/**
 * Functions for handling WorkerScripts, which are the underlying mechanism
 * that allows for scripts to run
 */
import { killWorkerScript } from "./Netscript/killWorkerScript";
import { WorkerScript } from "./Netscript/WorkerScript";
import { workerScripts } from "./Netscript/WorkerScripts";
import { WorkerScriptStartStopEventEmitter } from "./Netscript/WorkerScriptStartStopEventEmitter";

import { CONSTANTS } from "./Constants";
import { Engine } from "./engine";
import { Interpreter } from "./JSInterpreter";
import {
    isScriptErrorMessage,
    makeRuntimeRejectMsg,
} from "./NetscriptEvaluator";
import { NetscriptFunctions } from "./NetscriptFunctions";
import { executeJSScript } from "./NetscriptJSEvaluator";
import { NetscriptPort } from "./NetscriptPort";
import { Player } from "./Player";
import { RunningScript } from "./Script/RunningScript";
import { getRamUsageFromRunningScript } from "./Script/RunningScriptHelpers";
import {
    findRunningScript,
    scriptCalculateOfflineProduction,
} from "./Script/ScriptHelpers";
import { AllServers } from "./Server/AllServers";
import { Settings } from "./Settings/Settings";
import { setTimeoutRef } from "./utils/SetTimeoutRef";

import { generate } from "escodegen";

import { parse, Node } from "../utils/acorn";
import { dialogBoxCreate } from "../utils/DialogBox";
import { compareArrays } from "../utils/helpers/compareArrays";
import { arrayToString } from "../utils/helpers/arrayToString";
import { roundToTwo } from "../utils/helpers/roundToTwo";
import { isString } from "../utils/StringHelperFunctions";

const walk  = require("acorn/dist/walk");

// Netscript Ports are instantiated here
export const NetscriptPorts = [];
for (var i = 0; i < CONSTANTS.NumNetscriptPorts; ++i) {
    NetscriptPorts.push(new NetscriptPort());
}

export function prestigeWorkerScripts() {
    for (const ws of workerScripts.values()) {
        ws.env.stopFlag = true;
    }

    WorkerScriptStartStopEventEmitter.emitEvent();
    workerScripts.clear();
}

// JS script promises need a little massaging to have the same guarantees as netscript
// promises. This does said massaging and kicks the script off. It returns a promise
// that resolves or rejects when the corresponding worker script is done.
function startNetscript2Script(workerScript) {
    workerScript.running = true;

    // The name of the currently running netscript function, to prevent concurrent
    // calls to hack, grow, etc.
    let runningFn = null;

    // We need to go through the environment and wrap each function in such a way that it
    // can be called at most once at a time. This will prevent situations where multiple
    // hack promises are outstanding, for example.
    function wrap(propName, f) {
        // This function unfortunately cannot be an async function, because we don't
        // know if the original one was, and there's no way to tell.
        return function (...args) {
            // Wrap every netscript function with a check for the stop flag.
            // This prevents cases where we never stop because we are only calling
            // netscript functions that don't check this.
            // This is not a problem for legacy Netscript because it also checks the
            // stop flag in the evaluator.
            if (workerScript.env.stopFlag) {throw workerScript;}

            if (propName === "sleep") return f(...args);  // OK for multiple simultaneous calls to sleep.

            const msg = "Concurrent calls to Netscript functions not allowed! " +
                        "Did you forget to await hack(), grow(), or some other " +
                        "promise-returning function? (Currently running: %s tried to run: %s)"
            if (runningFn) {
                workerScript.errorMessage = makeRuntimeRejectMsg(workerScript, sprintf(msg, runningFn, propName), null)
                throw workerScript;
            }
            runningFn = propName;

            // If the function throws an error, clear the runningFn flag first, and then re-throw it
            // This allows people to properly catch errors thrown by NS functions without getting
            // the concurrent call error above
            let result;
            try {
                result = f(...args);
            } catch(e) {
                runningFn = null;
                throw(e);
            }

            if (result && result.finally !== undefined) {
                return result.finally(function () {
                    runningFn = null;
                });
            } else {
                runningFn = null;
                return result;
            }
        }
    };

    for (let prop in workerScript.env.vars) {
        if (typeof workerScript.env.vars[prop] !== "function") continue;
        workerScript.env.vars[prop] = wrap(prop, workerScript.env.vars[prop]);
    }

    // Note: the environment that we pass to the JS script only needs to contain the functions visible
    // to that script, which env.vars does at this point.
    return executeJSScript(workerScript.getServer().scripts,
                           workerScript).then(function (mainReturnValue) {
        if (mainReturnValue === undefined) return workerScript;
        return [mainReturnValue, workerScript];
    }).catch(e => {
        if (e instanceof Error) {
            workerScript.errorMessage = makeRuntimeRejectMsg(
                workerScript, e.message + (e.stack && ("\nstack:\n" + e.stack.toString()) || ""));
            throw workerScript;
        } else if (isScriptErrorMessage(e)) {
            workerScript.errorMessage = e;
            throw workerScript;
        }
        throw e; // Don't know what to do with it, let's rethrow.
    });
}

function startNetscript1Script(workerScript) {
    const code = workerScript.code;
    workerScript.running = true;

    //Process imports
    var codeWithImports, codeLineOffset;
    try {
        let importProcessingRes = processNetscript1Imports(code, workerScript);
        codeWithImports = importProcessingRes.code;
        codeLineOffset  = importProcessingRes.lineOffset;
    } catch(e) {
        dialogBoxCreate("Error processing Imports in " + workerScript.name + ":<br>" +  e);
        workerScript.env.stopFlag = true;
        workerScript.running = false;
        return;
    }

    var interpreterInitialization = function(int, scope) {
        //Add the Netscript environment
        var ns = NetscriptFunctions(workerScript);
        for (let name in ns) {
            let entry = ns[name];
            if (typeof entry === "function") {
                //Async functions need to be wrapped. See JS-Interpreter documentation
                if (name === "hack"     || name === "grow"  || name === "weaken" || name === "sleep" ||
                    name === "prompt"   || name === "run"   || name === "exec") {
                    let tempWrapper = function() {
                        let fnArgs = [];

                        //All of the Object/array elements are in JSInterpreter format, so
                        //we have to convert them back to native format to pass them to these fns
                        for (let i = 0; i < arguments.length-1; ++i) {
                            if (typeof arguments[i] === 'object' || arguments[i].constructor === Array) {
                                fnArgs.push(int.pseudoToNative(arguments[i]));
                            } else {
                                fnArgs.push(arguments[i]);
                            }
                        }
                        let cb = arguments[arguments.length-1];
                        let fnPromise = entry.apply(null, fnArgs);
                        fnPromise.then(function(res) {
                            cb(res);
                        }).catch(function(e) {
                            // Do nothing?
                        });
                    }
                    int.setProperty(scope, name, int.createAsyncFunction(tempWrapper));
                } else if (name === "sprintf" || name === "vsprintf" || name === "scp" ||
                           name == "write"    || name === "read"     || name === "tryWrite") {
                    let tempWrapper = function() {
                        let fnArgs = [];

                        //All of the Object/array elements are in JSInterpreter format, so
                        //we have to convert them back to native format to pass them to these fns
                        for (let i = 0; i < arguments.length; ++i) {
                            if (typeof arguments[i] === 'object' || arguments[i].constructor === Array) {
                                fnArgs.push(int.pseudoToNative(arguments[i]));
                            } else {
                                fnArgs.push(arguments[i]);
                            }
                        }

                        return entry.apply(null, fnArgs);
                    }
                    int.setProperty(scope, name, int.createNativeFunction(tempWrapper));
                } else {
                    let tempWrapper = function() {
                        let res = entry.apply(null, arguments);

                        if (res == null) {
                            return res;
                        } else if (res.constructor === Array || (res === Object(res))) {
                            //Objects and Arrays must be converted to the interpreter's format
                            return int.nativeToPseudo(res);
                        } else {
                            return res;
                        }
                    }
                    int.setProperty(scope, name, int.createNativeFunction(tempWrapper));
                }
            } else {
                //bladeburner, or anything else
                int.setProperty(scope, name, int.nativeToPseudo(entry));
            }
        }

        //Add the arguments
        int.setProperty(scope, "args", int.nativeToPseudo(workerScript.args));
    }

    var interpreter;
    try {
        interpreter = new Interpreter(codeWithImports, interpreterInitialization, codeLineOffset);
    } catch(e) {
        dialogBoxCreate("Syntax ERROR in " + workerScript.name + ":<br>" +  e);
        workerScript.env.stopFlag = true;
        workerScript.running = false;
        return;
    }

    return new Promise(function(resolve, reject) {
        function runInterpreter() {
            try {
                if (workerScript.env.stopFlag) { return reject(workerScript); }

                if (interpreter.step()) {
                    setTimeoutRef(runInterpreter, Settings.CodeInstructionRunTime);
                } else {
                    resolve(workerScript);
                }
            } catch(e) {
                e = e.toString();
                if (!isScriptErrorMessage(e)) {
                    e = makeRuntimeRejectMsg(workerScript, e);
                }
                workerScript.errorMessage = e;
                return reject(workerScript);
            }
        }

        try {
            runInterpreter();
        } catch(e) {
            if (isString(e)) {
                workerScript.errorMessage = e;
                return reject(workerScript);
            } else if (e instanceof WorkerScript) {
                return reject(e);
            } else {
                return reject(workerScript);
            }
        }
    });
}

/*  Since the JS Interpreter used for Netscript 1.0 only supports ES5, the keyword
    'import' throws an error. However, since we want to support import funtionality
    we'll implement it ourselves by parsing the Nodes in the AST out.

    @param code - The script's code
    @returns {Object} {
        code: Newly-generated code with imported functions
        lineOffset: Net number of lines of code added/removed due to imported functions
                    Should typically be positive
    }
*/
function processNetscript1Imports(code, workerScript) {
    //allowReserved prevents 'import' from throwing error in ES5
    const ast = parse(code, { ecmaVersion: 6, allowReserved: true, sourceType: "module" });

    var server = workerScript.getServer();
    if (server == null) {
        throw new Error("Failed to find underlying Server object for script");
    }

    function getScript(scriptName) {
        for (let i = 0; i < server.scripts.length; ++i) {
            if (server.scripts[i].filename === scriptName) {
                return server.scripts[i];
            }
        }
        return null;
    }

    let generatedCode = ""; // Generated Javascript Code
    let hasImports = false;

    // Walk over the tree and process ImportDeclaration nodes
    walk.simple(ast, {
        ImportDeclaration: (node) => {
            hasImports = true;
            let scriptName = node.source.value;
            if (scriptName.startsWith("./")) {
                scriptName = scriptName.slice(2);
            }
            let script = getScript(scriptName);
            if (script == null) {
                throw new Error("'Import' failed due to invalid script: " + scriptName);
            }
            let scriptAst = parse(script.code, {ecmaVersion:5, allowReserved:true, sourceType:"module"});

            if (node.specifiers.length === 1 && node.specifiers[0].type === "ImportNamespaceSpecifier") {
                // import * as namespace from script
                let namespace = node.specifiers[0].local.name;
                let fnNames         = []; //Names only
                let fnDeclarations  = []; //FunctionDeclaration Node objects
                walk.simple(scriptAst, {
                    FunctionDeclaration: (node) => {
                        fnNames.push(node.id.name);
                        fnDeclarations.push(node);
                    }
                });

                //Now we have to generate the code that would create the namespace
                generatedCode +=
                    "var " + namespace + ";\n" +
                    "(function (namespace) {\n";

                //Add the function declarations
                fnDeclarations.forEach((fn) => {
                    generatedCode += generate(fn);
                    generatedCode += "\n";
                });

                //Add functions to namespace
                fnNames.forEach((fnName) => {
                    generatedCode += ("namespace." + fnName + " = " + fnName);
                    generatedCode += "\n";
                });

                //Finish
                generatedCode += (
                    "})(" + namespace + " || " + "(" + namespace + " = {}));\n"
                )
            } else {
                //import {...} from script

                //Get array of all fns to import
                let fnsToImport = [];
                node.specifiers.forEach((e) => {
                    fnsToImport.push(e.local.name);
                });

                //Walk through script and get FunctionDeclaration code for all specified fns
                let fnDeclarations = [];
                walk.simple(scriptAst, {
                    FunctionDeclaration: (node) => {
                        if (fnsToImport.includes(node.id.name)) {
                            fnDeclarations.push(node);
                        }
                    }
                });

                //Convert FunctionDeclarations into code
                fnDeclarations.forEach((fn) => {
                    generatedCode += generate(fn);
                    generatedCode += "\n";
                });
            }
        }
    });

    //If there are no imports, just return the original code
    if (!hasImports) {return {code:code, lineOffset:0};}

    //Remove ImportDeclarations from AST. These ImportDeclarations must be in top-level
    var linesRemoved = 0;
    if (ast.type !== "Program" || ast.body == null) {
        throw new Error("Code could not be properly parsed");
    }
    for (let i = ast.body.length-1; i >= 0; --i) {
        if (ast.body[i].type === "ImportDeclaration") {
            ast.body.splice(i, 1);
            ++linesRemoved;
        }
    }

    //Calculated line offset
    var lineOffset = (generatedCode.match(/\n/g) || []).length - linesRemoved;

    //Convert the AST back into code
    code = generate(ast);

    //Add the imported code and re-generate in ES5 (JS Interpreter for NS1 only supports ES5);
    code = generatedCode + code;

    var res = {
        code:       code,
        lineOffset: lineOffset
    }
    return res;
}

/**
 *
 */
let pidCounter = 1;
function generateNextPid() {
    let tempCounter = pidCounter;

    // Cap the number of search iterations at some arbitrary value to avoid
    // infinite loops. We'll assume that players wont have 1mil+ running scripts
    let found = false;
    for (let i = 0; i < 1e6;) {
        if (!workerScripts.has(tempCounter + i)) {
            found = true;
            tempCounter = tempCounter + i;
            break;
        }

        if (i === Number.MAX_SAFE_INTEGER - 1) {
            i = 1;
        } else {
            ++i;
        }
    }

    if (found) {
        pidCounter = tempCounter + 1;
        if (pidCounter >= Number.MAX_SAFE_INTEGER) {
            pidCounter = 1;
        }

        return tempCounter;
    } else {
        return -1;
    }
}

/**
 * Start a script
 *
 * Given a RunningScript object, constructs a corresponding WorkerScript,
 * adds it to the global 'workerScripts' pool, and begins executing it.
 * @param {RunningScript} runningScriptObj - Script that's being run
 * @param {Server} server - Server on which the script is to be run
 */
export function addWorkerScript(runningScriptObj, server) {
	const filename = runningScriptObj.filename;

	// Update server's ram usage
    let threads = 1;
    if (runningScriptObj.threads && !isNaN(runningScriptObj.threads)) {
        threads = runningScriptObj.threads;
    } else {
        runningScriptObj.threads = 1;
    }
    const ramUsage = roundToTwo(getRamUsageFromRunningScript(runningScriptObj) * threads);
    const ramAvailable = server.maxRam - server.ramUsed;
    if (ramUsage > ramAvailable) {
        dialogBoxCreate(
            `Not enough RAM to run script ${runningScriptObj.filename} with args ` +
            `${arrayToString(runningScriptObj.args)}. This likely occurred because you re-loaded ` +
            `the game and the script's RAM usage increased (either because of an update to the game or ` +
            `your changes to the script.)`
        );
        return;
    }
	server.ramUsed = roundToTwo(server.ramUsed + ramUsage);

    // Get the pid
    const pid = generateNextPid();
    if (pid === -1) {
        throw new Error(
            `Failed to start script because could not find available PID. This is most ` +
            `because you have too many scripts running.`
        );
    }

	// Create the WorkerScript. NOTE: WorkerScript ctor will set the underlying
    // RunningScript's PID as well
	const s = new WorkerScript(runningScriptObj, pid, NetscriptFunctions);
	s.ramUsage 	= ramUsage;

    // Start the script's execution
    let p = null;  // Script's resulting promise
    if (s.name.endsWith(".js") || s.name.endsWith(".ns")) {
        p = startNetscript2Script(s);
    } else {
        p = startNetscript1Script(s);
        if (!(p instanceof Promise)) { return; }
    }

    // Once the code finishes (either resolved or rejected, doesnt matter), set its
    // running status to false
    p.then(function(w) {
        console.log("Stopping script " + w.name + " because it finished running naturally");
        killWorkerScript(s);
        w.scriptRef.log("Script finished running");
    }).catch(function(w) {
        if (w instanceof Error) {
            dialogBoxCreate("Script runtime unknown error. This is a bug please contact game developer");
            console.error("Evaluating workerscript returns an Error. THIS SHOULDN'T HAPPEN: " + w.toString());
            return;
        } else if (w.constructor === Array && w.length === 2 && w[0] === "RETURNSTATEMENT") {
            // Script ends with a return statement
            console.log("Script returning with value: " + w[1]);
            // TODO maybe do something with this in the future
            return;
        } else if (w instanceof WorkerScript) {
            if (isScriptErrorMessage(w.errorMessage)) {
                var errorTextArray = w.errorMessage.split("|");
                if (errorTextArray.length != 4) {
                    console.log("ERROR: Something wrong with Error text in evaluator...");
                    console.log("Error text: " + errorText);
                    return;
                }
                var serverIp = errorTextArray[1];
                var scriptName = errorTextArray[2];
                var errorMsg = errorTextArray[3];

                dialogBoxCreate("Script runtime error: <br>Server Ip: " + serverIp +
                                "<br>Script name: " + scriptName +
                                "<br>Args:" + arrayToString(w.args) + "<br>" + errorMsg);
                w.scriptRef.log("Script crashed with runtime error");
            } else {
                w.scriptRef.log("Script killed");
                return; // Already killed, so stop here
            }
            w.running = false;
            w.env.stopFlag = true;
        } else if (isScriptErrorMessage(w)) {
            dialogBoxCreate("Script runtime unknown error. This is a bug please contact game developer");
            console.log("ERROR: Evaluating workerscript returns only error message rather than WorkerScript object. THIS SHOULDN'T HAPPEN: " + w.toString());
            return;
        } else {
            dialogBoxCreate("An unknown script died for an unknown reason. This is a bug please contact game dev");
            console.log(w);
        }

        killWorkerScript(s);
    });

    // Add the WorkerScript to the global pool
    workerScripts.set(pid, s);
    WorkerScriptStartStopEventEmitter.emitEvent();
	return;
}

/**
 * Updates the online running time stat of all running scripts
 */
export function updateOnlineScriptTimes(numCycles = 1) {
	var time = (numCycles * Engine._idleSpeed) / 1000; //seconds
    for (const ws of workerScripts.values()) {
        ws.scriptRef.onlineRunningTime += time;
    }
}

/**
 * Called when the game is loaded. Loads all running scripts (from all servers)
 * into worker scripts so that they will start running
 */
export function loadAllRunningScripts() {
    var total = 0;
    let skipScriptLoad = (window.location.href.toLowerCase().indexOf("?noscripts") !== -1);
    if (skipScriptLoad) { console.info("Skipping the load of any scripts during startup"); }
	for (const property in AllServers) {
		if (AllServers.hasOwnProperty(property)) {
			const server = AllServers[property];

			// Reset each server's RAM usage to 0
			server.ramUsed = 0;

            // Reset modules on all scripts
            for (let i = 0; i < server.scripts.length; ++i) {
                server.scripts[i].markUpdated();
            }

            if (skipScriptLoad) {
                // Start game with no scripts
                server.runningScripts.length = 0;
            } else {
                for (let j = 0; j < server.runningScripts.length; ++j) {
    				addWorkerScript(server.runningScripts[j], server);

    				// Offline production
    				total += scriptCalculateOfflineProduction(server.runningScripts[j]);
    			}
            }
		}
	}

    return total;
}

/**
 * Run a script from inside another script (run(), exec(), spawn(), etc.)
 */
export function runScriptFromScript(server, scriptname, args, workerScript, threads=1) {
    //Check if the script is already running
    let runningScriptObj = findRunningScript(scriptname, args, server);
    if (runningScriptObj != null) {
        workerScript.scriptRef.log(scriptname + " is already running on " + server.hostname);
        return Promise.resolve(false);
    }

    //'null/undefined' arguments are not allowed
    for (let i = 0; i < args.length; ++i) {
        if (args[i] == null) {
            workerScript.scriptRef.log("ERROR: Cannot execute a script with null/undefined as an argument");
            return Promise.resolve(false);
        }
    }

    //Check if the script exists and if it does run it
    for (let i = 0; i < server.scripts.length; ++i) {
        if (server.scripts[i].filename == scriptname) {
            //Check for admin rights and that there is enough RAM availble to run
            var script = server.scripts[i];
            var ramUsage = script.ramUsage;
            threads = Math.round(Number(threads)); //Convert to number and round
            if (threads === 0) { return Promise.resolve(false); }
            ramUsage = ramUsage * threads;
            var ramAvailable = server.maxRam - server.ramUsed;

            if (server.hasAdminRights == false) {
                workerScript.scriptRef.log("Cannot run script " + scriptname + " on " + server.hostname + " because you do not have root access!");
                return Promise.resolve(false);
            } else if (ramUsage > ramAvailable){
                workerScript.scriptRef.log("Cannot run script " + scriptname + "(t=" + threads + ") on " + server.hostname + " because there is not enough available RAM!");
                return Promise.resolve(false);
            } else {
                //Able to run script
                if (workerScript.disableLogs.ALL == null && workerScript.disableLogs.exec == null && workerScript.disableLogs.run == null && workerScript.disableLogs.spawn == null) {
                    workerScript.scriptRef.log(`Running script: ${scriptname} on ${server.hostname} with ${threads} threads and args: ${arrayToString(args)}. May take a few seconds to start up...`);
                }
                let runningScriptObj = new RunningScript(script, args);
                runningScriptObj.threads = threads;
                addWorkerScript(runningScriptObj, server);

                // Push onto runningScripts.
                // This has to come after addWorkerScript() because that fn updates RAM usage
                server.runScript(runningScriptObj, Player.hacknet_node_money_mult);
                return Promise.resolve(true);
            }
        }
    }
    workerScript.scriptRef.log("Could not find script " + scriptname + " on " + server.hostname);
    return Promise.resolve(false);
}