import os
import re

def GetSettingsValues(debugger, setting_variable_name):
    """ Queries the lldb internal settings
        params:
            debugger : lldb.SBDebugger instance
            setting_variable_name: str - string name of the setting(eg prompt)
        returns:
            [] : Array of strings. Empty array if setting is not found/set
    """
    retval = []
    settings_val_list = debugger.GetInternalVariableValue(setting_variable_name, debugger.GetInstanceName())
    for s in settings_val_list:
        retval.append(str(s))
    return retval

def GetSymbolsFilePathFromModule(m):
    """ Get a file path from a module.
        params: m - lldb.target.module
        returns:
            str : path to first file based symbol. Note this might be dir path inside sources.
    """
    for s in m.symbols:
        if s.type == 8:
            return os.path.dirname(str(s.name))
    return ""

def GetSourcePathSettings(binary_path, symbols_path):
    """ Parse the binary path and symbols_path to find if source-map setting is applicable
        params:
            binary_path: str path of the kernel module
            symbols_path: str path of the symbols stored in binary. Use
        returns:
            str : string command to set the source-map setting.
    """
    retval = ""
    train_re = re.compile(r"dsyms/([a-zA-Z]+)/")
    _t_arr = train_re.findall(binary_path)
    train = ''
    if _t_arr:
        train = _t_arr[0]
    if not train:
        return retval
    new_path = "~rc/Software/{}/Projects/".format(train)
    new_path = os.path.expanduser(new_path)
    new_path = os.path.normpath(new_path)
    common_path_re = re.compile("(^.*?Sources/)(xnu.*?)/.*$")
    _t_arr = common_path_re.findall(symbols_path)
    srcpath = ""
    projpath = "xnu"
    if _t_arr:
        srcpath = "".join(_t_arr[0])
        projpath = _t_arr[0][-1]
    else:
        return retval

    new_path = new_path + os.path.sep +  projpath
    cmd = "settings append target.source-map {} {}"
    retval =  cmd.format(srcpath, new_path)
    return retval

def CheckMissingLibs(debugger):
    """ Check that required modules are installed. """

    # Convert LLDB version string to version tuple.
    # A version string may be of form: lldb_host-1403.2.6.11 (iPhoneOS)
    # Code below only matches 1403.2.6.11 and ignores rest of the string.
    ver_str = debugger.GetVersionString()
    lldb_ver = re.search("^lldb.*-([0-9.]+)", ver_str, re.MULTILINE).group(1)
    ver = tuple(map(int, lldb_ver.split('.')))

    # Display correct command to install missing packages.
    if ver[1] == 2:
        cmd_fmt = "Please install {mod:s}: xcrun --sdk <sdk> python3 -m pip install --user --ignore-installed {mod:s}"
    else:
        cmd_fmt = "Please install {mod:s}: xcrun pip3 install --user --ignore-installed {mod:s}"

    try:
        import macholib
    except:
        print(cmd_fmt.format(mod="macholib"))
        return False

    return True

def __lldb_init_module(debugger, internal_dict):

    if not CheckMissingLibs(debugger):
        print("Can't load LLDB macros. Please install dependencies first.")
        return

    debug_session_enabled = False
    if "DEBUG_XNU_LLDBMACROS" in os.environ and len(os.environ['DEBUG_XNU_LLDBMACROS']) > 0:
        debug_session_enabled = True
    prev_os_plugin = "".join(GetSettingsValues(debugger, 'target.process.python-os-plugin-path'))
    print("Loading kernel debugging from %s" % __file__)
    print("LLDB version %s" % debugger.GetVersionString())
    self_path = "{}".format(__file__)
    base_dir_name = self_path[:self_path.rfind("/")]
    core_os_plugin = base_dir_name + "/lldbmacros/core/operating_system.py"
    osplugin_cmd = "settings set target.process.python-os-plugin-path \"%s\"" % core_os_plugin
    intel_whitelist = ['hndl_allintrs', 'hndl_alltraps', 'trap_from_kernel', 'hndl_double_fault', 'hndl_machine_check']
    arm_whitelist = ['_fleh_prefabt', '_ExceptionVectorsBase', '_ExceptionVectorsTable', '_fleh_undef', '_fleh_dataabt', '_fleh_irq', '_fleh_decirq', '_fleh_fiq_generic', '_fleh_dec']
    whitelist_trap_cmd = "settings set target.trap-handler-names %s %s" % (' '.join(intel_whitelist), ' '.join(arm_whitelist))
    xnu_debug_path = base_dir_name + "/lldbmacros/xnu.py"
    xnu_load_cmd = "command script import \"%s\"" % xnu_debug_path
    disable_optimization_warnings_cmd = "settings set target.process.optimization-warnings false"

    # Single stepping support
    report_all_threads_cmd = "settings set target.process.experimental.os-plugin-reports-all-threads false"
    step_mode_cmd = "settings set target.process.run-all-threads true"

    source_map_cmd = ""
    try:
        source_map_cmd = GetSourcePathSettings(base_dir_name, GetSymbolsFilePathFromModule(debugger.GetTargetAtIndex(0).modules[0]) )
    except Exception as e:
        pass
    if debug_session_enabled :
        if len(prev_os_plugin) > 0:
            print("\nDEBUG_XNU_LLDBMACROS is set. Skipping the setting of OS plugin from dSYM.\nYou can manually set the OS plugin by running\n" + osplugin_cmd)
        else:
            print(osplugin_cmd)
            debugger.HandleCommand(osplugin_cmd)
        print("\nDEBUG_XNU_LLDBMACROS is set. Skipping the load of xnu debug framework.\nYou can manually load the framework by running\n" + xnu_load_cmd)
    else:
        print(osplugin_cmd)
        debugger.HandleCommand(osplugin_cmd)
        print(whitelist_trap_cmd)
        debugger.HandleCommand(whitelist_trap_cmd)
        print(xnu_load_cmd)
        debugger.HandleCommand(xnu_load_cmd)
        print(disable_optimization_warnings_cmd)
        debugger.HandleCommand(disable_optimization_warnings_cmd)
        print(report_all_threads_cmd)
        debugger.HandleCommand(report_all_threads_cmd)
        print(step_mode_cmd)
        debugger.HandleCommand(step_mode_cmd)
        if source_map_cmd:
            print(source_map_cmd)
            debugger.HandleCommand(source_map_cmd)

        load_kexts = True
        if "XNU_LLDBMACROS_NOBUILTINKEXTS" in os.environ and len(os.environ['XNU_LLDBMACROS_NOBUILTINKEXTS']) > 0:
            load_kexts = False
        builtinkexts_path = os.path.join(os.path.dirname(self_path), "lldbmacros", "builtinkexts")
        if os.access(builtinkexts_path, os.F_OK):
            kexts = os.listdir(builtinkexts_path)
            if len(kexts) > 0:
                print("\nBuiltin kexts: %s\n" % kexts)
                if not load_kexts:
                    print("XNU_LLDBMACROS_NOBUILTINKEXTS is set, not loading:\n")
                for kextdir in kexts:
                    # Python does not handle well modules that contain '-' in their names.
                    # Remap such scripts to use '_' instead.
                    script_name = kextdir.split('.')[-1].replace('-', '_') + ".py"
                    script = os.path.join(builtinkexts_path, kextdir, script_name)

                    import_kext_cmd = "command script import \"%s\"" % script
                    print("%s" % import_kext_cmd)
                    if load_kexts:
                        debugger.HandleCommand(import_kext_cmd)

    print("\n")