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from __future__ import print_function, absolute_import

import sys
import re
import warnings
import types
import keyword
import functools
from .mapping import type_map, update_mapping, __dict__ as namespace

_DEBUG = False

TYPE_MAP_DOC = """
    The type_map variable is central for the signature package.

    PySide has a new function 'CppGenerator::writeSignatureInfo()'
    that extracts the gathered information about the function arguments
    and defaults as good as it can. But what PySide generates is still
    very C-ish and has many constants that Python doesn't understand.

    The function 'try_to_guess()' below understands a lot of PySide's
    peculiar way to assume local context. If it is able to do the guess,
    then the result is inserted into the dict, so the search happens
    not again. For everything that is not covered by these automatic
    guesses, we provide an entry in 'type_map' that resolves it.

    In effect, 'type_map' maps text to real Python objects.
"""

def dprint(*args, **kw):
    if _DEBUG:
        import pprint
        for arg in args:
            pprint.pprint(arg)

def _parse_line(line):
    line_re = r"""
        ((?P<multi> ([0-9]+)) : )?    # the optional multi-index
        (?P<funcname> \w+(\.\w+)*)    # the function name
        \( (?P<arglist> .*?) \)       # the argument list
        ( -> (?P<returntype> .*) )?   # the optional return type
        $
        """
    ret = re.match(line_re, line, re.VERBOSE).groupdict()
    arglist = ret["arglist"]
    arglist = list(x.strip() for x in re.split(r"""
        (
            (?:                     # inner group is not capturing
                [^,()]              # no commas or braces
                |
                \(
                    (?:
                        [^()]*      # or one brace pair
                        |
                        \(
                            [^()]*  # or doubls nested pair
                        \)
                    )*
                \)
            )+                      # longest possible span
        )   # this list is interspersed with "," and surrounded by ""
        """, arglist, flags=re.VERBOSE)
        if x.strip() not in ("", ","))
    args = []
    for arg in arglist:
        name, ann = arg.split(":")
        if name in keyword.kwlist:
            name = name + "_"
        if "=" in ann:
            ann, default = ann.split("=")
            tup = name, ann, default
        else:
            tup = name, ann
        args.append(tup)
    ret["arglist"] = args
    multi = ret["multi"]
    if multi is not None:
        ret["multi"] = int(multi)
    return ret

def _resolve_number(thing):
    try:
        return eval(thing, namespace)
    except Exception:
        return None

def try_to_guess(thing, valtype):
    res = _resolve_number(thing)
    if res is not None:
        return res
    if "." not in thing and "(" not in thing:
        text = "{}.{}".format(valtype, thing)
        try:
            return eval(text, namespace)
        except Exception:
            pass
    typewords = valtype.split(".")
    valwords = thing.split(".")
    braceless = valwords[0]
    if "(" in braceless:
        braceless = braceless[:braceless.index("(")]
    for idx, w in enumerate(typewords):
        if w == braceless:
            text = ".".join(typewords[:idx] + valwords)
            try:
                return eval(text, namespace)
            except Exception:
                pass
    return None

def _resolve_value(thing, valtype, line):
    if thing in type_map:
        return type_map[thing]
    try:
        res = eval(thing, namespace)
        type_map[thing] = res
        return res
    except Exception:
        pass
    res = try_to_guess(thing, valtype) if valtype else None
    if res is not None:
        type_map[thing] = res
        return res
    warnings.warn("""pyside_type_init:

        UNRECOGNIZED:   {!r}
        OFFENDING LINE: {!r}
        """.format(thing, line), RuntimeWarning)
    return thing

def _resolve_type(thing, line):
    return _resolve_value(thing, None, line)

def calculate_props(line):
    line = line.strip()
    res = _parse_line(line)
    arglist = res["arglist"]
    annotations = {}
    _defaults = []
    for tup in arglist:
        name, ann = tup[:2]
        annotations[name] = _resolve_type(ann, line)
        if len(tup) == 3:
            default = _resolve_value(tup[2], ann, line)
            _defaults.append(default)
    defaults = tuple(_defaults)
    returntype = res["returntype"]
    if returntype is not None:
        annotations["return"] = _resolve_type(returntype, line)
    props = {}
    props["defaults"] = defaults
    props["kwdefaults"] = {}
    props["annotations"] = annotations
    props["varnames"] = varnames = tuple(tup[0] for tup in arglist)
    funcname = res["funcname"]
    props["fullname"] = funcname
    shortname = funcname[funcname.rindex(".")+1:]
    props["name"] = shortname
    props["multi"] = res["multi"]
    return props

def pyside_type_init(typemod, sig_str):
    dprint()
    if type(typemod) is types.ModuleType:
        dprint("Initialization of module '{}'".format(typemod.__name__))
    else:
        dprint("Initialization of type '{}.{}'".format(typemod.__module__,
                                                       typemod.__name__))
    update_mapping()
    ret = {}
    multi_props = []
    for line in sig_str.strip().splitlines():
        props = calculate_props(line)
        shortname = props["name"]
        multi = props["multi"]
        if multi is None:
            ret[shortname] = props
            dprint(props)
        else:
            fullname = props.pop("fullname")
            multi_props.append(props)
            if multi > 0:
                continue
            multi_props = {"multi": multi_props, "fullname": fullname}
            ret[shortname] = multi_props
            dprint(multi_props)
            multi_props = []
    return ret

# end of file