::itcl::class ::nv2::totalto_graph {
	common _dot_path "";
	proc arrowhead_list {} {
		::return {
            none
            normal
            inv
            dot
            odot
            invdot
            invodot
            tee
            empty
            invempty
            open
            halfopen
            diamond
            odiamond
            box
            obox
            crow
        }
	}
    /* {
        polygon
        Mdiamond
        Msquare
    */ }
	proc node_shape_list {} {
		::return {
            box
            ellipse
            circle
            point
            egg
            triangle
            plaintext
            diamond
            trpaezium
            parallelogram
            house
            pentagon
            hexagon
            septagon
            octagon
            doublecircle
            doubleoctagon
            tripleoctagon
            invtriangle
            invtrapezium
            invhouse
        }
    }
	proc node_style_list {} {
		::return {
            filled
            solid
            dashed
            dotted
            bold
            invis
        }
	}
	proc edge_style_list {} {
		::return {
            solid
            dashed
            dotted
            bold
            invis
        }
	}
    proc initialize {} {
        ::switch -- $::tcl_platform(platform) {
            "windows" {
                ::while {1} {
					# simulated if then else
                    ::set Path [::file join C:/ "Program Files" GraphViz bin dot.exe];
                    ::if {[::file exists $Path]} {
                        ::set _dot_path $Path;
                        ::break;
                    }
                    ::set Path [::file join C:/ Programme Graphviz bin dot.exe];
                    ::if {[::file exists $Path]} {
                        ::set _dot_path $Path;
                        ::break;
                    }
                    ::if {[auto_execok "dot"] ne ""} {
                        ::set _dot_path "dot";
                        ::break;
                    }
					::break;
                }
                ::if {$_dot_path eq ""} {
                    ::qw::throw \
                        .text "The Graphviz application is not installed." \
                        .error_id 314120250326175311 \
                        .help_page {
                            .id 314120250326141529
                            .tags {error}
                            .body {
                                [p {
                                    NewViews relies on the [qw_term Graphviz] application to draw graphs.

                                    It appears that Graphviz is not installed on this computer.

                                    See <a href="https://graphviz.org/download/" target="_blank">Installing Graphviz on Windows</a>
                                }]
                                [ol {
                                    [p {
                                        Step 1: Download Graphviz
                                    }]
                                    [p {
                                        Go to the official Graphviz website: https://graphviz.org/download/

                                        Click on the Windows section.

                                        Download the latest .exe installer (e.g., graphviz-<version>.msi).
                                    }]
                                    [p {
`		                                    Step 2: Install Graphviz
                                    }]
                                    [p {
                                        Run the downloaded .msi installer.

                                        Follow the installation prompts:

                                        Choose "Add Graphviz to the system PATH for all users" (recommended).

                                        Click Next and install.
                                    }]
                                    [p {
                                        Step 3: Verify Installation
                                    }]
                                    [p {
                                        Open Command Prompt (cmd) or PowerShell.
                                    }]
                                }]
                                [p {
                                    When insalling Graphviz on Windows, you will be peompted
                                    to specify the insallation folder.

                                    We recommend that you select [qw_directory c:\ProgramFiles].
                                }]
                            }
                        } \
                    ;
                }
            }
            "unix" {
                ::qw::throw "Graphs are not implemented on linux (yet)."
            }
		}
    }
}