from __future__ import print_function
import os
import pytsk3
import sys
import pyewf
from datetime import datetime

"""
MIT License

Copyright (c) 2017 Chapin Bryce, Preston Miller

Please share comments and questions at:
    https://github.com/PythonForensics/PythonForensicsCookbook
    or email pyforcookbook@gmail.com

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
"""


class EWFImgInfo(pytsk3.Img_Info):
    """EWF Image Format helper class"""
    def __init__(self, ewf_handle):
        self._ewf_handle = ewf_handle
        super(EWFImgInfo, self).__init__(url="", type=pytsk3.TSK_IMG_TYPE_EXTERNAL)

    def close(self):
        self._ewf_handle.close()

    def read(self, offset, size):
        self._ewf_handle.seek(offset)
        return self._ewf_handle.read(size)

    def get_size(self):
        return self._ewf_handle.get_media_size()


class TSKUtil(object):
    def __init__(self, evidence, image_type):
        self.evidence = evidence
        self.image_type = image_type

        # Assigned parameters
        self.vol = None
        self.image_handle = None
        self.fs = []

        # Prep volume and fs objects
        self.run()

    def run(self):
        self.open_vol()
        self.open_FS()

    def return_vol(self):
        sys.stderr.write("[+] Opening {}\n".format(self.evidence))
        # Handle EWF/Raw Images
        if self.image_type == "ewf":
            try:
                filenames = pyewf.glob(self.evidence)
            except IOError:
                _, e, _ = sys.exc_info()
                sys.stderr.write("[-] Invalid EWF format:\n {}\n".format(e))
                raise IOError

            ewf_handle = pyewf.handle()
            ewf_handle.open(filenames)

            # Open PYTSK3 handle on EWF Image
            self.image_handle = EWFImgInfo(ewf_handle)
        else:
            self.image_handle = pytsk3.Img_Info(self.evidence)

        # Open volume from image
        try:
            self.vol = pytsk3.Volume_Info(self.image_handle)
        except IOError:
            return None

        return self.vol

    def open_vol(self):
        sys.stderr.write("[+] Opening {}\n".format(self.evidence))
        # Handle EWF/Raw Images
        if self.image_type == "ewf":
            try:
                filenames = pyewf.glob(self.evidence)
            except IOError:
                _, e, _ = sys.exc_info()
                sys.stderr.write("[-] Invalid EWF format:\n {}\n".format(e))
                raise IOError

            ewf_handle = pyewf.handle()
            ewf_handle.open(filenames)

            # Open PYTSK3 handle on EWF Image
            self.image_handle = EWFImgInfo(ewf_handle)
        else:
            self.image_handle = pytsk3.Img_Info(self.evidence)

        # Open volume from image
        try:
            self.vol = pytsk3.Volume_Info(self.image_handle)
        except IOError:
            _, e, _ = sys.exc_info()
            sys.stderr.write("[-] Unable to read partition table. Possible logical image:\n {}\n".format(e))

    def open_FS(self):
        # Open FS and Recurse
        if self.vol is not None:
            for partition in self.vol:
                if partition.len > 2048 and "Unallocated" not in partition.desc and "Extended" not in partition.desc and "Primary Table" not in partition.desc:
                    try:
                        self.fs.append(pytsk3.FS_Info(
                            self.image_handle,
                            offset=partition.start * self.vol.info.block_size))
                    except IOError:
                        _, e, _ = sys.exc_info()
                        sys.stderr.write("[-] Unable to open FS:\n {}\n".format(e))
        else:
            try:
                self.fs.append(pytsk3.FS_Info(self.image_handle))
            except IOError:
                _, e, _ = sys.exc_info()
                sys.stderr.write("[-] Unable to open FS:\n {}\n".format(e))

    def detect_ntfs(self, vol, partition):
        try:
            block_size = vol.info.block_size
            fs_object = pytsk3.FS_Info(self.image_handle, offset=(partition.start * block_size))
        except Exception:
            sys.stderr.write("[-] Unable to open FS\n")
            return False
        if fs_object.info.ftype == pytsk3.TSK_FS_TYPE_NTFS_DETECT:
            return True
        else:
            return False

    def recurse_files(self, substring, path="/", logic="contains", case=False):
        files = []
        for i, fs in enumerate(self.fs):
            try:
                root_dir = fs.open_dir(path)
            except IOError:
                continue
            files += self.recurse_dirs(i, fs, root_dir, [], [], [""], substring, logic, case)

        if files == []:
            return None
        else:
            return files

    def query_directory(self, path):
        dirs = []
        for i, fs in enumerate(self.fs):
            try:
                dirs.append((i, fs.open_dir(path)))
            except IOError:
                continue

        if dirs == []:
            return None
        else:
            return dirs

    def recurse_dirs(self, part, fs, root_dir, dirs, data, parent, substring, logic, case):
        dirs.append(root_dir.info.fs_file.meta.addr)
        for fs_object in root_dir:
            # Skip ".", ".." or directory entries without a name.
            if not hasattr(fs_object, "info") or not hasattr(fs_object.info, "name") or not hasattr(fs_object.info.name, "name") or fs_object.info.name.name in [".", ".."]:
                continue
            try:
                file_name = fs_object.info.name.name
                file_path = "{}/{}".format("/".join(parent), fs_object.info.name.name)
                try:
                    if fs_object.info.meta.type == pytsk3.TSK_FS_META_TYPE_DIR:
                        f_type = "DIR"
                        file_ext = ""
                    else:
                        f_type = "FILE"

                except AttributeError:
                    continue  # Which object has the AttributeError?

                if f_type == "FILE":
                    if logic.lower() == 'contains':
                        if case is False:
                            if substring.lower() in file_name.lower():
                                data.append((file_name, file_path, fs_object, part))
                        else:
                            if substring in file_name:
                                data.append((file_name, file_path, fs_object, part))
                    elif logic.lower() == 'startswith':
                        if case is False:
                            if file_name.lower().startswith(substring.lower()):
                                data.append((file_name, file_path, fs_object, part))
                        else:
                            if file_name.startswith(substring):
                                data.append((file_name, file_path, fs_object, part))
                    elif logic.lower() == 'endswith':
                        if case is False:
                            if file_name.lower().endswith(substring.lower()):
                                data.append((file_name, file_path, fs_object, part))
                        else:
                            if file_name.endswith(substring):
                                data.append((file_name, file_path, fs_object, part))
                    elif logic.lower() == 'equal':
                        if case is False:
                            if substring.lower() == file_name.lower():
                                data.append((file_name, file_path, fs_object, part))
                        else:
                            if substring == file_name:
                                data.append((file_name, file_path, fs_object, part))
                    else:
                        sys.stderr.write("[-] Warning invalid logic {} provided\n".format(logic))
                        sys.exit()

                elif f_type == "DIR":
                    parent.append(fs_object.info.name.name)
                    sub_directory = fs_object.as_directory()
                    inode = fs_object.info.meta.addr

                    # This ensures that we don't recurse into a directory
                    # above the current level and thus avoid circular loops.
                    if inode not in dirs:
                        self.recurse_dirs(part, fs, sub_directory, dirs, data, parent, substring, logic, case)
                    parent.pop(-1)

            except IOError:
                pass
        dirs.pop(-1)
        return data


def openVSSFS(img, count):
    # Open FS and Recurse
    try:
        fs = pytsk3.FS_Info(img)
    except IOError:
        _, e, _ = sys.exc_info()
        sys.stderr.write("[-] Unable to open FS: {}".format(e))
    root = fs.open_dir(path="/")
    data = recurseFiles(count, fs, root, [], [], [""])
    return data


def recurseFiles(count, fs, root_dir, dirs, data, parent):
    dirs.append(root_dir.info.fs_file.meta.addr)
    for fs_object in root_dir:
        # Skip ".", ".." or directory entries without a name.
        if not hasattr(fs_object, "info") or not hasattr(fs_object.info, "name") or not hasattr(fs_object.info.name, "name") or fs_object.info.name.name in [".", ".."]:
            continue
        try:
            file_name = fs_object.info.name.name
            file_path = "{}/{}".format("/".join(parent), fs_object.info.name.name)
            try:
                if fs_object.info.meta.type == pytsk3.TSK_FS_META_TYPE_DIR:
                    f_type = "DIR"
                    file_ext = ""
                else:
                    f_type = "FILE"
                    if "." in file_name:
                        file_ext = file_name.rsplit(".")[-1].lower()
                    else:
                        file_ext = ""
            except AttributeError:
                continue

            size = fs_object.info.meta.size
            create = convertTime(fs_object.info.meta.crtime)
            change = convertTime(fs_object.info.meta.ctime)
            modify = convertTime(fs_object.info.meta.mtime)
            data.append(["VSS {}".format(count), file_name, file_ext, f_type, create, change, modify, size, file_path])

            if f_type == "DIR":
                parent.append(fs_object.info.name.name)
                sub_directory = fs_object.as_directory()
                inode = fs_object.info.meta.addr

                # This ensures that we don't recurse into a directory
                # above the current level and thus avoid circular loops.
                if inode not in dirs:
                    recurseFiles(count, fs, sub_directory, dirs, data, parent)
                parent.pop(-1)

        except IOError:
            pass
    dirs.pop(-1)
    return data


def convertTime(ts):
    if str(ts) == "0":
        return ""
    return datetime.utcfromtimestamp(ts)