import { pathUserData } from "../utils/UserDataUtils";
import { existsSync, readFileSync, unlinkSync, writeFileSync } from "fs";
import { AccountImage, AccountImageVisibilityLevel } from "../entities/AccountImage";

/**
 * Account image helper
 * 
 * @author Pierre HUBERT
 */

export class AccountImageHelper {

	/**
	 * Get information about the account image of a specific user ID
	 * 
	 * @param userID Target user ID
	 * @return The path to user image
	 */
	public static async Get(userID : number) : Promise<AccountImage> {
		
		const accountImageFileContent = this.GetFileAccountImage(userID);
		const level = this.GetVisibilityLevel(userID);

		return new AccountImage(userID, accountImageFileContent, level);
	}

	/**
	 * Set a new account image for a user
	 * 
	 * @param userID Target user ID
	 * @param path The path for the account image
	 */
	public static async Set(userID: number, path: string) {

		// First, delete any previous account image
		const currInfo = await this.Get(userID);
		if(currInfo.hasImage)
			unlinkSync(currInfo.sysPath);
		
		writeFileSync(this.GetPathMetadataFile(userID), path.replace("avatars/", ""));
	}

	/**
	 * Delete (remove) a user account image
	 * 
	 * @param userID Target user ID
	 */
	public static async Delete(userID: number) {
		const currInfo = await this.Get(userID);
		if(currInfo.hasImage) {
			unlinkSync(currInfo.sysPath);

			// Delete meta file
			unlinkSync(this.GetPathMetadataFile(userID));

			// Delete visiblity file (if any)
			const visibilityFile = this.GetPathVisibilityFile(userID);
			if(existsSync(visibilityFile))
				unlinkSync(visibilityFile);
		}
	}

	/**
	 * Change account image visiblity level
	 * 
	 * @param userID Target user ID
	 * @param level New level for account image
	 */
	public static async SetVisibilityLevel(userID: number, level: AccountImageVisibilityLevel) {
		const file = this.GetPathVisibilityFile(userID);

		// If the visiblity is set to everyone, we do not 
		// need to have a visibility file
		if(level == AccountImageVisibilityLevel.EVERYONE) {

			if(existsSync(file))
				unlinkSync(file);

			return;
		}

		else
			writeFileSync(file, level);
	}

	/**
	 * Get the content of the file associated to the user account image, if any
	 * 
	 * @param userID Target user ID
	 * @returns The content of the file
	 */
	private static GetFileAccountImage(userID: number) : string {
		const fileName = this.GetPathMetadataFile(userID);

		if(!existsSync(fileName))
			return "";
		
		return readFileSync(fileName, {encoding: "utf-8"});
		
	}

	/**
	 * Get the visibility leve of a user account image
	 * 
	 * @param userID Target user ID
	 */
	private static GetVisibilityLevel(userID: number) : AccountImageVisibilityLevel {
		const filePath = this.GetPathVisibilityFile(userID);

		if(!existsSync(filePath))
			return AccountImageVisibilityLevel.EVERYONE;
		
		return Number.parseInt(readFileSync(filePath, {encoding: "utf-8"}));
		
	}

	/**
	 * Get the path to the file that contains the path to user account image
	 * 
	 * @param userID Target user ID
	 */
	private static GetPathMetadataFile(userID: number) {
		return pathUserData("avatars/adresse_avatars/" + userID.toString() + ".txt", true);
	}

	/**
	 * Get the path to visibility file
	 * 
	 * @param userID Target user ID
	 */
	private static GetPathVisibilityFile(userID: number) {
		return pathUserData("avatars/adresse_avatars/limit_view_" + userID + ".txt", true);
	}
}