Assignment_5 03

note
    description: "Route information displays."

class
    DISPLAY

inherit
    ZURICH_OBJECTS

feature -- Explore Zurich

    add_public_transport
            -- Add a public transportation unit per line.
        do
            across
                Zurich.lines as line_pointer
            loop
                line_pointer.item.add_transport
            end
        end

    update_transport_display (t: PUBLIC_TRANSPORT)
            -- Update route information display inside transportation unit `t'.
        require
            t_exists: t /= Void
        local
            s: STATION
            total_stations_left: INTEGER
            i: INTEGER
        do
            -- Reset the console
            console.clear

            -- Count the number of stations left
            total_stations_left := 0
            from
                s := Zurich.station (t.arriving.name)
            invariant
                total_stations_left < Zurich.line (t.line.number).stations.count + 1
            until
                s = void
            loop
                total_stations_left := total_stations_left + 1
                s := Zurich.line (t.line.number).next_station (s, t.destination)
            variant
                Zurich.line (t.line.number).stations.count + 1 - total_stations_left
            end

            -- Output info
            if
                -- For 1 station left
                total_stations_left = 1
            then
                console.output ("Linie/Line " + t.line.number.out + " Willkommen/Welcome.")
                console.append_line (stop_info (t, t.destination))
            elseif
                -- For 2 stations left
                total_stations_left = 2
            then
                console.output ("Linie/Line " + t.line.number.out + " Willkommen/Welcome.")
                console.append_line (stop_info (t, t.arriving))
                console.append_line (stop_info (t, t.destination))
            elseif
                -- For 3 stations left
                total_stations_left = 3
            then
                console.output ("Linie/Line " + t.line.number.out + " Willkommen/Welcome.")
                from
                    s := Zurich.station (t.arriving.name)
                    i := 1
                invariant
                    i < Zurich.line (t.line.number).stations.count + 1
                until
                    i = 3
                loop
                    i := i + 1
                    console.append_line (stop_info (t, s))
                    s := Zurich.line (t.line.number).next_station (s, t.destination)
                variant
                    Zurich.line (t.line.number).stations.count + 1 - i
                end
                console.append_line (stop_info (t, t.destination))
            elseif
                -- For more than 3 stations left
                total_stations_left > 3
            then
                console.output ("Linie/Line " + t.line.number.out + " Willkommen/Welcome.")
                from
                    s := Zurich.station (t.arriving.name)
                    i := 1
                invariant
                    i < Zurich.line (t.line.number).stations.count + 1
                until
                    i = 4
                loop
                    i := i + 1
                    console.append_line (stop_info (t, s))
                    s := Zurich.line (t.line.number).next_station (s, t.destination)
                variant
                    Zurich.line (t.line.number).stations.count + 1 - i
                end
                console.append_line ("...")
                console.append_line (stop_info (t, t.destination))
            else
                -- The something-is-not-right case!
                console.append_line ("Oops, something went wrong.. please click again or terminate.")
            end
        end

    stop_info (t: PUBLIC_TRANSPORT; s: STATION): STRING
            -- Get the station info for the next stop(s)
        require
            t_is_there: t /= void
            s_is_there: s /= void
        local
            minutes: INTEGER
            looping_line: LINE
        do
            -- Time to station
            if
                t.time_to_station (s) < 60
            then
                Result := "<1 Min.%T" + s.name
            else
                minutes := t.time_to_station (s) // 60
                Result := minutes.out + " Min.%T" + s.name
            end

            -- Connecting lines at station
            if s.lines.is_empty = false then
                across
                    s.lines as z
                loop
                    if z.item.has_station (t.line.next_station (s, t.destination)) or z.item.has_station (t.line.next_station (s, t.line.first)) then
                        looping_line := void
                    else
                        looping_line := z.item
                    end
                    if looping_line /= void then
                        Result.append (" " + looping_line.number.out)
                    end
                end
            end
        ensure
            Result_is_there: Result /= void
        end

end