comunicapiv2/src/helpers/PostsHelper.ts

import { PostKind, PostVisibilityLevel, Post, PostPageKind, PostFile, PostLink } from "../entities/Post";
import { FriendsHelper } from "./FriendsHelper";
import { DatabaseHelper } from "./DatabaseHelper";

/**
 * Posts helper
 * 
 * @author Pierre HUBERT
 */

/**
 * Table name
 */
const TABLE_NAME = "texte";

/**
 * Database mapping
 */
const PostDBTypes : Record<string, PostKind> = {
	"texte": PostKind.POST_KIND_IMAGE,
	"image": PostKind.POST_KIND_IMAGE,
	"webpage_link": PostKind.POST_KIND_WEBLINK,
	"pdf": PostKind.POST_KIND_PDF,
	"video": PostKind.POST_KIND_MOVIE,
	"count_down": PostKind.POST_KIND_COUNTDOWN,
	"sondage": PostKind.POST_KIND_SURVEY,
	"youtube": PostKind.POST_KIND_YOUTUBE
}

/**
 * Posts helper
 */
export class PostsHelper {

	/**
	 * Get the posts of a user
	 * 
	 * @param userID The ID of the user making the request
	 * @param targetID The ID of the target user
	 * @param startFrom Start point (0 = none)
	 * @param limit Maximum number of messages to fetch
	 */
	public static async GetUserPosts(userID: number, targetID: number, 
		startFrom: number = 0, limit: number = 10) : Promise<Array<Post>> {
		
		if(limit < 1) 
			throw Error("Limit of post query must be greater or equal to one!");

		
		// Determine max user visibility
		let level : PostVisibilityLevel = PostVisibilityLevel.VISIBILITY_PUBLIC;

		if(userID == targetID)
			level = PostVisibilityLevel.VISIBILITY_USER;
		
		else if(userID > 0 && await FriendsHelper.AreFriend(userID, targetID))
			level = PostVisibilityLevel.VISIBILITY_FRIENDS;
		
		

		// Preprocess conditions
		
		/// ============= PERMISSION CONDITIONS =================
		// Visibility level
		let customWhere = "((niveau_visibilite <= ?) ";
		let customWhereArgs =  [level.toString()];

		// Add user post (if user signed in)
		if(userID > 0) {
			customWhere += " OR (ID_amis = ?) ";
			customWhereArgs.push(userID.toString());
		}

		customWhere += ")"
		/// ============= /PERMISSION CONDITIONS ================



		// ============== START POINT CONDITION =================
		if(startFrom != 0) {
			customWhere += " AND ID <= ?";
			customWhereArgs.push(startFrom.toString());
		}
		// ============== /START POINT CONDITION ================



		// Perform the request
		const entries = await DatabaseHelper.Query({
			table: TABLE_NAME,
			
			// Base conditions
			where: {
				ID_personne: targetID,
				group_id: 0
			},

			customWhere: customWhere,
			customWhereArgs: customWhereArgs,

			order: "ID DESC",
			limit: limit,
		});

		return entries.map((r) => this.DBToPost(r));
	}

	/**
	 * Turn a database entry into a row object
	 * 
	 * @param row The database entry
	 */
	private static DBToPost(row: any) : Post {

		const postPageKind = row.group_id == 0 ? PostPageKind.PAGE_KIND_USER : PostPageKind.PAGE_KIND_GROUP;

		const postType = PostDBTypes[row.type];

		return new Post({
			// General info
			id: row.ID,
			userID: row.ID_amis == 0 ? row.ID_personne : row.ID_amis,


			// Kind of target of the page and its ID
			kindPage: postPageKind,
			pageID: postPageKind == PostPageKind.PAGE_KIND_USER ? row.ID_personne : row.group_id,

			// Basic info
			timeCreate: row.time_insert == null ? (new Date(row.date_envoi).getTime() / 1000) : row.time_insert,
			content: row.texte,
			visibilityLevel: row.niveau_visibilite,
			kind: postType,

			// Files specific
			file: row.path == null ? undefined : new PostFile({
				size: Number(row.size),
				type: row.file_type,
				path: row.path
			}),

			// Movies specific
			movieID: row.idvideo == null ? undefined : row.idvideo,

			// Coutdown timer specific
			timeEnd: (row.time_end && row.time_end) > 0 ? row.time_end

				// Coutdown legacy support
				: (row.annee_fin && row.annee_fin > 2010 ? new Date(row.annee_fin + "/" + row.mois_fin + "/" + row.jour_fin).getTime() / 1000 : undefined),

			
			// Weblink - specific
			link: row.url_page == null ? undefined :
				new PostLink({
					url: row.url_page,
					title: row.titre_page,
					description: row.description_page,
					image: row.image_page
				}), 
		});
	}
}