"use strict";

const k_posts_max = 20;
const k_votes_max = 20;

var g_ready = false;
var g_selected = null;

var g_following_cache = {};
var g_following_deep_cache = {};
var g_stats = {};
var g_sequence = {};

async function following(db, id) {
	if (g_following_cache[id]) {
		return g_following_cache[id];
	}
	var o = await db.get(id + ":following");
	const k_version = 5;
	var f = o ? JSON.parse(o) : o;
	if (!f || f.version != k_version) {
		f = {users: [], sequence: 0, version: k_version};
	}
	f.users = new Set(f.users);
	await ssb.sqlStream(
		"SELECT "+
		"  sequence, "+
		"  json_extract(content, '$.contact') AS contact, "+
		"  json_extract(content, '$.following') AS following "+
		"FROM messages "+
		"WHERE "+
		"  author = ?1 AND "+
		"  sequence > ?2 AND "+
		"  json_extract(content, '$.type') = 'contact' "+
		"UNION SELECT MAX(sequence) AS sequence, NULL, NULL FROM messages WHERE author = ?1 "+
		"ORDER BY sequence",
		[id, f.sequence],
		function(row) {
			if (row.following) {
				f.users.add(row.contact);
			} else {
				f.users.delete(row.contact);
			}
			f.sequence = row.sequence;
			g_sequence[id] = row.sequence;
		});
	var as_set = f.users;
	f.users = Array.from(f.users).sort();
	var j = JSON.stringify(f);
	if (o != j) {
		await db.set(id + ":following", j);
	}
	f.users = as_set;
	g_following_cache[id] = f.users;
	return f.users;
}

async function followingDeep(db, seed_ids, depth) {
	if (depth <= 0) {
		return seed_ids;
	}
	var key = JSON.stringify([seed_ids, depth]);
	if (g_following_deep_cache[key]) {
		return g_following_deep_cache[key];
	}
	var f = await Promise.all(seed_ids.map(x => following(db, x).then(x => [...x])));
	var ids = [].concat(...f);
	var x = await followingDeep(db, [...new Set(ids)].sort(), depth - 1);
	x = [...new Set([].concat(...x, ...seed_ids))].sort();
	g_following_deep_cache[key] = x;
	return x;
}

async function getAbout(db, id) {
	var o = await db.get(id + ":about");
	const k_version = 4;
	var f = o ? JSON.parse(o) : o;
	if (!f || f.version != k_version) {
		f = {about: {}, sequence: 0, version: k_version};
	}
	if (g_sequence[id] > f.sequence) {
		await ssb.sqlStream(
			"SELECT "+
			"  sequence, "+
			"  content "+
			"FROM messages "+
			"WHERE "+
			"  author = ?1 AND "+
			"  sequence > ?2 AND "+
			"  json_extract(content, '$.type') = 'about' AND "+
			"  json_extract(content, '$.about') = ?1 "+
			"UNION SELECT MAX(sequence) as sequence, NULL FROM messages WHERE author = ?1 "+
			"ORDER BY sequence",
			[id, f.sequence],
			function(row) {
				g_stats.rows_read = (g_stats.rows_read || 0) + 1;
				f.sequence = row.sequence;
				if (row.content) {
					var about = {};
					try {
						about = JSON.parse(row.content);
					} catch {
					}
					delete about.about;
					delete about.type;
					f.about = Object.assign(f.about, about);
				}
			});
	}
	var j = JSON.stringify(f);
	if (o != j) {
		g_stats.rows_written = (g_stats.rows_written || 0) + 1;
		await db.set(id + ":about", j);
	}
	return f.about;
}

function fnv32a(value)
{
	var result = 0x811c9dc5;
	for (var i = 0; i < value.length; i++) {
		result ^= value.charCodeAt(i);
		result += (result << 1) + (result << 4) + (result << 7) + (result << 8) + (result << 24);
	}
	return result >>> 0;
}

async function getRecentPostsSingleId(db, id, limit) {
	var recent = [];
	await ssb.sqlStream(
		"SELECT "+
		"  rowid, "+
		"  id, "+
		"  timestamp "+
		"FROM messages "+
		"WHERE "+
		"  author = ? AND "+
		"  json_extract(content, '$.type') = 'post' "+
		"ORDER BY sequence DESC LIMIT ?",
		[id, limit],
		function(row) {
			if (row.id) {
				recent.push({id: row.id, timestamp: row.timestamp});
			}
		});
	recent.sort((x, y) => y.timestamp - x.timestamp);
	return recent.map(x => x.id);
}

async function getRecentPostIds(db, id, ids, limit) {
	if (ids.length == 1) {
		return await getRecentPostsSingleId(db, ids[0], limit);
	}
	const k_version = 11;
	const k_batch_max = 16;
	var o = await db.get(id + ':recent_posts');
	var recent = [];
	var f = o ? JSON.parse(o) : o;
	var ids_hash = fnv32a(JSON.stringify(ids));
	if (!f || f.version != k_version || f.ids_hash != ids_hash) {
		f = {recent: [], rowid: 0, version: k_version, ids_hash: ids_hash};
	}
	var row_id_max = 0;
	await ssb.sqlStream(
		"SELECT MAX(rowid) as rowid FROM messages",
		[],
		function(row) {
			row_id_max = row.rowid;
		});
	for (var i = 0; i < ids.length; i += k_batch_max) {
		var ids_batch = ids.slice(i, Math.min(i + k_batch_max, ids.length));
		await ssb.sqlStream(
			"SELECT "+
			"  rowid, "+
			"  id, "+
			"  timestamp "+
			"FROM messages "+
			"WHERE "+
			"  rowid > ? AND "+
			"  rowid <= ? AND "+
			"  author IN (" + ids_batch.map(x => '?').join(", ") + ") AND "+
			"  json_extract(content, '$.type') = 'post' "+
			"ORDER BY timestamp DESC LIMIT ?",
			[].concat([f.rowid, row_id_max], ids_batch, [limit]),
			function(row) {
				if (row.id) {
					recent.push({id: row.id, timestamp: row.timestamp});
				}
			});
	}
	f.rowid = row_id_max;
	f.recent = [].concat(recent, f.recent);
	var have = {};
	f.recent = f.recent.filter(function(x) {
		if (!have[x.id]) {
			have[x.id] = true;
			return true;
		}
	});
	f.recent.sort((x, y) => y.timestamp - x.timestamp);
	f.recent = f.recent.slice(0, limit);
	var j = JSON.stringify(f);
	if (o != j) {
		await db.set(id + ":recent_posts", j);
	}
	return f.recent.map(x => x.id);
}

async function getRelatedPostIds(db, message, ids, limit) {
	const k_batch_max = 16;
	var recent = [];
	var row_id_max = 0;
	await ssb.sqlStream(
		"SELECT MAX(rowid) as rowid FROM messages",
		[],
		function(row) {
			row_id_max = row.rowid;
		});
	var id = message.id;
	try {
		id = JSON.parse(message.content).root || id;
	} catch {
	}
	for (var i = 0; i < ids.length; i += k_batch_max) {
		var ids_batch = ids.slice(i, Math.min(i + k_batch_max, ids.length));
		await ssb.sqlStream(
			"SELECT "+
			"  rowid, "+
			"  id, "+
			"  timestamp "+
			"FROM messages "+
			"WHERE "+
			"  timestamp >= ? AND "+
			"  rowid <= ? AND "+
			"  author IN (" + ids_batch.map(x => '?').join(", ") + ") AND "+
			"  json_extract(content, '$.type') = 'post' AND "+
			"  (id = ? OR json_extract(content, '$.root') = ?) "+
			"ORDER BY timestamp DESC LIMIT ?",
			[].concat([message.timestamp || 0, row_id_max], ids_batch, [message.id, id, limit]),
			function(row) {
				if (row.id) {
					recent.push({id: row.id, timestamp: row.timestamp});
				}
			});
	}
	recent.sort((x, y) => y.timestamp - x.timestamp);
	recent = recent.slice(0, limit);
	return recent.map(x => x.id);
}

async function getVotes(db, id) {
	var o = await db.get(id + ":votes");
	const k_version = 7;
	var votes = [];
	var f = o ? JSON.parse(o) : o;
	if (!f || f.version != k_version) {
		f = {votes: [], sequence: 0, version: k_version};
	}
	if (g_sequence[id] > f.sequence) {
		await ssb.sqlStream(
			"SELECT "+
			"  author, "+
			"  id, "+
			"  sequence, "+
			"  timestamp, "+
			"  content "+
			"FROM messages "+
			"WHERE "+
			"  author = ? AND "+
			"  sequence > ? AND "+
			"  json_extract(content, '$.type') = 'vote' "+
			"UNION SELECT NULL, NULL, MAX(sequence), NULL, NULL FROM messages WHERE author = ? "+
			"ORDER BY sequence DESC LIMIT ?",
			[f.sequence, id, id, k_votes_max],
			function(row) {
				if (row.id) {
					votes.push(row);
				}
				f.sequence = Math.max(f.sequence, row.sequence);
			});
	}
	f.votes = [].concat(votes, f.votes).slice(0, k_votes_max);
	var j = JSON.stringify(f);
	if (o != j) {
		await db.set(id + ":votes", j);
	}
	return f.votes;
}

async function getPosts(db, ids) {
	var posts = [];
	if (ids.length) {
		await ssb.sqlStream(
			"SELECT rowid, * FROM messages WHERE id IN (" + ids.map(x => "?").join(", ") + ") ORDER BY timestamp DESC",
			ids,
			row => posts.push(row));
	}
	return posts;
}

async function ready() {
	g_ready = true;
	return refresh(g_selected);
}

ssb.addEventListener('broadcasts', async function() {
	await app.postMessage({broadcasts: await ssb.getBroadcasts()});
});

core.register('onConnectionsChanged', async function() {
	var connections = await ssb.connections();
	await app.postMessage({connections: connections});
});

async function refresh(selected) {
	var timing = [];
	timing.push({name: 'start', time: new Date()});
	g_following_cache = {};
	g_following_deep_cache = {};
	g_sequence = {};
	await app.postMessage({clear: true});
	var whoami = await ssb.whoami();
	var db = await database("ssb");
	timing.push({name: 'init', time: new Date()});
	var all_followed = await followingDeep(db, [whoami], 2);
	timing.push({name: 'all_followed', time: new Date()});
	if (selected) {
		g_selected = selected;
	} else {
		g_selected = all_followed;
	}
	await Promise.all([
		app.postMessage({whoami: whoami}),
		app.postMessage({hash: selected && selected.length == 1 ? selected[0] : null}),
		ssb.getBroadcasts().then(broadcasts => app.postMessage({broadcasts: broadcasts})),
		ssb.connections().then(connections => app.postMessage({connections: connections})),
		core.apps().then(apps => app.postMessage({apps: apps})),
	]);
	timing.push({name: 'core', time: new Date()});
	var ids;
	if (selected && selected.length == 1 && selected[0].startsWith('%')) {
		var m = await getPosts(db, selected);
		m = m.length ? m[0] : {id: selected[0]};
		ids = await getRelatedPostIds(db, m, all_followed, k_posts_max);
	} else {
		ids = await getRecentPostIds(db, whoami, g_selected, k_posts_max);
	}
	timing.push({name: 'get_post_ids', time: new Date()});
	var posts = await getPosts(db, ids);
	timing.push({name: 'get_posts', time: new Date()});
	var roots = posts.map(function(x) {
		try {
			return JSON.parse(x.content).root;
		} catch {
			return null;
		}
	});
	var have = new Set(posts.map(x => x.id));
	roots = [...new Set(roots)].filter(x => x && !have.has(x));
	var all_posts = [].concat(posts, await getPosts(db, roots));
	timing.push({name: 'get_root_posts', time: new Date()});
	await Promise.all(all_posts.map(x => app.postMessage({message: x})));
	timing.push({name: 'send_posts', time: new Date()});
	await Promise.all(all_followed.map(id => getAbout(db, id).then(results => Object.keys(results).length ? app.postMessage({user: {user: id, about: results}}) : null)));
	timing.push({name: 'about', time: new Date()});
	await Promise.all(all_followed.map(id => getVotes(db, id).then(results => results.length ? app.postMessage({votes: results}) : null)));
	timing.push({name: 'votes', time: new Date()});
	await all_followed.map(
		id => app.postMessage(
			{
				following: {
					id: id,
					users: [...(g_following_cache[id] || [])],
				}
			}
		)
	);
	timing.push({name: 'following', time: new Date()});

	print(JSON.stringify(g_stats));

	var times = {};
	var previous = null;
	for (let t of timing) {
		times[t.name] = t.time - (previous || t).time;
		previous = t;
	}

	await app.postMessage({ready: true, times: times});
}

ssb.addEventListener('message', async function(id) {
	var db = await database("ssb");
	var posts = await getPosts(db, [id]);
	for (let post of posts) {
		if (post.author == await ssb.whoami() ||
			JSON.parse(post.content).type != 'post') {
			await app.postMessage({message: post});
		} else {
			await app.postMessage({unread: 1});
		}
	}
});

async function addAppSources(message) {
	if (message.mentions) {
		for (let mention of message.mentions) {
			if (mention.type == 'application/tildefriends') {
				var blob = await ssb.blobGet(mention.link);
				var json = JSON.parse(utf8Decode(blob));
				for (let file of Object.keys(json.files)) {
					message.mentions.push({
						name: file,
						link: json.files[file],
					});
				}
			}
		}
	}
}

core.register('message', async function(m) {
	if (m.message == 'ready') {
		await ready();
	} else if (m.message) {
		if (m.message.connect) {
			await ssb.connect(m.message.connect);
		} else if (m.message.appendMessage) {
			await addAppSources(m.message.appendMessage);
			await ssb.appendMessage(m.message.appendMessage);
		} else if (m.message.refresh) {
			await refresh(g_selected);
		}
	} else if (m.event == 'hashChange') {
		if (m.hash.length > 1) {
			g_selected = [m.hash.substring(1)];
		} else {
			g_selected = null;
		}
		if (g_ready) {
			await refresh(g_selected);
		}
	} else if (m.event == 'storeBlobComplete') {
		await app.postMessage({storeBlobComplete: m.path});
	} else if (m.event == 'focus' || m.event == 'blur') {
		/* Shh. */
	} else {
		print(JSON.stringify(m));
	}
});

async function main() {
	if (core.user &&
		core.user.credentials &&
		core.user.credentials.permissions &&
		core.user.credentials.permissions.administration) {
		await app.setDocument(utf8Decode(await getFile("index.html")));
	} else {
		await app.setDocument('<div style="color: #f00">Only the administrator can use this app at this time.  Login at the top right.</div>');
	}
}

main();