Implement groups visibility system

src/helpers/GroupsHelper.ts

@@ -1,4 +1,6 @@
 import { DatabaseHelper } from "./DatabaseHelper";
+import { GroupsAccessLevel, GroupVisibilityLevel } from "../entities/Group";
+import { GroupMembershipLevels } from "../entities/GroupMember";
 
 /**
  * Groups helper
@@ -11,6 +13,20 @@ const GROUPS_MEMBERS_TABLE = "comunic_groups_members";
 
 export class GroupsHelper {
 
+	/**
+	 * Check out whether a group exists or not
+	 * 
+	 * @param groupID Target group ID
+	 */
+	public static async Exists(groupID: number) : Promise<boolean> {
+		return await DatabaseHelper.Count({
+			table: GROUPS_LIST_TABLE,
+			where: {
+				id: groupID
+			}
+		}) > 0;
+	}
+
 	/**
 	 * Get the list of groups of a user
 	 * 
@@ -28,4 +44,86 @@ export class GroupsHelper {
 		return list.map(e => e.groups_id);
 	}
 
+	/**
+	 * Get the visibility level of a group
+	 * 
+	 * @param groupID Target group ID
+	 */
+	public static async GetVisibility(groupID: number) : Promise<GroupVisibilityLevel> {
+		const result = await DatabaseHelper.QueryRow({
+			table: GROUPS_LIST_TABLE,
+			where: {
+				id: groupID
+			},
+			fields: ["visibility"]
+		});
+
+		if(result == null)
+			throw Error("Group " + groupID + " does not exists!");
+		
+		return result.visibility;
+	}
+
+	/**
+	 * Get the membership level of a user for a group
+	 * 
+	 * @param groupID The ID of target group
+	 * @param userID The ID of target user
+	 */
+	public static async GetMembershipLevel(groupID: number, userID: number) : Promise<GroupMembershipLevels> {
+		const result = await DatabaseHelper.Query({
+			table: GROUPS_MEMBERS_TABLE,
+			where: {
+				groups_id: groupID,
+				user_id: userID
+			},
+			fields: ["level"]
+		});
+
+		// If user has no membership
+		if(result.length == 0)
+			return GroupMembershipLevels.VISITOR;
+		
+		return result[0].level;
+
+	}
+
+	/**
+	 * Get the current access of a user to a group
+	 * 
+	 * @param groupID The ID of the target group
+	 * @param userID The ID of the target user
+	 */
+	public static async GetAccessLevel(groupID: number, userID: number) : Promise<GroupsAccessLevel> {
+
+		const membershipLevel = 
+			userID > 0 ? await this.GetMembershipLevel(userID, groupID) : GroupMembershipLevels.VISITOR;
+		
+		//Check if the user is a confirmed member of group
+		if(membershipLevel == GroupMembershipLevels.ADMINISTRATOR)
+			return GroupsAccessLevel.ADMIN_ACCESS;
+		if(membershipLevel == GroupMembershipLevels.MODERATOR)
+			return GroupsAccessLevel.MODERATOR_ACCESS;
+		if(membershipLevel == GroupMembershipLevels.MEMBER)
+			return GroupsAccessLevel.MEMBER_ACCESS;
+		
+		const groupVisibilityLevel = await this.GetVisibility(groupID);
+
+		//If the group is open, everyone has view access
+		if(groupVisibilityLevel == GroupVisibilityLevel.OPEN_GROUP)
+			return GroupsAccessLevel.VIEW_ACCESS;
+		
+		//Else, all pending and invited membership get limited access
+		if(membershipLevel == GroupMembershipLevels.PENDING ||
+			membershipLevel == GroupMembershipLevels.INVITED)
+			return GroupsAccessLevel.LIMITED_ACCESS;
+		
+		//Private groups gives limited access
+		if(groupVisibilityLevel == GroupVisibilityLevel.PRIVATE_GROUP)
+			return GroupsAccessLevel.LIMITED_ACCESS;
+
+		// Else the user can not see the group
+		// Especially in the case of secret groupe
+		return GroupsAccessLevel.NO_ACCESS;
+	}
 }