# From ttps://github.com/scivision/maidenhead

"""## mlocs - Maidenhead
toMaiden([lat, lon], level) returns a char (len = lvl*2)
toLoc(mloc) takes any string and returns topleft [lat,lon] within mloc

Beyond 8 characters is not defined for Maidenhead.
"""

def toLoc(maiden):
    """
    input: maidenhead locator of length 2 to 8
    output: [lat,lon]
    """
    assert isinstance(maiden, str), 'Maidenhead is a string'
    maiden = maiden.strip().upper()

    N = len(maiden)
    assert 8>=N>=2 and N%2==0,'Maidenhead locator requires 2-8 characters, even number of characters'

    O = ord('A')
    lon = -180
    lat = -90
#%% first pair
    lon += (ord(maiden[0])-O)*20
    lat += (ord(maiden[1])-O)*10
#%% second pair
    if N>=4:
        lon += int(maiden[2])*2 
        lat += int(maiden[3])*1 
        if N==4:
            lon += 1
            lat += 0.5
#%%
    if N>=6:
        lon += (ord(maiden[4])-O) * 5./60
        lat += (ord(maiden[5])-O) * 2.5/60
        if N==6:
            lon += 2.5/60
            lat += 1.25/60
#%%
    if N>=8:
        lon += int(maiden[6]) * 5./600 + 2.5/600
        lat += int(maiden[7]) * 2.5/600 + 1.25/600

    return lat,lon

def toMaiden(position, precision=3):
    """Returns a maidenloc for specified lat-lon tuple at specified level.
    """
    assert len(position)==2,'lat lon required'
    lat = float(position[0])
    lon = float(position[1])

    A = ord('A')
    a = divmod(lon+180, 20)
    b = divmod(lat+90, 10)
    astring = chr(A+int(a[0])) + chr(A+int(b[0]))
    lon = a[1] / 2.
    lat = b[1]
    i = 1
    while i < precision:
        i += 1
        a = divmod(lon,1)
        b = divmod(lat,1)
        if not (i%2):
            astring += str(int(a[0])) + str(int(b[0]))
            lon = 24 * a[1]
            lat = 24 * b[1]
        else:
            astring += chr(A+int(a[0])) + chr(A+int(b[0]))
            lon = 10 * a[1]
            lat = 10 * b[1]

    if len(astring)>=6:
        astring = astring[:4] + astring[4:6].lower() + astring[6:]

    return astring