# -*- coding: utf-8 -*-

## Create and compare lists of files/objects
## Author: Michal Ludvig <michal@logix.cz>
##         http://www.logix.cz/michal
## License: GPL Version 2
## Copyright: TGRMN Software and contributors

from __future__ import absolute_import

from .S3 import S3
from .Config import Config
from .S3Uri import S3Uri
from .FileDict import FileDict
from .Utils import *
from .Exceptions import ParameterError
from .HashCache import HashCache

from logging import debug, info, warning

import os
import sys
import glob
import re
import errno
import io

__all__ = ["fetch_local_list", "fetch_remote_list", "compare_filelists"]

def _os_walk_unicode(top):
    '''
    Reimplementation of python's os.walk to nicely support unicode in input as in output.
    '''
    try:
        names = os.listdir(deunicodise(top))
    except:
        return

    dirs, nondirs = [], []
    for name in names:
        name = unicodise(name)
        if os.path.isdir(deunicodise(os.path.join(top, name))):
            if not handle_exclude_include_walk_dir(top, name):
                dirs.append(name)
        else:
            nondirs.append(name)

    yield top, dirs, nondirs
    for name in dirs:
        new_path = os.path.join(top, name)
        if not os.path.islink(deunicodise(new_path)):
            for x in _os_walk_unicode(new_path):
                yield x

def handle_exclude_include_walk_dir(root, dirname):
    '''
    Should this root/dirname directory be excluded? (otherwise included by default)
    Exclude dir matches in the current directory
    This prevents us from recursing down trees we know we want to ignore
    return True for including, and False for excluding
    '''
    cfg = Config()
    d = os.path.join(root, dirname, '')
    debug(u"CHECK: %r" % d)
    excluded = False
    for r in cfg.exclude:
        # python versions end their patterns (from globs) differently, test for both styles.
        if not (r.pattern.endswith(u'\\/$') or r.pattern.endswith(u'\\/\\Z(?ms)')): continue # we only check for directory patterns here
        if r.search(d):
            excluded = True
            debug(u"EXCL-MATCH: '%s'" % (cfg.debug_exclude[r]))
            break
    if excluded:
        ## No need to check for --include if not excluded
        for r in cfg.include:
            # python versions end their patterns (from globs) differently, test for both styles.
            if not (r.pattern.endswith(u'\\/$') or r.pattern.endswith(u'\\/\\Z(?ms)')): continue # we only check for directory patterns here
            debug(u"INCL-TEST: %s ~ %s" % (d, r.pattern))
            if r.search(d):
                excluded = False
                debug(u"INCL-MATCH: '%s'" % (cfg.debug_include[r]))
                break
    if excluded:
        ## Still excluded - ok, action it
        debug(u"EXCLUDE: %r" % d)
    else:
        debug(u"PASS: %r" % d)
    return excluded

def _fswalk_follow_symlinks(path):
    '''
    Walk filesystem, following symbolic links (but without recursion), on python2.4 and later

    If a symlink directory loop is detected, emit a warning and skip.
    E.g.: dir1/dir2/sym-dir -> ../dir2
    '''
    assert os.path.isdir(deunicodise(path)) # only designed for directory argument
    walkdirs = set([path])
    for dirpath, dirnames, filenames in _os_walk_unicode(path):
        real_dirpath = unicodise(os.path.realpath(deunicodise(dirpath)))
        for dirname in dirnames:
            current = os.path.join(dirpath, dirname)
            real_current = unicodise(os.path.realpath(deunicodise(current)))
            if os.path.islink(deunicodise(current)):
                if (real_dirpath == real_current or
                    real_dirpath.startswith(real_current + os.path.sep)):
                    warning("Skipping recursively symlinked directory %s" % dirname)
                else:
                    walkdirs.add(current)
    for walkdir in walkdirs:
        for dirpath, dirnames, filenames in _os_walk_unicode(walkdir):
            yield (dirpath, dirnames, filenames)

def _fswalk_no_symlinks(path):
    '''
    Directory tree generator

    path (str) is the root of the directory tree to walk
    '''
    for dirpath, dirnames, filenames in _os_walk_unicode(path):
        yield (dirpath, dirnames, filenames)

def filter_exclude_include(src_list):
    debug(u"Applying --exclude/--include")
    cfg = Config()
    exclude_list = FileDict(ignore_case = False)
    for file in src_list.keys():
        debug(u"CHECK: %s" % file)
        excluded = False
        for r in cfg.exclude:
            if r.search(file):
                excluded = True
                debug(u"EXCL-MATCH: '%s'" % (cfg.debug_exclude[r]))
                break
        if excluded:
            ## No need to check for --include if not excluded
            for r in cfg.include:
                if r.search(file):
                    excluded = False
                    debug(u"INCL-MATCH: '%s'" % (cfg.debug_include[r]))
                    break
        if excluded:
            ## Still excluded - ok, action it
            debug(u"EXCLUDE: %s" % file)
            exclude_list[file] = src_list[file]
            del(src_list[file])
            continue
        else:
            debug(u"PASS: %r" % (file))
    return src_list, exclude_list


def _get_filelist_from_file(cfg, local_path):
    def _append(d, key, value):
        if key not in d:
            d[key] = [value]
        else:
            d[key].append(value)

    filelist = {}
    for fname in cfg.files_from:
        try:
            f = None
            if fname == u'-':
                f = io.open(sys.stdin.fileno(), mode='r', closefd=False)
            else:
                try:
                    f = io.open(deunicodise(fname), mode='r')
                except IOError as e:
                    warning(u"--files-from input file %s could not be opened for reading (%s), skipping." % (fname, e.strerror))
                    continue

            for line in f:
                line = unicodise(line).strip()
                line = os.path.normpath(os.path.join(local_path, line))
                dirname = unicodise(os.path.dirname(deunicodise(line)))
                basename = unicodise(os.path.basename(deunicodise(line)))
                _append(filelist, dirname, basename)
        finally:
            if f:
                f.close()

    # reformat to match os.walk()
    result = []
    keys = filelist.keys()
    keys.sort()
    for key in keys:
        values = filelist[key]
        values.sort()
        result.append((key, [], values))
    return result

def fetch_local_list(args, is_src = False, recursive = None):

    def _fetch_local_list_info(loc_list):
        len_loc_list = len(loc_list)
        total_size = 0
        info(u"Running stat() and reading/calculating MD5 values on %d files, this may take some time..." % len_loc_list)
        counter = 0
        for relative_file in loc_list:
            counter += 1
            if counter % 1000 == 0:
                info(u"[%d/%d]" % (counter, len_loc_list))

            if relative_file == '-': continue

            full_name = loc_list[relative_file]['full_name']
            try:
                sr = os.stat_result(os.stat(deunicodise(full_name)))
            except OSError as e:
                if e.errno == errno.ENOENT:
                    # file was removed async to us getting the list
                    continue
                else:
                    raise
            loc_list[relative_file].update({
                'size' : sr.st_size,
                'mtime' : sr.st_mtime,
                'dev'   : sr.st_dev,
                'inode' : sr.st_ino,
                'uid' : sr.st_uid,
                'gid' : sr.st_gid,
                'sr': sr # save it all, may need it in preserve_attrs_list
                ## TODO: Possibly more to save here...
            })
            total_size += sr.st_size
            if 'md5' in cfg.sync_checks:
                md5 = cache.md5(sr.st_dev, sr.st_ino, sr.st_mtime, sr.st_size)
                if md5 is None:
                        try:
                            md5 = loc_list.get_md5(relative_file) # this does the file I/O
                        except IOError:
                            continue
                        cache.add(sr.st_dev, sr.st_ino, sr.st_mtime, sr.st_size, md5)
                loc_list.record_hardlink(relative_file, sr.st_dev, sr.st_ino, md5, sr.st_size)
        return total_size


    def _get_filelist_local(loc_list, local_uri, cache):
        info(u"Compiling list of local files...")

        if local_uri.basename() == "-":
            try:
                uid = os.geteuid()
                gid = os.getegid()
            except:
                uid = 0
                gid = 0
            loc_list["-"] = {
                'full_name' : '-',
                'size' : -1,
                'mtime' : -1,
                'uid' : uid,
                'gid' : gid,
                'dev' : 0,
                'inode': 0,
            }
            return loc_list, True
        if local_uri.isdir():
            local_base = local_uri.basename()
            local_path = local_uri.path()
            if is_src and len(cfg.files_from):
                filelist = _get_filelist_from_file(cfg, local_path)
                single_file = False
            else:
                if cfg.follow_symlinks:
                    filelist = _fswalk_follow_symlinks(local_path)
                else:
                    filelist = _fswalk_no_symlinks(local_path)
                single_file = False
        else:
            local_base = ""
            local_path = local_uri.dirname()
            filelist = [( local_path, [], [local_uri.basename()] )]
            single_file = True
        for root, dirs, files in filelist:
            rel_root = root.replace(local_path, local_base, 1)
            for f in files:
                full_name = os.path.join(root, f)
                if not os.path.isfile(deunicodise(full_name)):
                    if os.path.exists(deunicodise(full_name)):
                        warning(u"Skipping over non regular file: %s" % full_name)
                    continue
                if os.path.islink(deunicodise(full_name)):
                    if not cfg.follow_symlinks:
                        warning(u"Skipping over symbolic link: %s" % full_name)
                        continue
                relative_file = os.path.join(rel_root, f)
                if os.path.sep != "/":
                    # Convert non-unix dir separators to '/'
                    relative_file = "/".join(relative_file.split(os.path.sep))
                if cfg.urlencoding_mode == "normal":
                    relative_file = replace_nonprintables(relative_file)
                if relative_file.startswith('./'):
                    relative_file = relative_file[2:]
                loc_list[relative_file] = {
                    'full_name' : full_name,
                }

        return loc_list, single_file

    def _maintain_cache(cache, local_list):
        # if getting the file list from files_from, it is going to be
        # a subset of the actual tree.  We should not purge content
        # outside of that subset as we don't know if it's valid or
        # not.  Leave it to a non-files_from run to purge.
        if cfg.cache_file and len(cfg.files_from) == 0:
            cache.mark_all_for_purge()
            for i in local_list.keys():
                cache.unmark_for_purge(local_list[i]['dev'], local_list[i]['inode'], local_list[i]['mtime'], local_list[i]['size'])
            cache.purge()
            cache.save(cfg.cache_file)

    cfg = Config()

    cache = HashCache()
    if cfg.cache_file:
        try:
            cache.load(cfg.cache_file)
        except IOError:
            info(u"No cache file found, creating it.")

    local_uris = []
    local_list = FileDict(ignore_case = False)
    single_file = False

    if type(args) not in (list, tuple, set):
        args = [args]

    if recursive == None:
        recursive = cfg.recursive

    for arg in args:
        uri = S3Uri(arg)
        if not uri.type == 'file':
            raise ParameterError("Expecting filename or directory instead of: %s" % arg)
        if uri.isdir() and not recursive:
            raise ParameterError("Use --recursive to upload a directory: %s" % arg)
        local_uris.append(uri)

    for uri in local_uris:
        list_for_uri, single_file = _get_filelist_local(local_list, uri, cache)

    ## Single file is True if and only if the user
    ## specified one local URI and that URI represents
    ## a FILE. Ie it is False if the URI was of a DIR
    ## and that dir contained only one FILE. That's not
    ## a case of single_file==True.
    if len(local_list) > 1:
        single_file = False

    local_list, exclude_list = filter_exclude_include(local_list)
    total_size = _fetch_local_list_info(local_list)
    _maintain_cache(cache, local_list)
    return local_list, single_file, exclude_list, total_size

def fetch_remote_list(args, require_attribs = False, recursive = None, uri_params = {}):
    def _get_remote_attribs(uri, remote_item):
        response = S3(cfg).object_info(uri)
        if not response.get('headers'):
            return

        remote_item.update({
        'size': int(response['headers']['content-length']),
        'md5': response['headers']['etag'].strip('"\''),
        'timestamp' : dateRFC822toUnix(response['headers']['last-modified'])
        })
        try:
            md5 = response['s3cmd-attrs']['md5']
            remote_item.update({'md5': md5})
            debug(u"retreived md5=%s from headers" % md5)
        except KeyError:
            pass

    def _get_filelist_remote(remote_uri, recursive = True):
        ## If remote_uri ends with '/' then all remote files will have
        ## the remote_uri prefix removed in the relative path.
        ## If, on the other hand, the remote_uri ends with something else
        ## (probably alphanumeric symbol) we'll use the last path part
        ## in the relative path.
        ##
        ## Complicated, eh? See an example:
        ## _get_filelist_remote("s3://bckt/abc/def") may yield:
        ## { 'def/file1.jpg' : {}, 'def/xyz/blah.txt' : {} }
        ## _get_filelist_remote("s3://bckt/abc/def/") will yield:
        ## { 'file1.jpg' : {}, 'xyz/blah.txt' : {} }
        ## Furthermore a prefix-magic can restrict the return list:
        ## _get_filelist_remote("s3://bckt/abc/def/x") yields:
        ## { 'xyz/blah.txt' : {} }

        info(u"Retrieving list of remote files for %s ..." % remote_uri)
        empty_fname_re = re.compile(r'\A\s*\Z')

        total_size = 0

        s3 = S3(Config())
        response = s3.bucket_list(remote_uri.bucket(), prefix = remote_uri.object(),
                                  recursive = recursive, uri_params = uri_params)

        rem_base_original = rem_base = remote_uri.object()
        remote_uri_original = remote_uri
        if rem_base != '' and rem_base[-1] != '/':
            rem_base = rem_base[:rem_base.rfind('/')+1]
            remote_uri = S3Uri(u"s3://%s/%s" % (remote_uri.bucket(), rem_base))
        rem_base_len = len(rem_base)
        rem_list = FileDict(ignore_case = False)
        break_now = False
        for object in response['list']:
            if object['Key'] == rem_base_original and object['Key'][-1] != "/":
                ## We asked for one file and we got that file :-)
                key = unicodise(os.path.basename(deunicodise(object['Key'])))
                object_uri_str = remote_uri_original.uri()
                break_now = True
                rem_list = FileDict(ignore_case = False)   ## Remove whatever has already been put to rem_list
            else:
                key = object['Key'][rem_base_len:]      ## Beware - this may be '' if object['Key']==rem_base !!
                object_uri_str = remote_uri.uri() + key
            if empty_fname_re.match(key):
                # Objects may exist on S3 with empty names (''), which don't map so well to common filesystems.
                warning(u"Empty object name on S3 found, ignoring.")
                continue
            rem_list[key] = {
                'size' : int(object['Size']),
                'timestamp' : dateS3toUnix(object['LastModified']), ## Sadly it's upload time, not our lastmod time :-(
                'md5' : object['ETag'].strip('"\''),
                'object_key' : object['Key'],
                'object_uri_str' : object_uri_str,
                'base_uri' : remote_uri,
                'dev' : None,
                'inode' : None,
            }
            if '-' in rem_list[key]['md5']: # always get it for multipart uploads
                _get_remote_attribs(S3Uri(object_uri_str), rem_list[key])
            md5 = rem_list[key]['md5']
            rem_list.record_md5(key, md5)
            total_size += int(object['Size'])
            if break_now:
                break
        return rem_list, total_size

    cfg = Config()
    remote_uris = []
    remote_list = FileDict(ignore_case = False)

    if type(args) not in (list, tuple, set):
        args = [args]

    if recursive == None:
        recursive = cfg.recursive

    for arg in args:
        uri = S3Uri(arg)
        if not uri.type == 's3':
            raise ParameterError("Expecting S3 URI instead of '%s'" % arg)
        remote_uris.append(uri)

    total_size = 0

    if recursive:
        for uri in remote_uris:
            objectlist, tmp_total_size = _get_filelist_remote(uri, recursive = True)
            total_size += tmp_total_size
            for key in objectlist:
                remote_list[key] = objectlist[key]
                remote_list.record_md5(key, objectlist.get_md5(key))
    else:
        for uri in remote_uris:
            uri_str = uri.uri()
            ## Wildcards used in remote URI?
            ## If yes we'll need a bucket listing...
            wildcard_split_result = re.split("\*|\?", uri_str, maxsplit=1)
            if len(wildcard_split_result) == 2: # wildcards found
                prefix, rest = wildcard_split_result
                ## Only request recursive listing if the 'rest' of the URI,
                ## i.e. the part after first wildcard, contains '/'
                need_recursion = '/' in rest
                objectlist, tmp_total_size = _get_filelist_remote(S3Uri(prefix), recursive = need_recursion)
                total_size += tmp_total_size
                for key in objectlist:
                    ## Check whether the 'key' matches the requested wildcards
                    if glob.fnmatch.fnmatch(objectlist[key]['object_uri_str'], uri_str):
                        remote_list[key] = objectlist[key]
            else:
                ## No wildcards - simply append the given URI to the list
                key = unicodise(os.path.basename(deunicodise(uri.object())))
                if not key:
                    raise ParameterError(u"Expecting S3 URI with a filename or --recursive: %s" % uri.uri())
                remote_item = {
                    'base_uri': uri,
                    'object_uri_str': uri.uri(),
                    'object_key': uri.object()
                }
                if require_attribs:
                    _get_remote_attribs(uri, remote_item)

                remote_list[key] = remote_item
                md5 = remote_item.get('md5')
                if md5:
                    remote_list.record_md5(key, md5)
                total_size += remote_item.get('size', 0)

    remote_list, exclude_list = filter_exclude_include(remote_list)
    return remote_list, exclude_list, total_size


def compare_filelists(src_list, dst_list, src_remote, dst_remote):
    def __direction_str(is_remote):
        return is_remote and "remote" or "local"

    def _compare(src_list, dst_lst, src_remote, dst_remote, file):
        """Return True if src_list[file] matches dst_list[file], else False"""
        attribs_match = True
        if not (file in src_list and file in dst_list):
            info(u"%s: does not exist in one side or the other: src_list=%s, dst_list=%s" % (file, file in src_list, file in dst_list))
            return False

        ## check size first
        if 'size' in cfg.sync_checks:
            if 'size' in dst_list[file] and 'size' in src_list[file]:
                if dst_list[file]['size'] != src_list[file]['size']:
                    debug(u"xfer: %s (size mismatch: src=%s dst=%s)" % (file, src_list[file]['size'], dst_list[file]['size']))
                    attribs_match = False

        ## check md5
        compare_md5 = 'md5' in cfg.sync_checks
        # Multipart-uploaded files don't have a valid md5 sum - it ends with "...-nn"
        if compare_md5:
            if (src_remote == True and '-' in src_list[file]['md5']) or (dst_remote == True and '-' in dst_list[file]['md5']):
                compare_md5 = False
                info(u"disabled md5 check for %s" % file)
        if attribs_match and compare_md5:
            try:
                src_md5 = src_list.get_md5(file)
                dst_md5 = dst_list.get_md5(file)
            except (IOError,OSError):
                # md5 sum verification failed - ignore that file altogether
                debug(u"IGNR: %s (disappeared)" % (file))
                warning(u"%s: file disappeared, ignoring." % (file))
                raise

            if src_md5 != dst_md5:
                ## checksums are different.
                attribs_match = False
                debug(u"XFER: %s (md5 mismatch: src=%s dst=%s)" % (file, src_md5, dst_md5))

        return attribs_match

    # we don't support local->local sync, use 'rsync' or something like that instead ;-)
    assert(not(src_remote == False and dst_remote == False))

    info(u"Verifying attributes...")
    cfg = Config()
    ## Items left on src_list will be transferred
    ## Items left on update_list will be transferred after src_list
    ## Items left on copy_pairs will be copied from dst1 to dst2
    update_list = FileDict(ignore_case = False)
    ## Items left on dst_list will be deleted
    copy_pairs = []

    debug("Comparing filelists (direction: %s -> %s)" % (__direction_str(src_remote), __direction_str(dst_remote)))

    for relative_file in src_list.keys():
        debug(u"CHECK: %s" % (relative_file))

        if relative_file in dst_list:
            ## Was --skip-existing requested?
            if cfg.skip_existing:
                debug(u"IGNR: %s (used --skip-existing)" % (relative_file))
                del(src_list[relative_file])
                del(dst_list[relative_file])
                continue

            try:
                same_file = _compare(src_list, dst_list, src_remote, dst_remote, relative_file)
            except (IOError,OSError):
                debug(u"IGNR: %s (disappeared)" % (relative_file))
                warning(u"%s: file disappeared, ignoring." % (relative_file))
                del(src_list[relative_file])
                del(dst_list[relative_file])
                continue

            if same_file:
                debug(u"IGNR: %s (transfer not needed)" % relative_file)
                del(src_list[relative_file])
                del(dst_list[relative_file])

            else:
                # look for matching file in src
                try:
                    md5 = src_list.get_md5(relative_file)
                except IOError:
                    md5 = None
                if md5 is not None and md5 in dst_list.by_md5:
                    # Found one, we want to copy
                    dst1 = list(dst_list.by_md5[md5])[0]
                    debug(u"DST COPY src: %s -> %s" % (dst1, relative_file))
                    copy_pairs.append((src_list[relative_file], dst1, relative_file))
                    del(src_list[relative_file])
                    del(dst_list[relative_file])
                else:
                    # record that we will get this file transferred to us (before all the copies), so if we come across it later again,
                    # we can copy from _this_ copy (e.g. we only upload it once, and copy thereafter).
                    dst_list.record_md5(relative_file, md5)
                    update_list[relative_file] = src_list[relative_file]
                    del src_list[relative_file]
                    del dst_list[relative_file]

        else:
            # dst doesn't have this file
            # look for matching file elsewhere in dst
            try:
                md5 = src_list.get_md5(relative_file)
            except IOError:
               md5 = None
            dst1 = dst_list.find_md5_one(md5)
            if dst1 is not None:
                # Found one, we want to copy
                debug(u"DST COPY dst: %s -> %s" % (dst1, relative_file))
                copy_pairs.append((src_list[relative_file], dst1, relative_file))
                del(src_list[relative_file])
            else:
                # we don't have this file, and we don't have a copy of this file elsewhere.  Get it.
                # record that we will get this file transferred to us (before all the copies), so if we come across it later again,
                # we can copy from _this_ copy (e.g. we only upload it once, and copy thereafter).
                dst_list.record_md5(relative_file, md5)

    for f in dst_list.keys():
        if f in src_list or f in update_list:
            # leave only those not on src_list + update_list
            del dst_list[f]

    return src_list, dst_list, update_list, copy_pairs

# vim:et:ts=4:sts=4:ai
