const Desklet = imports.ui.desklet;
const Settings = imports.ui.settings;
const Mainloop = imports.mainloop;
const Lang = imports.lang;
const Clutter = imports.gi.Clutter;
const Cinnamon = imports.gi.Cinnamon;
const Gio = imports.gi.Gio;
const Cairo = imports.cairo;
const St = imports.gi.St;
const Util = imports.misc.util;

const UUID = "system-monitor-graph@rcassani";
const DESKLET_PATH = imports.ui.deskletManager.deskletMeta[UUID].path;
const GB_TO_KB = 1048576; // 1 GB = 1,048,576 kB


function MyDesklet(metadata, desklet_id) {
  this._init(metadata, desklet_id);
}

function main(metadata, desklet_id) {
  return new MyDesklet(metadata, desklet_id);
}

MyDesklet.prototype = {
    __proto__: Desklet.Desklet.prototype,

    _init: function(metadata, desklet_id) {
        Desklet.Desklet.prototype._init.call(this, metadata, desklet_id);

        // initialize settings
        this.settings = new Settings.DeskletSettings(this, this.metadata["uuid"], desklet_id);
        this.settings.bindProperty(Settings.BindingDirection.IN, "type", "type", this.on_setting_changed);
        this.settings.bindProperty(Settings.BindingDirection.IN, "filesystem", "filesystem", this.on_setting_changed);
        this.settings.bindProperty(Settings.BindingDirection.IN, "refresh-interval", "refresh_interval", this.on_setting_changed);
        this.settings.bindProperty(Settings.BindingDirection.IN, "duration", "duration", this.on_setting_changed);
        this.settings.bindProperty(Settings.BindingDirection.IN, "background-color", "background_color", this.on_setting_changed);
        this.settings.bindProperty(Settings.BindingDirection.IN, "h-midlines", "h_midlines", this.on_setting_changed);
        this.settings.bindProperty(Settings.BindingDirection.IN, "v-midlines", "v_midlines", this.on_setting_changed);
        this.settings.bindProperty(Settings.BindingDirection.IN, "scale-size", "scale_size", this.on_setting_changed);
        this.settings.bindProperty(Settings.BindingDirection.IN, "midline-color", "midline_color", this.on_setting_changed);
        this.settings.bindProperty(Settings.BindingDirection.IN, "text-color", "text_color", this.on_setting_changed);
        this.settings.bindProperty(Settings.BindingDirection.IN, "line-color-cpu", "line_color_cpu", this.on_setting_changed);
        this.settings.bindProperty(Settings.BindingDirection.IN, "line-color-ram", "line_color_ram", this.on_setting_changed);
        this.settings.bindProperty(Settings.BindingDirection.IN, "line-color-hdd", "line_color_hdd", this.on_setting_changed);

        // initialize desklet GUI
        this.setupUI();
    },

    setupUI: function(){
        // initialize this.canvas
        this.canvas = new Clutter.Actor();
        this.canvas.remove_all_children();
        this.text1 = new St.Label();
        this.text2 = new St.Label();
        this.text3 = new St.Label();
        this.canvas.add_actor(this.text1);
        this.canvas.add_actor(this.text2);
        this.canvas.add_actor(this.text3);
        this.setContent(this.canvas);

        // flag to indicate the first loop of the Desklet
        this.first_run = true;
        // update loop for Desklet
        this.update();
    },

    update: function() {
        // monitors a given variable and plot its graph
        this.update_draw();
        // call this.update() every in refresh_interval seconds
        this.timeout = Mainloop.timeout_add_seconds(this.refresh_interval, Lang.bind(this, this.update));
    },

    update_draw: function() {
        // values needed in first run
        if (this.first_run){
            this.n_values = Math.floor(this.duration / this.refresh_interval)  + 1;
            this.values = new Array(this.n_values).fill(0.0);
            this.cpu_cpu_tot = 0;
            this.cpu_cpu_idl = 0;
            this.hdd_cpu_tot = 0;
            this.hdd_hdd_tot = 0;
            // set colors
            switch (this.type) {
              case "cpu":
                  this.line_color = this.line_color_cpu;
                  break;
              case "ram":
                  this.line_color = this.line_color_ram;
                  break;
              case "hdd":
                  this.line_color = this.line_color_hdd;
            }
            this.first_run = false;
        }

        // Desklet proportions
        let unit_size = 15 * this.scale_size;  // pixels
        var line_width = unit_size / 15;
        var margin_up = 3 * unit_size;
        var graph_w = 20 * unit_size;
        var graph_h =  4 * unit_size;
        let desklet_w = graph_w + (2 * unit_size);
        let desklet_h = graph_h + (4 * unit_size);
        var h_midlines = this.h_midlines;
        var v_midlines = this.v_midlines;
        let text1_size = 4 * unit_size / 3;
        let text2_size = 4 * unit_size / 3;
        let text3_size = 3 * unit_size / 3;
        var radius = 2 * unit_size / 3;;
        var degrees = Math.PI / 180.0;

        let n_values = this.n_values;
        let values = this.values;
        let graph_step = graph_w / (n_values -1);

        var value = 0.0;
        var text1 = '';
        var text2 = '';
        var text3 = '';
        var line_colors = this.parse_rgba_seetings(this.line_color);

        // current values
        switch (this.type) {
          case "cpu":
              let cpu_use = this.get_cpu_use();
              value = cpu_use / 100;
              text1 = "CPU";
              text2 = Math.round(cpu_use).toString() + "%";
              break;

          case "ram":
              let ram_values = this.get_ram_values();
              let ram_use = 100 * ram_values[1] / ram_values[0];
              value = ram_use / 100;
              text1 = "RAM";
              text2 = Math.round(ram_use).toString() + "%"
              text3 = ram_values[1].toFixed(1) + " / "
                    + ram_values[0].toFixed(1) + " GB";
              break;

          case "hdd":
              let dir_path = decodeURIComponent(this.filesystem.replace("file://", "").trim());
              if(dir_path == null || dir_path == "") dir_path = "/";
              let hdd_values = this.get_hdd_values(dir_path);
              let hdd_use = Math.min(hdd_values[1], 100); //already in %
              value = hdd_use / 100;
              text1 = hdd_values[0];
              text2 = Math.round(hdd_use).toString() + "%"
              text3 = hdd_values[3].toFixed(0) + " GB free of "
                    + hdd_values[2].toFixed(0) + " GB";


              break;
        }

        // concatenate new value
        values.push(value);
        values.shift();
        this.values = values;

        var background_colors = this.parse_rgba_seetings(this.background_color);
        var midline_colors = this.parse_rgba_seetings(this.midline_color);



        // draws graph
        let canvas = new Clutter.Canvas();
        canvas.set_size(desklet_w, desklet_h);
        canvas.connect('draw', function (canvas, ctx, desklet_w, desklet_h) {
            ctx.save();
            ctx.setOperator(Cairo.Operator.CLEAR);
            ctx.paint();
            ctx.restore();
            ctx.setOperator(Cairo.Operator.OVER);
            ctx.setLineWidth(2 * line_width);

            // desklet background
            ctx.setSourceRGBA(background_colors[0], background_colors[1], background_colors[2], background_colors[3]);
            ctx.newSubPath();
            ctx.arc(desklet_w - radius, radius, radius, -90 * degrees, 0 * degrees);
            ctx.arc(desklet_w - radius, desklet_h - radius, radius, 0 * degrees, 90 * degrees);
            ctx.arc(radius, desklet_h - radius, radius, 90 * degrees, 180 * degrees);
            ctx.arc(radius, radius, radius, 180 * degrees, 270 * degrees);
            ctx.closePath();
            ctx.fill();

            // graph border
            ctx.setSourceRGBA(line_colors[0], line_colors[1], line_colors[2], 1);
            ctx.rectangle(unit_size, margin_up, graph_w, graph_h);
            ctx.stroke();

            // graph V and H midlines
            ctx.setSourceRGBA(midline_colors[0], midline_colors[1], midline_colors[2], 1);
            ctx.setLineWidth(line_width);
            for (let i = 1; i<v_midlines; i++){
                ctx.moveTo((i * graph_w / v_midlines) + unit_size, margin_up);
                ctx.relLineTo(0, graph_h);
                ctx.stroke();
            }
            for (let i = 1; i<h_midlines; i++){
                ctx.moveTo(unit_size, margin_up + i * (graph_h / h_midlines));
                ctx.relLineTo(graph_w, 0);
                ctx.stroke();
            }

            // timeseries and area
            ctx.setLineWidth(2 * line_width);
            ctx.setSourceRGBA(line_colors[0], line_colors[1], line_colors[2], 1);
            ctx.moveTo(unit_size, margin_up + graph_h - (values[0] * graph_h));
            for (let i = 1; i<n_values; i++){
                ctx.lineTo(unit_size + (i * graph_step), margin_up + graph_h - (values[i] * graph_h));
            }
            ctx.strokePreserve();
            ctx.lineTo(unit_size + graph_w, margin_up + graph_h);
            ctx.lineTo(unit_size, margin_up + graph_h);
            ctx.closePath();
            ctx.setSourceRGBA(line_colors[0], line_colors[1], line_colors[2], 0.4);
            ctx.fill();

            return false;
        });

        // text position and content
        this.text1.set_position(unit_size, unit_size);
        this.text1.set_text(text1);
        this.text1.style = "font-size: " + text1_size + "px;"
                         + "color: " + this.text_color + ";";
        this.text2.set_position(5 * unit_size, unit_size);
        this.text2.set_text(text2);
        this.text2.style = "font-size: " + text2_size + "px;"
                         + "color: " + this.text_color + ";";
        this.text3.set_position(9.5 * unit_size, unit_size * 1.4);
        this.text3.set_text(text3);
        this.text3.style = "font-size: " + text3_size + "px;"
                         + "color: " + this.text_color + ";";

        // update canvas
        canvas.invalidate();
        this.canvas.set_content(canvas);
        this.canvas.set_size(desklet_w, desklet_h);
    },

    on_setting_changed: function() {
        // settings changed; instant refresh
        Mainloop.source_remove(this.timeout);
        this.first_run = true;
        this.update();
   },

    on_desklet_removed: function() {
        Mainloop.source_remove(this.timeout);
    },

    get_cpu_use: function() {
        // https://rosettacode.org/wiki/Linux_CPU_utilization
        let cpu_line = Cinnamon.get_file_contents_utf8_sync("/proc/stat").match(/cpu\s.+/)[0];
        let cpu_values = cpu_line.split(/\s+/);
        let cpu_idl = parseFloat(cpu_values[4]);
        let cpu_tot = 0;
        for (let i = 1; i<10; i++){
          cpu_tot += parseFloat(cpu_values[i])
        }
        let cpu_use = 100 * (1 - (cpu_idl - this.cpu_cpu_idl) / (cpu_tot - this.cpu_cpu_tot));
        this.cpu_cpu_tot = cpu_tot;
        this.cpu_cpu_idl = cpu_idl;
        return cpu_use;
    },

    get_ram_values: function() {
        // https://www.man7.org/linux/man-pages/man1/free.1.html
        let mem_out = Cinnamon.get_file_contents_utf8_sync("/proc/meminfo");
        let mem_tot = parseInt(mem_out.match(/(MemTotal):\D+(\d+)/)[2]);
        let mem_usd = mem_tot - parseInt(mem_out.match(/(MemFree):\D+(\d+)/)[2])
                             - parseInt(mem_out.match(/(Cached):\D+(\d+)/)[2])
                             - parseInt(mem_out.match(/(Buffers):\D+(\d+)/)[2])
                             - parseInt(mem_out.match(/(SReclaimable):\D+(\d+)/)[2]);

        let ram_tot = mem_tot / GB_TO_KB;
        let ram_usd = mem_usd / GB_TO_KB;
        return [ram_tot, ram_usd];
    },

    get_hdd_values: function(dir_path) {
        let subprocess = new Gio.Subprocess({
            argv: ['/bin/df', dir_path],
            flags: Gio.SubprocessFlags.STDOUT_PIPE,
        });
        subprocess.init(null);
        let [, out] = subprocess.communicate_utf8(null, null); // get full output from stdout
        let df_line = out.match(/.+/g)[1];
        let df_values = df_line.split(/\s+/); // split by space
        // values for partition space
        let hdd_tot = (parseFloat(df_values[3]) + parseFloat(df_values[2]) ) / GB_TO_KB;
        let hdd_fre = parseFloat(df_values[3]) / GB_TO_KB;
        // utilization of partition
        let dev_fs = df_values[0];
        let fs = dev_fs.split(/\/+/)[2];
        let hdd_use = this.get_hdd_use(fs);
        return [fs, hdd_use, hdd_tot, hdd_fre];
    },

    get_hdd_use: function(fs) {
      // https://stackoverflow.com/questions/4458183/how-the-util-of-iostat-is-computed
      let cpu_line = Cinnamon.get_file_contents_utf8_sync("/proc/stat").match(/cpu\s.+/)[0];
      let re = new RegExp(fs + '.+');
      let hdd_line = Cinnamon.get_file_contents_utf8_sync("/proc/diskstats").match(re)[0];
      // get total CPU time
      let cpu_values = cpu_line.split(/\s+/);
      let hdd_cpu_tot = 0;
      for (let i = 1; i<10; i++){
        hdd_cpu_tot += parseFloat(cpu_values[i])
      }
      // get total of IO times
      let hdd_hdd_tot = hdd_line.split(/\s+/)[10];
      // update HHD use
      let hdd_use = 100 * (hdd_hdd_tot - this.hdd_hdd_tot) / (hdd_cpu_tot - this.hdd_cpu_tot);
      // update global values
      this.hdd_cpu_tot = hdd_cpu_tot;
      this.hdd_hdd_tot = hdd_hdd_tot;

      return hdd_use;
    },

    parse_rgba_seetings: function(color_str) {
        let colors = color_str.match(/\((.*?)\)/)[1].split(","); // get contents inside brackets: "rgb(...)"
        let r = parseInt(colors[0])/255;
        let g = parseInt(colors[1])/255;
        let b = parseInt(colors[2])/255;
        let a = 1;
        if (colors.length > 3) a = colors[3];
        return [r, g, b, a];
    }

};