import { DifferenceStreamWriter } from './graph.js'
import type {
  BinaryOperator,
  DifferenceStreamReader,
  UnaryOperator,
} from './graph.js'
import type { MultiSet, MultiSetArray } from './multiset.js'
import type { ID2, IStreamBuilder, PipedOperator } from './types.js'

export class D2 implements ID2 {
  #operators: Array<UnaryOperator<any> | BinaryOperator<any>> = []
  #nextOperatorId = 0
  #finalized = false

  constructor() {}

  #checkNotFinalized(): void {
    if (this.#finalized) {
      throw new Error(`Graph already finalized`)
    }
  }

  getNextOperatorId(): number {
    this.#checkNotFinalized()
    return this.#nextOperatorId++
  }

  newInput<T>(): RootStreamBuilder<T> {
    this.#checkNotFinalized()
    const writer = new DifferenceStreamWriter<T>()
    // Use the root stream builder that exposes the sendData and sendFrontier methods
    const streamBuilder = new RootStreamBuilder<T>(this, writer)
    return streamBuilder
  }

  addOperator(operator: UnaryOperator<any> | BinaryOperator<any>): void {
    this.#checkNotFinalized()
    this.#operators.push(operator)
  }

  finalize() {
    this.#checkNotFinalized()
    this.#finalized = true
  }

  step(): void {
    if (!this.#finalized) {
      throw new Error(`Graph not finalized`)
    }
    for (const op of this.#operators) {
      op.run()
    }
  }

  pendingWork(): boolean {
    return this.#operators.some((op) => op.hasPendingWork())
  }

  run(): void {
    while (this.pendingWork()) {
      this.step()
    }
  }
}

export class StreamBuilder<T> implements IStreamBuilder<T> {
  #graph: ID2
  #writer: DifferenceStreamWriter<T>

  constructor(graph: ID2, writer: DifferenceStreamWriter<T>) {
    this.#graph = graph
    this.#writer = writer
  }

  connectReader(): DifferenceStreamReader<T> {
    return this.#writer.newReader()
  }

  get writer(): DifferenceStreamWriter<T> {
    return this.#writer
  }

  get graph(): ID2 {
    return this.#graph
  }

  // Don't judge, this is the only way to type this function.
  // rxjs has very similar code to type its pipe function
  // https://github.com/ReactiveX/rxjs/blob/master/packages/rxjs/src/internal/util/pipe.ts
  // We go to 20 operators deep, because surly that's enough for anyone...
  // A user can always split the pipe into multiple pipes to get around this.
  pipe<O>(o1: PipedOperator<T, O>): IStreamBuilder<O>
  // prettier-ignore
  pipe<T2, O>(o1: PipedOperator<T, T2>, o2: PipedOperator<T2, O>): IStreamBuilder<O>
  // prettier-ignore
  pipe<T2, T3, O>(o1: PipedOperator<T, T2>, o2: PipedOperator<T2, T3>, o3: PipedOperator<T3, O>): IStreamBuilder<O>
  // prettier-ignore
  pipe<T2, T3, T4, O>(o1: PipedOperator<T, T2>, o2: PipedOperator<T2, T3>, o3: PipedOperator<T3, T4>, o4: PipedOperator<T4, O>): IStreamBuilder<O>
  // prettier-ignore
  pipe<T2, T3, T4, T5, O>(o1: PipedOperator<T, T2>, o2: PipedOperator<T2, T3>, o3: PipedOperator<T3, T4>, o4: PipedOperator<T4, T5>, o5: PipedOperator<T5, O>): IStreamBuilder<O>
  // prettier-ignore
  pipe<T2, T3, T4, T5, T6, O>(o1: PipedOperator<T, T2>, o2: PipedOperator<T2, T3>, o3: PipedOperator<T3, T4>, o4: PipedOperator<T4, T5>, o5: PipedOperator<T5, T6>, o6: PipedOperator<T6, O>): IStreamBuilder<O>
  // prettier-ignore
  pipe<T2, T3, T4, T5, T6, T7, O>(o1: PipedOperator<T, T2>, o2: PipedOperator<T2, T3>, o3: PipedOperator<T3, T4>, o4: PipedOperator<T4, T5>, o5: PipedOperator<T5, T6>, o6: PipedOperator<T6, T7>, o7: PipedOperator<T7, O>): IStreamBuilder<O>
  // prettier-ignore
  pipe<T2, T3, T4, T5, T6, T7, T8, O>(o1: PipedOperator<T, T2>, o2: PipedOperator<T2, T3>, o3: PipedOperator<T3, T4>, o4: PipedOperator<T4, T5>, o5: PipedOperator<T5, T6>, o6: PipedOperator<T6, T7>, o7: PipedOperator<T7, T8>, o8: PipedOperator<T8, O>): IStreamBuilder<O>
  // prettier-ignore
  pipe<T2, T3, T4, T5, T6, T7, T8, T9, O>(o1: PipedOperator<T, T2>, o2: PipedOperator<T2, T3>, o3: PipedOperator<T3, T4>, o4: PipedOperator<T4, T5>, o5: PipedOperator<T5, T6>, o6: PipedOperator<T6, T7>, o7: PipedOperator<T7, T8>, o8: PipedOperator<T8, T9>, o9: PipedOperator<T9, O>): IStreamBuilder<O>
  // prettier-ignore
  pipe<T2, T3, T4, T5, T6, T7, T8, T9, T10, O>(o1: PipedOperator<T, T2>, o2: PipedOperator<T2, T3>, o3: PipedOperator<T3, T4>, o4: PipedOperator<T4, T5>, o5: PipedOperator<T5, T6>, o6: PipedOperator<T6, T7>, o7: PipedOperator<T7, T8>, o8: PipedOperator<T8, T9>, o9: PipedOperator<T9, T10>, o10: PipedOperator<T10, O>): IStreamBuilder<O>
  // prettier-ignore
  pipe<T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, O>(o1: PipedOperator<T, T2>, o2: PipedOperator<T2, T3>, o3: PipedOperator<T3, T4>, o4: PipedOperator<T4, T5>, o5: PipedOperator<T5, T6>, o6: PipedOperator<T6, T7>, o7: PipedOperator<T7, T8>, o8: PipedOperator<T8, T9>, o9: PipedOperator<T9, T10>, o10: PipedOperator<T10, T11>, o11: PipedOperator<T11, O>): IStreamBuilder<O>
  // prettier-ignore
  pipe<T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, O>(o1: PipedOperator<T, T2>, o2: PipedOperator<T2, T3>, o3: PipedOperator<T3, T4>, o4: PipedOperator<T4, T5>, o5: PipedOperator<T5, T6>, o6: PipedOperator<T6, T7>, o7: PipedOperator<T7, T8>, o8: PipedOperator<T8, T9>, o9: PipedOperator<T9, T10>, o10: PipedOperator<T10, T11>, o11: PipedOperator<T11, T12>, o12: PipedOperator<T12, O>): IStreamBuilder<O>
  // prettier-ignore
  pipe<T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, O>(o1: PipedOperator<T, T2>, o2: PipedOperator<T2, T3>, o3: PipedOperator<T3, T4>, o4: PipedOperator<T4, T5>, o5: PipedOperator<T5, T6>, o6: PipedOperator<T6, T7>, o7: PipedOperator<T7, T8>, o8: PipedOperator<T8, T9>, o9: PipedOperator<T9, T10>, o10: PipedOperator<T10, T11>, o11: PipedOperator<T11, T12>, o12: PipedOperator<T12, T13>, o13: PipedOperator<T13, O>): IStreamBuilder<O>
  // prettier-ignore
  pipe<T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, O>(o1: PipedOperator<T, T2>, o2: PipedOperator<T2, T3>, o3: PipedOperator<T3, T4>, o4: PipedOperator<T4, T5>, o5: PipedOperator<T5, T6>, o6: PipedOperator<T6, T7>, o7: PipedOperator<T7, T8>, o8: PipedOperator<T8, T9>, o9: PipedOperator<T9, T10>, o10: PipedOperator<T10, T11>, o11: PipedOperator<T11, T12>, o12: PipedOperator<T12, T13>, o13: PipedOperator<T13, T14>, o14: PipedOperator<T14, O>): IStreamBuilder<O>
  // prettier-ignore
  pipe<T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, O>(o1: PipedOperator<T, T2>, o2: PipedOperator<T2, T3>, o3: PipedOperator<T3, T4>, o4: PipedOperator<T4, T5>, o5: PipedOperator<T5, T6>, o6: PipedOperator<T6, T7>, o7: PipedOperator<T7, T8>, o8: PipedOperator<T8, T9>, o9: PipedOperator<T9, T10>, o10: PipedOperator<T10, T11>, o11: PipedOperator<T11, T12>, o12: PipedOperator<T12, T13>, o13: PipedOperator<T13, T14>, o14: PipedOperator<T14, T15>, o15: PipedOperator<T15, O>): IStreamBuilder<O>
  // prettier-ignore
  pipe<T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, O>(o1: PipedOperator<T, T2>, o2: PipedOperator<T2, T3>, o3: PipedOperator<T3, T4>, o4: PipedOperator<T4, T5>, o5: PipedOperator<T5, T6>, o6: PipedOperator<T6, T7>, o7: PipedOperator<T7, T8>, o8: PipedOperator<T8, T9>, o9: PipedOperator<T9, T10>, o10: PipedOperator<T10, T11>, o11: PipedOperator<T11, T12>, o12: PipedOperator<T12, T13>, o13: PipedOperator<T13, T14>, o14: PipedOperator<T14, T15>, o15: PipedOperator<T15, T16>, o16: PipedOperator<T16, O>): IStreamBuilder<O>
  // prettier-ignore
  pipe<T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, O>(o1: PipedOperator<T, T2>, o2: PipedOperator<T2, T3>, o3: PipedOperator<T3, T4>, o4: PipedOperator<T4, T5>, o5: PipedOperator<T5, T6>, o6: PipedOperator<T6, T7>, o7: PipedOperator<T7, T8>, o8: PipedOperator<T8, T9>, o9: PipedOperator<T9, T10>, o10: PipedOperator<T10, T11>, o11: PipedOperator<T11, T12>, o12: PipedOperator<T12, T13>, o13: PipedOperator<T13, T14>, o14: PipedOperator<T14, T15>, o15: PipedOperator<T15, T16>, o16: PipedOperator<T16, T17>, o17: PipedOperator<T17, O>): IStreamBuilder<O>
  // prettier-ignore
  pipe<T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, O>(o1: PipedOperator<T, T2>, o2: PipedOperator<T2, T3>, o3: PipedOperator<T3, T4>, o4: PipedOperator<T4, T5>, o5: PipedOperator<T5, T6>, o6: PipedOperator<T6, T7>, o7: PipedOperator<T7, T8>, o8: PipedOperator<T8, T9>, o9: PipedOperator<T9, T10>, o10: PipedOperator<T10, T11>, o11: PipedOperator<T11, T12>, o12: PipedOperator<T12, T13>, o13: PipedOperator<T13, T14>, o14: PipedOperator<T14, T15>, o15: PipedOperator<T15, T16>, o16: PipedOperator<T16, T17>, o17: PipedOperator<T17, T18>, o18: PipedOperator<T18, O>): IStreamBuilder<O>
  // prettier-ignore
  pipe<T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, O>(o1: PipedOperator<T, T2>, o2: PipedOperator<T2, T3>, o3: PipedOperator<T3, T4>, o4: PipedOperator<T4, T5>, o5: PipedOperator<T5, T6>, o6: PipedOperator<T6, T7>, o7: PipedOperator<T7, T8>, o8: PipedOperator<T8, T9>, o9: PipedOperator<T9, T10>, o10: PipedOperator<T10, T11>, o11: PipedOperator<T11, T12>, o12: PipedOperator<T12, T13>, o13: PipedOperator<T13, T14>, o14: PipedOperator<T14, T15>, o15: PipedOperator<T15, T16>, o16: PipedOperator<T16, T17>, o17: PipedOperator<T17, T18>, o18: PipedOperator<T18, T19>, o19: PipedOperator<T19, O>): IStreamBuilder<O>
  // prettier-ignore
  pipe<T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, O>(o1: PipedOperator<T, T2>, o2: PipedOperator<T2, T3>, o3: PipedOperator<T3, T4>, o4: PipedOperator<T4, T5>, o5: PipedOperator<T5, T6>, o6: PipedOperator<T6, T7>, o7: PipedOperator<T7, T8>, o8: PipedOperator<T8, T9>, o9: PipedOperator<T9, T10>, o10: PipedOperator<T10, T11>, o11: PipedOperator<T11, T12>, o12: PipedOperator<T12, T13>, o13: PipedOperator<T13, T14>, o14: PipedOperator<T14, T15>, o15: PipedOperator<T15, T16>, o16: PipedOperator<T16, T17>, o17: PipedOperator<T17, T18>, o18: PipedOperator<T18, T19>, o19: PipedOperator<T19, T20>, o20: PipedOperator<T20, O>): IStreamBuilder<O>

  pipe(...operators: Array<PipedOperator<any, any>>): IStreamBuilder<any> {
    return operators.reduce((stream, operator) => {
      return operator(stream)
    }, this as IStreamBuilder<any>)
  }
}

export class RootStreamBuilder<T> extends StreamBuilder<T> {
  sendData(collection: MultiSet<T> | MultiSetArray<T>): void {
    this.writer.sendData(collection)
  }
}