T,
    update: DocumentUpdate<T>,
    retrieve?: boolean,
    modifiedOn?: Timestamp,
    modifiedBy?: Ref<Account>
  ): Promise<TxResult> {
    const hierarchy = this.client.getHierarchy()
    const mixClass = Hierarchy.mixinOrClass(doc)
    if (hierarchy.isMixin(mixClass)) {
      const baseClass = hierarchy.getBaseClass(doc._class)

      const byClass = this.splitMixinUpdate(update, mixClass, baseClass)
      const ops = this.apply(doc._id)
      for (const it of byClass) {
        if (hierarchy.isMixin(it[0])) {
          await ops.updateMixin(doc._id, baseClass, doc.space, it[0], it[1], modifiedOn, modifiedBy)
        } else {
          if (hierarchy.isDerived(it[0], core.class.AttachedDoc)) {
            const adoc = doc as unknown as AttachedDoc
            return await this.updateCollection(
              it[0],
              doc.space,
              adoc._id,
              adoc.attachedTo,
              adoc.attachedToClass,
              adoc.collection,
              it[1],
              retrieve,
              modifiedOn,
              modifiedBy
            )
          }
          await ops.updateDoc(it[0], doc.space, doc._id, it[1], retrieve, modifiedOn, modifiedBy)
        }
      }
      return await ops.commit()
    }
    if (hierarchy.isDerived(doc._class, core.class.AttachedDoc)) {
      const adoc = doc as unknown as AttachedDoc
      return await this.updateCollection(
        doc._class,
        doc.space,
        adoc._id,
        adoc.attachedTo,
        adoc.attachedToClass,
        adoc.collection,
        update,
        retrieve,
        modifiedOn,
        modifiedBy
      )
    }
    return await this.updateDoc(doc._class, doc.space, doc._id, update, retrieve, modifiedOn, modifiedBy)
  }

  remove<T extends Doc>(doc: T, modifiedOn?: Timestamp, modifiedBy?: Ref<Account>): Promise<TxResult> {
    if (this.client.getHierarchy().isDerived(doc._class, core.class.AttachedDoc)) {
      const adoc = doc as unknown as AttachedDoc
      return this.removeCollection(
        doc._class,
        doc.space,
        adoc._id,
        adoc.attachedTo,
        adoc.attachedToClass,
        adoc.collection,
        modifiedOn,
        modifiedBy
      )
    }
    return this.removeDoc(doc._class, doc.space, doc._id)
  }

  apply (scope: string): ApplyOperations {
    return new ApplyOperations(this, scope)
  }

  async diffUpdate<T extends Doc = Doc>(
    doc: T,
    update: T | Data<T> | DocumentUpdate<T>,
    date?: Timestamp,
    account?: Ref<Account>
  ): Promise<T> {
    // We need to update fields if they are different.
    const documentUpdate: DocumentUpdate<T> = {}
    for (const [k, v] of Object.entries(update)) {
      if (['_class', '_id', 'modifiedBy', 'modifiedOn', 'space', 'attachedTo', 'attachedToClass'].includes(k)) {
        continue
      }
      const dv = (doc as any)[k]
      if (!deepEqual(dv, v) && v !== undefined) {
        ;(documentUpdate as any)[k] = v
      }
    }
    if (Object.keys(documentUpdate).length > 0) {
      await this.update(doc, documentUpdate, false, date ?? Date.now(), account)
      TxProcessor.applyUpdate(doc, documentUpdate)
    }
    return doc
  }

  async mixinDiffUpdate (
    doc: Doc,
    raw: Doc | Data<Doc>,
    mixin: Ref<Class<Mixin<Doc>>>,
    modifiedBy: Ref<Account>,
    modifiedOn: Timestamp
  ): Promise<Doc> {
    // We need to update fields if they are different.

    if (!this.getHierarchy().hasMixin(doc, mixin)) {
      await this.createMixin(doc._id, doc._class, doc.space, mixin, raw as MixinData<Doc, Doc>, modifiedOn, modifiedBy)
      TxProcessor.applyUpdate(this.getHierarchy().as(doc, mixin), raw)
      return doc
    }

    const documentUpdate: MixinUpdate<Doc, Doc> = {}
    for (const [k, v] of Object.entries(raw)) {
      if (['_class', '_id', 'modifiedBy', 'modifiedOn', 'space', 'attachedTo', 'attachedToClass'].includes(k)) {
        continue
      }
      const dv = (doc as any)[k]
      if (!deepEqual(dv, v) && v != null) {
        ;(documentUpdate as any)[k] = v
      }
    }
    if (Object.keys(documentUpdate).length > 0) {
      await this.updateMixin(doc._id, doc._class, doc.space, mixin, documentUpdate, modifiedOn, modifiedBy)
      TxProcessor.applyUpdate(this.getHierarchy().as(doc, mixin), documentUpdate)
    }
    return doc
  }

  private splitMixinUpdate<T extends Doc>(
    update: DocumentUpdate<T>,
    mixClass: Ref<Class<T>>,
    baseClass: Ref<Class<T>>
  ): Map<Ref<Class<Doc>>, DocumentUpdate<T>> {
    const hierarchy = this.getHierarchy()
    const attributes = hierarchy.getAllAttributes(mixClass)

    const updateAttrs = Object.fromEntries(
      Object.entries(update).filter((it) => !it[0].startsWith('$'))
    ) as DocumentUpdate<T>
    const updateOps = Object.fromEntries(
      Object.entries(update).filter((it) => it[0].startsWith('$'))
    ) as DocumentUpdate<T>

    const result: Map<Ref<Class<Doc>>, DocumentUpdate<T>> = this.splitObjectAttributes(
      updateAttrs,
      baseClass,
      attributes
    )

    for (const [key, value] of Object.entries(updateOps)) {
      const updates = this.splitObjectAttributes(value as object, baseClass, attributes)

      for (const [opsClass, opsUpdate] of updates) {
        const upd: DocumentUpdate<T> = result.get(opsClass) ?? {}
        result.set(opsClass, { ...upd, [key]: opsUpdate })
      }
    }

    return result
  }

  private splitObjectAttributes<T extends object>(
    obj: T,
    objClass: Ref<Class<Doc>>,
    attributes: Map<String, AnyAttribute>
  ): Map<Ref<Class<Doc>>, object> {
    const hierarchy = this.getHierarchy()

    const result: Map<Ref<Class<Doc>>, any> = new Map()
    for (const [key, value] of Object.entries(obj)) {
      const attributeOf = attributes.get(key)?.attributeOf
      const clazz = attributeOf !== undefined && hierarchy.isMixin(attributeOf) ? attributeOf : objClass
      result.set(clazz, { ...(result.get(clazz) ?? {}), [key]: value })
    }

    return result
  }
}

/**
 * @public
 *
 * Builder for ApplyOperation, with same syntax as TxOperations.
 *
 * Will send real command on commit and will return boolean of operation success.
 */
export class ApplyOperations extends TxOperations {
  txes: TxCUD<Doc>[] = []
  matches: DocumentClassQuery<Doc>[] = []
  notMatches: DocumentClassQuery<Doc>[] = []
  constructor (readonly ops: TxOperations, readonly scope: string) {
    const txClient: Client = {
      getHierarchy: () => ops.client.getHierarchy(),
      getModel: () => ops.client.getModel(),
      close: () => ops.client.close(),
      findOne: (_class, query, options?) => ops.client.findOne(_class, query, options),
      findAll: (_class, query, options?) => ops.client.findAll(_class, query, options),
      tx: async (tx): Promise<TxResult> => {
        if (ops.getHierarchy().isDerived(tx._class, core.class.TxCUD)) {
          this.txes.push(tx as TxCUD<Doc>)
        }
        return {}
      }
    }
    super(txClient, ops.user)
  }

  match<T extends Doc>(_class: Ref<Class<T>>, query: DocumentQuery<T>): ApplyOperations {
    this.matches.push({ _class, query })
    return this
  }

  notMatch<T extends Doc>(_class: Ref<Class<T>>, query: DocumentQuery<T>): ApplyOperations {
    this.notMatches.push({ _class, query })
    return this
  }

  async commit (notify: boolean = true, extraNotify: Ref<Class<Doc>>[] = []): Promise<boolean> {
    if (this.txes.length > 0) {
      return await ((await this.ops.tx(
        this.ops.txFactory.createTxApplyIf(
          core.space.Tx,
          this.scope,
          this.matches,
          this.notMatches,
          this.txes,
          notify,
          extraNotify
        )
      )) as Promise<boolean>)
    }
    return true
  }
}

/**
 * @public
 *
 * Builder for TxOperations.
 */
export class TxBuilder extends TxOperations {
  txes: TxCUD<Doc>[] = []
  matches: DocumentClassQuery<Doc>[] = []
  constructor (readonly hierarchy: Hierarchy, readonly modelDb: ModelDb, user: Ref<Account>) {
    const txClient: Client = {
      getHierarchy: () => this.hierarchy,
      getModel: () => this.modelDb,
      close: async () => {},
      findOne: async (_class, query, options?) => undefined,
      findAll: async (_class, query, options?) => toFindResult([]),
      tx: async (tx): Promise<TxResult> => {
        if (this.hierarchy.isDerived(tx._class, core.class.TxCUD)) {
          this.txes.push(tx as TxCUD<Doc>)
        }
        return {}
      }
    }
    super(txClient, user)
  }
}

/**
 * @public
 */
export async function updateAttribute (
  client: TxOperations,
  object: Doc,
  _class: Ref<Class<Doc>>,
  attribute: { key: string, attr: AnyAttribute },
  value: any,
  modifyBy?: Ref<Account>
): Promise<void> {
  const doc = object
  const attributeKey = attribute.key
  if ((doc as any)[attributeKey] === value) return
  const attr = attribute.attr
  if (client.getHierarchy().isMixin(attr.attributeOf)) {
    await client.updateMixin(
      doc._id,
      _class,
      doc.space,
      attr.attributeOf,
      { [attributeKey]: value },
      Date.now(),
      modifyBy
    )
  } else {
    if (client.getHierarchy().isDerived(attribute.attr.type._class, core.class.ArrOf)) {
      const oldValue: any[] = (object as any)[attributeKey] ?? []
      const val: any[] = value
      const toPull = oldValue.filter((it: any) => !val.includes(it))

      const toPush = val.filter((it) => !oldValue.includes(it))
      if (toPull.length > 0) {
        await client.update(object, { $pull: { [attributeKey]: { $in: toPull } } }, false, Date.now(), modifyBy)
      }
      if (toPush.length > 0) {
        await client.update(
          object,
          { $push: { [attributeKey]: { $each: toPush, $position: 0 } } },
          false,
          Date.now(),
          modifyBy
        )
      }
    } else {
      await client.update(object, { [attributeKey]: value }, false, Date.now(), modifyBy)
    }
  }
}