#!/usr/bin/env python

"""
This file contains classes that represent C declarations. cparser produces
declarations in this format, and ctypesparser reformats them into a format that
is not C-specific. The other modules don't need to touch these.
"""

__docformat__ = "restructuredtext"

# --------------------------------------------------------------------------
# C Object Model
# --------------------------------------------------------------------------


class Declaration(object):
    def __init__(self):
        self.declarator = None
        self.type = Type()
        self.storage = None
        self.attrib = Attrib()

    def __repr__(self):
        d = {"declarator": self.declarator, "type": self.type}
        if self.storage:
            d["storage"] = self.storage
        l = ["%s=%r" % (k, v) for k, v in d.items()]
        return "Declaration(%s)" % ", ".join(l)


class Declarator(object):
    pointer = None

    def __init__(self):
        self.identifier = None
        self.initializer = None
        self.array = None
        self.parameters = None
        self.bitfield = None
        self.attrib = Attrib()

    # make pointer read-only to catch mistakes early
    pointer = property(lambda self: None)

    def __repr__(self):
        s = self.identifier or ""
        if self.bitfield:
            s += ":%d" % self.bitfield
        if self.array:
            s += repr(self.array)
        if self.initializer:
            s += " = %r" % self.initializer
        if self.parameters is not None:
            s += "(" + ", ".join([repr(p) for p in self.parameters]) + ")"
        return s


class Pointer(Declarator):
    pointer = None

    def __init__(self):
        super(Pointer, self).__init__()
        self.qualifiers = []

    def __repr__(self):
        q = ""
        if self.qualifiers:
            q = "<%s>" % " ".join(self.qualifiers)
        return "POINTER%s(%r)" % (q, self.pointer) + super(Pointer, self).__repr__()


class Array(object):
    def __init__(self):
        self.size = None
        self.array = None

    def __repr__(self):
        if self.size:
            a = "[%r]" % self.size
        else:
            a = "[]"
        if self.array:
            return repr(self.array) + a
        else:
            return a


class Parameter(object):
    def __init__(self):
        self.type = Type()
        self.storage = None
        self.declarator = None
        self.attrib = Attrib()

    def __repr__(self):
        d = {"type": self.type}
        if self.declarator:
            d["declarator"] = self.declarator
        if self.storage:
            d["storage"] = self.storage
        l = ["%s=%r" % (k, v) for k, v in d.items()]
        return "Parameter(%s)" % ", ".join(l)


class Type(object):
    def __init__(self):
        self.qualifiers = []
        self.specifiers = []

    def __repr__(self):
        return " ".join(self.qualifiers + [str(s) for s in self.specifiers])


# These are used only internally.


class StorageClassSpecifier(str):
    def __repr__(self):
        return "StorageClassSpecifier({})".format(str(self))


class TypeSpecifier(str):
    def __repr__(self):
        return "TypeSpecifier({})".format(str(self))


class StructTypeSpecifier(object):
    def __init__(self, is_union, attrib, tag, declarations):
        self.is_union = is_union
        self.attrib = attrib
        self.tag = tag
        self.declarations = declarations
        self.filename = None
        self.lineno = -1

    def __repr__(self):
        if self.is_union:
            s = "union"
        else:
            s = "struct"
        if self.attrib:
            attrs = list()
            for attr, val in self.attrib.items():
                if val and type(val) == str:
                    attrs.append("{}({})".format(attr, val))
                elif val:
                    attrs.append(attr)

            s += " __attribute__(({}))".format(",".join(attrs))
        if self.tag and type(self.tag) != int:
            s += " %s" % self.tag
        if self.declarations:
            s += " {%s}" % "; ".join([repr(d) for d in self.declarations])
        return s


class EnumSpecifier(object):
    def __init__(self, tag, enumerators, src=None):
        self.tag = tag
        self.enumerators = enumerators
        self.filename = None
        self.lineno = -1

    def __repr__(self):
        s = "enum"
        if self.tag:
            s += " %s" % self.tag
        if self.enumerators:
            s += " {%s}" % ", ".join([repr(e) for e in self.enumerators])
        return s


class Enumerator(object):
    def __init__(self, name, expression):
        self.name = name
        self.expression = expression

    def __repr__(self):
        s = self.name
        if self.expression:
            s += " = %r" % self.expression
        return s


class TypeQualifier(str):
    def __repr__(self):
        return "TypeQualifier({})".format(str(self))


class PragmaPack(object):
    DEFAULT = None

    def __init__(self):
        self.current = self.DEFAULT
        self.stack = list()

    def set_default(self):
        self.current = self.DEFAULT

    def push(self, id=None, value=None):
        item = (id, self.current)
        self.stack.append(item)

        if value is not None:
            self.current = value

    def pop(self, id=None):
        if not self.stack:
            if id:
                return (
                    "#pragma pack(pop, {id}) encountered without matching "
                    "#pragma pack(push, {id})".format(id=id),
                )
            else:
                return "#pragma pack(pop) encountered without matching #pragma pack(push)"

        item = None
        err = None

        if id is not None:
            i = len(self.stack) - 1
            while i >= 0 and self.stack[i][0] != id:
                i -= 1

            if i >= 0:
                item = self.stack[i]
                self.stack = self.stack[:i]
            else:
                err = (
                    "#pragma pack(pop, {id}) encountered without matching "
                    "#pragma pack(push, {id}); popped last".format(id=id)
                )

        if item is None:
            item = self.stack.pop()

        self.current = item[1]
        return err


pragma_pack = PragmaPack()


class Attrib(dict):
    def __init__(self, *a, **kw):
        if pragma_pack.current:
            super(Attrib, self).__init__(packed=True, aligned=[pragma_pack.current])
            super(Attrib, self).update(*a, **kw)
        else:
            super(Attrib, self).__init__(*a, **kw)
        self._unalias()

    def __repr__(self):
        return "Attrib({})".format(dict(self))

    def update(self, *a, **kw):
        super(Attrib, self).update(*a, **kw)
        self._unalias()

    def _unalias(self):
        """
        Check for any attribute aliases and remove leading/trailing '__'

        According to https://gcc.gnu.org/onlinedocs/gcc/Attribute-Syntax.html,
        an attribute can also be preceeded/followed by a double underscore
        ('__').
        """

        self.pop(None, None)  # remove dummy empty attribute

        fixes = [attr for attr in self if attr.startswith("__") and attr.endswith("__")]
        for attr in fixes:
            self[attr[2 : (len(attr) - 2)]] = self.pop(attr)


def apply_specifiers(specifiers, declaration):
    """Apply specifiers to the declaration (declaration may be
    a Parameter instead)."""
    for s in specifiers:
        if type(s) == StorageClassSpecifier:
            if declaration.storage:
                # Multiple storage classes, technically an error... ignore it
                pass
            declaration.storage = s
        elif type(s) in (TypeSpecifier, StructTypeSpecifier, EnumSpecifier):
            declaration.type.specifiers.append(s)
        elif type(s) == TypeQualifier:
            declaration.type.qualifiers.append(s)
        elif type(s) == Attrib:
            declaration.attrib.update(s)
