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"""
signature_bootstrap.py
----------------------

This file was originally directly embedded into the C source.
After it grew more and more, I now prefer to have it as Python file.

Meanwhile, there is also no more a stub loader necessary:
Because we meanwhile have embedding support, we could also load this file
directly from a .pyc file.

This file replaces the hard to read Python stub in 'signature.cpp', and we
could distinguish better between bootstrap related functions and loader
functions.
It is embedded into 'signature.cpp' as "embed/signature_bootstrap.inc".
"""

from __future__ import print_function, absolute_import

recursion_trap = 0

# We avoid real imports in phase 1 that could fail (simply removed all).
# Python 2 is not able to import when the extension import is still active.
# Phase 1 simply defines the functions, which will be used in Phase 2.

def bootstrap():
    import sys
    import os
    import tempfile
    import traceback
    from contextlib import contextmanager

    global recursion_trap
    if recursion_trap:
        # we are probably called from outside, already
        print("Recursion occurred in Bootstrap. Did you start by hand? Then it's ok.")
        print("But you should trigger start by '_init_pyside_extension()', only!")
    recursion_trap += 1

    @contextmanager
    def ensure_shibokensupport(target, support_path):
        # Make sure that we always have the shibokensupport containing package first.
        # Also remove any prior loaded module of this name, just in case.
        # PYSIDE-1621: support_path can also be a finder instance.
        target.insert(0, support_path)

        sbks = "shibokensupport"
        if sbks in sys.modules:
            del sys.modules[sbks]
        prefix = sbks + "."
        for key in list(key for key in sys.modules if key.startswith(prefix)):
            del sys.modules[key]
        try:
            import shibokensupport
            yield
        except Exception as e:
            print("Problem importing shibokensupport:")
            print(e)
            traceback.print_exc()
            print("sys.path:")
            for p in sys.path:
                print("  " + p)
            sys.stdout.flush()
            sys.exit(-1)
        target.remove(support_path)

    try:
        import shiboken2 as root
    except ImportError:
        # uninstalled case without ctest, try only this one which has __init__:
        import shibokenmodule as root
    rp = os.path.realpath(os.path.dirname(root.__file__))
    # This can be the shiboken2 directory or the binary module, so search.
    look_for = os.path.join("files.dir", "shibokensupport", "signature", "loader.py")
    while not os.path.exists(os.path.join(rp, look_for)):
        dir = os.path.dirname(rp)
        if dir == rp:  # Hit root, '/', 'C:\', '\\server\share'
            break
        rp = dir

    # Here we decide if we work embedded or not.
    embedding_var = "pyside_uses_embedding"
    use_embedding = bool(getattr(sys, embedding_var, False))
    loader_path = os.path.join(rp, look_for)
    files_dir = os.path.abspath(os.path.join(loader_path, "..", "..", ".."))
    assert files_dir.endswith("files.dir")

    # We report in sys what we used. We could put more here as well.
    if not os.path.exists(loader_path):
        use_embedding = True
    support_path = prepare_zipfile() if use_embedding else files_dir
    setattr(sys, embedding_var, use_embedding)

    if use_embedding:
        target, support_path = prepare_zipfile()
    else:
        target, support_path = sys.path, files_dir

    try:
        with ensure_shibokensupport(target, support_path):
            from shibokensupport.signature import loader

    except Exception as e:
        print('Exception:', e)
        traceback.print_exc(file=sys.stdout)

    return loader


# New functionality: Loading from a zip archive.
# There exists the zip importer, but as it is written, only real zip files are
# supported. Before I will start an own implementation, it is easiest to use
# a temporary zip file.
# PYSIDE-1621: make zip file access totally virtual

def prepare_zipfile():
    """
    Write the zip file to a real file and return its name.
    It will be implicitly opened as such when we add the name to sys.path .

    New approach (Python 3, only):

    Use EmbeddableZipImporter and pass the zipfile structure directly.
    The sys.path way does not work, instead we need to use sys.meta_path .
    See https://docs.python.org/3/library/sys.html#sys.meta_path
    """
    import base64
    import io
    import sys
    import zipfile

    # 'zipstring_sequence' comes from signature.cpp
    zipbytes = base64.b64decode(''.join(zipstring_sequence))
    if sys.version_info[0] >= 3:
        vzip = zipfile.ZipFile(io.BytesIO(zipbytes))
        return sys.meta_path, EmbeddableZipImporter(vzip)

    # Old version for Python 2.7, only.
    import os
    import tempfile

    fd, fname = tempfile.mkstemp(prefix='embedded.', suffix='.zip')
    os.write(fd, zipbytes)
    os.close(fd)
    # Let us test the zipfile if it really is one.
    # Otherwise, zipimporter would simply ignore it without notice.
    try:
        z = zipfile.ZipFile(fname)
        z.close()
    except zipfile.BadZipFile as e:
        print('Broken Zip File:', e)
        traceback.print_exc(file=sys.stdout)
    finally:
        return sys.path, fname


class EmbeddableZipImporter(object):

    def __init__(self, zip_file):
        def p2m(filename):
            if filename.endswith("/__init__.py"):
                return filename[:-12].replace("/", ".")
            if filename.endswith(".py"):
                return filename[:-3].replace("/", ".")
            return None

        self.zfile = zip_file
        self._path2mod = {_.filename : p2m(_.filename) for _ in zip_file.filelist}
        self._mod2path = {_[1] : _[0] for _ in self._path2mod.items()}

    def find_module(self, fullname, path):
        return self if self._mod2path.get(fullname) else None

    def load_module(self, fullname):
        import importlib
        import sys

        filename = self._mod2path.get(fullname)
        if filename not in self._path2mod:
            raise ImportError(fullname)
        module_spec = importlib.machinery.ModuleSpec(fullname, None)
        new_module = importlib.util.module_from_spec(module_spec)
        with self.zfile.open(filename, "r") as f:   # "rb" not for zipfile
            exec(f.read(), new_module.__dict__)
        new_module.__file__ = filename
        new_module.__loader__ = self
        if filename.endswith("/__init__.py"):
            new_module.__path__ = []
            new_module.__package__ = fullname
        else:
            new_module.__package__ = fullname.rpartition('.')[0]
        sys.modules[fullname] = new_module
        return new_module

# eof
