// detachable_elements.ysl2
//
// compute what elements are required by pages
// and decide where to cut when removing/attaching 
// pages elements on page switch

const "hmi_pages", "$hmi_elements[func:parselabel(@inkscape:label)/widget/@type = 'Page']";

const "default_page" choose {
    when "count($hmi_pages) > 1" {
        const "Home_page", 
            "$hmi_pages[func:parselabel(@inkscape:label)/widget/arg[1]/@value = 'Home']";
        choose {
            when "$Home_page" > Home
            otherwise {
                error "No Home page defined!";
            }
        }
    }
    when "count($hmi_pages) = 0" {
        error "No page defined!";
    }
    otherwise > «func:parselabel($hmi_pages/@inkscape:label)/widget/arg[1]/@value»
}

// returns all directly or indirectly refered elements
def "func:refered_elements" {
    param "elems";
    const "descend", "$elems/descendant-or-self::svg:*";
    const "clones", "$descend[self::svg:use]";
    const "originals", "//svg:*[concat('#',@id) = $clones/@xlink:href]";
    choose {
        when "$originals"
            result "$descend | func:refered_elements($originals)";
        otherwise
            result "$descend";
    }
}

def "func:all_related_elements" {
    param "page";
    const "page_overlapping_geometry", "func:overlapping_geometry($page)";
    const "page_overlapping_elements", "//svg:*[@id = $page_overlapping_geometry/@Id]";
    const "page_sub_elements", "func:refered_elements($page | $page_overlapping_elements)";
    result "$page_sub_elements";
}

def "func:required_elements" {
    param "pages"; 
    choose{
        when "$pages"{
            result """func:all_related_elements($pages[1])
                      | func:required_elements($pages[position()!=1])""";
        }otherwise{
            result "/..";
        }
    }
}

const "required_elements",
    """//svg:defs/descendant-or-self::svg:*
       | func:required_elements($hmi_pages)/ancestor-or-self::svg:*""";

const "discardable_elements", "//svg:*[not(@id = $required_elements/@id)]";

def "func:sumarized_elements" {
    param "elements";
    const "short_list", "$elements[not(ancestor::*/@id = $elements/@id)]";
    const "filled_groups", """$short_list/parent::svg:*[
        not(descendant::*[
            not(self::svg:g) and
            not(@id = $discardable_elements/@id) and
            not(@id = $short_list/descendant-or-self::*[not(self::svg:g)]/@id)
        ])]""";
    const "groups_to_add", "$filled_groups[not(ancestor::*/@id = $filled_groups/@id)]";
    result "$groups_to_add | $short_list[not(ancestor::svg:g/@id = $filled_groups/@id)]";
}

def "func:detachable_elements" {
    param "pages";
    choose{
        when "$pages"{
            result """func:sumarized_elements(func:all_related_elements($pages[1]))
                      | func:detachable_elements($pages[position()!=1])""";
        }otherwise{
            result "/..";
        }
    }
}

// Avoid nested detachables
const "_detachable_elements", "func:detachable_elements($hmi_pages)";
const "detachable_elements", "$_detachable_elements[not(ancestor::*/@id = $_detachable_elements/@id)]";

def "func:is_descendant_path" {
    param "descend";
    param "ancest";
    result "string-length($ancest) > 0 and starts-with($descend,$ancest)";
}

template "svg:*", mode="page_desc" {
    const "desc", "func:parselabel(@inkscape:label)/widget";
    const "page", ".";
    const "p", "$geometry[@Id = $page/@id]";

    const "page_all_elements", "func:all_related_elements($page)";

    const "all_page_widgets","$hmi_elements[@id = $page_all_elements/@id and @id != $page/@id]";

    const "page_relative_widgets",
        "$all_page_widgets[func:is_descendant_path(func:parselabel(@inkscape:label)/widget/path/@value, $desc/path/@value)]";

    // Take closest ancestor in detachable_elements
    // since nested detachable elements are filtered out
    const "required_detachables", 
        """func:sumarized_elements($page_all_elements)/
           ancestor-or-self::*[@id = $detachable_elements/@id]""";

    |   "«$desc/arg[1]/@value»": {
    |     widget: hmi_widgets["«@id»"],
    |     bbox: [«$p/@x», «$p/@y», «$p/@w», «$p/@h»],
    if "$desc/path/@value" {
        if "count($desc/path/@index)=0"
            warning > Page id="«$page/@id»" : No match for path "«$desc/path/@value»" in HMI tree
    |     page_index: «$desc/path/@index»,
    }
    |     relative_widgets: [
    foreach "$page_relative_widgets" {
    |         hmi_widgets["«@id»"]`if "position()!=last()" > ,`
    }
    |     ],
    |     absolute_widgets: [
    foreach "$all_page_widgets[not(@id = $page_relative_widgets/@id)]" {
    |         hmi_widgets["«@id»"]`if "position()!=last()" > ,`
    }
    |     ],
    |     required_detachables: {
    foreach "$required_detachables" {
    |         "«@id»": detachable_elements["«@id»"]`if "position()!=last()" > ,`
    }
    |     }
    |   }`if "position()!=last()" > ,`
}

function "debug_detachables" {
    foreach "$detachable_elements"{
        |  «@id»
    }
}
!debug_output_calls.append("debug_detachables")