// widget_button.ysl2

widget_desc("Button") {
    longdesc
    ||
    Button widget takes one boolean variable path, and reflect current true
    or false value by showing "active" or "inactive" labeled element
    respectively. Pressing and releasing button changes variable to true and
    false respectively. Potential inconsistency caused by quick consecutive
    presses on the button is mitigated by using a state machine that wait for
    previous state change to be reflected on variable before applying next one.
    ||

    shortdesc > Push button reflecting consistently given boolean variable

    path name="value" accepts="HMI_BOOL" > Boolean variable
    
}

// Finite state machine
decl fsm(name);
decl state(name);
decl on_mouse(position);
decl on_dispatch(value);
decl jump(state);
decl show(eltname);
decl hmi_value(value);

gen_index_xhtml {

// State machine to drive HMI_BOOL on a potentially laggy connection
const "_button_fsm" fsm {
    state "init" {
        on_dispatch "false" jump "released";
        on_dispatch "true" jump "pressed";
    }

    state "pressing" {
        // show "waitactive";
        hmi_value "true";
        on_dispatch "true" jump "pressed";
        on_mouse "up" jump "shortpress";
    }
    state "pressed" {
        show "active";
        on_mouse "up" jump "releasing";
        on_dispatch "false" jump "released";
    }
    state "shortpress" {
        on_dispatch "true" jump "releasing";
        on_mouse "down" jump "pressing";
    }

    state "releasing" {
        // show "waitinactive";
        hmi_value "false";
        on_dispatch "false" jump "released";
        on_mouse "down" jump "shortrelease";
    }
    state "released" {
        show "inactive";
        on_mouse "down" jump "pressing";
        on_dispatch "true" jump "pressed";
    }
    state "shortrelease" {
        on_dispatch "false" jump "pressing";
        on_mouse "up" jump "releasing";
    }
}

template "fsm", mode="dispatch_transition" {
    |         switch (this.state) {
    apply "state", mode="dispatch_transition";
    |         }
}
template "state", mode="dispatch_transition" {
    |           case "«@name»":
       apply "on-dispatch";
    |             break;
}
template "on-dispatch" {
    |             if(value ==  «@value») {
    apply "jump", mode="transition";
    |             }
}

template "fsm", mode="mouse_transition" {
    param "position";
    |         switch (this.state) {
    apply "state", mode="mouse_transition" with "position", "$position";
    |         }
}
template "state", mode="mouse_transition" {
    param "position";
    |           case "«@name»":
    apply "on-mouse[@position = $position]";
    |             break;
}
template "on-mouse" {
    // up or down state is already assumed because apply statement filters it
    apply "jump", mode="transition";
}

template "jump", mode="transition" {
    |             this.state = "«@state»";
    |             this.«@state»_action();
}

template "fsm", mode="actions" {
    apply "state", mode="actions";
}
template "state", mode="actions" {
    |     «@name»_action(){
    //| console.log("Entering state «@name»");
    apply "*", mode="actions";
    |     }
}
template "show", mode="actions" {
    |         this.display = "«@eltname»";
    |         this.request_animate();
}
template "hmi-value", mode="actions" {
    |         this.apply_hmi_value(0, «@value»);
}

}

widget_class("Button"){
    const "fsm","exsl:node-set($_button_fsm)";
    |     frequency = 5;

    |     display = "inactive";
    |     state = "init";

    |     dispatch(value) {
    // |         console.log("dispatch"+value);
    apply "$fsm", mode="dispatch_transition";
    |     }

    |     onmouseup(evt) {
    |         svg_root.removeEventListener("pointerup", this.bound_onmouseup, true);
    // |         console.log("onmouseup");
    apply "$fsm", mode="mouse_transition" with "position", "'up'";
    |     }
    |     onmousedown(evt) {
    |         svg_root.addEventListener("pointerup", this.bound_onmouseup, true);
    // |         console.log("onmousedown");
    apply "$fsm", mode="mouse_transition" with "position", "'down'";
    |     }

    apply "$fsm", mode="actions";

    |     animate(){
    |         if (this.active_elt && this.inactive_elt) {
    foreach "str:split('active inactive')" {
    |             if(this.display == "«.»")
    |                 this.«.»_elt.style.display = "";
    |             else
    |                 this.«.»_elt.style.display = "none";
    }
    |         }
    |     }

    |     init() {
    |         this.bound_onmouseup = this.onmouseup.bind(this);
    |         this.element.addEventListener("pointerdown", this.onmousedown.bind(this));
    |     }
}

widget_defs("Button") {
    optional_labels("active inactive");
}