"use strict";
const jwt = require("jsonwebtoken");
const util = require("util");
const winston = require("winston");

const libConfig = require("@clusterio/lib/config");
const libErrors = require("@clusterio/lib/errors");
const libLink = require("@clusterio/lib/link");
const { levels, logger } = require("@clusterio/lib/logging");
const libLoggingUtils = require("@clusterio/lib/logging_utils");
const libPlugin = require("@clusterio/lib/plugin");
const libPrometheus = require("@clusterio/lib/prometheus");
const libUsers = require("@clusterio/lib/users");

const BaseConnection = require("./BaseConnection");
const routes = require("./routes");

const lastQueryLogTime = new libPrometheus.Gauge(
	"clusterio_master_last_query_log_duration_seconds",
	"Time in seconds the last log query took to execute."
);

/**
 * Represents the connection to a control link
 *
 * @extends module:master/src/BaseConnection
 * @alias module:master/src/ControlConnection
 */
class ControlConnection extends BaseConnection {
	constructor(registerData, connector, master, user) {
		super("control", connector, master);

		this._agent = registerData.agent;
		this._version = registerData.version;

		/**
		 * The user making this connection.
		 * @type {module:lib/users.User}
		 */
		this.user = user;

		this.slaveSubscriptions = {
			all: false,
			slave_ids: [],
		};

		this.instanceSubscriptions = {
			all: false,
			instance_ids: [],
		};

		this.saveListSubscriptions = {
			all: false,
			instance_ids: [],
		};

		this.logTransport = null;
		this.logSubscriptions = {
			all: false,
			master: false,
			slave_ids: [],
			instance_ids: [],
		};

		this.ws_dumper = null;
		this.connector.on("connect", () => {
			this.connector._socket.clusterio_ignore_dump = Boolean(this.ws_dumper);
		});
		this.connector.on("close", () => {
			if (this.logTransport) {
				this.logTransport = null;
				logger.remove(this.logTransport);
			}
			if (this.ws_dumper) {
				this._master.debugEvents.off("message", this.ws_dumper);
			}
		});

		for (let event of ["connect", "drop", "resume", "close"]) {
			this.connector.on(event, () => {
				for (let masterPlugin of this._master.plugins.values()) {
					masterPlugin.onControlConnectionEvent(this, event);
				}
			});
		}
	}

	async getMasterConfigRequestHandler() {
		return { serialized_config: this._master.config.serialize("control") };
	}

	async setMasterConfigFieldRequestHandler(message) {
		this._master.config.set(message.data.field, message.data.value, "control");
	}

	async setMasterConfigPropRequestHandler(message) {
		let { field, prop, value } = message.data;
		this._master.config.setProp(field, prop, value, "control");
	}

	async listSlavesRequestHandler(message) {
		let list = [];
		for (let slave of this._master.slaves.values()) {
			list.push({
				agent: slave.agent,
				version: slave.version,
				id: slave.id,
				name: slave.name,
				public_address: slave.public_address,
				connected: this._master.wsServer.slaveConnections.has(slave.id),
			});
		}
		return { list };
	}

	async setSlaveSubscriptionsRequestHandler(message) {
		this.slaveSubscriptions = message.data;
	}

	slaveUpdated(slave, update) {
		if (
			this.slaveSubscriptions.all
			|| this.slaveSubscriptions.slave_ids.includes(slave.id)
		) {
			libLink.messages.slaveUpdate.send(this, update);
		}
	}

	generateSlaveToken(slaveId) {
		return jwt.sign(
			{ aud: "slave", slave: slaveId },
			Buffer.from(this._master.config.get("master.auth_secret"), "base64")
		);
	}

	async generateSlaveTokenRequestHandler(message) {
		let slaveId = message.data.slave_id;
		if (slaveId === null) {
			slaveId = Math.random() * 2**31 | 0;
		}
		return { token: this.generateSlaveToken(slaveId) };
	}

	async createSlaveConfigRequestHandler(message) {
		let slaveConfig = new libConfig.SlaveConfig("control");
		await slaveConfig.init();

		slaveConfig.set("slave.master_url", this._master.getMasterUrl());
		if (message.data.id !== null) {
			slaveConfig.set("slave.id", message.data.id);
		}
		if (message.data.name !== null) {
			slaveConfig.set("slave.name", message.data.name);
		}
		if (message.data.generate_token) {
			this.user.checkPermission("core.slave.generate_token");
			slaveConfig.set("slave.master_token", this.generateSlaveToken(slaveConfig.get("slave.id")));
		}
		return { serialized_config: slaveConfig.serialize() };
	}

	async getInstanceRequestHandler(message) {
		let id = message.data.id;
		let instance = this._master.instances.get(id);
		if (!instance) {
			throw new libErrors.RequestError(`Instance with ID ${id} does not exist`);
		}

		return {
			id,
			name: instance.config.get("instance.name"),
			assigned_slave: instance.config.get("instance.assigned_slave"),
			game_port: instance.config.get("factorio.game_port"),
			status: instance.status,
		};
	}

	async listInstancesRequestHandler(message) {
		let list = [];
		for (let instance of this._master.instances.values()) {
			list.push({
				id: instance.config.get("instance.id"),
				name: instance.config.get("instance.name"),
				assigned_slave: instance.config.get("instance.assigned_slave"),
				game_port: instance.config.get("factorio.game_port"),
				status: instance.status,
			});
		}
		return { list };
	}

	async setInstanceSubscriptionsRequestHandler(message) {
		this.instanceSubscriptions = message.data;
	}

	instanceUpdated(instance) {
		if (
			this.instanceSubscriptions.all
			|| this.instanceSubscriptions.instance_ids.includes(instance.config.get("instance.id"))
		) {
			libLink.messages.instanceUpdate.send(this, {
				id: instance.config.get("instance.id"),
				name: instance.config.get("instance.name"),
				assigned_slave: instance.config.get("instance.assigned_slave"),
				game_port: instance.config.get("factorio.game_port"),
				status: instance.status,
			});
		}
	}

	// XXX should probably add a hook for slave reuqests?
	async createInstanceRequestHandler(message) {
		let instanceConfig = new libConfig.InstanceConfig("master");
		await instanceConfig.load(message.data.serialized_config);

		let instanceId = instanceConfig.get("instance.id");
		if (this._master.instances.has(instanceId)) {
			throw new libErrors.RequestError(`Instance with ID ${instanceId} already exists`);
		}

		// Add common settings for the Factorio server
		let settings = {
			"name": `${this._master.config.get("master.name")} - ${instanceConfig.get("instance.name")}`,
			"description": `Clusterio instance for ${this._master.config.get("master.name")}`,
			"tags": ["clusterio"],
			"max_players": 0,
			"visibility": { "public": true, "lan": true },
			"username": "",
			"token": "",
			"game_password": "",
			"require_user_verification": true,
			"max_upload_in_kilobytes_per_second": 0,
			"max_upload_slots": 5,
			"ignore_player_limit_for_returning_players": false,
			"allow_commands": "admins-only",
			"autosave_interval": 10,
			"autosave_slots": 5,
			"afk_autokick_interval": 0,
			"auto_pause": false,
			"only_admins_can_pause_the_game": true,
			"autosave_only_on_server": true,

			...instanceConfig.get("factorio.settings"),
		};
		instanceConfig.set("factorio.settings", settings);

		let instance = { config: instanceConfig, status: "unassigned" };
		this._master.instances.set(instanceId, instance);
		await libPlugin.invokeHook(this._master.plugins, "onInstanceStatusChanged", instance, null);
		this._master.addInstanceHooks(instance);
	}

	async deleteInstanceRequestHandler(message, request) {
		let instance = this._master.instances.get(message.data.instance_id);
		if (!instance) {
			throw new libErrors.RequestError(`Instance with ID ${message.data.instance_id} does not exist`);
		}

		if (instance.config.get("instance.assigned_slave") !== null) {
			await this.forwardRequestToInstance(message, request);
		}
		this._master.instances.delete(message.data.instance_id);

		let prev = instance.status;
		instance.status = "deleted";
		this._master.instanceUpdated(instance);
		await libPlugin.invokeHook(this._master.plugins, "onInstanceStatusChanged", instance, prev);
	}

	async getInstanceConfigRequestHandler(message) {
		let instance = this._master.instances.get(message.data.instance_id);
		if (!instance) {
			throw new libErrors.RequestError(`Instance with ID ${message.data.instance_id} does not exist`);
		}

		return {
			serialized_config: instance.config.serialize("control"),
		};
	}

	async updateInstanceConfig(instance) {
		let slaveId = instance.config.get("instance.assigned_slave");
		if (slaveId) {
			let connection = this._master.wsServer.slaveConnections.get(slaveId);
			if (connection) {
				await libLink.messages.assignInstance.send(connection, {
					instance_id: instance.config.get("instance.id"),
					serialized_config: instance.config.serialize("slave"),
				});
			}
		}
	}

	async setInstanceConfigFieldRequestHandler(message) {
		let instance = this._master.instances.get(message.data.instance_id);
		if (!instance) {
			throw new libErrors.RequestError(`Instance with ID ${message.data.instance_id} does not exist`);
		}

		if (message.data.field === "instance.assigned_slave") {
			throw new libErrors.RequestError("instance.assigned_slave must be set through the assign-slave interface");
		}

		if (message.data.field === "instance.id") {
			// XXX is this worth implementing?  It's race condition galore.
			throw new libErrors.RequestError("Setting instance.id is not supported");
		}

		instance.config.set(message.data.field, message.data.value, "control");
		await this.updateInstanceConfig(instance);
	}

	async setInstanceConfigPropRequestHandler(message) {
		let instance = this._master.instances.get(message.data.instance_id);
		if (!instance) {
			throw new libErrors.RequestError(`Instance with ID ${message.data.instance_id} does not exist`);
		}

		let { field, prop, value } = message.data;
		instance.config.setProp(field, prop, value, "control");
		await this.updateInstanceConfig(instance);
	}

	async assignInstanceCommandRequestHandler(message, request) {
		let { slave_id, instance_id } = message.data;
		let instance = this._master.instances.get(instance_id);
		if (!instance) {
			throw new libErrors.RequestError(`Instance with ID ${instance_id} does not exist`);
		}

		// Check if target slave is connected
		let newSlaveConnection;
		if (slave_id !== null) {
			newSlaveConnection = this._master.wsServer.slaveConnections.get(slave_id);
			if (!newSlaveConnection) {
				// The case of the slave not getting the assign instance message
				// still have to be handled, so it's not a requirement that the
				// target slave be connected to the master while doing the
				// assignment, but it is IMHO a better user experience if this
				// is the case.
				throw new libErrors.RequestError("Target slave is not connected to the master server");
			}
		}

		// Unassign from currently assigned slave if it is connected.
		let currentAssignedSlave = instance.config.get("instance.assigned_slave");
		if (currentAssignedSlave !== null && slave_id !== currentAssignedSlave) {
			let oldSlaveConnection = this._master.wsServer.slaveConnections.get(currentAssignedSlave);
			if (oldSlaveConnection && !oldSlaveConnection.connector.closing) {
				await libLink.messages.unassignInstance.send(oldSlaveConnection, { instance_id });
			}
		}

		// Assign to target
		instance.config.set("instance.assigned_slave", slave_id);
		if (slave_id !== null) {
			await libLink.messages.assignInstance.send(newSlaveConnection, {
				instance_id,
				serialized_config: instance.config.serialize("slave"),
			});
		}
	}

	async setSaveListSubscriptionsRequestHandler(message) {
		this.saveListSubscriptions = message.data;
	}

	saveListUpdate(data) {
		if (
			this.saveListSubscriptions.all
			|| this.saveListSubscriptions.instance_ids.includes(data.instance_id)
		) {
			libLink.messages.saveListUpdate.send(this, data);
		}
	}

	async downloadSaveRequestHandler(message) {
		let { instance_id, save } = message.data;
		let stream = await routes.createProxyStream(this._master.app);
		stream.filename = save;

		let ready = new Promise((resolve, reject) => {
			stream.events.on("source", resolve);
			stream.events.on("timeout", () => reject(
				new libErrors.RequestError("Timed out establishing stream from slave")
			));
		});
		ready.catch(() => {});

		let result = await this._master.forwardRequestToInstance(libLink.messages.pushSave, {
			instance_id,
			stream_id: stream.id,
			save,
		});

		await ready;
		return { stream_id: stream.id };
	}

	async setLogSubscriptionsRequestHandler(message) {
		this.logSubscriptions = message.data;
		this.updateLogSubscriptions();
	}

	static logFilter({ all, master, slave_ids, instance_ids, max_level }) {
		return info => {
			// Note: reversed to filter out undefined levels
			if (max_level && !(levels[info.level] <= levels[max_level])) {
				return false;
			}

			if (all) {
				return true;
			}
			if (master && info.slave_id === undefined) {
				return true;
			}
			if (info.slave_id && slave_ids.includes(info.slave_id)) {
				return true;
			}
			if (info.instance_id && instance_ids.includes(info.instance_id)) {
				return true;
			}
			return false;
		};
	}

	updateLogSubscriptions() {
		let { all, master, slave_ids, instance_ids } = this.logSubscriptions;
		if (all || master || slave_ids.length || instance_ids.length) {
			if (!this.logTransport) {
				this.logTransport = new libLoggingUtils.LinkTransport({ link: this });
				this._master.clusterLogger.add(this.logTransport);
			}
			this.logTransport.filter = this.constructor.logFilter(this.logSubscriptions);

		} else if (this.logTransport) {
			this._master.clusterLogger.remove(this.logTransport);
			this.logTransport = null;
		}
	}

	async queryLogRequestHandler(message) {
		let transport = new winston.transports.File({ filename: "cluster.log" });
		let query = util.promisify((options, callback) => transport.query(options, callback));

		// Available options and defaults inferred from reading the source
		// rows: number = limit || 10
		// limit: number // alias of rows.
		// start: number = 0
		// until: Date = now
		// from: Date = until - 24h
		// order: "asc"|"desc" = "desc"
		// fields: Array<string>
		// level: string
		// This interface is junk:
		// - The level option filters by exact match
		// - No way to add your own filter
		// - No way to stream results
		// - The log file is read starting from the beginning
		let setDuration = lastQueryLogTime.startTimer();
		let log = await query({
			order: message.data.order,
			limit: Infinity,
			from: new Date(0),
		});

		log = log.filter(this.constructor.logFilter(message.data));
		if (message.data.limit) {
			log = log.slice(0, message.data.limit);
		}
		setDuration();
		return { log };
	}

	async listPermissionsRequestHandler(message) {
		let list = [];
		for (let permission of libUsers.permissions.values()) {
			list.push({
				name: permission.name,
				title: permission.title,
				description: permission.description,
			});
		}
		return { list };
	}

	async listRolesRequestHandler(message) {
		let list = [];
		for (let role of this._master.userManager.roles.values()) {
			list.push({
				id: role.id,
				name: role.name,
				description: role.description,
				permissions: [...role.permissions],
			});
		}
		return { list };
	}

	async createRoleRequestHandler(message) {
		let lastId = Math.max.apply(null, [...this._master.userManager.roles.keys()]);

		// Start at 5 to leave space for future default roles
		let id = Math.max(5, lastId+1);
		this._master.userManager.roles.set(id, new libUsers.Role({ id, ...message.data }));
		return { id };
	}

	async updateRoleRequestHandler(message) {
		let { id, name, description, permissions } = message.data;
		let role = this._master.userManager.roles.get(id);
		if (!role) {
			throw new libErrors.RequestError(`Role with ID ${id} does not exist`);
		}

		role.name = name;
		role.description = description;
		role.permissions = new Set(permissions);
		this._master.rolePermissionsUpdated(role);
	}

	async grantDefaultRolePermissionsRequestHandler(message) {
		let role = this._master.userManager.roles.get(message.data.id);
		if (!role) {
			throw new libErrors.RequestError(`Role with ID ${message.data.id} does not exist`);
		}

		role.grantDefaultPermissions();
		this._master.rolePermissionsUpdated(role);
	}

	async deleteRoleRequestHandler(message) {
		let id = message.data.id;
		let role = this._master.userManager.roles.get(id);
		if (!role) {
			throw new libErrors.RequestError(`Role with ID ${id} does not exist`);
		}

		this._master.userManager.roles.delete(id);
		for (let user of this._master.userManager.users.values()) {
			user.roles.delete(role);
			this._master.userPermissionsUpdated(user);
		}
	}

	async listUsersRequestHandler(message) {
		let list = [];
		for (let user of this._master.userManager.users.values()) {
			list.push({
				name: user.name,
				roles: [...user.roles].map(role => role.id),
				is_admin: user.isAdmin,
				is_banned: user.isBanned,
				is_whitelisted: user.isWhitelisted,
				instances: [...user.instances],
			});
		}
		return { list };
	}

	async createUserRequestHandler(message) {
		this._master.userManager.createUser(message.data.name);
	}

	async updateUserRolesRequestHandler(message) {
		let user = this._master.userManager.users.get(message.data.name);
		if (!user) {
			throw new libErrors.RequestError(`User '${message.data.name}' does not exist`);
		}

		let resolvedRoles = new Set();
		for (let roleId of message.data.roles) {
			let role = this._master.userManager.roles.get(roleId);
			if (!role) {
				throw new libErrors.RequestError(`Role with ID ${roleId} does not exist`);
			}

			resolvedRoles.add(role);
		}

		user.roles = resolvedRoles;
		this._master.userPermissionsUpdated(user);
	}

	async setUserAdminRequestHandler(message) {
		let { name, create, admin } = message.data;
		let user = this._master.userManager.users.get(name);
		if (!user) {
			if (create) {
				this.user.checkPermission("core.user.create");
				user = this._master.userManager.createUser(name);
			} else {
				throw new libErrors.RequestError(`User '${name}' does not exist`);
			}
		}

		user.isAdmin = admin;
		this.broadcastEventToSlaves({ data: { name, admin }}, libLink.messages.adminlistUpdate);
	}

	async setUserBannedRequestHandler(message) {
		let { name, create, banned, reason } = message.data;
		let user = this._master.userManager.users.get(name);
		if (!user) {
			if (create) {
				this.user.checkPermission("core.user.create");
				user = this._master.userManager.createUser(name);
			} else {
				throw new libErrors.RequestError(`User '${name}' does not exist`);
			}
		}

		user.isBanned = banned;
		user.banReason = reason;
		this.broadcastEventToSlaves({ data: { name, banned, reason }}, libLink.messages.banlistUpdate);
	}

	async setUserWhitelistedRequestHandler(message) {
		let { name, create, whitelisted } = message.data;
		let user = this._master.userManager.users.get(name);
		if (!user) {
			if (create) {
				this.user.checkPermission("core.user.create");
				user = this._master.userManager.createUser(name);
			} else {
				throw new libErrors.RequestError(`User '${name}' does not exist`);
			}
		}

		user.isWhitelisted = whitelisted;
		this.broadcastEventToSlaves({ data: { name, whitelisted }}, libLink.messages.whitelistUpdate);
	}

	async deleteUserRequestHandler(message) {
		let user = this._master.userManager.users.get(message.data.name);
		if (!user) {
			throw new libErrors.RequestError(`User '${message.data.name}' does not exist`);
		}

		if (user.is_admin) {
			this.broadcastEventToSlaves({ data: { name, admin: false }}, libLink.messages.adminlistUpdate);
		}
		if (user.is_whitelisted) {
			this.broadcastEventToSlaves({ data: { name, whitelisted: false }}, libLink.messages.whitelistUpdate);
		}
		if (user.is_banned) {
			this.broadcastEventToSlaves({ data: { name, banned: false, reason: "" }}, libLink.messages.banlistUpdate);
		}
		this._master.userManager.users.delete(message.data.name);
	}

	async debugDumpWsRequestHandler(message) {
		this.ws_dumper = data => {
			if (this.connector.connected) {
				libLink.messages.debugWsMessage.send(this, data);
			}
		};
		this.connector._socket.clusterio_ignore_dump = true;
		this._master.debugEvents.on("message", this.ws_dumper);
	}
}

module.exports = ControlConnection;