/* -*- mode: js2; js2-basic-offset: 4; indent-tabs-mode: nil -*- */

/* exported init */

const { Clutter, GLib, GTop, Shell, St } = imports.gi;
const Signals = imports.signals;

const ExtensionUtils = imports.misc.extensionUtils;
const Main = imports.ui.main;
const MessageList = imports.ui.messageList;
const Tweener = imports.ui.tweener;

const Gettext = imports.gettext.domain('gnome-shell-extensions');
const _ = Gettext.gettext;

const INDICATOR_UPDATE_INTERVAL = 500;
const INDICATOR_NUM_GRID_LINES = 3;

const ITEM_LABEL_SHOW_TIME = 0.15;
const ITEM_LABEL_HIDE_TIME = 0.1;
const ITEM_HOVER_TIMEOUT = 300;

const Indicator = class {
    constructor() {
        this._initValues();
        this._drawingArea = new St.DrawingArea();
        this._drawingArea.connect('repaint', this._draw.bind(this));

        this.actor = new St.Button({
            style_class: 'message message-content extension-systemMonitor-indicator-area',
            child: this._drawingArea,
            x_expand: true,
            x_fill: true,
            y_fill: true,
            can_focus: true
        });

        this.actor.connect('clicked', () => {
            let app = Shell.AppSystem.get_default().lookup_app('gnome-system-monitor.desktop');
            app.open_new_window(-1);

            Main.overview.hide();
            Main.panel.closeCalendar();
        });

        this.actor.connect('destroy', this._onDestroy.bind(this));

        this._timeout = GLib.timeout_add(GLib.PRIORITY_DEFAULT,
            INDICATOR_UPDATE_INTERVAL,
            () => {
                this._updateValues();
                this._drawingArea.queue_repaint();
                return GLib.SOURCE_CONTINUE;
            });
    }

    showLabel() {
        if (this.label == null)
            return;

        this.label.opacity = 0;
        this.label.show();

        let [stageX, stageY] = this.actor.get_transformed_position();

        let itemWidth = this.actor.allocation.x2 - this.actor.allocation.x1;

        let labelWidth = this.label.width;
        let xOffset = Math.floor((itemWidth - labelWidth) / 2);

        let x = stageX + xOffset;

        let node = this.label.get_theme_node();
        let yOffset = node.get_length('-y-offset');

        let y = stageY - this.label.get_height() - yOffset;

        this.label.set_position(x, y);
        this.label.get_parent().set_child_above_sibling(this.label, null);
        Tweener.addTween(this.label, {
            opacity: 255,
            time: ITEM_LABEL_SHOW_TIME,
            transition: 'easeOutQuad',
        });
    }

    setLabelText(text) {
        if (this.label == null)
            this.label = new St.Label({
                style_class: 'extension-systemMonitor-indicator-label'
            });

        this.label.set_text(text);
        Main.layoutManager.addChrome(this.label);
        this.label.hide();
    }

    hideLabel() {
        Tweener.addTween(this.label, {
            opacity: 0,
            time: ITEM_LABEL_HIDE_TIME,
            transition: 'easeOutQuad',
            onComplete: () => this.label.hide()
        });
    }

    /* MessageList.Message boilerplate */
    canClose() {
        return false;
    }

    clear() {
    }

    destroy() {
        this.actor.destroy();
    }

    _onDestroy() {
        GLib.source_remove(this._timeout);

        if (this.label)
            this.label.destroy();
    }

    _initValues() {
    }

    _updateValues() {
    }

    _draw(area) {
        let [width, height] = area.get_surface_size();
        let themeNode = this.actor.get_theme_node();
        let cr = area.get_context();

        //draw the background grid
        let color = themeNode.get_color(this.gridColor);
        let gridOffset = Math.floor(height / (INDICATOR_NUM_GRID_LINES + 1));
        for (let i = 1; i <= INDICATOR_NUM_GRID_LINES; ++i) {
            cr.moveTo(0, i * gridOffset + .5);
            cr.lineTo(width, i * gridOffset + .5);
        }
        Clutter.cairo_set_source_color(cr, color);
        cr.setLineWidth(1);
        cr.setDash([4, 1], 0);
        cr.stroke();

        //draw the foreground

        function makePath(values, reverse, nudge) {
            if (nudge == null) {
                nudge = 0;
            }
            //if we are going in reverse, we are completing the bottom of a chart, so use lineTo
            if (reverse) {
                cr.lineTo(values.length - 1, (1 - values[values.length - 1]) * height + nudge);
                for (let k = values.length - 2; k >= 0; --k) {
                    cr.lineTo(k, (1 - values[k]) * height + nudge);
                }
            } else {
                cr.moveTo(0, (1 - values[0]) * height + nudge);
                for (let k = 1; k < values.length; ++k) {
                    cr.lineTo(k, (1 - values[k]) * height + nudge);
                }

            }
        }

        let renderStats = this.renderStats;

        // Make sure we don't have more sample points than pixels
        renderStats.map(k => {
            let stat = this.stats[k];
            if (stat.values.length > width) {
                stat.values = stat.values.slice(stat.values.length - width, stat.values.length);
            }
        });

        for (let i = 0; i < renderStats.length; ++i) {
            let stat = this.stats[renderStats[i]];
            // We outline at full opacity and fill with 40% opacity
            let outlineColor = themeNode.get_color(stat.color);
            let color = new Clutter.Color(outlineColor);
            color.alpha = color.alpha * .4;

            // Render the background between us and the next level
            makePath(stat.values, false);
            // If there is a process below us, render the cpu between us and it, otherwise,
            // render to the bottom of the chart
            if (i == renderStats.length - 1) {
                cr.lineTo(stat.values.length - 1, height);
                cr.lineTo(0, height);
                cr.closePath();
            } else {
                let nextStat = this.stats[renderStats[i + 1]];
                makePath(nextStat.values, true);
            }
            cr.closePath();
            Clutter.cairo_set_source_color(cr, color);
            cr.fill();

            // Render the outline of this level
            makePath(stat.values, false, .5);
            Clutter.cairo_set_source_color(cr, outlineColor);
            cr.setLineWidth(1.0);
            cr.setDash([], 0);
            cr.stroke();
        }
    }
};
Signals.addSignalMethods(Indicator.prototype); // For MessageList.Message compat

const CpuIndicator = class extends Indicator {
    constructor() {
        super();

        this.gridColor = '-grid-color';
        this.renderStats = ['cpu-user', 'cpu-sys', 'cpu-iowait'];

        // Make sure renderStats is sorted as necessary for rendering
        let renderStatOrder = {
            'cpu-total': 0,
            'cpu-user': 1,
            'cpu-sys': 2,
            'cpu-iowait': 3
        };
        this.renderStats = this.renderStats.sort((a, b) => {
            return renderStatOrder[a] - renderStatOrder[b];
        });

        this.setLabelText(_('CPU'));
    }

    _initValues() {
        this._prev = new GTop.glibtop_cpu;
        GTop.glibtop_get_cpu(this._prev);

        this.stats = {
            'cpu-user': { color: '-cpu-user-color', values: [] },
            'cpu-sys': { color: '-cpu-sys-color', values: [] },
            'cpu-iowait': { color: '-cpu-iowait-color', values: [] },
            'cpu-total': { color: '-cpu-total-color', values: [] }
        };
    }

    _updateValues() {
        let cpu = new GTop.glibtop_cpu;
        let t = 0.0;
        GTop.glibtop_get_cpu(cpu);
        let total = cpu.total - this._prev.total;
        let user = cpu.user - this._prev.user;
        let sys = cpu.sys - this._prev.sys;
        let iowait = cpu.iowait - this._prev.iowait;
        let idle = cpu.idle - this._prev.idle;

        t += iowait / total;
        this.stats['cpu-iowait'].values.push(t);
        t += sys / total;
        this.stats['cpu-sys'].values.push(t);
        t += user / total;
        this.stats['cpu-user'].values.push(t);
        this.stats['cpu-total'].values.push(1 - idle / total);

        this._prev = cpu;
    }
};

const MemoryIndicator = class extends Indicator {
    constructor() {
        super();

        this.gridColor = '-grid-color';
        this.renderStats = ['mem-user', 'mem-other', 'mem-cached'];

        // Make sure renderStats is sorted as necessary for rendering
        let renderStatOrder = { 'mem-cached': 0, 'mem-other': 1, 'mem-user': 2 };
        this.renderStats = this.renderStats.sort((a, b) => {
            return renderStatOrder[a] - renderStatOrder[b];
        });

        this.setLabelText(_('Memory'));
    }

    _initValues() {
        this.mem = new GTop.glibtop_mem;
        this.stats = {
            'mem-user': { color: '-mem-user-color', values: [] },
            'mem-other': { color: '-mem-other-color', values: [] },
            'mem-cached': { color: '-mem-cached-color', values: [] }
        };
    }

    _updateValues() {
        GTop.glibtop_get_mem(this.mem);

        let t = this.mem.user / this.mem.total;
        this.stats['mem-user'].values.push(t);
        t += (this.mem.used - this.mem.user - this.mem.cached) / this.mem.total;
        this.stats['mem-other'].values.push(t);
        t += this.mem.cached / this.mem.total;
        this.stats['mem-cached'].values.push(t);
    }
};

class SystemMonitorSection extends MessageList.MessageListSection {
    constructor() {
        super(_('System Monitor'));
    }

    _onTitleClicked() {
        super._onTitleClicked();

        let appSys = Shell.AppSystem.get_default();
        let app = appSys.lookup_app('gnome-system-monitor.desktop');
        if (app)
            app.open_new_window(-1);
    }
}

const INDICATORS = [CpuIndicator, MemoryIndicator];

class Extension {
    constructor() {
        ExtensionUtils.initTranslations();

        this._showLabelTimeoutId = 0;
        this._resetHoverTimeoutId = 0;
        this._labelShowing = false;
    }

    enable() {
        this._section = new SystemMonitorSection();
        this._indicators = [];

        for (let i = 0; i < INDICATORS.length; i++) {
            let indicator = new (INDICATORS[i])();

            indicator.actor.connect('notify::hover', () => {
                this._onHover(indicator);
            });
            this._section.addMessage(indicator, false);
            this._indicators.push(indicator);
        }

        Main.panel.statusArea.dateMenu._messageList._addSection(this._section);
        this._section.actor.get_parent().set_child_at_index(this._section.actor, 0);
    }

    disable() {
        this._indicators.forEach(i => i.destroy());

        Main.panel.statusArea.dateMenu._messageList._removeSection(this._section);
    }

    _onHover(item) {
        if (item.actor.get_hover()) {
            if (this._showLabelTimeoutId)
                return;

            let timeout = this._labelShowing ? 0 : ITEM_HOVER_TIMEOUT;
            this._showLabelTimeoutId = GLib.timeout_add(GLib.PRIORITY_DEFAULT,
                timeout,
                () => {
                    this._labelShowing = true;
                    item.showLabel();
                    this._showLabelTimeoutId = 0;
                    return GLib.SOURCE_REMOVE;
                });

            if (this._resetHoverTimeoutId > 0) {
                GLib.source_remove(this._resetHoverTimeoutId);
                this._resetHoverTimeoutId = 0;
            }
        } else {
            if (this._showLabelTimeoutId > 0)
                GLib.source_remove(this._showLabelTimeoutId);
            this._showLabelTimeoutId = 0;
            item.hideLabel();
            if (!this._labelShowing)
                return;

            this._resetHoverTimeoutId = GLib.timeout_add(GLib.PRIORITY_DEFAULT,
                ITEM_HOVER_TIMEOUT,
                () => {
                    this._labelShowing = false;
                    return GLib.SOURCE_REMOVE;
                });
        }
    }
}

function init() {
    return new Extension();
}