class EmulatorJS {
    createElement(type) {
        return document.createElement(type);
    }
    addEventListener(element, listener, callback) {
        const listeners = listener.split(" ");
        for (let i=0; i<listeners.length; i++) {
            element.addEventListener(listeners[i], callback);
            this.listeners.push({cb:callback, elem:element, listener:listeners[i]});
        }
    }
    downloadFile(path, cb, progressCB, notWithPath, opts) {
        const basePath = notWithPath ? '' : this.config.dataPath;
        path = basePath + path;
        let url;
        try {url=new URL(path)}catch(e){};
        if ((url && ['http:', 'https:'].includes(url.protocol)) || !url) {
            const xhr = new XMLHttpRequest();
            if (progressCB instanceof Function) {
                xhr.addEventListener('progress', (e) => {
                    const progress = e.total ? ' '+Math.floor(e.loaded / e.total * 100).toString()+'%' : ' '+(e.loaded/1048576).toFixed(2)+'MB';
                    progressCB(progress);
                });
            }
            xhr.onload = function() {
                if (xhr.readyState === xhr.DONE) {
                    let data = xhr.response;
                    try {data=JSON.parse(data)}catch(e){}
                    cb({
                        data: data,
                        headers: {
                            "content-length": xhr.getResponseHeader('content-length'),
                            "content-type": xhr.getResponseHeader('content-type'),
                            "last-modified": xhr.getResponseHeader('last-modified')
                        }
                    });
                }
            }
            xhr.responseType = opts.responseType;
            xhr.onerror = () => cb(-1);
            xhr.open(opts.method, path, true);
            xhr.send();
        } else {
            (async () => {
                //Most commonly blob: urls. Not sure what else it could be
                if (opts.method === 'HEAD') {
                    cb({headers:{}});
                    return;
                }
                let res;
                try {
                    res = await fetch(path);
                    if (opts.type && opts.type.toLowerCase() === 'arraybuffer') {
                        res = await res.arrayBuffer();
                    } else {
                        res = await res.text();
                        try {res = JSON.parse(res)} catch(e) {}
                    }
                } catch(e) {
                    cb(-1);
                }
                if (path.startsWith('blob:')) URL.revokeObjectURL(path);
                cb({
                    data: res,
                    headers: {}
                });
            })
        }
    }
    constructor(element, config) {
        this.debug = (window.EJS_DEBUG_XX === true);
        this.setElements(element);
        this.started = false;
        this.paused = true;
        this.listeners = [];
        this.config = config;
        this.canvas = this.createElement('canvas');
        this.canvas.classList.add('ejs_canvas');
        this.bindListeners();
        
        
        this.game.classList.add("ejs_game");
        
        this.createStartButton();
        
        console.log(this)
    }
    setElements(element) {
        this.game =  document.querySelector(element);
        this.elements = {
            main: this.game,
            parent: this.game.parentElement
        }
        this.elements.parent.classList.add("ejs_parent");
    }
    // Start button
    createStartButton() {
        const button = this.createElement("div");
        button.classList.add("ejs_start_button");
        button.innerText = this.localization("Start Game");
        this.elements.parent.appendChild(button);
        this.addEventListener(button, "click", this.startButtonClicked.bind(this));
    }
    startButtonClicked(e) {
        e.preventDefault();
        e.target.remove();
        this.createText();
        this.downloadGameCore();
    }
    // End start button
    createText() {
        this.textElem = this.createElement("div");
        this.textElem.classList.add("ejs_loading_text");
        this.textElem.innerText = this.localization("Loading...");
        this.elements.parent.appendChild(this.textElem);
    }
    localization(text) {
        //todo
        return text;
    }
    checkCompression(data, msg) {
        if (msg) {
            this.textElem.innerText = msg;
        }
        //to be put in another file
        function isCompressed(data) { //https://www.garykessler.net/library/file_sigs.html
            //todo. Use hex instead of numbers
            if ((data[0] === 80 && data[1] === 75) && ((data[2] === 3 && data[3] === 4) || (data[2] === 5 && data[3] === 6) || (data[2] === 7 && data[3] === 8))) {
                return 'zip';
            } else if (data[0] === 55 && data[1] === 122 && data[2] === 188 && data[3] === 175 && data[4] === 39 && data[5] === 28) {
                return '7z';
            } else if ((data[0] === 82 && data[1] === 97 && data[2] === 114 && data[3] === 33 && data[4] === 26 && data[5] === 7) && ((data[6] === 0) || (data[6] === 1 && data[7] == 0))) {
                return 'rar';
            }
        }
        const createWorker = (path) => {
            return new Promise((resolve, reject) => {
                this.downloadFile(path, (res) => {
                    if (res === -1) {
                        this.textElem.innerText = "Error";
                        this.textElem.style.color = "red";
                        return;
                    }
                    const blob = new Blob([res.data], {
                        'type': 'application/javascript'
                    })
                    const url = window.URL.createObjectURL(blob);
                    resolve(new Worker(url));
                }, null, false, {responseType: "arraybuffer", method: "GET"});
            })
        }
        const decompress7z = (file) => {
            return new Promise((resolve, reject) => {
                const files = {};
                const onMessage = (data) => {
                    if (!data.data) return;
                    //data.data.t/ 4=progress, 2 is file, 1 is zip done
                    if (data.data.t === 4 && msg) {
                        const pg = data.data;
                        const num = Math.floor(pg.current / pg.total * 100);
                        if (isNaN(num)) return;
                        const progress = ' '+num.toString()+'%';
                        this.textElem.innerText = msg + progress;
                    }
                    if (data.data.t === 2) {
                        files[data.data.file] = data.data.data;
                    }
                    if (data.data.t === 1) {
                        resolve(files);
                    }
                }
                
                createWorker('compression/extract7z.js').then((worker) => {
                    worker.onmessage = onMessage;
                    worker.postMessage(file);
                    //console.log(file);
                })
            })
        }
        async function decompressRar() {
            
        }
        const compression = isCompressed(data.slice(0, 10));
        if (compression) {
            //Need to do zip and rar still
            return decompress7z(data);
        } else {
            return new Promise(resolve => resolve(data));
        }
        
    }
    downloadGameCore() {
        this.textElem.innerText = this.localization("Download Game Core");
        this.downloadFile('cores/'+this.getCore()+'-wasm.data', (res) => {
            if (res === -1) {
                this.textElem.innerText = "Error";
                this.textElem.style.color = "red";
                return;
            }
            this.checkCompression(new Uint8Array(res.data), this.localization("Decompress Game Core")).then((data) => {
                //console.log(data);
                let js, wasm;
                for (let k in data) {
                    if (k.endsWith(".wasm")) {
                        wasm = data[k];
                    } else if (k.endsWith(".js")) {
                        js = data[k];
                    }
                }
                this.initGameCore(js, wasm);
            });
        }, (progress) => {
            this.textElem.innerText = this.localization("Download Game Core") + progress;
        }, false, {responseType: "arraybuffer", method: "GET"});
        
    }
    initGameCore(js, wasm) {
        this.initModule(wasm);
        let script = this.createElement("script");
        script.src = URL.createObjectURL(new Blob([js], {type: "application/javascript"}));
        document.body.appendChild(script);
    }
    getCore() {
        const core = this.config.system;
        //switch case or an object holding this data
        if (core === 'nes') {
            return 'fceumm';
        }
    }
    downloadRom() {
        this.gameManager = new window.EJS_GameManager(this.Module);
        
        this.textElem.innerText = this.localization("Download Game Data");
        this.downloadFile(this.config.gameUrl, (res) => {
            if (res === -1) {
                this.textElem.innerText = "Error";
                this.textElem.style.color = "red";
                return;
            }
            this.checkCompression(new Uint8Array(res.data), this.localization("Decompress Game Data")).then((data) => {
                FS.writeFile("/game", data);
                this.startGame();
            });
        }, (progress) => {
            this.textElem.innerText = this.localization("Download Game Data") + progress;
        }, true, {responseType: "arraybuffer", method: "GET"});
    }
    initModule(wasmData) {
        window.Module = {
            'TOTAL_MEMORY': 0x10000000,
            'noInitialRun': true,
            'onRuntimeInitialized': this.downloadRom.bind(this),
            'arguments': [],
            'preRun': [],
            'postRun': [],
            'canvas': this.canvas,
            'print': (msg) => {
                if (this.debug) {
                    console.log(msg);
                }
            },
            'printErr': (msg) => {
                if (this.debug) {
                    console.log(msg);
                }
            },
            'totalDependencies': 0,
            'monitorRunDependencies': () => {},
            'locateFile': function(fileName) {
                console.log(fileName);
                if (fileName.endsWith(".wasm")) {
                    return URL.createObjectURL(new Blob([wasmData], {type: "application/wasm"}));
                }
            },
            'readAsync': function(a, b, c) {
                console.log(a, b, c)
            }
        };
        this.Module = window.Module;
    }
    startGame() {
        this.textElem.remove();
        this.textElem = null;
        this.game.classList.remove("ejs_game");
        this.game.appendChild(this.canvas);
        const args = [];
        if (this.debug) args.push('-v');
        args.push('/game');
        Module.callMain(args);
        Module.resumeMainLoop();
        this.started = true;
        this.paused = false;
        Module.setCanvasSize(800, 600);
        let i=0;
        // this needs to be fixed. Ugh.
        let j = setInterval(function() { // some cores have a messed up screen size on load (for example - gba)
            if (i>20) clearInterval(j);
            i++;
            Module.setCanvasSize(800, 600);
        }, 100)
    }
    bindListeners() {
        this.createContextMenu();
        this.createBottomMenuBar();
        //keyboard, etc...
    }
    createContextMenu() {
        this.elements.contextmenu = this.createElement('div');
        this.elements.contextmenu.classList.add("ejs_context_menu");
        this.addEventListener(this.game, 'contextmenu', (e) => {
            if (this.started) {
                this.elements.contextmenu.style.display = "block";
                this.elements.contextmenu.style.left = e.offsetX;
                this.elements.contextmenu.style.top = e.offsetY;
            }
            e.preventDefault();
        })
        const hideMenu = () => {
            this.elements.contextmenu.style.display = "none";
        }
        this.addEventListener(this.elements.contextmenu, 'contextmenu', (e) => e.preventDefault());
        this.addEventListener(this.elements.parent, 'contextmenu', (e) => e.preventDefault());
        this.addEventListener(this.game, 'mousedown', hideMenu);
        const parent = this.createElement("ul");
        const addButton = (title, hidden, functi0n) => {
            //<li><a href="#" onclick="return false">'+title+'</a></li>
            const li = this.createElement("li");
            if (hidden) li.hidden = true;
            const a = this.createElement("a");
            if (functi0n instanceof Function) {
                this.addEventListener(li, 'click', (e) => {
                    e.preventDefault();
                    functi0n();
                });
            }
            a.href = "#";
            a.onclick = "return false";
            a.innerText = title;
            li.appendChild(a);
            parent.appendChild(li);
            hideMenu();
        }
        let screenshotUrl;
        addButton("Take Screenshot", false, () => {
            if (screenshotUrl) URL.revokeObjectURL(screenshotUrl);
            const screenshot = this.gameManager.screenshot();
            const blob = new Blob([screenshot]);
            screenshotUrl = URL.createObjectURL(blob);
            const a = this.createElement("a");
            a.href = screenshotUrl;
            a.download = "screenshot.png";
            a.click();
            hideMenu();
        });
        addButton("Quick Save", false, () => {
            this.gameManager.quickSave();
            hideMenu();
        });
        addButton("Quick Load", false, () => {
            this.gameManager.quickLoad();
            hideMenu();
        });
        addButton("EmulatorJS", false, () => {
            hideMenu();
            const body = this.createPopup("EmulatorJS", {
                "Close": () => {
                    this.closePopup();
                }
            });
            body.innerText = "Todo. Write about, include tabs on side with licenses, links to docs/repo/discord?";
            
        });
        
        this.elements.contextmenu.appendChild(parent);
        
        this.elements.parent.appendChild(this.elements.contextmenu);
    }
    closePopup() {
        if (this.currentPopup !== null) {
            try {
                this.currentPopup.remove();
            } catch(e){}
            this.currentPopup = null;
        }
    }
    //creates a full box popup.
    createPopup(popupTitle, buttons) {
        this.closePopup();
        this.currentPopup = this.createElement('div');
        this.currentPopup.classList.add("ejs_popup_container");
        this.elements.parent.appendChild(this.currentPopup);
        const title = this.createElement("h4");
        title.innerText = popupTitle;
        const main = this.createElement("div");
        main.classList.add("ejs_popup_body");
        
        this.currentPopup.appendChild(title);
        this.currentPopup.appendChild(main);
        
        for (let k in buttons) {
            const button = this.createElement("a");
            if (buttons[k] instanceof Function) {
                button.addEventListener("click", (e) => {
                    buttons[k]();
                    e.preventDefault();
                });
            }
            button.classList.add("ejs_button");
            button.innerText = k;
            this.currentPopup.appendChild(button);
        }
        
        return main;
    }
    selectFile() {
        return new Promise((resolve, reject) => {
            const file = this.createElement("input");
            file.type = "file";
            this.addEventListener(file, "change", (e) => {
                resolve(e.target.files[0]);
            })
            file.click();
        })
    }
    createBottomMenuBar() {
        this.elements.menu = this.createElement("div");
        this.elements.menu.classList.add("ejs_menu_bar");
        this.elements.menu.classList.add("ejs_menu_bar_hidden");
        
        let timeout = null;
        const hide = () => {
            if (this.paused) return;
            this.elements.menu.classList.add("ejs_menu_bar_hidden");
        }
        
        this.addEventListener(this.elements.parent, 'mousemove click', (e) => {
            if (!this.started) return;
            if (timeout !== null) clearTimeout(timeout);
            timeout = setTimeout(hide, 3000);
            this.elements.menu.classList.remove("ejs_menu_bar_hidden");
        })
        this.menu = {
            close: () => {
                if (!this.started) return;
                if (timeout !== null) clearTimeout(timeout);
                this.elements.menu.classList.remove("ejs_menu_bar_hidden");
            },
            open: () => {
                if (!this.started) return;
                if (timeout !== null) clearTimeout(timeout);
                timeout = setTimeout(hide, 3000);
                this.elements.menu.classList.remove("ejs_menu_bar_hidden");
            }
        }
        this.elements.parent.appendChild(this.elements.menu);
        
        //Now add buttons
        const addButton = (title, image, callback) => {
            const button = this.createElement("button");
            button.type = "button";
            const svg = document.createElementNS('http://www.w3.org/2000/svg', 'svg');
            svg.setAttribute("role", "presentation");
            svg.setAttribute("focusable", "false");
            svg.innerHTML = image;
            const text = this.createElement("span");
            text.innerText = title;
            text.classList.add("ejs_menu_text");
            
            button.classList.add("ejs_menu_button");
            button.appendChild(svg);
            button.appendChild(text);
            this.elements.menu.appendChild(button);
            if (callback instanceof Function) {
                this.addEventListener(button, 'click', callback);
            }
        }
        
        //todo. Center text on not restart button
        
        addButton("Restart", '<svg viewBox="0 0 512 512"><path d="M496 48V192c0 17.69-14.31 32-32 32H320c-17.69 0-32-14.31-32-32s14.31-32 32-32h63.39c-29.97-39.7-77.25-63.78-127.6-63.78C167.7 96.22 96 167.9 96 256s71.69 159.8 159.8 159.8c34.88 0 68.03-11.03 95.88-31.94c14.22-10.53 34.22-7.75 44.81 6.375c10.59 14.16 7.75 34.22-6.375 44.81c-39.03 29.28-85.36 44.86-134.2 44.86C132.5 479.9 32 379.4 32 256s100.5-223.9 223.9-223.9c69.15 0 134 32.47 176.1 86.12V48c0-17.69 14.31-32 32-32S496 30.31 496 48z"/></svg>', () => {
            this.gameManager.restart();
        });
        let stateUrl;
        addButton("Save State", '<svg viewBox="0 0 448 512"><path fill="currentColor" d="M433.941 129.941l-83.882-83.882A48 48 0 0 0 316.118 32H48C21.49 32 0 53.49 0 80v352c0 26.51 21.49 48 48 48h352c26.51 0 48-21.49 48-48V163.882a48 48 0 0 0-14.059-33.941zM224 416c-35.346 0-64-28.654-64-64 0-35.346 28.654-64 64-64s64 28.654 64 64c0 35.346-28.654 64-64 64zm96-304.52V212c0 6.627-5.373 12-12 12H76c-6.627 0-12-5.373-12-12V108c0-6.627 5.373-12 12-12h228.52c3.183 0 6.235 1.264 8.485 3.515l3.48 3.48A11.996 11.996 0 0 1 320 111.48z"/></svg>', async () => {
            if (stateUrl) URL.revokeObjectURL(stateUrl);
            const state = await this.gameManager.getState();
            const blob = new Blob([state]);
            stateUrl = URL.createObjectURL(blob);
            const a = this.createElement("a");
            a.href = stateUrl;
            a.download = "game.state";
            a.click();
        });
        addButton("Load State", '<svg viewBox="0 0 576 512"><path fill="currentColor" d="M572.694 292.093L500.27 416.248A63.997 63.997 0 0 1 444.989 448H45.025c-18.523 0-30.064-20.093-20.731-36.093l72.424-124.155A64 64 0 0 1 152 256h399.964c18.523 0 30.064 20.093 20.73 36.093zM152 224h328v-48c0-26.51-21.49-48-48-48H272l-64-64H48C21.49 64 0 85.49 0 112v278.046l69.077-118.418C86.214 242.25 117.989 224 152 224z"/></svg>', async () => {
            const file = await this.selectFile();
            const state = new Uint8Array(await file.arrayBuffer());
            this.gameManager.loadState(state);
        });
        
    }
    
}