// svghmi.js

var need_cache_apply = [];

function dispatch_value(index, value) {
    let widgets = subscribers(index);

    let oldval = cache[index];
    cache[index] = value;

    if(widgets.size > 0) {
        for(let widget of widgets){
            widget.new_hmi_value(index, value, oldval);
        }
    }
};

function init_widgets() {
    Object.keys(hmi_widgets).forEach(function(id) {
        let widget = hmi_widgets[id];
        widget.do_init();
    });
};

// Open WebSocket to relative "/ws" address
var has_watchdog = window.location.hash == "#watchdog";

var ws_url = 
    window.location.href.replace(/^http(s?:\/\/[^\/]*)\/.*$/, 'ws$1/ws')
    + '?mode=' + (has_watchdog ? "watchdog" : "multiclient");

var ws = new WebSocket(ws_url);
ws.binaryType = 'arraybuffer';

const dvgetters = {
    INT: (dv,offset) => [dv.getInt16(offset, true), 2],
    BOOL: (dv,offset) => [dv.getInt8(offset, true), 1],
    NODE: (dv,offset) => [dv.getInt8(offset, true), 1],
    REAL: (dv,offset) => [dv.getFloat32(offset, true), 4],
    STRING: (dv, offset) => {
        const size = dv.getInt8(offset);
        return [
            String.fromCharCode.apply(null, new Uint8Array(
                dv.buffer, /* original buffer */
                offset + 1, /* string starts after size*/
                size /* size of string */
            )), size + 1]; /* total increment */
    }
};

// Apply updates recieved through ws.onmessage to subscribed widgets
function apply_updates() {
    updates.forEach((value, index) => {
        dispatch_value(index, value);
    });
    updates.clear();
}

// Called on requestAnimationFrame, modifies DOM
var requestAnimationFrameID = null;
function animate() {
    // Do the page swith if any one pending
    if(current_subscribed_page != current_visible_page){
        switch_visible_page(current_subscribed_page);
    }

    while(widget = need_cache_apply.pop()){
        widget.apply_cache();
    }

    if(jumps_need_update) update_jumps();

    apply_updates();

    pending_widget_animates.forEach(widget => widget._animate());
    pending_widget_animates = [];

    requestAnimationFrameID = null;
}

function requestHMIAnimation() {
    if(requestAnimationFrameID == null){
        requestAnimationFrameID = window.requestAnimationFrame(animate);
    }
}

// Message reception handler
// Hash is verified and HMI values updates resulting from binary parsing
// are stored until browser can compute next frame, DOM is left untouched
ws.onmessage = function (evt) {

    let data = evt.data;
    let dv = new DataView(data);
    let i = 0;
    try {
        for(let hash_int of hmi_hash) {
            if(hash_int != dv.getUint8(i)){
                throw new Error("Hash doesn't match");
            };
            i++;
        };

        while(i < data.byteLength){
            let index = dv.getUint32(i, true);
            i += 4;
            let iectype = hmitree_types[index];
            if(iectype != undefined){
                let dvgetter = dvgetters[iectype];
                let [value, bytesize] = dvgetter(dv,i);
                updates.set(index, value);
                i += bytesize;
            } else {
                throw new Error("Unknown index "+index);
            }
        };
        // register for rendering on next frame, since there are updates
        requestHMIAnimation();
    } catch(err) {
        // 1003 is for "Unsupported Data"
        // ws.close(1003, err.message);

        // TODO : remove debug alert ?
        alert("Error : "+err.message+"\\\\nHMI will be reloaded.");

        // force reload ignoring cache
        location.reload(true);
    }
};

hmi_hash_u8 = new Uint8Array(hmi_hash);

function send_blob(data) {
    if(data.length > 0) {
        ws.send(new Blob([hmi_hash_u8].concat(data)));
    };
};

const typedarray_types = {
    INT: (number) => new Int16Array([number]),
    BOOL: (truth) => new Int16Array([truth]),
    NODE: (truth) => new Int16Array([truth]),
    REAL: (number) => new Float32Array([number]),
    STRING: (str) => {
        // beremiz default string max size is 128
        str = str.slice(0,128);
        binary = new Uint8Array(str.length + 1);
        binary[0] = str.length;
        for(let i = 0; i < str.length; i++){
            binary[i+1] = str.charCodeAt(i);
        }
        return binary;
    }
    /* TODO */
};

function send_reset() {
    send_blob(new Uint8Array([1])); /* reset = 1 */
};

var subscriptions = [];

function subscribers(index) {
    let entry = subscriptions[index];
    let res;
    if(entry == undefined){
        res = new Set();
        subscriptions[index] = [res,0];
    }else{
        [res, _ign] = entry;
    }
    return res
}

function get_subscription_period(index) {
    let entry = subscriptions[index];
    if(entry == undefined)
        return 0;
    let [_ign, period] = entry;
    return period;
}

function set_subscription_period(index, period) {
    let entry = subscriptions[index];
    if(entry == undefined){
        subscriptions[index] = [new Set(), period];
    } else {
        entry[1] = period;
    }
}

if(has_watchdog){
    // artificially subscribe the watchdog widget to "/heartbeat" hmi variable
    // Since dispatch directly calls change_hmi_value,
    // PLC will periodically send variable at given frequency
    subscribers(heartbeat_index).add({
        /* type: "Watchdog", */
        frequency: 1,
        indexes: [heartbeat_index],
        new_hmi_value: function(index, value, oldval) {
            apply_hmi_value(heartbeat_index, value+1);
        }
    });
}

// subscribe to per instance current page hmi variable
// PLC must prefix page name with "!" for page switch to happen
subscribers(current_page_var_index).add({
    frequency: 1,
    indexes: [current_page_var_index],
    new_hmi_value: function(index, value, oldval) {
        if(value.startsWith("!"))
            switch_page(value.slice(1));
    }
});

function svg_text_to_multiline(elt) {
    return(Array.prototype.map.call(elt.children, x=>x.textContent).join("\\\\n")); 
}

function multiline_to_svg_text(elt, str) {
    str.split('\\\\n').map((line,i) => {elt.children[i].textContent = line;});
}

function switch_langnum(langnum) {
    langnum = Math.max(0, Math.min(langs.length - 1, langnum));

    for (let translation of translations) {
        let [objs, msgs] = translation;
        let msg = msgs[langnum];
        for (let obj of objs) {
            multiline_to_svg_text(obj, msg);
            obj.setAttribute("lang",langnum);
        }
    }
    return langnum;
}

// backup original texts
for (let translation of translations) {
    let [objs, msgs] = translation;
    msgs.unshift(svg_text_to_multiline(objs[0])); 
}

var lang_local_index = hmi_local_index("lang");
var langcode_local_index = hmi_local_index("lang_code");
var langname_local_index = hmi_local_index("lang_name");
subscribers(lang_local_index).add({
    indexes: [lang_local_index],
    new_hmi_value: function(index, value, oldval) {
        let current_lang =  switch_langnum(value);
        let [langname,langcode] = langs[current_lang];
        apply_hmi_value(langcode_local_index, langcode);
        apply_hmi_value(langname_local_index, langname);
        switch_page();
    }
});

// returns en_US, fr_FR or en_UK depending on selected language
function get_current_lang_code(){
    return cache[langcode_local_index];
}

function setup_lang(){
    let current_lang = cache[lang_local_index];
    let new_lang = switch_langnum(current_lang);
    if(current_lang != new_lang){
        apply_hmi_value(lang_local_index, new_lang);
    }
}

setup_lang();

function update_subscriptions() {
    let delta = [];
    for(let index in subscriptions){
        let widgets = subscribers(index);

        // periods are in ms
        let previous_period = get_subscription_period(index);

        // subscribing with a zero period is unsubscribing
        let new_period = 0;
        if(widgets.size > 0) {
            let maxfreq = 0;
            for(let widget of widgets){
                let wf = widget.frequency;
                if(wf != undefined && maxfreq < wf)
                    maxfreq = wf;
            }

            if(maxfreq != 0)
                new_period = 1000/maxfreq;
        }

        if(previous_period != new_period) {
            set_subscription_period(index, new_period);
            if(index <= last_remote_index){
                delta.push(
                    new Uint8Array([2]), /* subscribe = 2 */
                    new Uint32Array([index]),
                    new Uint16Array([new_period]));
            }
        }
    }
    send_blob(delta);
};

function send_hmi_value(index, value) {
    if(index > last_remote_index){
        updates.set(index, value);

        if(persistent_indexes.has(index)){
            let varname = persistent_indexes.get(index);
            document.cookie = varname+"="+value+"; max-age=3153600000";
        }

        requestHMIAnimation();
        return;
    }

    let iectype = hmitree_types[index];
    let tobinary = typedarray_types[iectype];
    send_blob([
        new Uint8Array([0]),  /* setval = 0 */
        new Uint32Array([index]),
        tobinary(value)]);

    // DON'T DO THAT unless read_iterator in svghmi.c modifies wbuf as well, not only rbuf
    // cache[index] = value;
};

function apply_hmi_value(index, new_val) {
    // Similarly to previous comment, taking decision to update based 
    // on cache content is bad and can lead to inconsistency
    /*let old_val = cache[index];*/
    if(new_val != undefined /*&& old_val != new_val*/)
        send_hmi_value(index, new_val);
    return new_val;
}

const quotes = {"'":null, '"':null};

function eval_operation_string(old_val, opstr) {
    let op = opstr[0];
    let given_val;
    if(opstr.length < 2) 
        return undefined;
    if(opstr[1] in quotes){
        if(opstr.length < 3) 
            return undefined;
        if(opstr[opstr.length-1] == opstr[1]){
            given_val = opstr.slice(2,opstr.length-1);
        }
    } else {
        given_val = Number(opstr.slice(1));
    }
    let new_val;
    switch(op){
      case "=":
        new_val = given_val;
        break;
      case "+":
        new_val = old_val + given_val;
        break;
      case "-":
        new_val = old_val - given_val;
        break;
      case "*":
        new_val = old_val * given_val;
        break;
      case "/":
        new_val = old_val / given_val;
        break;
    }
    return new_val;
}

var current_visible_page;
var current_subscribed_page;
var current_page_index;
var page_node_local_index = hmi_local_index("page_node");

function toggleFullscreen() {
  let elem = document.documentElement;

  if (!document.fullscreenElement) {
    elem.requestFullscreen().catch(err => {
      console.log("Error attempting to enable full-screen mode: "+err.message+" ("+err.name+")");
    });
  } else {
    document.exitFullscreen();
  }
}

function prepare_svg() {
    // prevents context menu from appearing on right click and long touch
    document.body.addEventListener('contextmenu', e => {
        toggleFullscreen();
        e.preventDefault();
    });

    for(let eltid in detachable_elements){
        let [element,parent] = detachable_elements[eltid];
        parent.removeChild(element);
    }
};

function switch_page(page_name, page_index) {
    if(current_subscribed_page != current_visible_page){
        /* page switch already going */
        /* TODO LOG ERROR */
        return false;
    }

    if(page_name == undefined)
        page_name = current_subscribed_page;
    else if(page_index == undefined){
        [page_name, page_index] = page_name.split('@')
    }

    let old_desc = page_desc[current_subscribed_page];
    let new_desc = page_desc[page_name];

    if(new_desc == undefined){
        /* TODO LOG ERROR */
        return false;
    }

    if(page_index == undefined)
        page_index = new_desc.page_index;
    else if(typeof(page_index) == "string") {
        let hmitree_node = hmitree_nodes[page_index];
        if(hmitree_node !== undefined){
            let [int_index, hmiclass] = hmitree_node;
            if(hmiclass == new_desc.page_class)
                page_index = int_index;
            else
                page_index = new_desc.page_index;
        } else {
            page_index = new_desc.page_index;
        }
    }

    if(old_desc){
        old_desc.widgets.map(([widget,relativeness])=>widget.unsub());
    }
    const new_offset = page_index == undefined ? 0 : page_index - new_desc.page_index;

    const container_id = page_name + (page_index != undefined ? page_index : "");

    new_desc.widgets.map(([widget,relativeness])=>widget.sub(new_offset,relativeness,container_id));

    update_subscriptions();

    current_subscribed_page = page_name;
    current_page_index = page_index;
    let page_node;
    if(page_index != undefined){
        page_node = hmitree_paths[page_index];
    }else{
        page_node = "";
    }
    apply_hmi_value(page_node_local_index, page_node);

    jumps_need_update = true;

    requestHMIAnimation();
    jump_history.push([page_name, page_index]);
    if(jump_history.length > 42)
        jump_history.shift();

    apply_hmi_value(current_page_var_index, page_index == undefined
        ? page_name
        : page_name + "@" + hmitree_paths[page_index]);

    return true;
};

function switch_visible_page(page_name) {

    let old_desc = page_desc[current_visible_page];
    let new_desc = page_desc[page_name];

    if(old_desc){
        for(let eltid in old_desc.required_detachables){
            if(!(eltid in new_desc.required_detachables)){
                let [element, parent] = old_desc.required_detachables[eltid];
                parent.removeChild(element);
            }
        }
        for(let eltid in new_desc.required_detachables){
            if(!(eltid in old_desc.required_detachables)){
                let [element, parent] = new_desc.required_detachables[eltid];
                parent.appendChild(element);
            }
        }
    }else{
        for(let eltid in new_desc.required_detachables){
            let [element, parent] = new_desc.required_detachables[eltid];
            parent.appendChild(element);
        }
    }

    svg_root.setAttribute('viewBox',new_desc.bbox.join(" "));
    current_visible_page = page_name;
};

// Once connection established
ws.onopen = function (evt) {
    init_widgets();
    send_reset();
    // show main page
    prepare_svg();
    switch_page(default_page);
};

ws.onclose = function (evt) {
    // TODO : add visible notification while waiting for reload
    console.log("Connection closed. code:"+evt.code+" reason:"+evt.reason+" wasClean:"+evt.wasClean+" Reload in 10s.");
    // TODO : re-enable auto reload when not in debug
    //window.setTimeout(() => location.reload(true), 10000);
    alert("Connection closed. code:"+evt.code+" reason:"+evt.reason+" wasClean:"+evt.wasClean+".");

};

const xmlns = "http://www.w3.org/2000/svg";
var edit_callback;
const localtypes = {"PAGE_LOCAL":null, "HMI_LOCAL":null}
function edit_value(path, valuetype, callback, initial) {
    if(valuetype in localtypes){
        valuetype = (typeof initial) == "number" ? "HMI_REAL" : "HMI_STRING";
    }
    let [keypadid, xcoord, ycoord] = keypads[valuetype];
    edit_callback = callback;
    let widget = hmi_widgets[keypadid];
    widget.start_edit(path, valuetype, callback, initial);
};

var current_modal; /* TODO stack ?*/

function show_modal() {
    let [element, parent] = detachable_elements[this.element.id];

    tmpgrp = document.createElementNS(xmlns,"g");
    tmpgrpattr = document.createAttribute("transform");
    let [xcoord,ycoord] = this.coordinates;
    let [xdest,ydest] = page_desc[current_visible_page].bbox;
    tmpgrpattr.value = "translate("+String(xdest-xcoord)+","+String(ydest-ycoord)+")";

    tmpgrp.setAttributeNode(tmpgrpattr);

    tmpgrp.appendChild(element);
    parent.appendChild(tmpgrp);

    current_modal = [this.element.id, tmpgrp];
};

function end_modal() {
    let [eltid, tmpgrp] = current_modal;
    let [element, parent] = detachable_elements[this.element.id];

    parent.removeChild(tmpgrp);

    current_modal = undefined;
};