import curses
import itertools

colors = {}
_colors = []
_pairs  = {}
index   = 1
attributes = {
    'bold':      curses.A_BOLD,
    'reverse':   curses.A_REVERSE,
    'normal':    curses.A_NORMAL,
    'underline': curses.A_UNDERLINE,
    'dim':       curses.A_DIM,
    'standout':  curses.A_STANDOUT,
}

inited        = False
default_color = True

ascii_map     = {
    '*': 'bold',
}
rev_ascii_map = {
    'bold': '*',
}

# add a particular color
def add_color(name, value, abbrev):
    colors[name]        = value
    ascii_map[abbrev]   = name
    rev_ascii_map[name] = abbrev

# assign every RGB triple (0-5) to one of six basic colors (red, yellow, green,
# cyan, blue, magenta) based on some semi-arbitrary rules i came up with.
def iter256():
    ns = list(range(0, 6))
    for r in ns:
        for g in ns:
            for b in ns:
                if r >= g and g > b: name = 'yellow'
                elif r >= b and b - g > 1: name = 'magenta'

                elif b >= g and g - r > 2: name = 'cyan'
                elif b >= r and r > g: name = 'magenta'

                elif g >= r and r - b > 2: name = 'yellow'
                elif g >= b and b - r > 1: name = 'cyan'

                elif r > b and r > g: name = 'red'
                elif g > b and g > r: name = 'green'
                elif b > r and b > g: name = 'blue'

                else: continue

                yield (name, r, g, b)
    return

# if we can support 256 colors, create all of the color names and map them to
# the correct RGB value.
def color256(name, fallback, abbrev, r, g, b):
    name2   = '%s%d%d%d' % (name, r, g, b)
    abbrev2 = '%s%d%d%d' % (abbrev, r, g, b)
    if curses.COLORS == 256:
        value = 16 + r * 36 + g * 6 + b
        if curses.can_change_color():
            curses.init_color(value, r * 200, g * 200, b* 200)
    else:
        value = fallback
    add_color(name2, value, abbrev2)

def init():
    global _pairs, inited
    if inited: return
    inited = True

    # create the basic 8 colors of curses
    add_color('cyan', curses.COLOR_CYAN, 'c')
    add_color('blue', curses.COLOR_BLUE, 'b')
    add_color('green', curses.COLOR_GREEN, 'g')
    add_color('red', curses.COLOR_RED, 'r')
    add_color('yellow', curses.COLOR_YELLOW, 'y')
    add_color('magenta', curses.COLOR_MAGENTA, 'm')
    add_color('black', curses.COLOR_BLACK, 'B')
    add_color('white', curses.COLOR_WHITE, 'w')

    # initialize the "default" color if possible
    if default_color:
        colors['default']        = -1
        ascii_map['d']           = 'default'
        rev_ascii_map['default'] = 'd'

    # add in hex aliases to 256 colors; used by color-data buffers
    for i in range(0, 256):
        name   = 'f%02x' % i
        abbrev = 'f%02x' % i
        add_color(name, i, abbrev)

    # create the 24 flavors of grey in 256 colors
    for i in range(0, 24):
        name2   = 'grey%d' % i
        abbrev2 = 'G%d' % i
        if curses.COLORS == 256:
            value = 232 + i
            if curses.can_change_color():
                curses.init_color(value, i * 41, i * 41, i * 41)
        else:
            value = curses.COLOR_WHITE
        add_color(name2, value, abbrev2)

    # create 256 colors
    for name, r, g, b in iter256():
        color256(name, colors[name], rev_ascii_map[name], r, g, b)

def build(fg, bg, *attr):
    v = curses.A_NORMAL | pairs(fg, bg)
    for x in attr:
        if type(x) == type(''):
            x = attributes[x]
        v = v | x
    return v

def pairs(fg, bg):
    if not curses.has_colors():
        return curses.color_pair(0)

    global index
    fgi = colors.get(fg, colors['white'])
    bgi = colors.get(bg, colors['black'])
    key = (fgi, bgi)
    if key not in _pairs:
        assert index < curses.COLOR_PAIRS, "too many colors"
        assert type(fgi) == type(0), "illegal fgi: %r" % fgi
        assert type(bgi) == type(0), "illegal bgi: %r" % bgi
        try:
            curses.init_pair(index, fgi, bgi)
        except:
            raise Exception('failed to init %d,%d,%d' % (index, fgi, bgi))
        _pairs[key] = curses.color_pair(index)
        _colors.append(key)
        index = len(_colors) + 1
    return _pairs[key]