"""Utilities for selecting and enumerating the Type Libraries installed on the system
"""

from win32 import api as win32api
from win32 import constants as win32con
from win32 import com as pythoncom


class TypelibSpec:

    def __init__(self, clsid, lcid, major, minor, flags=0):
        self.clsid = str(clsid)
        self.lcid = int(lcid)
        # We avoid assuming 'major' or 'minor' are integers - when
        # read from the registry there is some confusion about if
        # they are base 10 or base 16 (they *should* be base 16, but
        # how they are written is beyond our control.)
        self.major = major
        self.minor = minor
        self.dll = None
        self.desc = None
        self.ver_desc = None
        self.flags = flags
    # For the SelectList

    def __getitem__(self, item):
        if item == 0:
            return self.ver_desc
        raise IndexError("Cant index me!")

    def __lt__(self, other):  # rich-cmp/py3k-friendly version
        me = (self.ver_desc or "").lower(
        ), (self.desc or "").lower(), self.major, self.minor
        them = (other.ver_desc or "").lower(
        ), (other.desc or "").lower(), other.major, other.minor
        return me < them

    def __eq__(self, other):  # rich-cmp/py3k-friendly version
        return ((self.ver_desc or "").lower() == (other.ver_desc or "").lower() and
                (self.desc or "").lower() == (other.desc or "").lower() and
                self.major == other.major and
                self.minor == other.minor)

    def Resolve(self):
        if self.dll is None:
            return 0
        tlb = pythoncom.LoadTypeLib(self.dll)
        self.FromTypelib(tlb, None)
        return 1

    def FromTypelib(self, typelib, dllName=None):
        la = typelib.GetLibAttr()
        self.clsid = str(la[0])
        self.lcid = la[1]
        self.major = la[3]
        self.minor = la[4]
        if dllName:
            self.dll = dllName


def EnumKeys(root):
    index = 0
    ret = []
    while True:
        try:
            item = win32api.RegEnumKey(root, index)
        except win32api.error:
            break
        try:
            # Note this doesn't handle REG_EXPAND_SZ, but the implementation
            # here doesn't need to - that is handled as the data is read.
            val = win32api.RegQueryValue(root, item)
        except win32api.error:
            val = ""  # code using this assumes a string.

        ret.append((item, val))
        index = index + 1
    return ret

FLAG_RESTRICTED = 1
FLAG_CONTROL = 2
FLAG_HIDDEN = 4


def EnumTlbs(excludeFlags=0):
    """Return a list of TypelibSpec objects, one for each registered library.
    """
    key = win32api.RegOpenKey(win32con.HKEY_CLASSES_ROOT, "Typelib")
    iids = EnumKeys(key)
    results = []
    for iid, crap in iids:
        try:
            key2 = win32api.RegOpenKey(key, str(iid))
        except win32api.error:
            # A few good reasons for this, including "access denied".
            continue
        for version, tlbdesc in EnumKeys(key2):
            major_minor = version.split('.', 1)
            if len(major_minor) < 2:
                major_minor.append('0')
            # For some reason, this code used to assume the values were hex.
            # This seems to not be true - particularly for CDO 1.21
            # *sigh* - it appears there are no rules here at all, so when we need
            # to know the info, we must load the tlb by filename and request it.
            # The Resolve() method on the TypelibSpec does this.
            # For this reason, keep the version numbers as strings - that
            # way we can't be wrong!  Let code that really needs an int to work
            # out what to do.  FWIW, http://support.microsoft.com/kb/816970 is
            # pretty clear that they *should* be hex.
            major = major_minor[0]
            minor = major_minor[1]
            key3 = win32api.RegOpenKey(key2, str(version))
            try:
                # The "FLAGS" are at this point
                flags = int(win32api.RegQueryValue(key3, "FLAGS"))
            except (win32api.error, ValueError):
                flags = 0
            if flags & excludeFlags == 0:
                for lcid, crap in EnumKeys(key3):
                    try:
                        lcid = int(lcid)
                    except ValueError:  # not an LCID entry
                        continue
                    # Only care about "{lcid}\win32" key - jump straight there.
                    try:
                        key4 = win32api.RegOpenKey(key3, "%s\\win32" % (lcid,))
                    except win32api.error:
                        continue
                    try:
                        dll, typ = win32api.RegQueryValueEx(key4, None)
                        if typ == win32con.REG_EXPAND_SZ:
                            dll = win32api.ExpandEnvironmentStrings(dll)
                    except win32api.error:
                        dll = None
                    spec = TypelibSpec(iid, lcid, major, minor, flags)
                    spec.dll = dll
                    spec.desc = tlbdesc
                    spec.ver_desc = tlbdesc + " (" + version + ")"
                    results.append(spec)
    return results


def FindTlbsWithDescription(desc):
    """Find all installed type libraries with the specified description
    """
    ret = []
    items = EnumTlbs()
    for item in items:
        if item.desc == desc:
            ret.append(item)
    return ret


def SelectTlb(title="Select Library", excludeFlags=0):
    """Display a list of all the type libraries, and select one.   Returns None if cancelled
    """
    import pywin.dialogs.list
    items = EnumTlbs(excludeFlags)
    # fixup versions - we assume hex (see __init__ above)
    for i in items:
        i.major = int(i.major, 16)
        i.minor = int(i.minor, 16)
    items.sort()
    rc = pywin.dialogs.list.SelectFromLists(title, items, ["Type Library"])
    if rc is None:
        return None
    return items[rc]

# Test code.
if __name__ == '__main__':
    print(SelectTlb().__dict__)
