import type { SharedSlice, SliceZone } from "@prismicio/client"

import { __PRODUCTION__ } from "../lib/__PRODUCTION__"
import { EventEmitter } from "../lib/EventEmitter"
import { throttle } from "../lib/throttle"
import type { ActiveSlice } from "../types"
import { getActiveSliceDOM, getSliceZoneDOM } from "./domHelpers"
import { getDefaultSlices } from "./getDefault"
import type { StateEvents } from "./types"
import { StateEventType } from "./types"

type StateConstructorArgs = {
	slices?: SliceZone
}

export class State extends EventEmitter<StateEvents> {
	private _slices: SliceZone
	public set slices(slices: SliceZone) {
		this._slices = slices
		// Clean up message
		this.message = ""
		// Dispatch event
		this.emit(StateEventType.Slices, this.slices)
	}
	public get slices(): SliceZone {
		return window.parent !== window ? this._slices : []
	}

	private _activeSlice: ActiveSlice | null
	public set activeSlice(activeSlice: ActiveSlice | null) {
		this._activeSlice = activeSlice
		this.emit(StateEventType.ActiveSlice, this.activeSlice)
	}
	public get activeSlice(): ActiveSlice | null {
		return this._activeSlice
	}

	private _message: string
	public set message(message: string) {
		this._message = message
		this.emit(StateEventType.Message, this.message)
	}
	public get message(): string {
		return this._message
	}

	private _mouse: { x: number; y: number }

	constructor(args?: StateConstructorArgs) {
		super()

		this._slices = args?.slices || getDefaultSlices()
		this._activeSlice = null
		this._message = ""

		// StateManager needs to keep track of mouse position for the active slice
		this._mouse = { x: 0, y: 0 }
	}

	async init(): Promise<void> {
		// Init listener
		window.addEventListener("mousemove", (event) => {
			this._mouse = { x: event.clientX, y: event.clientY }
		})
	}

	private _setActiveSlice = (): void => {
		// There can't be an active slice if there's no slice displayed
		if (this.slices.length === 0) {
			this.activeSlice = null

			return
		}

		const $sliceZone = getSliceZoneDOM(this.slices.length)

		// SliceZone has not been found, therefore active slice cannot be found
		if (!$sliceZone) {
			this.activeSlice = null

			return
		}

		const $activeSlice = getActiveSliceDOM($sliceZone, this._mouse)

		// Active slice has not been found
		if (!$activeSlice) {
			this.activeSlice = null

			return
		}

		const activeSliceIndex = Array.prototype.indexOf.call($sliceZone.children, $activeSlice)

		// Active slice has been found
		this.activeSlice = {
			rect: $activeSlice.getBoundingClientRect(),
			sliceID: this.slices[activeSliceIndex].slice_type,
			variationID: (this.slices[activeSliceIndex] as SharedSlice).variation,
			index: activeSliceIndex,
		}
	}
	setActiveSlice = throttle(this._setActiveSlice, 16)

	setSliceZone(slices: SliceZone): void {
		// Set slices
		this.slices = slices
	}
}