import { RequestHandler } from "../entities/RequestHandler";
import { ConversationsHelper } from "../helpers/ConversationsHelper";
import { Conversation, BaseConversation } from "../entities/Conversation";
import { UserHelper } from "../helpers/UserHelper";
import { removeHTMLNodes } from "../utils/StringUtils";
import { ConversationMessage } from "../entities/ConversationMessage";

/**
 * Conversations controller
 * 
 * @author Pierre HUBERT
 */

export class ConversationsController {

	/**
	 * Create a new conversation
	 * 
	 * @param h Request handler
	 */
	public static async CreateConversation(h : RequestHandler) {

		const name = h.postString("name");

		const members = h.postNumbersSet("users");
		
		// Check if the users exists
		for (const userID of members) {
			if(!await UserHelper.Exists(userID))
				h.error(404, "User " + userID + " not found!");
		}

		if(!members.has(h.getUserId()))
			members.add(h.getUserId());

		const conv : BaseConversation = {
			ownerID: h.getUserId(),
			name: name == "false" ? "" : removeHTMLNodes(name),
			following: h.postBool("follow"),
			members: members,
		}

		const convID = await ConversationsHelper.Create(conv);

		// Success
		h.send({
			conversationID: convID,
			success: "The conversation was successfully created!"
		})
	}

	/**
	 * Get the list of conversations of the user
	 * 
	 * @param handler 
	 */
	public static async GetList(handler: RequestHandler) {
		const list = await ConversationsHelper.GetListUser(handler.getUserId());
		handler.send(list.map(c => this.ConversationToAPI(c)));
	}

	/**
	 * Get information about a single conversation
	 * 
	 * @param handler 
	 */
	public static async GetInfoSingle(handler: RequestHandler) {
		const conversationID = await this.GetPostConversationId("conversationID", handler);
		const conv = await ConversationsHelper.GetSingle(conversationID, handler.getUserId());

		if(!conv)
			throw Error("Could not get information about the conversation (but it should have been found though) !!");
		
		handler.send(this.ConversationToAPI(conv));
	}

	/**
	 * Update conversation settings
	 * 
	 * @param h Request handler
	 */
	public static async UpdateSettings(h: RequestHandler) : Promise<void> {
		const convID = await this.GetPostConversationId("conversationID", h);

		// Update following state, if required
		if(h.hasPostParameter("following")) {
			await ConversationsHelper.SetFollowing(
				h.getUserId(),
				convID,
				h.postBool("following")
			);
		}
	
		// Change moderator settings
		if(h.hasPostParameter("members") || h.hasPostParameter("name")) {
			
			// Check if user is the moderator of the conversation
			if(!await ConversationsHelper.IsUserModerator(h.getUserId(), convID))
				h.error(401, "You are not allowed to perform changes on this conversation !");
			
			
			// Update conversation name (if required)
			if(h.hasPostParameter("name")) {
				const name = h.postString("name");
				await ConversationsHelper.SetName(convID, name == "false" ? "" : removeHTMLNodes(name));
			}

			// Update the list of members of the conversation (if required)
			if(h.hasPostParameter("members")) {
				const members = h.postNumbersSet("members");

				// Make sure current user is on the list
				if(!members.has(h.getUserId()))
					members.add(h.getUserId());
				
				await ConversationsHelper.SetMembers(convID, members);
			}

		}

		h.success("Conversation information successfully updated!");
	}

	/**
	 * Refresh current user conversations
	 * 
	 * @param h Request handler
	 */
	public static async RefreshList(h: RequestHandler) {

		const list = {};

		// Check for new conversations
		if(h.hasPostParameter("newConversations")) {
			for(const convID of h.postNumbersSet("newConversations", 0)) {
				if(!ConversationsHelper.DoesUsersBelongsTo(h.getUserId(), convID))
					h.error(401, "You are not allowed to fetch the messages of this conversation ("+convID+")!");
				
				list["conversation-" + convID] = (await ConversationsHelper.GetLastMessages(convID, 10))
					.map(e => this.ConversationMessageToAPI(e));
				
				// Mark the user has seen the messages
				await ConversationsHelper.MarkUserSeen(convID, h.getUserId());
			}
		}

		// Check for refresh on some conversations
		if(h.hasPostParameter("toRefresh")) {
			const toRefresh = h.postJSON("toRefresh");

			for (const key in toRefresh) {
				if (toRefresh.hasOwnProperty(key)) {
					const element = toRefresh[key];
					
					// Extract conversation ID
					if(!key.startsWith("conversation-"))
						h.error(400, "Entries of 'toRefresh' should start with 'conversation-' !");
					const convID = Number.parseInt(key.replace("conversation-", ""));

					// Extract last message ID
					if(!element.hasOwnProperty("last_message_id"))
						h.error(400, "Missing last_message_id for conversation " + convID + "!");
					const lastMessageID = Number.parseInt(element.last_message_id);

					// Check user rights
					if(!ConversationsHelper.DoesUsersBelongsTo(h.getUserId(), convID))
						h.error(401, "You are not allowed to fetch the messages of this conversation ("+convID+")!");
					
					// Get the messages
					list["conversation-" + convID] = (await ConversationsHelper.GetNewMessages(convID, lastMessageID))
						.map(e => this.ConversationMessageToAPI(e));

					// Mark the user has seen the messages
					await ConversationsHelper.MarkUserSeen(convID, h.getUserId());
				}
			}
		}

		h.send(list);
	}

	/**
	 * Refresh the messages of a single conversation
	 * 
	 * @param h Request handler
	 */
	public static async RefreshSingleConversation(h: RequestHandler) {
		const convID = await this.GetPostConversationId("conversationID", h);
		const lastMessageID = h.postInt("last_message_id");

		const messages = lastMessageID == 0 ?
			
			// Get lastest messages (the user has no message yet)
			await ConversationsHelper.GetLastMessages(convID, 10) :

			// Get new messages
			await ConversationsHelper.GetNewMessages(convID, lastMessageID);
		
		// Specify the user has seen the last message
		await ConversationsHelper.MarkUserSeen(convID, h.getUserId());

		h.send(h.send(messages.map(e => this.ConversationMessageToAPI(e)));
	}

	/**
	 * Get and return safely a conversation ID specified in a $_POST Request
	 * 
	 * @param name The name of the POST field containing the ID of the conversation
	 * @param handler
	 */
	private static async GetPostConversationId(name : string, handler: RequestHandler) : Promise<number> {
		const convID = handler.postInt(name);

		// Check out whether the user belongs to the conversation or not
		if(!await ConversationsHelper.DoesUsersBelongsTo(handler.getUserId(), convID))
			handler.error(401, "You are not allowed to perform queries on this conversation!");

		return convID;
	}

	/**
	 * Turn a conversation object into an API entry
	 * 
	 * @param c 
	 */
	private static ConversationToAPI(c : Conversation) : any {
		return {
			ID: c.id,
			ID_owner: c.ownerID,
			last_active: c.lastActive,
			name: c.name.length > 0 ? c.name : false,
			following: c.following ? 1 : 0,
			saw_last_message: c.sawLastMessage ? 1 : 0,
			members: [...c.members]
		};
	}

	/**
	 * Turn a conversation message into an API object
	 * 
	 * @param c Information about the conversation
	 */
	private static ConversationMessageToAPI(c: ConversationMessage) : any {
		return {
			ID: c.id,
			ID_user: c.userID,
			time_insert: c.timeSent,
			message: c.message,
			image_path: c.hasImage ? c.imageURL : null
		};
	}
}