import { RequestHandler } from "../entities/RequestHandler";
import { GroupsHelper, PATH_GROUPS_LOGOS } from "../helpers/GroupsHelper";
import { GroupsAccessLevel, GroupInfo, GroupVisibilityLevel, GroupPostsCreationLevel, GroupRegistrationLevel } from "../entities/Group";
import { GroupMembershipLevels, GroupMember } from "../entities/GroupMember";
import { time } from "../utils/DateUtils";
import { LikesHelper, LikesType } from "../helpers/LikesHelper";
import { GroupSettings } from "../entities/GroupSettings";
import { removeHTMLNodes, checkURL } from "../utils/StringUtils";
import { findKey } from "../utils/ArrayUtils";
import { checkVirtualDirectoryAvailability, VirtualDirType } from "../utils/VirtualDirsUtils";

/**
 * Groups API controller
 * 
 * @author Pierre HUBERT
 */

/**
 * API groups registration levels
 */
const GROUPS_REGISTRATION_LEVELS = {};
GROUPS_REGISTRATION_LEVELS[GroupRegistrationLevel.OPEN_REGISTRATION] = "open";
GROUPS_REGISTRATION_LEVELS[GroupRegistrationLevel.MODERATED_REGISTRATION] = "moderated";
GROUPS_REGISTRATION_LEVELS[GroupRegistrationLevel.CLOSED_REGISTRATION] = "closed";

/**
 * API groups membership levels
 */
const GROUPS_MEMBERSHIP_LEVELS = {};
GROUPS_MEMBERSHIP_LEVELS[GroupMembershipLevels.ADMINISTRATOR] = "administrator";
GROUPS_MEMBERSHIP_LEVELS[GroupMembershipLevels.MODERATOR] = "moderator";
GROUPS_MEMBERSHIP_LEVELS[GroupMembershipLevels.MEMBER] = "member";
GROUPS_MEMBERSHIP_LEVELS[GroupMembershipLevels.INVITED] = "invited";
GROUPS_MEMBERSHIP_LEVELS[GroupMembershipLevels.PENDING] = "pending";
GROUPS_MEMBERSHIP_LEVELS[GroupMembershipLevels.VISITOR] = "visitor";


/**
 * API groups visibility levels
 */
const GROUPS_VISIBILITY_LEVELS = {};
GROUPS_VISIBILITY_LEVELS[GroupVisibilityLevel.OPEN_GROUP] = "open";
GROUPS_VISIBILITY_LEVELS[GroupVisibilityLevel.PRIVATE_GROUP] = "private";
GROUPS_VISIBILITY_LEVELS[GroupVisibilityLevel.SECRETE_GROUP] = "secrete";


/**
 * API posts creation levels
 */
const GROUPS_POSTS_LEVELS = [];
GROUPS_POSTS_LEVELS[GroupPostsCreationLevel.POSTS_LEVEL_MODERATORS] = "moderators";
GROUPS_POSTS_LEVELS[GroupPostsCreationLevel.POSTS_LEVEL_ALL_MEMBERS] = "members";


export class GroupsController {

	/**
	 * Create a new group
	 * 
	 * @param h Request handler
	 */
	public static async Create(h: RequestHandler) {
		const name = h.postString("name", 3);

		const groupID = await GroupsHelper.Create({
			name: name,
			userID: h.getUserId(),
			timeCreate: time()
		});

		h.send({
			success: "The group has been successfully created!",
			id: groupID
		});
	}

	/**
	 * Get the list of groups of the user
	 * 
	 * @param h Request handler
	 */
	public static async GetListUser(h: RequestHandler) {
		h.send(await GroupsHelper.GetListUser(h.getUserId()));
	}

	/**
	 * Get information about a single group
	 * 
	 * @param h Request handler
	 */
	public static async GetInfoSingle(h: RequestHandler) {
		const groupID = await h.postGroupIDWithAccess("id", GroupsAccessLevel.LIMITED_ACCESS);
		const groupInfo = await GroupsHelper.GetInfo(groupID);
		
		h.send(await this.GroupInfoToAPI(groupInfo, h));
	}

	/**
	 * Get information about multiple users
	 * 
	 * @param h Request handler
	 */
	public static async GetInfoMultiple(h: RequestHandler) {
		const ids = h.postNumbersList("list");

		const result = {};

		for (const id of ids) {
			
			// Check group existence & user authorization
			if(!await GroupsHelper.Exists(id)
				|| await GroupsHelper.GetAccessLevel(id, h.getUserId()) < GroupsAccessLevel.LIMITED_ACCESS)
				h.error(404, "Group " + id + " not found");

			const group = await GroupsHelper.GetInfo(id);

			result[id] = await this.GroupInfoToAPI(group, h);
		}

		h.send(result);
	}

	/**
	 * Get advanced information about a group
	 * 
	 * @param h Request handler
	 */
	public static async GetAdvancedInfo(h: RequestHandler) {
		const groupID = await h.postGroupIDWithAccess("id", GroupsAccessLevel.VIEW_ACCESS);

		const group = await GroupsHelper.GetInfo(groupID);

		h.send(await this.GroupInfoToAPI(group, h, true));
	}

	/**
	 * Get group settings
	 * 
	 * @param h Request handler
	 */
	public static async GetSettings(h: RequestHandler) {
		const groupID = await h.postGroupIDWithAccess("id", GroupsAccessLevel.ADMIN_ACCESS);

		// For now, this method is the same as the get advanced info methods,
		// but this might change in the future...
		const group = await GroupsHelper.GetInfo(groupID);

		h.send(await this.GroupInfoToAPI(group, h, true));
	}

	/**
	 * Set (update) group settings
	 * 
	 * @param h Request handler
	 */
	public static async SetSettings(h: RequestHandler) {
		const groupID = await h.postGroupIDWithAccess("id", GroupsAccessLevel.ADMIN_ACCESS);

		// Check group visibility
		const visibilityKey = findKey(GROUPS_VISIBILITY_LEVELS, h.postString("visibility", 3));
		if(visibilityKey == null)
			h.error(400, "Group visibility level not recognized!");

		// Check group registration level
		const registrationKey = findKey(GROUPS_REGISTRATION_LEVELS, h.postString("registration_level", 3));
		if(registrationKey == null)
			h.error(400, "Group registration level not recognized!");

		// Check post creation level
		const postLevelKey = findKey(GROUPS_POSTS_LEVELS, h.postString("posts_level", 3));
		if(postLevelKey == null)
			h.error(400, "Group post creation level not recognized!");
		

		// Check URL
		const url = h.postString("url", 0);
		if(url.length > 0 && ! checkURL(url))
			h.error(401, "Invalid group URL!");


		// Check virtual directory
		let virtualDirectory = "";
		if(h.hasPostString("virtual_directory", 1)) {
			virtualDirectory = h.postVirtualDirectory("virtual_directory");

			// Check out whether virtual directory is available or not
			if(!await checkVirtualDirectoryAvailability(virtualDirectory, groupID, VirtualDirType.GROUP))
				h.error(401, "Requested virtual directory is not available!");
		}

		const settings = new GroupSettings({
			// Basic information
			id: groupID,
			name: removeHTMLNodes(h.postString("name", 3)),
			visiblity: <GroupVisibilityLevel>Number(visibilityKey),
			registrationLevel: <GroupRegistrationLevel>Number(registrationKey),
			postsCreationLevel: <GroupPostsCreationLevel>Number(postLevelKey),
			
			// Useless info
			membersCount: -1,
			timeCreate: -1,

			// Optionnal
			description: removeHTMLNodes(h.postString("description", 0)),
			
			// Optionnal
			url: url,

			// Optionnal
			virtualDirectory: virtualDirectory, 

		});

		await GroupsHelper.SetSettings(settings);

		h.success("Group settings have been successfully updated!");
	}

	/**
	 * Check the availability of a virtual directory for a given group
	 * 
	 * @param h Request handler
	 */
	public static async CheckVirtualDirectory(h: RequestHandler) {
		const groupID = await h.postGroupIDWithAccess("groupID", GroupsAccessLevel.ADMIN_ACCESS);
		const virtualDirectory = h.postVirtualDirectory("directory");

		if(!await checkVirtualDirectoryAvailability(virtualDirectory, groupID, VirtualDirType.GROUP))
			h.error(401, "The requested virtual directory seems not to be available!");
		
		h.success("Requested virtual directory seems to be available!");
	}

	/**
	 * Upload a new group logo
	 * 
	 * @param h Request handler
	 */
	public static async UploadLogo(h: RequestHandler) {
		const groupID = await h.postGroupIDWithAccess("id", GroupsAccessLevel.ADMIN_ACCESS);

		if(!h.hasFile("logo"))
			h.error(400, "An error occured while receiving logo !");

		// Delete current logo (if any)
		await GroupsHelper.DeleteLogo(groupID);

		// Save the new group logo
		const targetFilePath = await h.savePostImage("logo", PATH_GROUPS_LOGOS, 500, 500);

		// Update the settings of the group
		const settings = await GroupsHelper.GetInfo(groupID);
		settings.logo = targetFilePath;
		await GroupsHelper.SetSettings(settings);

		h.send({
			success: "Group logo has been successfully updated!",
			url: settings.logoURL
		});
	}

	/**
	 * Delete the current logo of a group
	 * 
	 * @param h Request handler
	 */
	public static async DeleteLogo(h: RequestHandler) {
		const groupID = await h.postGroupIDWithAccess("id", GroupsAccessLevel.ADMIN_ACCESS);

		await GroupsHelper.DeleteLogo(groupID);

		h.send({
			success: "Group logo has been successfully deleted!",
			url: (await GroupsHelper.GetInfo(groupID)).logoURL
		})
	}

	/**
	 * Get the entire list of members of the group
	 * 
	 * @param h Request handler
	 */
	public static async GetMembers(h: RequestHandler) {
		const groupID = await h.postGroupIDWithAccess("id", GroupsAccessLevel.MODERATOR_ACCESS);

		const members = await GroupsHelper.GetListMembers(groupID);

		// Parse the list of members
		h.send(members.map((m) => this.GroupMemberToAPI(m)));
	}

	/**
	 * Invite a user to join the network
	 * 
	 * @param h Request handler
	 */
	public static async InviteUser(h: RequestHandler) {
		const groupID = await h.postGroupIDWithAccess("group_id", GroupsAccessLevel.MODERATOR_ACCESS);
		const userID = await h.postUserId("userID");

		if(!await GroupsHelper.GetMembershipLevel(groupID, userID))
			h.error(401, "The user is not a visitor of the group!");
		
		await GroupsHelper.SendInvitation(groupID, userID);

		// TODO : Create a notification

		h.success("The user has been successfully invited to join the group!");
	}

	/**
	 * Respond to a user invitation
	 * 
	 * @param h Request handler
	 */
	public static async RespondInvitation(h: RequestHandler) {
		const groupID = await h.postGroupIDWithAccess("id", GroupsAccessLevel.LIMITED_ACCESS);
		const accept = h.postBool("accept");

		// Check if the user really received an invitation to join the group
		if(!await GroupsHelper.ReceivedInvitation(groupID, h.getUserId()))
			h.error(404, "Invitation not found!");
		
		// Respond to the invitation
		await GroupsHelper.RespondInvitation(groupID, h.getUserId(), accept);

		// TODO : Create a notification

		h.success("Response to the invitation was successfully saved!");
	}

	/**
	 * Send a request to join a server
	 * 
	 * @param h Request handler
	 */
	public static async SendRequest(h: RequestHandler) {

		const groupID = await h.postGroupIDWithAccess("id", GroupsAccessLevel.LIMITED_ACCESS);

		// Check the user is really a visitor of the group
		if(await GroupsHelper.GetMembershipLevel(groupID, h.getUserId()) != GroupMembershipLevels.VISITOR)
			h.error(401, "You are not currently a visitor of the group!");

		
		// Check the user is allowed to send a request to join the group
		const group = await GroupsHelper.GetInfo(groupID);
		if(group.registrationLevel == GroupRegistrationLevel.CLOSED_REGISTRATION)
			h.error(401, "You are not authorized to send a registration request for this group!");
		
		// Create & insert membership
		const member = new GroupMember({
			id: -1,
			userID: h.getUserId(),
			timeCreate: time(),
			groupID: groupID,
			level: group.registrationLevel == GroupRegistrationLevel.MODERATED_REGISTRATION
				 ? GroupMembershipLevels.PENDING : GroupMembershipLevels.MEMBER,
			following: true,
		});

		await GroupsHelper.InsertMember(member);

		if(group.registrationLevel == GroupRegistrationLevel.MODERATED_REGISTRATION) {
			//TODO : Send a notification
		}

		h.success("The membership has been successfully saved!");
	}

	/**
	 * Cancel a membership request
	 * 
	 * @param h Request handler
	 */
	public static async CancelRequest(h: RequestHandler) {
		const groupID = await h.postGroupIDWithAccess("id", GroupsAccessLevel.LIMITED_ACCESS);

		if(await GroupsHelper.GetMembershipLevel(groupID, h.getUserId()) != GroupMembershipLevels.PENDING)
			h.error(401, "You did not send a membership request to this group!");
		
		// Delete membership of the user
		await GroupsHelper.DeleteMember(groupID, h.getUserId());

		// TODO : delete any potential notificaton

		h.success("The request has been successfully cancelled!");
	}

	/**
	 * Delete a member from a group (as a moderator or an admin)
	 * 
	 * @param h Request handler
	 */
	public static async DeleteMember(h: RequestHandler) {
		const groupID = await h.postGroupIDWithAccess("groupID", GroupsAccessLevel.MODERATOR_ACCESS);
		
		// Get the membership of the user making the request
		const currUserMembership = await GroupsHelper.GetMembershipInfo(groupID, h.getUserId());

		// Get the ID of the member to delete
		const userID = await h.postUserId("userID");
		const membership = await GroupsHelper.GetMembershipInfo(groupID, userID);

		if(membership == null)
			h.error(404, "Membership not found!");

		// If the user is an admin, he must not be the last admin of the group
		if(userID == h.getUserId() && currUserMembership.level == GroupMembershipLevels.ADMINISTRATOR
			&& await GroupsHelper.CountMembersAtLevel(groupID, GroupMembershipLevels.ADMINISTRATOR) == 1)
			h.error(401, "You are the last administrator of this group!");
		
		
		// Only administrator can delete members that are more than member (moderators & administrators)
		if(membership.level < GroupMembershipLevels.MEMBER && currUserMembership.level != GroupMembershipLevels.ADMINISTRATOR)
			h.error(401, "Only an administrator can delete this membership!");
		
		// Delete the membership
		await GroupsHelper.DeleteMember(groupID, userID);

		// TODO : delete any group membership notifications

		h.success("Membership of the user has been successfully deleted!");
	}

	/**
	 * Update a user membership
	 * 
	 * @param h Request handler
	 */
	public static async UpdateMembership(h: RequestHandler) {
		
		// Get information about the target
		const groupID = await h.postGroupIDWithAccess("groupID", GroupsAccessLevel.ADMIN_ACCESS);
		const userID = await h.postUserId("userID");

		if(userID == h.getUserId())
			h.error(400, "You can not update your own membership!");
		
		// Get current user membership
		const level = await GroupsHelper.GetMembershipLevel(groupID, userID);
		
		// Check if user is at least a member of the group
		if(level > GroupMembershipLevels.MEMBER)
			h.error(401, "This user is not a member of the group!");
		
		// Get the new membership of the user
		const membershipKey = findKey(GROUPS_MEMBERSHIP_LEVELS, h.postString("level", 3));
		if(membershipKey == null)
			h.error(400, "New user membership level not recognized!");
		const newLevel = <GroupMembershipLevels>Number(membershipKey);
		
		if(newLevel > GroupMembershipLevels.MEMBER)
			h.error(401, "You can not assign this visibility level to a group member!");
		
		await GroupsHelper.UpdateMembershipLevel(groupID, userID, newLevel);

		h.success("User membership has been successfully updated!");
	}

	/**
	 * Respond to a membership request
	 * 
	 * @param h Request handler
	 */
	public static async RespondRequest(h: RequestHandler) {
		const groupID = await h.postGroupIDWithAccess("groupID", GroupsAccessLevel.MODERATOR_ACCESS);
		const userID = await h.postUserId("userID");
		const accept = h.postBool("accept");

		if(await GroupsHelper.GetMembershipLevel(groupID, userID) != GroupMembershipLevels.PENDING)
			h.error(401, "This user has not requested a membership for this group!");
		
		// Respond to the request
		await GroupsHelper.RespondRequest(groupID, userID, accept);

		// TODO : create a notification

		h.success("The response to the request has been successfully saved!");
	}

	/**
	 * Get information about a single membership
	 * 
	 * @param h Request handler
	 */
	public static async GetMembership(h: RequestHandler) {
		const groupID = await h.postGroupIDWithAccess("groupID", GroupsAccessLevel.MODERATOR_ACCESS);
		const userID = await h.postUserId("userID");

		const membership = await GroupsHelper.GetMembershipInfo(groupID, userID);

		if(membership == null)
			h.error(404, "Specified user does not have any membership in this group!");
		
		h.send(this.GroupMemberToAPI(membership));
	}

	/**
	 * Cancel a group membership invitation
	 * 
	 * @param h Request handler
	 */
	public static async CancelInvitation(h: RequestHandler) {
		const groupID = await h.postGroupIDWithAccess("groupID", GroupsAccessLevel.MODERATOR_ACCESS);
		const userID = await h.postUserId("userID");

		if(await GroupsHelper.GetMembershipLevel(groupID, userID) != GroupMembershipLevels.INVITED)
			h.error(401, "This user has not been invited to join this group!");
		
		// Cancel group invitation
		await GroupsHelper.DeleteMember(groupID, userID);

		// TODO : delete related notifications

		h.success("Membership invitation has been cancelled!");
	}

	/**
	 * Delete the membership of a user to a group
	 * 
	 * @param h Request handler
	 */
	public static async RemoveMembership(h: RequestHandler) {
		const groupID = await h.postGroupIDWithAccess("id", GroupsAccessLevel.LIMITED_ACCESS);
		const level = await GroupsHelper.GetMembershipLevel(groupID, h.getUserId());

		if(level == GroupMembershipLevels.ADMINISTRATOR
			&& await GroupsHelper.CountMembersAtLevel(groupID, GroupMembershipLevels.ADMINISTRATOR) == 1)
			h.error(401, "You are the last administrator of the group!");
		
		// Delete mebmership
		await GroupsHelper.DeleteMember(groupID, h.getUserId());

		// TODO : delete group membership notifications

		h.success("Your membership has been successfully deleted!");
	}


	/**
	 * Update the following status of a user
	 * 
	 * @param h Request handler
	 */
	public static async SetFollowing(h: RequestHandler) {
		const groupID = await h.postGroupIDWithAccess("groupID", GroupsAccessLevel.MEMBER_ACCESS);
		const following = h.postBool("follow");

		await GroupsHelper.SetFollowing(groupID, h.getUserId(), following);

		h.success("Follow status has been successfully updated!");
	}

	/**
	 * Turn a GroupInfo object into a valid API object
	 * 
	 * @param info Information about the group
	 * @param h Request handler
	 * @param advanced Specify whether advanced information should be returned
	 * in the request or not
	 * @returns Generated object
	 */
	private static async GroupInfoToAPI(info: GroupInfo, h: RequestHandler, advanced: boolean = false) : Promise<any> {
		
		const membership = await GroupsHelper.GetMembershipInfo(info.id, h.optionnalUserID)
		
		const data = {
			id: info.id,
			name: info.name,
			icon_url: info.logoURL,
			number_members: info.membersCount,
			visibility: GROUPS_VISIBILITY_LEVELS[info.visiblity],
			registration_level: GROUPS_REGISTRATION_LEVELS[info.registrationLevel],
			posts_level: GROUPS_POSTS_LEVELS[info.postsCreationLevel],
			virtual_directory: info.virtualDirectory ? info.virtualDirectory : "null",

			membership: GROUPS_MEMBERSHIP_LEVELS[membership ? membership.level : GroupMembershipLevels.VISITOR],
			following: membership ? membership.following : false
		}

		if(advanced) {
			data["time_create"] = info.timeCreate;
			data["description"] = info.hasDescription ? info.description : "null";
			data["url"] = info.url ? info.hasURL : "null";

			data["number_likes"] = await LikesHelper.Count(info.id, LikesType.GROUP);
			data["is_liking"] = h.signedIn ? await LikesHelper.IsLiking(h.getUserId(), info.id, LikesType.GROUP) : false;
		}

		return data;
	}

	/**
	 * Convert a {GroupMember} object into an API entry
	 * 
	 * @param m Group Member to transform
	 */
	private static GroupMemberToAPI(m: GroupMember) : Object {
		return {
			user_id: m.userID,
			group_id: m.groupID,
			time_create: m.timeCreate,
			level: GROUPS_MEMBERSHIP_LEVELS[m.level]
		};
	}
}