import type { APIFileComponent, APIUnfurledMediaItem } from "discord.js";
import { ComponentBuilder, ComponentType } from "discord.js";

/**
 * Builder for creating file components in Discord messages
 * File components must be used alone in an action row
 *
 * IMPORTANT: File URLs must use the `attachment://` protocol.
 * Use the `createAttachmentUrl()` helper to ensure correct URL format.
 */
export class V2FileBuilder extends ComponentBuilder<APIFileComponent> {
	private file!: APIUnfurledMediaItem;
	private spoiler?: boolean;

	constructor() {
		super({ type: ComponentType.File });
	}

	/**
	 * Sets the file data for this component
	 * @param file - The file data with url in `attachment://` format
	 * @throws {Error} If the file URL doesn't use the attachment:// protocol
	 */
	setFile(file: APIUnfurledMediaItem) {
		if (!file.url.startsWith("attachment://")) {
			throw new Error(
				"File URL must use the attachment:// protocol. Use createAttachmentUrl() helper.",
			);
		}
		this.file = file;
		return this;
	}

	/**
	 * Sets whether the file should be marked as a spoiler
	 * @param spoiler - Whether to mark as spoiler
	 */
	setSpoiler(spoiler: boolean) {
		this.spoiler = spoiler;
		return this;
	}

	/**
	 * Get the API-compatible JSON data for this component
	 */
	toJSON(): APIFileComponent {
		if (!this.file) {
			throw new Error("File data must be set using setFile()");
		}

		return {
			id: this.data.id,
			type: ComponentType.File,
			file: this.file,
			spoiler: this.spoiler ?? false,
		};
	}
}

/**
 * Creates a properly formatted attachment URL for Discord file components
 * @param filename - The name of the file to reference
 * @returns A properly formatted attachment URL
 */
export function createAttachmentUrl(filename: string): string {
	// Remove any leading 'attachment://' if present to avoid duplication
	const cleanFilename = filename.replace(/^attachment:\/\//, "");
	return `attachment://${cleanFilename}`;
}

/**
 * Helper function to create a file component
 * @param file - The file data (must use attachment:// protocol)
 * @param options - Optional configuration
 * @returns A new file component builder instance
 *
 * @example
 * ```typescript
 * // Correct usage with attachment protocol
 * const fileComponent = makeFile(
 *   { url: createAttachmentUrl('avatar.png') },
 *   { id: 123, spoiler: false }
 * );
 *
 * // When sending the message, provide the actual file:
 * channel.send({
 *   files: [
 *     { attachment: './path/to/avatar.png', name: 'avatar.png' }
 *   ],
 *   components: [new Discord.ActionRowBuilder().addComponents(fileComponent)]
 * });
 * ```
 */
export function makeFile(
	file: APIUnfurledMediaItem,
	options?: { id?: number; spoiler?: boolean },
): V2FileBuilder {
	const builder = new V2FileBuilder();
	builder.setFile(file);

	if (options?.id !== undefined) {
		builder.setId(options.id);
	}
	if (options?.spoiler !== undefined) {
		builder.setSpoiler(options.spoiler);
	}

	return builder;
}