import type { Signal, ValueReactor } from "../reactor-core/index.ts"
import { effect, signal } from "../reactor-core/index.ts"

import { castValueInitializer } from "./utility.ts"

export interface CloneOptions<V> {
  target: ValueReactor<V>
}
/**
 * @description Creates a Signal that mirrors the value of the target ValueReactor.
 */
export const clone = <V>(options: CloneOptions<V>): Signal<V> => {
  const { target } = options

  const result = signal(castValueInitializer<V>(), {
    onDispose: () => {
      eTarget.dispose()
    },
  })

  const eTarget = effect(() => {
    const value = target.get()
    result.set(value)
  })

  return result
}

export interface PartitionOptions<V> {
  target: ValueReactor<V>
  predicate: (value: V) => boolean
}
/**
 * @description Partitions values from a ValueReactor into two Signals based on a predicate function.
 * The first Signal emits values that satisfy the predicate, while the second Signal
 * emits values that do not satisfy the predicate.
 */
export const partition = <V>(
  options: PartitionOptions<V>,
): [Signal<V | undefined>, Signal<V | undefined>] => {
  const { target, predicate } = options

  const trueSignal = signal(castValueInitializer<V | undefined>(), {
    onDispose: () => {
      eTarget.dispose()
    },
  })
  const falseSignal = signal(castValueInitializer<V | undefined>(), {
    onDispose: () => {
      eTarget.dispose()
    },
  })

  const eTarget = effect(() => {
    const value = target.get()
    if (predicate(value) === true) {
      trueSignal.set(value)
    } else {
      falseSignal.set(value)
    }
  })

  return [trueSignal, falseSignal]
}