import { Subject } from "rxjs"
import { concatMap } from "rxjs/operators"
import { Container } from "../container.js"
import type { ComponentInteraction } from "../interaction"
import type { Message, MessageOptions } from "../message"
import type { Node } from "../node.js"

type UpdatePayload =
  | { action: "update" | "deactivate"; options: MessageOptions }
  | { action: "deferUpdate"; interaction: ComponentInteraction }
  | { action: "destroy" }

export abstract class Renderer {
  readonly nodes = new Container<Node<unknown>>()
  private componentInteraction?: ComponentInteraction
  private message?: Message
  private active = true
  private updates = new Subject<UpdatePayload>()

  private updateSubscription = this.updates
    .pipe(concatMap((payload) => this.updateMessage(payload)))
    .subscribe({ error: console.error })

  render() {
    if (!this.active) {
      console.warn("Attempted to update a deactivated message")
      return
    }

    this.updates.next({
      options: this.getMessageOptions(),
      action: "update",
    })
  }

  deactivate() {
    this.active = false
    this.updates.next({
      options: this.getMessageOptions(),
      action: "deactivate",
    })
  }

  destroy() {
    this.active = false
    this.updates.next({ action: "destroy" })
  }

  handleComponentInteraction(interaction: ComponentInteraction) {
    this.componentInteraction = interaction

    setTimeout(() => {
      this.updates.next({ action: "deferUpdate", interaction })
    }, 500)

    for (const node of this.nodes) {
      if (node.handleComponentInteraction(interaction)) {
        return true
      }
    }
  }

  protected abstract createMessage(options: MessageOptions): Promise<Message>

  private getMessageOptions(): MessageOptions {
    const options: MessageOptions = {
      content: "",
      embeds: [],
      actionRows: [],
    }
    for (const node of this.nodes) {
      node.modifyMessageOptions(options)
    }
    return options
  }

  private async updateMessage(payload: UpdatePayload) {
    if (payload.action === "destroy") {
      this.updateSubscription.unsubscribe()
      await this.message?.delete()
      return
    }

    if (payload.action === "deactivate") {
      this.updateSubscription.unsubscribe()
      await this.message?.disableComponents()
      return
    }

    if (payload.action === "deferUpdate") {
      await payload.interaction.deferUpdate()
      return
    }

    if (this.componentInteraction) {
      const promise = this.componentInteraction.update(payload.options)
      this.componentInteraction = undefined
      await promise
      return
    }

    if (this.message) {
      await this.message.edit(payload.options)
      return
    }

    this.message = await this.createMessage(payload.options)
  }
}