import { useEffect, useMemo, useRef, useState } from 'react'
import { useLocation, useSearchParams } from 'react-router-dom'

const DESIGNER_QUERY_KEY = 'design'

interface UseDesignerStateOptions {
	currentLanguage?: string
	supportedLanguages?: string[]
}

function serializeValue<T>(value: T | null | undefined) {
	if (value === undefined) {
		return '__undefined__'
	}

	if (value === null) {
		return '__null__'
	}

	try {
		return JSON.stringify(value)
	} catch {
		return '__unserializable__'
	}
}

function normalizeLanguageKey(language?: string) {
	if (!language) {
		return 'tr'
	}

	return language.toLowerCase().split('-')[0]
}

function cloneValue<T>(value: T): T {
	try {
		return JSON.parse(JSON.stringify(value)) as T
	} catch {
		return value
	}
}

export function useDesignerState<T>(
	pageKey: string,
	initialContent: T | null,
	options?: UseDesignerStateOptions,
) {
	const location = useLocation()
	const [searchParams] = useSearchParams()
	const isDesignMode =
		searchParams.get(DESIGNER_QUERY_KEY) === '1' || location.pathname.endsWith('/designer')
	const currentLanguage = normalizeLanguageKey(options?.currentLanguage)
	const supportedLanguages = useMemo(() => {
		const base = (options?.supportedLanguages ?? [currentLanguage]).map((language) =>
			normalizeLanguageKey(language),
		)
		if (!base.includes(currentLanguage)) {
			return [currentLanguage, ...base]
		}

		return Array.from(new Set(base))
	}, [currentLanguage, options?.supportedLanguages])

	const [selectedLanguage, setSelectedLanguage] = useState(currentLanguage)
	const [byLanguage, setByLanguage] = useState<Record<string, T>>({})
	const [selectedBlockId, setSelectedBlockId] = useState<string | null>(null)
	const seededDefaultsRef = useRef<Record<string, string>>({})

	const selectedLanguagePrefix = normalizeLanguageKey(selectedLanguage)
	const content =
		byLanguage[selectedLanguage] ??
		byLanguage[selectedLanguagePrefix] ??
		byLanguage[currentLanguage] ??
		initialContent ??
		null

	useEffect(() => {
		setSelectedLanguage(normalizeLanguageKey(currentLanguage))
	}, [currentLanguage])

	useEffect(() => {
		if (!initialContent) {
			return
		}

		const nextSerializedInitial = serializeValue(initialContent)

		setByLanguage((prev) => {
			const currentValue = prev[currentLanguage]
			const currentSerialized = serializeValue(currentValue)
			const previousSeed = seededDefaultsRef.current[currentLanguage]

			if (currentValue !== undefined && previousSeed !== undefined && currentSerialized !== previousSeed) {
				return prev
			}

			if (currentSerialized === nextSerializedInitial) {
				seededDefaultsRef.current[currentLanguage] = nextSerializedInitial
				return prev
			}

			seededDefaultsRef.current[currentLanguage] = nextSerializedInitial

			return {
				...prev,
				[currentLanguage]: cloneValue(initialContent),
			}
		})

		if (!isDesignMode && selectedBlockId !== null) {
			setSelectedBlockId(null)
		}
	}, [currentLanguage, initialContent, isDesignMode, selectedBlockId])

	useEffect(() => {
		if (!isDesignMode || !initialContent) {
			return
		}

		const normalizedSelectedLanguage = normalizeLanguageKey(selectedLanguage)
		const hasSelectedLanguageContent =
			byLanguage[normalizedSelectedLanguage] !== undefined ||
			byLanguage[selectedLanguage] !== undefined

		if (hasSelectedLanguageContent) {
			return
		}

		// If selected language has no saved value, initialize it from the current translated defaults.
		seededDefaultsRef.current[normalizedSelectedLanguage] = serializeValue(initialContent)
		setByLanguage((prev) => ({
			...prev,
			[normalizedSelectedLanguage]: cloneValue(initialContent),
		}))
	}, [byLanguage, initialContent, isDesignMode, selectedLanguage])

	const setContent = (updater: (current: T | null) => T | null) => {
		setByLanguage((prev) => {
			const current =
				prev[selectedLanguage] ??
				prev[normalizeLanguageKey(selectedLanguage)] ??
				prev[currentLanguage] ??
				initialContent ??
				null
			const next = updater(current)

			if (!next) {
				return prev
			}

			return {
				...prev,
				[normalizeLanguageKey(selectedLanguage)]: cloneValue(next),
			}
		})
	}

	const resetContent = () => {
		if (!initialContent) {
			return
		}

		const normalizedSelectedLanguage = normalizeLanguageKey(selectedLanguage)
		seededDefaultsRef.current[normalizedSelectedLanguage] = serializeValue(initialContent)

		setByLanguage((prev) => ({
			...prev,
			[normalizedSelectedLanguage]: cloneValue(initialContent),
		}))
	}

	return {
		content,
		isDesignMode,
		selectedBlockId,
		selectedLanguage,
		supportedLanguages,
		setContent,
		setSelectedBlockId,
		setSelectedLanguage,
		resetContent,
	}
}