import { onBeforeUnmount, ref } from 'vue'
import {
	useMediaPurge,
	type PurgeSettings,
	type PurgeSettingsPatch,
} from '@/composables/useMediaPurge'
import { isForbidden, isHandledGlobally } from '@/lib/mediaPurge'

export type CleanupLoadState = 'loading' | 'ready' | 'error'
export type SaveStatus = 'idle' | 'saving' | 'saved'
export type SaveFailure = 'enabled' | 'days'

const SKELETON_DELAY_MS = 150
const SAVED_VISIBLE_MS = 2000

export function useMediaCleanupSettings(onForbidden: () => void) {
	const { getSettings, updateSettings } = useMediaPurge()

	const settings = ref<PurgeSettings | null>(null)
	const loadState = ref<CleanupLoadState>('loading')
	const showSkeleton = ref(false)
	const saveStatus = ref<SaveStatus>('idle')
	const saveFailure = ref<SaveFailure | null>(null)
	let skeletonTimer: ReturnType<typeof setTimeout> | null = null
	let savedTimer: ReturnType<typeof setTimeout> | null = null
	let latestLoad = 0
	let pendingSaves = 0

	function clearSkeletonTimer() {
		if (skeletonTimer !== null) {
			clearTimeout(skeletonTimer)
			skeletonTimer = null
		}
	}

	function clearSavedTimer() {
		if (savedTimer !== null) {
			clearTimeout(savedTimer)
			savedTimer = null
		}
	}

	async function load() {
		latestLoad += 1
		const ticket = latestLoad
		loadState.value = 'loading'
		showSkeleton.value = false
		clearSkeletonTimer()
		skeletonTimer = setTimeout(() => {
			showSkeleton.value = true
		}, SKELETON_DELAY_MS)
		try {
			const loaded = await getSettings()
			if (ticket === latestLoad) {
				settings.value = loaded
				loadState.value = 'ready'
			}
		} catch (error) {
			if (ticket !== latestLoad) {
				return
			}
			if (isHandledGlobally(error)) {
				if (isForbidden(error)) {
					onForbidden()
				}
				return
			}
			loadState.value = 'error'
		} finally {
			if (ticket === latestLoad) {
				clearSkeletonTimer()
				showSkeleton.value = false
			}
		}
	}

	async function refresh() {
		try {
			settings.value = await getSettings()
		} catch (error) {
			if (isForbidden(error)) {
				onForbidden()
			}
		}
	}

	function finishSaving(succeeded: boolean) {
		if (pendingSaves > 0) {
			return
		}
		if (!succeeded) {
			saveStatus.value = 'idle'
			return
		}
		saveStatus.value = 'saved'
		savedTimer = setTimeout(() => {
			saveStatus.value = 'idle'
		}, SAVED_VISIBLE_MS)
	}

	async function save(patch: PurgeSettingsPatch, field: SaveFailure) {
		pendingSaves += 1
		clearSavedTimer()
		saveStatus.value = 'saving'
		let succeeded = false
		try {
			settings.value = await updateSettings(patch)
			saveFailure.value = null
			succeeded = true
		} catch (error) {
			if (isForbidden(error)) {
				onForbidden()
			} else if (!isHandledGlobally(error)) {
				saveFailure.value = field
			}
		} finally {
			pendingSaves -= 1
			finishSaving(succeeded)
		}
		return succeeded
	}

	onBeforeUnmount(() => {
		clearSkeletonTimer()
		clearSavedTimer()
	})

	return { settings, loadState, showSkeleton, saveStatus, saveFailure, load, refresh, save }
}