import type { LocationQuery } from 'vue-router'
import { MEDIA_PAGE_SIZE_KEY, resolvePageSize } from '@/lib/pageSizeMemory'

export type MediaFilter = 'all' | 'unused' | 'duplicates'
export type MediaSort = 'newest' | 'oldest' | 'name' | 'largest' | 'total_size'
export type MediaVariantsFilter = 'all' | 'with' | 'without'
export type MediaView = 'grid' | 'list'

export interface MediaControls {
	q: string
	filter: MediaFilter
	sort: MediaSort
	variants: MediaVariantsFilter
	view: MediaView
	page: number
	size: number
}

export const MEDIA_PAGE_SIZES = [5, 25, 50, 100]
export const DEFAULT_MEDIA_PAGE_SIZE = 25
export const MEDIA_FULL_SET_PAGE_SIZE = 100
const FIRST_PAGE = 1
const POSITIVE_INTEGER = /^[1-9]\d*$/

export const DEFAULT_CONTROLS: MediaControls = {
	q: '',
	filter: 'all',
	sort: 'newest',
	variants: 'all',
	view: 'grid',
	page: FIRST_PAGE,
	size: DEFAULT_MEDIA_PAGE_SIZE,
}

const FILTERS: MediaFilter[] = ['all', 'unused', 'duplicates']
const SORTS: MediaSort[] = ['newest', 'oldest', 'name', 'largest', 'total_size']
const VARIANTS_FILTERS: MediaVariantsFilter[] = ['all', 'with', 'without']
const VIEWS: MediaView[] = ['grid', 'list']

function firstValue(value: LocationQuery[string] | undefined) {
	return (Array.isArray(value) ? value[0] : value) ?? ''
}

function pick<T extends string>(allowed: T[], value: string, fallback: T) {
	return (allowed as string[]).includes(value) ? (value as T) : fallback
}

function parsePage(value: string) {
	return POSITIVE_INTEGER.test(value) ? Number(value) : FIRST_PAGE
}

function parseSize(value: LocationQuery[string] | undefined, useStoredSize: boolean) {
	const first = Array.isArray(value) ? value[0] : value
	const raw = first === null ? '' : first
	if (raw === undefined && !useStoredSize) {
		return DEFAULT_MEDIA_PAGE_SIZE
	}
	return resolvePageSize(raw, MEDIA_PAGE_SIZE_KEY, MEDIA_PAGE_SIZES, DEFAULT_MEDIA_PAGE_SIZE)
}

export function parseMediaControls(query: LocationQuery, useStoredSize = true): MediaControls {
	return {
		q: firstValue(query.q).trim(),
		filter: pick(FILTERS, firstValue(query.filter), DEFAULT_CONTROLS.filter),
		sort: pick(SORTS, firstValue(query.sort), DEFAULT_CONTROLS.sort),
		variants: pick(VARIANTS_FILTERS, firstValue(query.variants), DEFAULT_CONTROLS.variants),
		view: pick(VIEWS, firstValue(query.view), DEFAULT_CONTROLS.view),
		page: parsePage(firstValue(query.page)),
		size: parseSize(query.size, useStoredSize),
	}
}

export function isFullSet(controls: MediaControls) {
	return controls.filter === 'duplicates'
}

export function sameMediaControls(left: MediaControls, right: MediaControls) {
	const samePaging =
		(isFullSet(left) && isFullSet(right)) ||
		(left.page === right.page && left.size === right.size)
	return (
		left.q === right.q &&
		left.filter === right.filter &&
		left.sort === right.sort &&
		left.variants === right.variants &&
		left.view === right.view &&
		samePaging
	)
}

export function toRouteQuery(controls: MediaControls) {
	const query: Record<string, string> = {}
	if (!isFullSet(controls) && controls.page !== DEFAULT_CONTROLS.page) {
		query.page = String(controls.page)
	}
	if (!isFullSet(controls) && controls.size !== DEFAULT_CONTROLS.size) {
		query.size = String(controls.size)
	}
	if (controls.q) {
		query.q = controls.q
	}
	if (controls.filter !== DEFAULT_CONTROLS.filter) {
		query.filter = controls.filter
	}
	if (controls.sort !== DEFAULT_CONTROLS.sort) {
		query.sort = controls.sort
	}
	if (controls.variants !== DEFAULT_CONTROLS.variants) {
		query.variants = controls.variants
	}
	if (controls.view !== DEFAULT_CONTROLS.view) {
		query.view = controls.view
	}
	return query
}

export function toRequestQuery(controls: MediaControls) {
	const parts = [
		...(controls.q ? [`q=${encodeURIComponent(controls.q)}`] : []),
		`filter=${controls.filter}`,
		`sort=${controls.sort}`,
		...(controls.variants === 'all' ? [] : [`variants=${controls.variants}`]),
		`page=${controls.page}`,
		`size=${controls.size}`,
	]
	return parts.join('&')
}

export function toHashRequestQuery(hash: string) {
	return `hash=${hash}&page=${FIRST_PAGE}&size=${MEDIA_FULL_SET_PAGE_SIZE}`
}