/**
 * Command library
 *
 * Data types and utilites for commands to clusterioctl's CLI.
 *
 * @author Hornwitser
 * @module lib/command
 */
"use strict";
const libLink = require("./link");
const libErrors = require("./errors");

/**
 * Represents a command that can be runned by clusterioctl
 * @static
 */
class Command {
	/**
	 * Define an executable command.
	 *
	 * @param {Object} cmd - Command definiton.
	 * @param {Array} cmd.definiton -
	 *     Arguments to pass to yargs .command method to define this
	 *     command.
	 * @param {function(args, control)} handler -
	 *     Async function invoked when the command is executed.  Is given
	 *     the parsed args and a reference to the {@link
	 *     module:ctl/ctl.Control} instance.
	 */
	constructor({ definition, handler }) {
		if (definition[0] instanceof Array) {
			this.name = definition[0][0].split(" ")[0];
			this.alias = definition[0].slice(1);
		} else {
			this.name = definition[0].split(" ")[0];
			this.alias = [];
		}
		this._definition = definition;
		this._handler = handler;
	}

	register(yargs) {
		yargs.command(...this._definition);
	}

	async run(args, control) {
		await this._handler(args, control);
	}
}

/**
 * A node in the command tree that can hold commands and sub trees
 *
 * Container which can contain {@link module:lib/command.Command}s and other
 * CommandTrees.  This is used by clusterioctl to hold the full tree of
 * available commands, you may extend this tree by using a control plugin,
 * see {@link module:lib/plugin.BaseControlPlugin#addCommands}
 *
 * @static
 */
class CommandTree {
	/**
	 * Define a command containing sub commands.
	 *
	 * @param {Object} cmd - Command definition
	 * @param {string} cmd.name - Name of the command.
	 * @param {Array<string>} cmd.alias - Aliases for this tree.
	 * @param {description} cmd.description -
	 *     Descripton to provide for this command tree node.
	 */
	constructor({ name, alias, description }) {
		if (typeof name !== "string") {
			throw new Error("name must be a string");
		}

		this.name = name;
		this.alias = alias || [];
		this.description = description;
		this.subCommands = new Map();
	}

	/**
	 * Add a command or command tree to this tree
	 *
	 * @param {module:lib/command.Command|module:lib/command.CommandTree} command -
	 *    The command to add to this command tree.
	 */
	add(command) {
		if (this.subCommands.has(command.name)) {
			throw new Error(`Command ${command.name} already exists`);
		}
		this.subCommands.set(command.name, command);
		for (let alias of command.alias) {
			if (this.subCommands.has(alias)) {
				throw new Error(`Alias ${alias} for command ${command.name} already exists`);
			}
			this.subCommands.set(alias, command);
		}
	}

	/**
	 * Get a command or command tree from this tree
	 *
	 * @param {string} name -
	 *     The name of the command or command tree to retrieve.
	 * @return {?module:lib/command.Command|module:lib/command.CommandTree}
	 *    The command to add to this command tree.
	 */
	get(name) {
		return this.subCommands.get(name) || null;
	}

	/**
	 * Insert the registered commands into the given yargs parser
	 *
	 * Traverses the the tree of sub-commands recursively and adds all of
	 * them to the given yargs parser.
	 *
	 * @param {Object} yargs - yargs parser to register with.
	 */
	register(yargs) {
		yargs.command([this.name].concat(this.alias), this.description, (yargs) => {
			for (let [name, command] of this.subCommands) {
				// Check if the entry is not an alias.
				if (name === command.name) {
					command.register(yargs);
				}
			}
		}, () => {
			yargs.showHelp();
			yargs.exit();
		});
	}
}


/**
 * Resolve a string into a slave ID
 *
 * Resolves a string with either an slave name or an id into an integer with
 * the slave ID.
 *
 * @param {module:lib/link.Link} client - link to master server to query slave on.
 * @param {string} slaveName - string with name or id of slave.
 * @returns {number} slave ID.
 * @static
 */
async function resolveSlave(client, slaveName) {
	let slaveId;
	if (/^-?\d+$/.test(slaveName)) {
		slaveId = parseInt(slaveName, 10);
	} else {
		let response = await libLink.messages.listSlaves.send(client);
		for (let slave of response.list) {
			if (slave.name === slaveName) {
				slaveId = slave.id;
				break;
			}
		}

		if (slaveId === undefined) {
			throw new libErrors.CommandError(`No slave named ${slaveName}`);
		}
	}

	return slaveId;
}

/**
 * Resolve a string to an instance ID
 *
 * Resolves a string with either an instance name or an id into an integer
 * with the instance ID.
 *
 * @param {module:lib/link.Link} client - link to master server to query instance on.
 * @param {string} instanceName - string with name or id of instance.
 * @returns {number} instance ID.
 * @static
 */
async function resolveInstance(client, instanceName) {
	let instanceId;
	if (/^-?\d+$/.test(instanceName)) {
		instanceId = parseInt(instanceName, 10);
	} else {
		let response = await libLink.messages.listInstances.send(client);
		for (let instance of response.list) {
			if (instance.name === instanceName) {
				instanceId = instance.id;
				break;
			}
		}

		if (instanceId === undefined) {
			throw new libErrors.CommandError(`No instance named ${instanceName}`);
		}
	}

	return instanceId;
}

/**
 * Retrieve role object from string
 *
 * Resolves a string with either a role name or an id into an object
 * representing the role.
 *
 * @param {module:lib/link.Link} client - link to master server to query role on.
 * @param {string} roleName - string with name or id of role.
 * @returns {Object} Role info.
 * @static
 */
async function retrieveRole(client, roleName) {
	let response = await libLink.messages.listRoles.send(client);

	let resolvedRole;
	if (/^-?\d+$/.test(roleName)) {
		let roleId = parseInt(roleName, 10);
		for (let role of response.list) {
			if (role.id === roleId) {
				resolvedRole = role;
				break;
			}
		}

	} else {
		for (let role of response.list) {
			if (role.name === roleName) {
				resolvedRole = role;
				break;
			}
		}
	}

	if (!resolvedRole) {
		throw new libErrors.CommandError(`No role named ${roleName}`);
	}

	return resolvedRole;
}

module.exports = {
	Command,
	CommandTree,

	resolveSlave,
	resolveInstance,
	retrieveRole,
};