"use client"

import { cn } from "@lib/utils"
import { Button } from "@ui/components/button"
import { UploadIcon } from "lucide-react"
import type { ReactNode } from "react"
import { createContext, useContext } from "react"
import type { DropEvent, DropzoneOptions, FileRejection } from "react-dropzone"
import { useDropzone } from "react-dropzone"

type DropzoneContextType = {
	src?: File[]
	accept?: DropzoneOptions["accept"]
	maxSize?: DropzoneOptions["maxSize"]
	minSize?: DropzoneOptions["minSize"]
	maxFiles?: DropzoneOptions["maxFiles"]
}

const renderBytes = (bytes: number) => {
	const units = ["B", "KB", "MB", "GB", "TB", "PB"]
	let size = bytes
	let unitIndex = 0

	while (size >= 1024 && unitIndex < units.length - 1) {
		size /= 1024
		unitIndex++
	}

	return `${size.toFixed(2)}${units[unitIndex]}`
}

const DropzoneContext = createContext<DropzoneContextType | undefined>(
	undefined,
)

export type DropzoneProps = Omit<DropzoneOptions, "onDrop"> & {
	src?: File[]
	className?: string
	onDrop?: (
		acceptedFiles: File[],
		fileRejections: FileRejection[],
		event: DropEvent,
	) => void
	children?: ReactNode
}

export const Dropzone = ({
	accept,
	maxFiles = 1,
	maxSize,
	minSize,
	onDrop,
	onError,
	disabled,
	src,
	className,
	children,
	...props
}: DropzoneProps) => {
	const { getRootProps, getInputProps, isDragActive } = useDropzone({
		accept,
		maxFiles,
		maxSize,
		minSize,
		onError,
		disabled,
		onDrop: (acceptedFiles, fileRejections, event) => {
			if (fileRejections.length > 0) {
				const message = fileRejections.at(0)?.errors.at(0)?.message
				onError?.(new Error(message))
				return
			}

			onDrop?.(acceptedFiles, fileRejections, event)
		},
		...props,
	})

	return (
		<DropzoneContext.Provider
			key={JSON.stringify(src)}
			value={{ src, accept, maxSize, minSize, maxFiles }}
		>
			<Button
				className={cn(
					"relative h-auto w-full flex-col overflow-hidden p-8 cursor-pointer",
					isDragActive && "outline-none ring-1 ring-ring",
					className,
				)}
				disabled={disabled}
				type="button"
				variant="outline"
				{...getRootProps()}
			>
				<input {...getInputProps()} disabled={disabled} />
				{children}
			</Button>
		</DropzoneContext.Provider>
	)
}

const useDropzoneContext = () => {
	const context = useContext(DropzoneContext)

	if (!context) {
		throw new Error("useDropzoneContext must be used within a Dropzone")
	}

	return context
}

export type DropzoneContentProps = {
	children?: ReactNode
	className?: string
}

const maxLabelItems = 1

export const DropzoneContent = ({
	children,
	className,
}: DropzoneContentProps) => {
	const { src } = useDropzoneContext()

	if (!src) {
		return null
	}

	if (children) {
		return children
	}

	return (
		<div className={cn("flex flex-col items-center justify-center", className)}>
			<div className="flex size-8 items-center justify-center rounded-md bg-muted text-muted-foreground">
				<UploadIcon size={16} />
			</div>
			<p className="my-2 w-full truncate font-medium text-sm">
				{src.length > maxLabelItems
					? `${new Intl.ListFormat("en").format(
							src.slice(0, maxLabelItems).map((file) => file.name),
						)} and ${src.length - maxLabelItems} more`
					: new Intl.ListFormat("en").format(src.map((file) => file.name))}
			</p>
			<p className="w-full text-wrap text-muted-foreground text-xs">
				Drag and drop or click to replace
			</p>
		</div>
	)
}

export type DropzoneEmptyStateProps = {
	children?: ReactNode
	className?: string
}

export const DropzoneEmptyState = ({
	children,
	className,
}: DropzoneEmptyStateProps) => {
	const { src, accept, maxSize, minSize, maxFiles } = useDropzoneContext()

	if (src) {
		return null
	}

	if (children) {
		return children
	}

	let caption = ""

	if (accept) {
		caption += "Accepts "
		caption += new Intl.ListFormat("en").format(Object.keys(accept))
	}

	if (minSize && maxSize) {
		caption += ` between ${renderBytes(minSize)} and ${renderBytes(maxSize)}`
	} else if (minSize) {
		caption += ` at least ${renderBytes(minSize)}`
	} else if (maxSize) {
		caption += ` less than ${renderBytes(maxSize)}`
	}

	return (
		<div className={cn("flex flex-col items-center justify-center", className)}>
			<div className="flex size-8 items-center justify-center rounded-md bg-muted text-muted-foreground">
				<UploadIcon size={16} />
			</div>
			<p className="my-2 w-full truncate text-wrap font-medium text-sm">
				Upload {maxFiles === 1 ? "a file" : "files"}
			</p>
			<p className="w-full truncate text-wrap text-muted-foreground text-xs">
				Drag and drop or click to upload
			</p>
			{caption && (
				<p className="text-wrap text-muted-foreground text-xs">{caption}.</p>
			)}
		</div>
	)
}