# Copyright (C) 2009 Google Inc. All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are
# met:
#
#    * Redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer.
#    * Redistributions in binary form must reproduce the above
# copyright notice, this list of conditions and the following disclaimer
# in the documentation and/or other materials provided with the
# distribution.
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# contributors may be used to endorse or promote products derived from
# this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

import StringIO
import errno
import hashlib
import os
import re

from webkitpy.common.system import path
from webkitpy.common.system import ospath


class MockFileSystem(object):
    def __init__(self, files=None, dirs=None, cwd='/'):
        """Initializes a "mock" filesystem that can be used to completely
        stub out a filesystem.

        Args:
            files: a dict of filenames -> file contents. A file contents
                value of None is used to indicate that the file should
                not exist.
        """
        self.files = files or {}
        self.written_files = {}
        self._sep = '/'
        self.current_tmpno = 0
        self.cwd = cwd
        self.dirs = set(dirs or [])
        self.dirs.add(cwd)
        for f in self.files:
            d = self.dirname(f)
            while not d in self.dirs:
                self.dirs.add(d)
                d = self.dirname(d)

    def _get_sep(self):
        return self._sep

    sep = property(_get_sep, doc="pathname separator")

    def clear_written_files(self):
        # This function can be used to track what is written between steps in a test.
        self.written_files = {}

    def _raise_not_found(self, path):
        raise IOError(errno.ENOENT, path, os.strerror(errno.ENOENT))

    def _split(self, path):
        return path.rsplit(self.sep, 1)

    def abspath(self, path):
        if os.path.isabs(path):
            return self.normpath(path)
        return self.abspath(self.join(self.cwd, path))

    def basename(self, path):
        return self._split(path)[1]

    def expanduser(self, path):
        if path[0] != "~":
            return path
        parts = path.split(self.sep, 1)
        home_directory = self.sep + "Users" + self.sep + "mock"
        if len(parts) == 1:
            return home_directory
        return home_directory + self.sep + parts[1]

    def path_to_module(self, module_name):
        return "/mock-checkout/Tools/Scripts/" + module_name.replace('.', '/') + ".py"

    def chdir(self, path):
        path = self.normpath(path)
        if not self.isdir(path):
            raise OSError(errno.ENOENT, path, os.strerror(errno.ENOENT))
        self.cwd = path

    def copyfile(self, source, destination):
        if not self.exists(source):
            self._raise_not_found(source)
        if self.isdir(source):
            raise IOError(errno.EISDIR, source, os.strerror(errno.ISDIR))
        if self.isdir(destination):
            raise IOError(errno.EISDIR, destination, os.strerror(errno.ISDIR))

        self.files[destination] = self.files[source]
        self.written_files[destination] = self.files[source]

    def dirname(self, path):
        return self._split(path)[0]

    def exists(self, path):
        return self.isfile(path) or self.isdir(path)

    def files_under(self, path, dirs_to_skip=[], file_filter=None):
        def filter_all(fs, dirpath, basename):
            return True

        file_filter = file_filter or filter_all
        files = []
        if self.isfile(path):
            if file_filter(self, self.dirname(path), self.basename(path)):
                files.append(path)
            return files

        if self.basename(path) in dirs_to_skip:
            return []

        if not path.endswith(self.sep):
            path += self.sep

        dir_substrings = [self.sep + d + self.sep for d in dirs_to_skip]
        for filename in self.files:
            if not filename.startswith(path):
                continue

            suffix = filename[len(path) - 1:]
            if any(dir_substring in suffix for dir_substring in dir_substrings):
                continue

            dirpath, basename = self._split(filename)
            if file_filter(self, dirpath, basename):
                files.append(filename)

        return files

    def getcwd(self):
        return self.cwd

    def glob(self, glob_string):
        # FIXME: This handles '*', but not '?', '[', or ']'.
        glob_string = re.escape(glob_string)
        glob_string = glob_string.replace('\\*', '[^\\/]*') + '$'
        glob_string = glob_string.replace('\\/', '/')
        path_filter = lambda path: re.match(glob_string, path)

        # We could use fnmatch.fnmatch, but that might not do the right thing on windows.
        existing_files = [path for path, contents in self.files.items() if contents is not None]
        return filter(path_filter, existing_files) + filter(path_filter, self.dirs)

    def isabs(self, path):
        return path.startswith(self.sep)

    def isfile(self, path):
        return path in self.files and self.files[path] is not None

    def isdir(self, path):
        if path in self.files:
            return False
        path = self.normpath(path)
        if path in self.dirs:
            return True

        # We need to use a copy of the keys here in order to avoid switching
        # to a different thread and potentially modifying the dict in
        # mid-iteration.
        files = self.files.keys()[:]
        result = any(f.startswith(path) for f in files)
        if result:
            self.dirs.add(path)
        return result

    def join(self, *comps):
        # FIXME: might want tests for this and/or a better comment about how
        # it works.
        return re.sub(re.escape(os.path.sep), self.sep, os.path.join(*comps))

    def listdir(self, path):
        if not self.isdir(path):
            raise OSError("%s is not a directory" % path)

        if not path.endswith(self.sep):
            path += self.sep

        dirs = []
        files = []
        for f in self.files:
            if self.exists(f) and f.startswith(path):
                remaining = f[len(path):]
                if self.sep in remaining:
                    dir = remaining[:remaining.index(self.sep)]
                    if not dir in dirs:
                        dirs.append(dir)
                else:
                    files.append(remaining)
        return dirs + files

    def mtime(self, path):
        if self.exists(path):
            return 0
        self._raise_not_found(path)

    def _mktemp(self, suffix='', prefix='tmp', dir=None, **kwargs):
        if dir is None:
            dir = self.sep + '__im_tmp'
        curno = self.current_tmpno
        self.current_tmpno += 1
        return self.join(dir, "%s_%u_%s" % (prefix, curno, suffix))

    def mkdtemp(self, **kwargs):
        class TemporaryDirectory(object):
            def __init__(self, fs, **kwargs):
                self._kwargs = kwargs
                self._filesystem = fs
                self._directory_path = fs._mktemp(**kwargs)
                fs.maybe_make_directory(self._directory_path)

            def __str__(self):
                return self._directory_path

            def __enter__(self):
                return self._directory_path

            def __exit__(self, type, value, traceback):
                # Only self-delete if necessary.

                # FIXME: Should we delete non-empty directories?
                if self._filesystem.exists(self._directory_path):
                    self._filesystem.rmtree(self._directory_path)

        return TemporaryDirectory(fs=self, **kwargs)

    def maybe_make_directory(self, *path):
        norm_path = self.normpath(self.join(*path))
        while norm_path and not self.isdir(norm_path):
            self.dirs.add(norm_path)
            norm_path = self.dirname(norm_path)

    def move(self, source, destination):
        if self.files[source] is None:
            self._raise_not_found(source)
        self.files[destination] = self.files[source]
        self.written_files[destination] = self.files[destination]
        self.files[source] = None
        self.written_files[source] = None

    def normpath(self, path):
        # Like join(), relies on os.path functionality but normalizes the
        # path separator to the mock one.
        return re.sub(re.escape(os.path.sep), self.sep, os.path.normpath(path))

    def open_binary_tempfile(self, suffix=''):
        path = self._mktemp(suffix)
        return (WritableBinaryFileObject(self, path), path)

    def open_binary_file_for_reading(self, path):
        if self.files[path] is None:
            self._raise_not_found(path)
        return ReadableBinaryFileObject(self, path, self.files[path])

    def read_binary_file(self, path):
        # Intentionally raises KeyError if we don't recognize the path.
        if self.files[path] is None:
            self._raise_not_found(path)
        return self.files[path]

    def write_binary_file(self, path, contents):
        # FIXME: should this assert if dirname(path) doesn't exist?
        self.files[path] = contents
        self.written_files[path] = contents

    def open_text_file_for_reading(self, path):
        if self.files[path] is None:
            self._raise_not_found(path)
        return ReadableTextFileObject(self, path, self.files[path])

    def open_text_file_for_writing(self, path):
        return WritableTextFileObject(self, path)

    def read_text_file(self, path):
        return self.read_binary_file(path).decode('utf-8')

    def write_text_file(self, path, contents):
        return self.write_binary_file(path, contents.encode('utf-8'))

    def sha1(self, path):
        contents = self.read_binary_file(path)
        return hashlib.sha1(contents).hexdigest()

    def relpath(self, path, start='.'):
        return ospath.relpath(path, start, self.abspath, self.sep)

    def remove(self, path):
        if self.files[path] is None:
            self._raise_not_found(path)
        self.files[path] = None
        self.written_files[path] = None

    def rmtree(self, path):
        path = self.normpath(path)

        for f in self.files:
            if f.startswith(path):
                self.files[f] = None

        self.dirs = set(filter(lambda d: not d.startswith(path), self.dirs))

    def split(self, path):
        idx = path.rfind(self.sep)
        if idx == -1:
            return ('', path)
        return (path[:idx], path[(idx + 1):])

    def splitext(self, path):
        idx = path.rfind('.')
        if idx == -1:
            idx = 0
        return (path[0:idx], path[idx:])


class WritableBinaryFileObject(object):
    def __init__(self, fs, path):
        self.fs = fs
        self.path = path
        self.closed = False
        self.fs.files[path] = ""

    def __enter__(self):
        return self

    def __exit__(self, type, value, traceback):
        self.close()

    def close(self):
        self.closed = True

    def write(self, str):
        self.fs.files[self.path] += str
        self.fs.written_files[self.path] = self.fs.files[self.path]


class WritableTextFileObject(WritableBinaryFileObject):
    def write(self, str):
        WritableBinaryFileObject.write(self, str.encode('utf-8'))


class ReadableBinaryFileObject(object):
    def __init__(self, fs, path, data):
        self.fs = fs
        self.path = path
        self.closed = False
        self.data = data
        self.offset = 0

    def __enter__(self):
        return self

    def __exit__(self, type, value, traceback):
        self.close()

    def close(self):
        self.closed = True

    def read(self, bytes=None):
        if not bytes:
            return self.data[self.offset:]
        start = self.offset
        self.offset += bytes
        return self.data[start:self.offset]


class ReadableTextFileObject(ReadableBinaryFileObject):
    def __init__(self, fs, path, data):
        super(ReadableTextFileObject, self).__init__(fs, path, StringIO.StringIO(data))

    def close(self):
        self.data.close()
        super(ReadableTextFileObject, self).close()

    def read(self, bytes=-1):
        return self.data.read(bytes)

    def readline(self, length=None):
        return self.data.readline(length)

    def __iter__(self):
        return self.data.__iter__()

    def next(self):
        return self.data.next()

    def seek(self, offset, whence=os.SEEK_SET):
        self.data.seek(offset, whence)