import re

class Sha1File:
    """ Manages file names such as "name-{5}.txt" """

    DIGEST_LEN = 40

    def __init__(self, fileName):
        self._fileName = fileName
        res = re.findall(r'{(\d+)}', fileName)
        self._ok = bool(res) and len(res)==1 and int(res[0])>0
        self._occurences = int(res[0]) if self._ok else None
        self._left, self._right = re.split(r'{\d+}', fileName) if self._ok else (None, None)

    def __bool__(self): return self._ok

    def __repr__(self): return self._fileName

    def __int__(self): return self._occurences

    def __len__(self):
        if self._ok:
            return self.DIGEST_LEN + len(self._left+self._right)
        else:
            return len(self._fileName)

    def nameWithSha1(self, sha1):
        assert(len(sha1)==self.DIGEST_LEN)
        return self._left + sha1 + self._right


class StrKey:
    """ Manages string key parameters enclosed by underscores such _string key_ """

    def __init__(self, strKey):
        m = re.match('^_(.+)_$', strKey)
        self._ok, self._value = (True, m.group(1)) if m else (False, None)

    def __bool__(self): return self._ok

    def __repr__(self): return self._value

    def __len__(self): return len(self._value)


def evalMultiple(size):
    """ Takes size as "123k" and return "123000", same for m, g, and t.
        1024 multiples are also supported: ki, mi, gi, ti
        Raises ValueError if size malformed
    """

    size = ''.join(size.split()).lower() # remove any blank caracter
    multiples = {"ki":1024, "mi":1024**2, "gi":1024**3, "ti":1024**4,
                  "k":1000,  "m":1000**2,  "g":1000**3,  "t":1000**4, }
    for m in multiples:
        if size.endswith(m):
            size = int(size[:-len(m)]) * multiples[m]
            break
    return int(size)


def splitList(L, needle):
    """ Splits a list in chuncks around the needle
    [1,2,3], 2     -->   [ [1], [3]     ]
    [1,2,2,3], 2   -->   [ [1], [], [3] ]
    [2,1,2], 2     -->   [ [], [1], []  ]
    [4,5,6], 2     -->   [ [4, 5, 6]    ]
    """
    output, lastPos = [], 0
    while True:
        try:
            pos = L.index(needle, lastPos)
            output.append(L[lastPos:pos])
            lastPos = pos+1
        except ValueError:
            output.append(L[lastPos:])
            break
    return output