import {Health, MeiliSearch, Stats} from "meilisearch";
import {dbLogger} from "./logger.js";

import config from "@/config/index.js";
import {Note} from "@/models/entities/note.js";
import * as url from "url";
import {ILocalUser, User} from "@/models/entities/user.js";
import {Followings, Users} from "@/models/index.js";

const logger = dbLogger.createSubLogger("meilisearch", "gray", false);

logger.info("Connecting to MeiliSearch");

const hasConfig =
	config.meilisearch &&
	(config.meilisearch.host ||
		config.meilisearch.port ||
		config.meilisearch.apiKey);

const host = hasConfig ? config.meilisearch.host ?? "localhost" : "";
const port = hasConfig ? config.meilisearch.port ?? 7700 : 0;
const auth = hasConfig ? config.meilisearch.apiKey ?? "" : "";
const ssl = hasConfig ? config.meilisearch.ssl ?? false : false;

const client: MeiliSearch = new MeiliSearch({
	host: `${ssl ? "https" : "http"}://${host}:${port}`,
	apiKey: auth,
});

const posts = client.index("posts");

posts
	.updateSearchableAttributes(["text"])
	.catch((e) =>
		logger.error(`Setting searchable attr failed, searches won't work: ${e}`),
	);

posts
	.updateFilterableAttributes([
		"userName",
		"userHost",
		"mediaAttachment",
		"createdAt",
		"userId",
	])
	.catch((e) =>
		logger.error(
			`Setting filterable attr failed, advanced searches won't work: ${e}`,
		),
	);

posts
	.updateSortableAttributes(["createdAt"])
	.catch((e) =>
		logger.error(
			`Setting sortable attr failed, placeholder searches won't sort properly: ${e}`,
		),
	);

logger.info("Connected to MeiliSearch");

export type MeilisearchNote = {
	id: string;
	text: string;
	userId: string;
	userHost: string;
	userName: string;
	channelId: string;
	mediaAttachment: string;
	createdAt: number;
};

export default hasConfig
	? {
		search: async (
			query: string,
			limit: number,
			offset: number,
			userCtx: ILocalUser | null,
		) => {
			/// Advanced search syntax
			/// from:user => filter by user + optional domain
			/// has:image/video/audio/text/file => filter by attachment types
			/// domain:domain.com => filter by domain
			/// before:Date => show posts made before Date
			/// after: Date => show posts made after Date
			/// "text" => get posts with exact text between quotes
			/// filter:following => show results only from users you follow
			/// filter:followers => show results only from followers

			let constructedFilters: string[] = [];

			let splitSearch = query.split(" ");

			// Detect search operators and remove them from the actual query
			let filteredSearchTerms = (
				await Promise.all(
					splitSearch.map(async (term) => {
						if (term.startsWith("has:")) {
							let fileType = term.slice(4);
							constructedFilters.push(`mediaAttachment = "${fileType}"`);
							return null;
						} else if (term.startsWith("from:")) {
							let user = term.slice(5);
							constructedFilters.push(`userName = ${user}`);
							return null;
						} else if (term.startsWith("domain:")) {
							let domain = term.slice(7);
							constructedFilters.push(`userHost = ${domain}`);
							return null;
						} else if (term.startsWith("after:")) {
							let timestamp = term.slice(6);
							// Try to parse the timestamp as JavaScript Date
							let date = Date.parse(timestamp);
							if (isNaN(date)) return null;
							constructedFilters.push(`createdAt > ${date / 1000}`);
							return null;
						} else if (term.startsWith("before:")) {
							let timestamp = term.slice(7);
							// Try to parse the timestamp as JavaScript Date
							let date = Date.parse(timestamp);
							if (isNaN(date)) return null;
							constructedFilters.push(`createdAt < ${date / 1000}`);
							return null;
						} else if (term.startsWith("filter:following")) {
							// Check if we got a context user
							if (userCtx) {
								// Fetch user follows from DB
								let followedUsers = await Followings.find({
									where: {
										followerId: userCtx.id,
									},
									select: {
										followeeId: true,
									},
								});
								let followIDs = followedUsers.map((user) => user.followeeId);

								if (followIDs.length === 0) return null;

								constructedFilters.push(`userId IN [${followIDs.join(",")}]`);
							} else {
								logger.warn(
									"search filtered to follows called without user context",
								);
							}

							return null;
						} else if (term.startsWith("filter:followers")) {
							// Check if we got a context user
							if (userCtx) {
								// Fetch users follows from DB
								let followedUsers = await Followings.find({
									where: {
										followeeId: userCtx.id,
									},
									select: {
										followerId: true,
									},
								});
								let followIDs = followedUsers.map((user) => user.followerId);

								if (followIDs.length === 0) return null;

								constructedFilters.push(`userId IN [${followIDs.join(",")}]`);
							} else {
								logger.warn(
									"search filtered to followers called without user context",
								);
							}

							return null;
						}

						return term;
					}),
				)
			).filter((term) => term !== null);

			let sortRules = [];

			// An empty search term with defined filters means we have a placeholder search => https://www.meilisearch.com/docs/reference/api/search#placeholder-search
			// These have to be ordered manually, otherwise the *oldest* posts are returned first, which we don't want
			if (filteredSearchTerms.length === 0 && constructedFilters.length > 0) {
				sortRules.push("createdAt:desc");
			}

			logger.info(`Searching for ${filteredSearchTerms.join(" ")}`);
			logger.info(`Limit: ${limit}`);
			logger.info(`Offset: ${offset}`);
			logger.info(`Filters: ${constructedFilters}`);
			logger.info(`Ordering: ${sortRules}`);

			return posts.search(filteredSearchTerms.join(" "), {
				limit: limit,
				offset: offset,
				filter: constructedFilters,
				sort: sortRules,
			});
		},
		ingestNote: async (ingestNotes: Note | Note[]) => {
			if (ingestNotes instanceof Note) {
				ingestNotes = [ingestNotes];
			}

			let indexingBatch: MeilisearchNote[] = [];

			for (let note of ingestNotes) {
				if (note.user === undefined) {
					note.user = await Users.findOne({
						where: {
							id: note.userId,
						},
					});
				}

				let attachmentType = "";
				if (note.attachedFileTypes.length > 0) {
					attachmentType = note.attachedFileTypes[0].split("/")[0];
					switch (attachmentType) {
						case "image":
						case "video":
						case "audio":
						case "text":
							break;
						default:
							attachmentType = "file";
							break;
					}
				}

				indexingBatch.push(<MeilisearchNote>{
					id: note.id.toString(),
					text: note.text ? note.text : "",
					userId: note.userId,
					userHost:
						note.userHost !== ""
							? note.userHost
							: url.parse(config.host).host,
					channelId: note.channelId ? note.channelId : "",
					mediaAttachment: attachmentType,
					userName: note.user?.username ?? "UNKNOWN",
					createdAt: note.createdAt.getTime() / 1000, // division by 1000 is necessary because Node returns in ms-accuracy
				});
			}

			return posts
				.addDocuments(indexingBatch, {
					primaryKey: "id",
				})
				.then(() =>
					console.log(`sent ${indexingBatch.length} posts for indexing`),
				);
		},
		serverStats: async () => {
			let health: Health = await client.health();
			let stats: Stats = await client.getStats();

			return {
				health: health.status,
				size: stats.databaseSize,
				indexed_count: stats.indexes["posts"].numberOfDocuments,
			};
		},
	}
	: null;