/*
 * decaffeinate suggestions:
 * DS101: Remove unnecessary use of Array.from
 * DS102: Remove unnecessary code created because of implicit returns
 * DS207: Consider shorter variations of null checks
 * Full docs: https://github.com/decaffeinate/decaffeinate/blob/master/docs/suggestions.md
 */
let RangesManager;
const RangesTracker = require("./RangesTracker");
const logger = require("logger-sharelatex");
const _ = require("lodash");

module.exports = (RangesManager = {
	MAX_COMMENTS: 500,
	MAX_CHANGES: 2000,

	applyUpdate(project_id, doc_id, entries, updates, newDocLines, callback) {
		let error;
		if (entries == null) { entries = {}; }
		if (updates == null) { updates = []; }
		if (callback == null) { callback = function(error, new_entries, ranges_were_collapsed) {}; }
		const {changes, comments} = _.cloneDeep(entries);
		const rangesTracker = new RangesTracker(changes, comments);
		const emptyRangeCountBefore = RangesManager._emptyRangesCount(rangesTracker);
		for (let update of Array.from(updates)) {
			rangesTracker.track_changes = !!update.meta.tc;
			if (!!update.meta.tc) {
				rangesTracker.setIdSeed(update.meta.tc);
			}
			for (let op of Array.from(update.op)) {
				try {
					rangesTracker.applyOp(op, { user_id: (update.meta != null ? update.meta.user_id : undefined) });
				} catch (error1) {
					error = error1;
					return callback(error);
				}
			}
		}
		
		if (((rangesTracker.changes != null ? rangesTracker.changes.length : undefined) > RangesManager.MAX_CHANGES) || ((rangesTracker.comments != null ? rangesTracker.comments.length : undefined) > RangesManager.MAX_COMMENTS)) {
			return callback(new Error("too many comments or tracked changes"));
		}

		try {
			// This is a consistency check that all of our ranges and
			// comments still match the corresponding text
			rangesTracker.validate(newDocLines.join("\n"));
		} catch (error2) {
			error = error2;
			logger.error({err: error, project_id, doc_id, newDocLines, updates}, "error validating ranges");
			return callback(error);
		}

		const emptyRangeCountAfter = RangesManager._emptyRangesCount(rangesTracker);
		const rangesWereCollapsed = emptyRangeCountAfter > emptyRangeCountBefore;
		const response = RangesManager._getRanges(rangesTracker);
		logger.log({project_id, doc_id, changesCount: (response.changes != null ? response.changes.length : undefined), commentsCount: (response.comments != null ? response.comments.length : undefined), rangesWereCollapsed}, "applied updates to ranges");
		return callback(null, response, rangesWereCollapsed);
	},

	acceptChanges(change_ids, ranges, callback) {
		if (callback == null) { callback = function(error, ranges) {}; }
		const {changes, comments} = ranges;
		logger.log(`accepting ${ change_ids.length } changes in ranges`);
		const rangesTracker = new RangesTracker(changes, comments);
		rangesTracker.removeChangeIds(change_ids);
		const response = RangesManager._getRanges(rangesTracker);
		return callback(null, response);
	},

	deleteComment(comment_id, ranges, callback) {
		if (callback == null) { callback = function(error, ranges) {}; }
		const {changes, comments} = ranges;
		logger.log({comment_id}, "deleting comment in ranges");
		const rangesTracker = new RangesTracker(changes, comments);
		rangesTracker.removeCommentId(comment_id);
		const response = RangesManager._getRanges(rangesTracker);
		return callback(null, response);
	},
	
	_getRanges(rangesTracker) {
		// Return the minimal data structure needed, since most documents won't have any
		// changes or comments
		let response = {};
		if ((rangesTracker.changes != null ? rangesTracker.changes.length : undefined) > 0) {
			if (response == null) { response = {}; }
			response.changes = rangesTracker.changes;
		}
		if ((rangesTracker.comments != null ? rangesTracker.comments.length : undefined) > 0) {
			if (response == null) { response = {}; }
			response.comments = rangesTracker.comments;
		}
		return response;
	},

	_emptyRangesCount(ranges) {
		let count = 0;
		for (let comment of Array.from((ranges.comments || []))) {
			if (comment.op.c === "") {
				count++;
			}
		}
		for (let change of Array.from((ranges.changes || []))) {
			if (change.op.i != null) {
				if (change.op.i === "") {
					count++;
				}
			}
		}
		return count;
	}
});