/**
	Copyright: © 2013 rejectedsoftware e.K.
	License: Subject to the terms of the GNU GPLv3 license, as written in the included LICENSE.txt file.
	Authors: Sönke Ludwig
*/
module dubregistry.dbcontroller;

import dub.semver;
import std.array;
import std.algorithm;
import std.exception;
//import std.string;
import std.typecons : tuple;
import std.uni;
import vibe.vibe;


class DbController {
	private {
		MongoCollection m_packages;
		MongoCollection m_downloads;
	}

	private alias bson = serializeToBson;

	this(string dbname)
	{
		auto db = connectMongoDB("127.0.0.1").getDatabase(dbname);
		m_packages = db["packages"];
		m_downloads = db["downloads"];

		// migrations

		// update package format
		foreach(p; m_packages.find()){
			bool any_change = false;
			if (p["branches"].type == Bson.Type.object) {
				Bson[] branches;
				foreach( b; p["branches"] )
					branches ~= b;
				p["branches"] = branches;
				any_change = true;
			}
			if (p["branches"].type == Bson.Type.array) {
				auto versions = p["versions"].get!(Bson[]);
				foreach (b; p["branches"]) versions ~= b;
				p["branches"] = Bson(null);
				p["versions"] = Bson(versions);
				any_change = true;
			}
			if (any_change) m_packages.update(["_id": p["_id"]], p);
		}

		// add updateCounter field for packages that don't have it yet
		m_packages.update(["updateCounter": ["$exists": false]], ["$set" : ["updateCounter" : 0L]], UpdateFlags.multiUpdate);

		// add default non-@optional stats to packages
		DbPackageStats stats;
		m_packages.update(["stats": ["$exists": false]], ["$set": ["stats": stats]], UpdateFlags.multiUpdate);

		// create indices
		m_packages.ensureIndex([tuple("name", 1)], IndexFlags.Unique);
		m_downloads.ensureIndex([tuple("package", 1), tuple("version", 1)]);

		Bson[string] doc;
		doc["v"] = 1;
		doc["key"] = ["_fts": Bson("text"), "_ftsx": Bson(1)];
		doc["ns"] = db.name ~ "." ~ m_packages.name;
		doc["name"] = "packages_full_text_search_index";
		doc["weights"] = [
			"name": Bson(4),
			"versions.info.description" : Bson(3),
			// TODO: try to index readme
			"versions.info.homepage" : Bson(1),
			"versions.info.author" : Bson(1),
		];
		doc["background"] = true;
		db["system.indexes"].insert(doc);

		// sort package versions newest to oldest
		// TODO: likely can be removed as we're now sorting on insert
		repairVersionOrder();
	}

	void addPackage(ref DbPackage pack)
	{
		enforce(m_packages.findOne(["name": pack.name], ["_id": true]).isNull(), "A package with the same name is already registered.");
		if (pack._id == BsonObjectID.init)
			pack._id = BsonObjectID.generate();
		m_packages.insert(pack);
	}

	void addOrSetPackage(ref DbPackage pack)
	{
		enforce(pack._id != BsonObjectID.init, "Cannot update a packag with no ID.");
		m_packages.update(["_id": pack._id], pack, UpdateFlags.upsert);
	}

	DbPackage getPackage(string packname)
	{
		auto bpack = m_packages.findOne(["name": packname]);
		enforce!RecordNotFound(!bpack.isNull(), "Unknown package name.");
		return deserializeBson!DbPackage(bpack);
	}

	BsonObjectID getPackageID(string packname)
	{
		auto bpack = m_packages.findOne(["name": packname], ["_id": 1]);
		enforce(!bpack.isNull(), "Unknown package name.");
		return bpack["_id"].get!BsonObjectID;
	}

	DbPackage getPackage(BsonObjectID id)
	{
		auto bpack = m_packages.findOne(["_id": id]);
		enforce!RecordNotFound(!bpack.isNull(), "Unknown package ID.");
		return deserializeBson!DbPackage(bpack);
	}

	auto getAllPackages()
	{
		return m_packages.find(Bson.emptyObject, ["name": 1]).map!(p => p["name"].get!string)();
	}

	auto getAllPackageIDs()
	{
		return m_packages.find(Bson.emptyObject, ["_id": 1]).map!(p => p["_id"].get!BsonObjectID)();
	}

	auto getPackageDump()
	{
		return m_packages.find(Bson.emptyObject).map!(p => p.deserializeBson!DbPackage);
	}

	auto getUserPackages(BsonObjectID user_id)
	{
		return m_packages.find(["owner": user_id], ["name": 1]).map!(p => p["name"].get!string)();
	}

	bool isUserPackage(BsonObjectID user_id, string package_name)
	{
		return !m_packages.findOne(["owner": Bson(user_id), "name": Bson(package_name)]).isNull();
	}

	void removePackage(string packname, BsonObjectID user)
	{
		m_packages.remove(["name": Bson(packname), "owner": Bson(user)]);
	}

	void setPackageErrors(string packname, string[] error...)
	{
		m_packages.update(["name": packname], ["$set": ["errors": error]]);
	}

	void setPackageCategories(string packname, string[] categories...)
	{
		m_packages.update(["name": packname], ["$set": ["categories": categories]]);
	}

	void setPackageRepository(string packname, DbRepository repo)
	{
		m_packages.update(["name": packname], ["$set": ["repository": repo]]);
	}

	void addVersion(string packname, DbPackageVersion ver)
	{
		assert(ver.version_.startsWith("~") || ver.version_.isValidVersion());

		size_t nretrys = 0;

		while (true) {
			auto pack = m_packages.findOne(["name": packname], ["versions": true, "updateCounter": true]);
			auto counter = pack["updateCounter"].get!long;
			auto versions = deserializeBson!(DbPackageVersion[])(pack["versions"]);
			auto new_versions = versions ~ ver;
			new_versions.sort!((a, b) => vcmp(a, b));

			// remove versions with invalid dependency names to avoid the findAndModify below to fail
			new_versions = new_versions.filter!(
					v => !v.info["dependencies"].opt!(Json[string]).byKey.canFind!(k => k.canFind("."))
				).array;

			//assert((cast(Json)bversions).toString() == (cast(Json)serializeToBson(versions)).toString());

			auto res = m_packages.findAndModify(
				["name": Bson(packname), "updateCounter": Bson(counter)],
				["$set": ["versions": serializeToBson(new_versions), "updateCounter": Bson(counter+1)]],
				["_id": true]);

			if (!res.isNull) return;

			enforce(nretrys++ < 20, format("Failed to store updated version list for %s", packname));
			logDebug("Failed to update version list atomically, retrying...");
		}
	}

	void removeVersion(string packname, string ver)
	{
		assert(ver.startsWith("~") || ver.isValidVersion());
		m_packages.update(["name": packname], ["$pull": ["versions": ["version": ver]]]);
	}

	void updateVersion(string packname, DbPackageVersion ver)
	{
		assert(ver.version_.startsWith("~") || ver.version_.isValidVersion());
		m_packages.update(["name": packname, "versions.version": ver.version_], ["$set": ["versions.$": ver]]);
	}

	bool hasVersion(string packname, string ver)
	{
		auto ret = m_packages.findOne(["name": packname, "versions.version" : ver], ["_id": true]);
		return !ret.isNull();
	}

	string getLatestVersion(string packname)
	{
		auto slice = serializeToBson(["$slice": -1]);
		auto pack = m_packages.findOne(["name": packname], ["_id": Bson(true), "versions": slice]);
		if (pack.isNull() || pack["versions"].isNull() || pack["versions"].length != 1) return null;
		return deserializeBson!(string)(pack["versions"][0]["version"]);
	}

	DbPackageVersion getVersionInfo(string packname, string ver)
	{
		auto pack = m_packages.findOne(["name": packname, "versions.version": ver], ["versions.$": true]);
		enforce(!pack.isNull(), "unknown package/version");
		assert(pack["versions"].length == 1);
		return deserializeBson!(DbPackageVersion)(pack["versions"][0]);
	}

	DbPackage[] searchPackages(string query)
	{
		if (!query.strip.length) {
			return m_packages.find()
				.sort(["name": 1])
				.map!(deserializeBson!DbPackage)
				.array;
		}

		return m_packages
			.find(["$text": ["$search": query]], ["score": ["$meta": "textScore"]])
			.sort(["score": ["$meta": "textScore"]])
			.map!(deserializeBson!DbPackage)
			.array;
	}

	BsonObjectID addDownload(BsonObjectID pack, string ver, string user_agent)
	{
		DbPackageDownload download;
		download._id = BsonObjectID.generate();
		download.package_ = pack;
		download.version_ = ver;
		download.time = Clock.currTime(UTC());
		download.userAgent = user_agent;
		m_downloads.insert(download);
		return download._id;
	}

	DbPackageStats getPackageStats(string packname)
	{
		auto pack = m_packages.findOne(["name": Bson(packname)], ["stats": true]);
		enforce!RecordNotFound(!pack.isNull(), "Unknown package name.");
		logDebug("getPackageStats(%s) %s", packname, pack["stats"]);
		return pack["stats"].deserializeBson!DbPackageStats;
	}

	void updatePackageStats(BsonObjectID packId, ref DbPackageStats stats)
	{
		stats.updatedAt = Clock.currTime(UTC());
		logDebug("updatePackageStats(%s, %s)", packId, stats);
		m_packages.update(["_id": packId], ["$set": ["stats": stats]]);
	}

	DbDownloadStats aggregateDownloadStats(BsonObjectID packId, string ver = null)
	{
		static Bson newerThan(SysTime time)
		{
			// doc.time >= time ? 1 : 0
			alias bs = serializeToBson;
			return bs([
				"$cond": [bs(["$gte": [bs("$time"), bs(time)]]), bs(1), bs(0)]
			]);
		}

		auto match = Bson.emptyObject();
		match["package"] = Bson(packId);
		if (ver.length) match["version"] = ver;

		immutable now = Clock.currTime;
		auto res = m_downloads.aggregate(
			["$match": match],
			["$project": [
					"_id": Bson(false),
					"total": serializeToBson(["$literal": 1]),
					"monthly": newerThan(now - 30.days),
					"weekly": newerThan(now - 7.days),
					"daily": newerThan(now - 1.days)]],
			["$group": [
					"_id": Bson(null), // single group
					"total": Bson(["$sum": Bson("$total")]),
					"monthly": Bson(["$sum": Bson("$monthly")]),
					"weekly": Bson(["$sum": Bson("$weekly")]),
					"daily": Bson(["$sum": Bson("$daily")])]]);
		assert(res.length <= 1);
		return res.length ? deserializeBson!DbDownloadStats(res[0]) : DbDownloadStats.init;
	}

	private void repairVersionOrder()
	{
		foreach( bp; m_packages.find() ){
			auto p = deserializeBson!DbPackage(bp);
			auto newversions = p.versions
				.filter!(v => v.version_.startsWith("~") || v.version_.isValidVersion)
				.array
				.sort!((a, b) => vcmp(a, b))
				.uniq!((a, b) => a.version_ == b.version_)
				.array;
			if (p.versions != newversions)
				m_packages.update(["_id": p._id], ["$set": ["versions": newversions]]);
		}
	}
}

class RecordNotFound : Exception
{
    @nogc @safe pure nothrow this(string msg, string file = __FILE__, size_t line = __LINE__, Throwable next = null)
    {
        super(msg, file, line, next);
    }

    @nogc @safe pure nothrow this(string msg, Throwable next, string file = __FILE__, size_t line = __LINE__)
    {
        super(msg, file, line, next);
    }
}

struct DbPackage {
	BsonObjectID _id;
	BsonObjectID owner;
	string name;
	DbRepository repository;
	DbPackageVersion[] versions;
	DbPackageStats stats;
	string[] errors;
	string[] categories;
	long updateCounter = 0; // used to implement lockless read-modify-write cycles
}

struct DbRepository {
	string kind;
	string owner;
	string project;
}

struct DbPackageVersion {
	SysTime date;
	string version_;
	@optional string commitID;
	Json info;
	@optional string readme;
}

struct DbPackageDownload {
	BsonObjectID _id;
	BsonObjectID package_;
	string version_;
	SysTime time;
	string userAgent;
}

struct DbPackageStats {
	SysTime updatedAt;
	DbDownloadStats downloads;
	DbRepoStats repo;
}

struct DbDownloadStats {
	uint total, monthly, weekly, daily;
}

struct DbRepoStats {
	uint stars, watchers, forks, issues;
}

bool vcmp(DbPackageVersion a, DbPackageVersion b)
{
	return vcmp(a.version_, b.version_);
}

bool vcmp(string va, string vb)
{
	import dub.dependency;
	return Version(va) < Version(vb);
}

private string[] splitAlphaNumParts(string str)
{
	string[] ret;
	while (!str.empty) {
		while (!str.empty && !str.front.isIdentChar()) str.popFront();
		if (str.empty) break;
		size_t i = str.length;
		foreach (j, dchar ch; str)
			if (!isIdentChar(ch)) {
				i = j;
				break;
			}
		if (i > 0) {
			ret ~= str[0 .. i];
			str = str[i .. $];
		}
		if (!str.empty) str.popFront(); // pop non-ident-char
	}
	return ret;
}

private bool isIdentChar(dchar ch)
{
	return std.uni.isAlpha(ch) || std.uni.isNumber(ch);
}