const fs = require("fs");
const path = require("path");
const components = require("./components");
const HTTPServer = require("./components/_http");
const { createHash } = require("crypto");

// General regexps
// const FIND_ADDRESS_INSTR_REGEX = /([0-9]{1,3}\.){3}[0-9]{1,3}:[0-9]{1,5}\s{0,}\{[\s\n\r0-9a-z;:\/\."',]{0,}\}/gmi;
const DOMAINER_REGEX = /domain\s{1,}[a-z0-9\.]{1,}\s{1,}\{[\s\n\r0-9a-z;:\/\."',_-]{0,}\}/gmi;
const DOMAINER_VALUE_FIND_REGEX = /domain\s{1,}[a-z0-9\.]{1,}\s{1,}\{/gmi;
const ADDRESS_WITH_PORT_REGEX = /([0-9]{1,3}\.){3}[0-9]{1,3}:[0-9]{1,5}/mi;
const FIND_ADDRESS_INSTR_REGEX = /([0-9]{1,3}\.){3}[0-9]{1,3}:[0-9]{1,5}\s{0,}\{([\s\n\r0-9a-z;:\/\."',_-]|domain\s{1,}[a-z0-9\._]{1,}\s{1,}\{[\s\n\r0-9a-z;:\/\."',_-]{0,}\}){0,}\}/gmi;
const COMMENT_REGEX = /#.{0,}(\n|\r|$)/gmi;
const CONTENT_INTO_CURLY_BRACES = /\{[\s\n\r0-9a-z;:\/\."',_-]{0,}\}{0,}\}/gmi;

// Instruction regexps
function readInstructions (instructions, fullCode, forDomains=false) {
	const syntaxTree = { firewall: false, encryption: {}, modules: new Set(), showDir: false };
	const moduleOpsQueue = new Array();

	for (let instruction of instructions) {
		if (!instruction) {
			if (instructions.indexOf(instruction) === instructions.length - 1) {
				break;
			}
			throw new SyntaxError("Invalid syntax: `;;`");
		}
		const instructionParts = instruction.split(/\s{1,}/);
		const mainOperator = instructionParts[0];

		switch (mainOperator) {
			case "type":
				if (instructionParts.length !== 2)
					throw new SyntaxError("Invalid syntax of operator `type`: type <type_of_connection>");
				const SelectedComponent = components[instructionParts[1]];
				if (SelectedComponent === undefined)
					throw new SyntaxError(`Unknown component: ${instructionParts[1]}. Valid components: ${Object.keys(components).join(", ")}`);
				syntaxTree.Type = SelectedComponent;
				break;
			case "target":
				if (instructionParts.length !== 2)
					throw new SyntaxError("Invalid syntax of operator `target`: target <connection_target>");
				syntaxTree.target = instructionParts[1];
				break;
			case "cert":
				if (instructionParts.length < 3)
					throw new SyntaxError("Invalid syntax of operator `cert`: cert <type:(public|private)> <path_to_cert>");
				if (!["public", "private"].includes(instructionParts[1]))
					throw new SyntaxError("Cert type can be only private or public, not " + instructionParts[1]);
				syntaxTree.encryption[instructionParts[1]] = instructionParts.slice(2,).join(" ");
				break;
			case "auth":
				if (instructionParts.length < 4 || instructionParts.length < 2)
					throw new SyntaxError("Invalid syntax of operator `auth`: auth <mode:(loopback|strict)> <login> <password> OR auth null");
				if (!["loopback", "strict", "null"].includes(instructionParts[1]))
					throw new SyntaxError("Invalid mode: " + instructionParts[1] + ", valid modes: loopback, strict, null");
				syntaxTree.auth = instructionParts[1] !== "null" ? {
					mode: instructionParts[1],
					login: instructionParts[2],
					password: instructionParts.slice(3,).join(" ")
				} : null;
				break;
			case "showdir":
				syntaxTree.showDir = true;
				break;
			case "firewall":
				break;
			case "import":
				if (instructionParts.length < 2)
					throw new SyntaxError("Invalid syntax of operator `import`: import <module_name> OR import <module_name1>, <module_name2>, ..., <module_name3>");
				const modules = instructionParts.slice(1,).join(" ").split(/\s{0,},\s{0,}/gmi);
				modules.forEach(m => syntaxTree.modules.add(new (require(`./modules/${m}`))()));
				break;
			case "#instuction:domain":
				if (forDomains)
					throw new SyntaxError("Nested use of domains doesn't not supported");
				break;
			default:
				let mopFlag = false
				for (let module of syntaxTree.modules) {
					for (let op of module.operators) {
						if (op.operator === mainOperator) {
							// Нуждается в доработке!
							if (!op.handlers.argv(instructionParts.slice(1,)))
								throw new SyntaxError("Custom module's operator error. Invalid argv syntax on operator: " + mainOperator);

							moduleOpsQueue.push(
								(st) => op.handlers.exec(instructionParts.slice(1,), module, st)
							);
							mopFlag = true;
							break;
						}
					}
					if (mopFlag)
						break;
				}
				if (mopFlag) break;
				throw new SyntaxError(`Unknown routemap's operator: ${mainOperator}`);
		}
	}

	if (Object.keys(syntaxTree.encryption).length === 0)
		syntaxTree.encryption = null;
	else if (Object.keys(syntaxTree.encryption).length === 1)
		throw new SyntaxError("No private or public key specified");

	if (!forDomains) {
		syntaxTree.domains = new Object();
		const allDomains = Object.fromEntries((fullCode.match(DOMAINER_REGEX) ?? [])
			.map(x => [x.match(DOMAINER_VALUE_FIND_REGEX)[0].split(/\s{1,}/gmi)[1], x.match(CONTENT_INTO_CURLY_BRACES)[0].slice(1, -1).split(/\s{0,};\s{0,}/g).map(x => x.trim())]));

		for (let domain in allDomains) {
			syntaxTree.domains[domain] = readInstructions(allDomains[domain], "", true);
		}
	}

	syntaxTree.modules = Array.from(syntaxTree.modules);

	// Object.assign needs replace to object which give only-read access
	moduleOpsQueue.forEach(h => {
		const st = Object.assign({}, syntaxTree);
		return h(st);
	});

	return syntaxTree;
}

function logger (...p) {
	return;
	console.debug("[DEBUG.routemap]:", ...p);
}

module.exports.parse = function () {
	const syntaxTree = new Object();
	const routemapContent = fs.readFileSync(path.join(__dirname, "./routemap.txt"), { encoding: "utf-8" })
		.replace(COMMENT_REGEX, "\n");
	const findedAdrInstructions = routemapContent.match(FIND_ADDRESS_INSTR_REGEX);
	logger("findedAdrInstructions:", findedAdrInstructions);
	if (findedAdrInstructions === null)
		throw new SyntaxError("routemap.txt is empty");
	for (let itemAdrInst of findedAdrInstructions) {
		itemAdrInst = itemAdrInst.replace(/[\n\r]{1,}/g, "");
		const content = itemAdrInst
			.replace(ADDRESS_WITH_PORT_REGEX, "")
			.replace(DOMAINER_REGEX, "#instuction:domain")
			.trim()
			.slice(1, -1)
			.split(/\s{0,};\s{0,}/g).map(x => x.trim());
		logger("itemAdrInst:", itemAdrInst, "with content:", content);
		const localSyntaxTree = readInstructions(content, itemAdrInst);
		syntaxTree[itemAdrInst.match(ADDRESS_WITH_PORT_REGEX)[0]] = localSyntaxTree;
	}
	logger("Full syntax tree:", syntaxTree);
	return syntaxTree;
}

module.exports.hash = function () {
	const content = fs.readFileSync(path.join(__dirname, "./routemap.txt"), { encoding: "utf-8" })
		.replace(COMMENT_REGEX, "\n");
	const hash = createHash('sha256').update(content, "utf8")
		.digest().toString("hex");
	return hash;
}