import os
import ctypes
import subprocess
import time
import _winreg as reg

class disable_file_system_redirection:
    _disable = ctypes.windll.kernel32.Wow64DisableWow64FsRedirection
    _revert = ctypes.windll.kernel32.Wow64RevertWow64FsRedirection
    def __enter__(self):
        self.old_value = ctypes.c_long()
        self.success = self._disable(ctypes.byref(self.old_value))
    def __exit__(self, type, value, traceback):
        if self.success:
            self._revert(self.old_value)

UNINSTALLERS = [
    r"C:\Program Files (x86)\Bitvise SSH Client\uninst.exe",
    r"C:\Program Files\Bitvise SSH Client\uninst.exe"
]
KEY_PATH = r"SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall"
WOW_PATH = r"SOFTWARE\Wow6432Node\Microsoft\Windows\CurrentVersion\Uninstall"

def find_uninstaller():
    for u in UNINSTALLERS:
        if os.path.exists(u):
            return u
    return None

def bitvise_registered():
    # True if "Bitvise SSH Client ..." entry still exists in Uninstall keys
    for path, flag in ((KEY_PATH, reg.KEY_WOW64_64KEY), (WOW_PATH, reg.KEY_WOW64_32KEY)):
        try:
            main = reg.OpenKey(reg.HKEY_LOCAL_MACHINE, path, 0, reg.KEY_READ | flag)
        except Exception:
            continue
        try:
            for i in range(reg.QueryInfoKey(main)[0]):
                try:
                    sub = reg.OpenKey(main, reg.EnumKey(main, i), 0, reg.KEY_READ | flag)
                    try:
                        name = reg.QueryValueEx(sub, "DisplayName")[0]
                        if name.startswith("Bitvise SSH Client"):
                            return True
                    finally:
                        reg.CloseKey(sub)
                except Exception:
                    continue
        finally:
            reg.CloseKey(main)
    return False

def uninst_running():
    try:
        p = subprocess.Popen('tasklist /FI "IMAGENAME eq uninst.exe" /NH',
                             shell=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
        out = p.communicate()[0]
        return 'uninst.exe' in out.lower()
    except Exception:
        return False

def kill_bitvise():
    for proc in ("BvSsh.exe", "BvSshClient.exe"):
        os.system('taskkill /f /im "%s" >nul 2>&1' % proc)

def spm_uninstall(dir, args):
    with disable_file_system_redirection():
        uninst = find_uninstaller()

        # Already removed -> success
        if uninst is None and not bitvise_registered():
            print 'retcode' + str(0) + 'retcode'
            return

        if uninst is None:
            # registry entry exists but no uninstaller file
            print 'retcode' + str(1) + 'retcode'
            return

        kill_bitvise()
        try:
            # Exit code is ignored: parent uninst.exe returns 1 while the child keeps working
            subprocess.call('"%s" "BvSshClient" -unat' % uninst, shell=True)
        except Exception:
            pass

        # Wait up to ~3 minutes for the child uninst.exe to finish and the registry entry to go
        for _ in range(60):
            time.sleep(3)
            if not uninst_running() and not bitvise_registered():
                break
        time.sleep(3)

        if bitvise_registered():
            print 'retcode' + str(1) + 'retcode'
        else:
            print 'retcode' + str(0) + 'retcode'

def spm_install(dir, args):
    os.chdir(dir)
    argslist = args.split()
    try:
        subprocess.check_call(argslist)
        print 'retcode' + str(0) + 'retcode'
    except subprocess.CalledProcessError as e:
        print 'retcode' + str(e.returncode) + 'retcode'

def spm_update(dir, args):
    os.chdir(dir)
    argslist = args.split()
    try:
        subprocess.check_call(argslist)
        print 'retcode' + str(0) + 'retcode'
    except subprocess.CalledProcessError as e:
        print 'retcode' + str(e.returncode) + 'retcode'