# head up display - draws a semi-transparent text box.
class Hud(object):
    def __init__(self):
        self.app = []
        self.strs = []
        self.fontbase = []
        self.hud_lines = []
        self.show_tags = []
        self.hide_alls = []
        self.hud_rgba_r = 0
        self.hud_rgba_g = 0.2
        self.hud_rgba_b = 0
        self.hud_rgba_a = 0.5
        self.hud_text_rgb_r = 1
        self.hud_text_rgb_g = 0.8
        self.hud_text_rgb_b = 0.4

    # legacy vismach models used this
    def show(self, string):
        self.add_txt(string)

    # displays a string, optionally a tag or list of tags can be assigned
    def add_txt(self, string, tag=None):
        self.hud_lines += [[str(string), None, tag]]

    # displays a formatted pin value (can be embedded in a string)
    def add_pin(self, string, pin=None, tag=None):
        self.hud_lines += [[str(string), pin, tag]]

    # shows all lines with the specified tag if the pin value = val
    def show_tag_if_same(self, tag, pin, val=True):
        self.show_tags += [[tag, pin, val]]

    # shows all lines with a tag equal to the pin value + offset
    def show_tags_in_pin(self, pin, offs=0):
        self.show_tags += [[pin, None, offs]]

    # hides the complete hud if the pin value is equal to val
    def hide_all(self, pin, val=True):
        self.hide_alls += [[pin, val]]

    # changes the hud color and transparency
    def set_hud_rgba(self, r, g, b, a):
        self.hud_rgba_r = r
        self.hud_rgba_g = g
        self.hud_rgba_b = b
        self.hud_rgba_a = a

    # changes the hud text color
    def set_hud_text_rgb(self, r, g, b):
        self.hud_text_rgb_r = r
        self.hud_text_rgb_g = g
        self.hud_text_rgb_b = b

    # update the lines in the hud using the lists created above
    def draw(self):
        hide_hud = 0
        strs = []
        show_list = [None]
        # check if hud should be hidden
        for a in self.hide_alls:
            if hal.get_value(a[0]) == a[1]:
                hide_hud = 1
        if hide_hud == 0:
            # create list of all line tags to be shown
            for b in self.show_tags:
                if b[1] == None: # _show_tags_in_pin
                    tag = int(hal.get_value(b[0]) + b[2])
                else: # _show_tag_if_same
                    if  hal.get_value(b[1]) == b[2]:
                        tag = b[0]
                if not isinstance(tag, list):
                    tag = [tag]
                show_list = show_list + tag
            # build the
            for c in self.hud_lines:
                if not isinstance(c[2], list):
                    c[2] = [c[2]]
                if any(item in c[2] for item in show_list):
                    if c[1] == None: # _txt
                        strs += [c[0]]
                    else: # _pin
                        strs += [c[0].format(hal.get_value(c[1]))]
        drawtext = strs

        # draw head-up-display
        # see axis.py for more font/color configurability
        if len(drawtext) == 0:
                return

        glMatrixMode(GL_PROJECTION)
        glPushMatrix()
        glLoadIdentity()

        if not self.fontbase:
                self.fontbase = int(self.app.loadbitmapfont("9x15"))
        char_width, char_height = 9, 15
        xmargin,ymargin = 5,5
        ypos = float(self.app.winfo_height())

        glOrtho(0.0, self.app.winfo_width(), 0.0, ypos, -1.0, 1.0)
        glMatrixMode(GL_MODELVIEW)
        glPushMatrix()
        glLoadIdentity()

        # draw the text box
        maxlen = max([len(p) for p in drawtext])
        box_width = maxlen * char_width
        glDepthFunc(GL_ALWAYS)
        glDepthMask(GL_FALSE)
        glDisable(GL_LIGHTING)
        glEnable(GL_BLEND)
        glEnable(GL_NORMALIZE)
        glBlendFunc(GL_ONE, GL_CONSTANT_ALPHA)
        # sets the color of the hud overlay
        glColor3f(self.hud_rgba_r, self.hud_rgba_g, self.hud_rgba_b)
        # rgba, sets the transparency of the overlay using the 'a' value
        glBlendColor(0,0,0,self.hud_rgba_a)
        glBegin(GL_QUADS)
        # upper left
        glVertex3f(0, ypos, 1)
        # lower left
        glVertex3f(0, ypos - 2*ymargin - char_height*len(drawtext), 1)
        # lower right
        glVertex3f(box_width+2*xmargin, ypos - 2*ymargin - char_height*len(drawtext), 1)
        # upper right
        glVertex3f(box_width+2*xmargin,  ypos , 1)
        glEnd()
        glDisable(GL_BLEND)
        glEnable(GL_LIGHTING)

        # fill the box with text
        maxlen = 0
        ypos -= char_height+ymargin
        i = 0
        glDisable(GL_LIGHTING)
        # sets the color of the text in the hud
        glColor3f(self.hud_text_rgb_r, self.hud_text_rgb_g, self.hud_text_rgb_b)
        for string in drawtext:
                maxlen = max(maxlen, len(string))
                glRasterPos2i(xmargin, int(ypos))
                for char in string:
                        glCallList(self.fontbase + ord(char))
                ypos -= char_height
                i = i + 1
        glDepthFunc(GL_LESS)
        glDepthMask(GL_TRUE)
        glEnable(GL_LIGHTING)

        glPopMatrix()
        glMatrixMode(GL_PROJECTION)
        glPopMatrix()
        glMatrixMode(GL_MODELVIEW)