"use client"

import type { ImageFieldImage } from "@prismicio/client"
import { isFilled } from "@prismicio/client"
import type { ImgixURLParams } from "imgix-url-builder"
import { buildURL } from "imgix-url-builder"
import type { ImageProps } from "next/image"
import Image from "next/image"
import type { ForwardRefExoticComponent, PropsWithoutRef, RefAttributes } from "react"
import { forwardRef } from "react"

import { imgixLoader } from "./imgixLoader"
import { devMsg } from "./lib/devMsg"
import { resolveDefaultExport } from "./lib/resolveDefaultExport"

const castInt = (input: string | number | undefined): number | undefined => {
	if (typeof input === "number" || typeof input === "undefined") {
		return input
	} else {
		const parsed = Number.parseInt(input)

		if (Number.isNaN(parsed)) {
			return undefined
		} else {
			return parsed
		}
	}
}

export type PrismicNextImageProps = Omit<ImageProps, "src" | "alt" | "loader"> & {
	/** The Prismic Image field or thumbnail to render. */
	field: ImageFieldImage | null | undefined

	/**
	 * An object of Imgix URL API parameters to transform the image.
	 *
	 * @see https://docs.imgix.com/apis/rendering
	 */
	imgixParams?: { [P in keyof ImgixURLParams]: ImgixURLParams[P] | null }

	/**
	 * Declare an image as decorative by providing `alt=""`.
	 *
	 * See: https://developer.mozilla.org/en-US/docs/Web/API/HTMLImageElement/alt#decorative_images
	 */
	alt?: ""

	/**
	 * Declare an image as decorative only if the Image field does not have alternative text by
	 * providing `fallbackAlt=""`.
	 *
	 * See: https://developer.mozilla.org/en-US/docs/Web/API/HTMLImageElement/alt#decorative_images
	 */
	fallbackAlt?: ""

	/** Rendered when the field is empty. If a fallback is not given, `null` will be rendered. */
	fallback?: React.ReactNode

	loader?: ImageProps["loader"] | null
}

/**
 * React component that renders an image from a Prismic Image field or one of its thumbnails using
 * `next/image`. It will automatically set the `alt` attribute using the Image field's `alt`
 * property.
 *
 * It uses an Imgix URL-based loader by default. A custom loader can be provided with the `loader`
 * prop. If you would like to use the Next.js Image Optimization API instead, set
 * `loader={undefined}`.
 *
 * @param props - Props for the component.
 * @returns A responsive image component using `next/image` for the given Image
 * field.
 * @see To learn more about `next/image`, see: https://nextjs.org/docs/api-reference/next/image
 */
// The type annotation is necessary to avoid a type reference issue.
export const PrismicNextImage: ForwardRefExoticComponent<
	PropsWithoutRef<PrismicNextImageProps> & RefAttributes<HTMLImageElement>
> = forwardRef<HTMLImageElement, PrismicNextImageProps>(function PrismicNextImage(
	{
		field,
		imgixParams = {},
		alt,
		fallbackAlt,
		fill,
		width,
		height,
		fallback = null,
		loader = imgixLoader,
		...restProps
	},
	ref,
) {
	if (process.env.NODE_ENV === "development") {
		if (typeof alt === "string" && alt !== "") {
			console.warn(
				`[PrismicNextImage] The "alt" prop can only be used to declare an image as decorative by passing an empty string (alt="") but was provided a non-empty string. You can resolve this warning by removing the "alt" prop or changing it to alt="". For more details, see ${devMsg(
					"alt-must-be-an-empty-string",
				)}`,
			)
		}

		if (typeof fallbackAlt === "string" && fallbackAlt !== "") {
			console.warn(
				`[PrismicNextImage] The "fallbackAlt" prop can only be used to declare an image as decorative by passing an empty string (fallbackAlt="") but was provided a non-empty string. You can resolve this warning by removing the "fallbackAlt" prop or changing it to fallbackAlt="". For more details, see ${devMsg(
					"alt-must-be-an-empty-string",
				)}`,
			)
		}
	}

	if (!isFilled.imageThumbnail(field)) {
		return <>{fallback}</>
	}

	const resolvedImgixParams = imgixParams
	for (const x in imgixParams) {
		if (resolvedImgixParams[x as keyof typeof resolvedImgixParams] === null) {
			resolvedImgixParams[x as keyof typeof resolvedImgixParams] = undefined
		}
	}

	const src = buildURL(field.url, imgixParams as ImgixURLParams)

	const ar = field.dimensions.width / field.dimensions.height

	const castedWidth = castInt(width)
	const castedHeight = castInt(height)

	let resolvedWidth = castedWidth ?? field.dimensions.width
	let resolvedHeight = castedHeight ?? field.dimensions.height

	if (castedWidth != null && castedHeight == null) {
		resolvedHeight = castedWidth / ar
	} else if (castedWidth == null && castedHeight != null) {
		resolvedWidth = castedHeight * ar
	}

	// A non-null assertion is required since we can't statically
	// know if an alt attribute is available.
	const resolvedAlt = (alt ?? (field.alt || fallbackAlt))!

	if (process.env.NODE_ENV === "development" && typeof resolvedAlt !== "string") {
		console.error(
			`[PrismicNextImage] The following image is missing an "alt" property. Please add Alternative Text to the image in Prismic. To mark the image as decorative instead, add one of \`alt=""\` or \`fallbackAlt=""\`.`,
			src,
		)
	}

	const ResolvedImage = resolveDefaultExport(Image)

	return (
		<ResolvedImage
			ref={ref}
			src={src}
			width={fill ? undefined : resolvedWidth}
			height={fill ? undefined : resolvedHeight}
			alt={resolvedAlt}
			fill={fill}
			loader={loader === null ? undefined : loader}
			{...restProps}
		/>
	)
})