import re
import time
from decimal import Decimal

from cpython cimport datetime

from .constants.FIELD_TYPE import *
from .errors import ProgrammingError


cpdef escape_item(val, str charset, mapping: dict = None):
    if mapping is None:
        mapping = encoders
    encoder = mapping.get(type(val))

    # Fallback to default when no encoder found
    if not encoder:
        try:
            encoder = mapping[str]
        except KeyError:
            raise TypeError("no default type converter defined")

    if encoder in (escape_dict, escape_sequence):
        val = encoder(val, charset, mapping)
    else:
        val = encoder(val, mapping)
    return val

cpdef dict escape_dict(dict val, str charset, mapping: dict = None):
    n = {}
    for k, v in val.items():
        quoted = escape_item(v, charset, mapping)
        n[k] = quoted
    return n

cpdef str escape_sequence(tuple val, str charset, mapping: dict = None):
    n = []
    for item in val:
        quoted = escape_item(item, charset, mapping)
        n.append(quoted)
    return "(" + ",".join(n) + ")"

cpdef str escape_set(set val, str charset, mapping: dict = None):
    return ",".join([escape_item(x, charset, mapping) for x in val])

cpdef str escape_bool(int value, mapping: dict = None):
    return str(int(value))

cpdef str escape_int(long long value, mapping: dict = None):
    return str(value)

cpdef str escape_float(double value, mapping: dict = None):
    s = repr(value)
    if s in ("inf", "nan"):
        raise ProgrammingError("%s can not be used with MySQL" % s)
    if "e" not in s:
        s += "e0"
    return s

cdef list _escape_table = [chr(x) for x in range(128)]
_escape_table[0] = "\\0"
_escape_table[ord("\\")] = "\\\\"
_escape_table[ord("\n")] = "\\n"
_escape_table[ord("\r")] = "\\r"
_escape_table[ord("\032")] = "\\Z"
_escape_table[ord('"')] = '\\"'
_escape_table[ord("'")] = "\\'"

cpdef str escape_string(value, mapping: dict = None):
    """
    escapes *value* without adding quote.

    Value should be unicode
    """
    return value.translate(_escape_table)

cpdef str escape_bytes_prefixed(bytes value, mapping: dict = None):
    return "_binary'%s'" % value.decode(b"ascii", "surrogateescape").translate(_escape_table)

cpdef str escape_bytes(bytes value, mapping: dict = None):
    return "'%s'" % value.decode(b"ascii", "surrogateescape").translate(_escape_table)

cpdef str escape_str(value, mapping: dict = None):
    return "'%s'" % escape_string(str(value), mapping)

cpdef str escape_None(value, mapping: dict = None):
    return "NULL"

cpdef str escape_timedelta(obj: datetime.timedelta, mapping: dict = None):
    seconds = int(obj.seconds) % 60
    minutes = int(obj.seconds // 60) % 60
    hours = int(obj.seconds // 3600) % 24 + int(obj.days) * 24
    if obj.microseconds:
        fmt = "'{0:02d}:{1:02d}:{2:02d}.{3:06d}'"
    else:
        fmt = "'{0:02d}:{1:02d}:{2:02d}'"
    return fmt.format(hours, minutes, seconds, obj.microseconds)

cpdef str escape_time(obj, mapping: dict = None):
    if obj.microsecond:
        fmt = "'{0.hour:02}:{0.minute:02}:{0.second:02}.{0.microsecond:06}'"
    else:
        fmt = "'{0.hour:02}:{0.minute:02}:{0.second:02}'"
    return fmt.format(obj)

cpdef str escape_datetime(datetime.datetime obj, mapping: dict = None):
    if obj.microsecond:
        fmt = "'{0.year:04}-{0.month:02}-{0.day:02} {0.hour:02}:{0.minute:02}:{0.second:02}.{0.microsecond:06}'"
    else:
        fmt = "'{0.year:04}-{0.month:02}-{0.day:02} {0.hour:02}:{0.minute:02}:{0.second:02}'"
    return fmt.format(obj)

cpdef str escape_date(datetime.date obj, mapping: dict = None):
    fmt = "'{0.year:04}-{0.month:02}-{0.day:02}'"
    return fmt.format(obj)

cpdef str escape_struct_time(obj: time.struct_time, mapping: dict = None):
    return escape_datetime(datetime.datetime(*obj[:6]))

cpdef str decimal2literal(o, d):
    return format(o, "f")

cpdef int _convert_second_fraction(s):
    if not s:
        return 0
    # Pad zeros to ensure the fraction length in microseconds
    s = s.ljust(6, "0")
    return int(s[:6])

DATETIME_RE = re.compile(
    r"(\d{1,4})-(\d{1,2})-(\d{1,2})[T ](\d{1,2}):(\d{1,2}):(\d{1,2})(?:.(\d{1,6}))?"
)

cpdef datetime.datetime convert_datetime(str obj):
    """Returns a DATETIME or TIMESTAMP column value as a datetime object:

      >>> convert_datetime('2007-02-25 23:06:20')
      datetime.datetime(2007, 2, 25, 23, 6, 20)
      >>> convert_datetime('2007-02-25T23:06:20')
      datetime.datetime(2007, 2, 25, 23, 6, 20)

    Illegal values are returned as None:

      >>> convert_datetime('2007-02-31T23:06:20') is None
      True
      >>> convert_datetime('0000-00-00 00:00:00') is None
      True

    """
    if isinstance(obj, (bytes, bytearray)):
        obj = obj.decode("ascii")

    m = DATETIME_RE.match(obj)
    if not m:
        return convert_date(obj)

    try:
        groups = list(m.groups())
        groups[-1] = _convert_second_fraction(groups[-1])
        return datetime.datetime(*[int(x) for x in groups])
    except ValueError:
        return convert_date(obj)

TIMEDELTA_RE = re.compile(r"(-)?(\d{1,3}):(\d{1,2}):(\d{1,2})(?:.(\d{1,6}))?")

cpdef datetime.timedelta convert_timedelta(str obj):
    """Returns a TIME column as a timedelta object:

      >>> convert_timedelta('25:06:17')
      datetime.timedelta(1, 3977)
      >>> convert_timedelta('-25:06:17')
      datetime.timedelta(-2, 83177)

    Illegal values are returned as None:

      >>> convert_timedelta('random crap') is None
      True

    Note that MySQL always returns TIME columns as (+|-)HH:MM:SS, but
    can accept values as (+|-)DD HH:MM:SS. The latter format will not
    be parsed correctly by this function.
    """
    if isinstance(obj, (bytes, bytearray)):
        obj = obj.decode("ascii")

    m = TIMEDELTA_RE.match(obj)
    if not m:
        return obj

    try:
        groups = list(m.groups())
        groups[-1] = _convert_second_fraction(groups[-1])
        negate = -1 if groups[0] else 1
        hours, minutes, seconds, microseconds = groups[1:]

        tdelta = (
                datetime.timedelta(
                    hours=int(hours),
                    minutes=int(minutes),
                    seconds=int(seconds),
                    microseconds=int(microseconds),
                )
                * negate
        )
        return tdelta
    except ValueError:
        return obj

TIME_RE = re.compile(r"(\d{1,2}):(\d{1,2}):(\d{1,2})(?:.(\d{1,6}))?")

cpdef datetime.time convert_time(str obj):
    """Returns a TIME column as a time object:

      >>> convert_time('15:06:17')
      datetime.time(15, 6, 17)

    Illegal values are returned as None:

      >>> convert_time('-25:06:17') is None
      True
      >>> convert_time('random crap') is None
      True

    Note that MySQL always returns TIME columns as (+|-)HH:MM:SS, but
    can accept values as (+|-)DD HH:MM:SS. The latter format will not
    be parsed correctly by this function.

    Also note that MySQL's TIME column corresponds more closely to
    Python's timedelta and not time. However if you want TIME columns
    to be treated as time-of-day and not a time offset, then you can
    use set this function as the converter for TIME.
    """
    if isinstance(obj, (bytes, bytearray)):
        obj = obj.decode("ascii")

    m = TIME_RE.match(obj)
    if not m:
        return obj

    try:
        groups = list(m.groups())
        groups[-1] = _convert_second_fraction(groups[-1])
        hours, minutes, seconds, microseconds = groups
        return datetime.time(
            hour=int(hours),
            minute=int(minutes),
            second=int(seconds),
            microsecond=int(microseconds),
        )
    except ValueError:
        return obj

cpdef datetime.date convert_date(obj):
    """Returns a DATE column as a date object:

      >>> convert_date('2007-02-26')
      datetime.date(2007, 2, 26)

    Illegal values are returned as None:

      >>> convert_date('2007-02-31') is None
      True
      >>> convert_date('0000-00-00') is None
      True

    """
    if isinstance(obj, (bytes, bytearray)):
        obj = obj.decode("ascii")
    try:
        return datetime.date(*[int(x) for x in obj.split("-", 2)])
    except ValueError:
        return obj

cpdef through(x):
    return x

# def convert_bit(b):
#    b = "\x00" * (8 - len(b)) + b # pad w/ zeroes
#    return struct.unpack(">Q", b)[0]
#
#     the snippet above is right, but MySQLdb doesn't process bits,
#     so we shouldn't either
convert_bit = through

cdef dict encoders = {
    bool: escape_bool,
    int: escape_int,
    float: escape_float,
    str: escape_str,
    bytes: escape_bytes,
    tuple: escape_sequence,
    list: escape_sequence,
    set: escape_sequence,
    frozenset: escape_sequence,
    dict: escape_dict,
    type(None): escape_None,
    datetime.date: escape_date,
    datetime.datetime: escape_datetime,
    datetime.timedelta: escape_timedelta,
    datetime.time: escape_time,
    time.struct_time: escape_struct_time,
    Decimal: decimal2literal,
}

cdef dict decoders = {
    BIT: convert_bit,
    TINY: int,
    SHORT: int,
    LONG: int,
    FLOAT: float,
    DOUBLE: float,
    LONGLONG: int,
    INT24: int,
    YEAR: int,
    TIMESTAMP: convert_datetime,
    DATETIME: convert_datetime,
    TIME: convert_timedelta,
    DATE: convert_date,
    BLOB: through,
    TINY_BLOB: through,
    MEDIUM_BLOB: through,
    LONG_BLOB: through,
    STRING: through,
    VAR_STRING: through,
    VARCHAR: through,
    DECIMAL: Decimal,
    NEWDECIMAL: Decimal,
}

# for MySQLdb compatibility
conversions = encoders.copy()
conversions.update(decoders)
