"""
"""
from __future__ import absolute_import
import os

try:
    from urllib.request import urlopen
    from urllib.parse import urlparse
except ImportError:
    from urlparse import urlparse
    from urllib import urlopen

from flask import Blueprint, url_for, render_template, request, session, redirect, g, current_app
from .decorators import login_required, guest_or_login_required, with_lock
from flask_babel import Babel, gettext, ngettext, lazy_gettext
_ = gettext

worksheet_listing = Blueprint('worksheet_listing',
                              'sagenb.flask_version.worksheet_listing')

def render_worksheet_list(args, pub, username):
    """
    Returns a rendered worksheet listing.

    INPUT:

    -  ``args`` - ctx.args where ctx is the dict passed
       into a resource's render method

    -  ``pub`` - boolean, True if this is a listing of
       public worksheets

    -  ``username`` - the user whose worksheets we are
       listing

    OUTPUT:

    a string
    """

    from sagenb.notebook.notebook import sort_worksheet_list
    from sagenb.misc.misc import unicode_str, SAGE_VERSION

    typ = args['typ'] if 'typ' in args else 'active'
    search = unicode_str(args['search']) if 'search' in args else None
    sort = args['sort'] if 'sort' in args else 'last_edited'
    reverse = (args['reverse'] == 'True') if 'reverse' in args else False
    readonly = g.notebook.readonly_user(g.username)
    try:
        if not pub:
            worksheets = g.notebook.worksheet_list_for_user(username, typ=typ, sort=sort,
                                                              search=search, reverse=reverse)
        else:
            worksheets = g.notebook.worksheet_list_for_public(username, sort=sort,
                                                                search=search, reverse=reverse)
    except ValueError as E:
        # for example, the sort key was not valid
        print("Error displaying worksheet listing: {}".format(E))
        return current_app.message(_("Error displaying worksheet listing."))

    worksheet_filenames = [x.filename() for x in worksheets]

    if pub and (not username or username == tuple([])):
        username = 'pub'

    accounts = g.notebook.user_manager().get_accounts()
    sage_version = SAGE_VERSION
    return render_template('html/worksheet_listing.html', **locals())

@worksheet_listing.route('/home/<username>/')
@login_required
def home(username):
    if not g.notebook.user_manager().user_is_admin(g.username) and username != g.username:
        return current_app.message(_("User '%(user)s' does not have permission to view the home page of '%(name)s'.", user=g.username, name=username), username=g.username)
    else:
        return render_worksheet_list(request.args, pub=False, username=username)

@worksheet_listing.route('/home/')
@login_required
def bare_home():
    return redirect(url_for('home', username=g.username))

###########
# Folders #
###########

def get_worksheets_from_request():
    U = g.notebook.user_manager().user(g.username)

    if 'filename' in request.form:
        filenames = [request.form['filename']]
    elif 'filenames' in request.form:
        import json
        filenames = json.loads(request.form['filenames'])
    else:
        filenames = []
    worksheets = []
    for filename in filenames:
        W = g.notebook.get_worksheet_with_filename(filename)
        if W.owner() != g.username:
            # TODO BUG: if trying to stop a shared worksheet, this check means that
            # only the owner can stop from the worksheet listing (using /send_to_stop), but any
            # shared person can stop the worksheet by quitting it.
            continue
        worksheets.append(W)

    return worksheets

@worksheet_listing.route('/send_to_trash', methods=['POST'])
@login_required
def send_worksheet_to_trash():
    for W in get_worksheets_from_request():
        W.move_to_trash(g.username)
    return ''

@worksheet_listing.route('/send_to_archive', methods=['POST'])
@login_required
def send_worksheet_to_archive():
    for W in get_worksheets_from_request():
        W.move_to_archive(g.username)
    return ''

@worksheet_listing.route('/send_to_active', methods=['POST'])
@login_required
def send_worksheet_to_active():
    for W in get_worksheets_from_request():
        W.set_active(g.username)
    return ''

@worksheet_listing.route('/send_to_stop', methods=['POST'])
@login_required
def send_worksheet_to_stop():
    for W in get_worksheets_from_request():
        W.quit()
    return ''

@worksheet_listing.route('/emptytrash', methods=['POST'])
@login_required
def empty_trash():
    g.notebook.empty_trash(g.username)
    if 'referer' in request.headers:
        return redirect(request.headers['referer'])
    else:
        return redirect(url_for('home', typ='trash'))


#####################
# Public Worksheets #
#####################
@worksheet_listing.route('/pub/')
@guest_or_login_required
def pub():
    return render_worksheet_list(request.args, pub=True, username=g.username)

@worksheet_listing.route('/home/pub/<id>/')
@guest_or_login_required
def public_worksheet(id):
    from .worksheet import pub_worksheet
    filename = 'pub/%s'%id
    if g.notebook.conf()['pub_interact']:
        try:
            original_worksheet = g.notebook.get_worksheet_with_filename(filename)
        except KeyError:
            return _("Requested public worksheet does not exist"), 404
        worksheet = pub_worksheet(original_worksheet)

        owner = worksheet.owner()
        worksheet.set_owner('pub')
        s = g.notebook.html(worksheet_filename=worksheet.filename(),
                            username=g.username)
        worksheet.set_owner(owner)
    else:
        s = g.notebook.html(worksheet_filename=filename, username = g.username)
    return s

@worksheet_listing.route('/home/pub/<id>/download/<path:title>')
def public_worksheet_download(id, title):
    from .worksheet import unconditional_download
    worksheet_filename =  "pub" + "/" + id
    try:
        worksheet = g.notebook.get_worksheet_with_filename(worksheet_filename)
    except KeyError:
        return current_app.message(_("You do not have permission to access this worksheet"), username=g.username)
    return unconditional_download(worksheet, title)

@worksheet_listing.route('/home/pub/<id>/cells/<path:filename>')
def public_worksheet_cells(id, filename):
    worksheet_filename =  "pub" + "/" + id
    try:
        worksheet = g.notebook.get_worksheet_with_filename(worksheet_filename)
    except KeyError:
        return current_app.message(_("You do not have permission to access this worksheet"), username=g.username)
    from flask.helpers import send_from_directory
    return send_from_directory(worksheet.cells_directory(), filename)

#######################
# Download Worksheets #
#######################
@worksheet_listing.route('/download_worksheets.zip')
@login_required
def download_worksheets():
    from sagenb.misc.misc import walltime, tmp_filename

    t = walltime()
    print("Starting zipping a group of worksheets in a separate thread...")
    zip_filename = tmp_filename() + ".zip"

    # child
    worksheet_names = set()
    if 'filenames' in request.values:
        import json
        filenames = json.loads(request.values['filenames'])
        worksheets = [g.notebook.get_worksheet_with_filename(x.strip())
                      for x in filenames if len(x.strip()) > 0]
    else:
        worksheets = g.notebook.worksheet_list_for_user(g.username)

    import zipfile
    zip = zipfile.ZipFile(zip_filename, 'w', zipfile.ZIP_STORED)
    for worksheet in worksheets:
        sws_filename = tmp_filename() + '.sws'
        g.notebook.export_worksheet(worksheet.filename(), sws_filename)
        entry_name = worksheet.name()
        if entry_name in worksheet_names:
            i = 2
            while ("%s_%s" % (entry_name, i)) in worksheet_names:
                i += 1
            entry_name = "%s_%s" % (entry_name, i)
        zip.write(sws_filename, entry_name + ".sws")
        os.unlink(sws_filename)
    zip.close()
    r = open(zip_filename, 'rb').read()
    os.unlink(zip_filename)
    print("Finished zipping %s worksheets (%s seconds)" % (len(worksheets), walltime(t)))

    response = current_app.make_response(r)
    response.headers['Content-Type'] = 'application/zip'
    return response


#############
# Uploading #
#############
@worksheet_listing.route('/upload')
@login_required
def upload():
    from sagenb.misc.misc import SAGE_VERSION
    if g.notebook.readonly_user(g.username):
        return current_app.message(_("Account is in read-only mode"), cont=url_for('home', username=g.username), username=g.username)
    return render_template(os.path.join('html', 'upload.html'),
                           username=g.username, sage_version=SAGE_VERSION)

class RetrieveError(Exception):
    """
    Use this in my_urlretrieve below, and when calling that function, do:

    try:
        my_urlretrive(...)
    except RetrieveError as err:
        return current_app.message(str(err), username=g.username)

    This allows us to factor out all the error message handling into
    my_urlretrieve.
    """
    pass

def my_urlretrieve(url, *args, **kwargs):
    """
    Call urllib.urlretrieve and give friendly error messages depending
    on the result. If successful, return exactly what urllib.urlretrieve
    would. Arguments are exactly the same as urlretrieve, except that
    you can also specify a ``backlinks`` keyword used in the error
    message.

    Raises RetrieveError when an error occurs for which we can figure
    out a sensible error message.
    """
    try:
        backlinks = kwargs.pop('backlinks')
    except KeyError:
        backlinks = ''
    try:
        return urllib.urlretrieve(url, *args, **kwargs)
    except IOError as err:
        if err.strerror == 'unknown url type' and err.filename == 'https':
            raise RetrieveError(_("This Sage notebook is not configured to load worksheets from 'https' URLs. Try a different URL or download the worksheet and upload it directly from your computer.\n%(backlinks)s",backlinks=backlinks))
        else:
            raise

def parse_link_rel(url, fn):
    """
    Read through html file ``fn`` downloaded from ``url``, looking for a
    link tag of the form:

    <link rel="alternate"
          type="application/sage"
          title="currently ignored"
          href=".../example.sws" />

    This function reads ``fn`` looking for such tags and returns a list
    of dictionaries of the form

    {'title': from title field in link, 'url': absolute URL to .sws file}

    for the corresponding ``.sws`` files. Naturally if there are no
    appropriate link tags found, the returned list is empty. If the HTML
    parser raises an HTMLParseError, we simply return an empty list.
    """
    from HTMLParser import HTMLParser
    class GetLinkRelWorksheets(HTMLParser):
        def __init__(self):
            HTMLParser.__init__(self)
            self.worksheets = []

        def handle_starttag(self, tag, attrs):
            if (tag == 'link' and
                ('rel', 'alternate') in attrs and
                ('type', 'application/sage') in attrs):
                self.worksheets.append({'title': [_ for _ in attrs if _[0] == 'title'][0][1],
                                          'url': [_ for _ in attrs if _[0] == 'href'][0][1]})

    parser = GetLinkRelWorksheets()
    with open(fn) as f:
        try:
            parser.feed(f.read())
        except HTMLParseError:
            return []

    ret = []
    for d in parser.worksheets:
        sws = d['url']
        # is that link a relative URL?
        if not urlparse.urlparse(sws).netloc:
            # unquote-then-quote to avoid turning %20 into %2520, etc
            ret.append({'url': urlparse.urljoin(url, urllib.quote(urllib.unquote(sws))),
                        'title': d['title']})
        else:
            ret.append({'url': sws, 'title': d['title']})
    return ret

@worksheet_listing.route('/upload_worksheet', methods=['GET', 'POST'])
@login_required
def upload_worksheet():
    from sage.misc.all import tmp_filename, tmp_dir
    from werkzeug.utils import secure_filename
    import zipfile

    if g.notebook.readonly_user(g.username):
        return current_app.message(_("Account is in read-only mode"), cont=url_for('home', username=g.username), username=g.username)

    backlinks = _("""Return to <a href="/upload" title="Upload a worksheet"><strong>Upload File</strong></a>.""")

    url = request.values['url'].strip()
    dir = ''
    if url != '':
        #Downloading a file from the internet
        # The file will be downloaded from the internet and saved
        # to a temporary file with the same extension
        path = urlparse.urlparse(url).path
        extension = os.path.splitext(path)[1].lower()
        if extension not in ["", ".txt", ".sws", ".zip", ".html", ".rst"]:
            # Or shall we try to import the document as an sws when in doubt?
            return current_app.message(_("Unknown worksheet extension: %(ext)s. %(links)s", ext=extension, links=backlinks), username=g.username)
        filename = tmp_filename()+extension
        try:
            import re
            matches = re.match("file://(?:localhost)?(/.+)", url)
            if matches:
                if g.notebook.interface != 'localhost':
                    return current_app.message(_("Unable to load file URL's when not running on localhost.\n%(backlinks)s",backlinks=backlinks), username=g.username)

                import shutil
                shutil.copy(matches.group(1),filename)
            else:
                my_urlretrieve(url, filename, backlinks=backlinks)

        except RetrieveError as err:
            return current_app.message(str(err), username=g.username)

    else:
        #Uploading a file from the user's computer
        dir = tmp_dir()
        file = request.files['file']
        if file.filename is None:
            return current_app.message(_("Please specify a worksheet to load.\n%(backlinks)s",backlinks=backlinks), username=g.username)

        filename = secure_filename(file.filename)
        if len(filename)==0:
            return current_app.message(_("Invalid filename.\n%(backlinks)s",backlinks=backlinks), username=g.username)

        filename = os.path.join(dir, filename)
        file.save(filename)

    new_name = request.values.get('name', None)

    try:
        try:
            if filename.endswith('.zip'):
                # Extract all the .sws files from a zip file.
                zip_file = zipfile.ZipFile(filename)
                for subfilename in zip_file.namelist():
                    prefix, extension = os.path.splitext(subfilename)
                    # Mac zip files contain files like __MACOSX/._worksheet.sws
                    # which are metadata files, so we skip those as
                    # well as any other files we won't understand
                    if extension in ['.sws', '.html', '.txt', '.rst'] and not prefix.startswith('__MACOSX/'):
                        tmpfilename = os.path.join(dir, "tmp" + extension)
                        try:
                            tmpfilename = zip_file.extract(subfilename, tmpfilename)
                        except AttributeError:
                            open(tmpfilename, 'w').write(zip_file.read(subfilename))
                        W = g.notebook.import_worksheet(tmpfilename, g.username)
                        if new_name:
                            W.set_name("%s - %s" % (new_name, W.name()))
                    else:
                        print("Unknown extension, file %s is ignored" % subfilename)
                return redirect(url_for('home', username=g.username))

            else:
                if url and extension in ['', '.html']:
                    linked_sws = parse_link_rel(url, filename)
                    if linked_sws:
                        # just grab 1st URL; perhaps later add interface for
                        # downloading multiple linked .sws
                        try:
                            filename = my_urlretrieve(linked_sws[0]['url'], backlinks=backlinks)[0]
                            print('Importing {0}, linked to from {1}'.format(linked_sws[0]['url'], url))
                        except RetrieveError as err:
                            return current_app.message(str(err), username=g.username)
                W = g.notebook.import_worksheet(filename, g.username)
        except Exception as msg:
            print('error uploading worksheet {}'.format(msg))
            s = _('There was an error uploading the worksheet.  It could be an old unsupported format or worse.  If you desperately need its contents contact the <a href="http://groups.google.com/group/sage-support">sage-support group</a> and post a link to your worksheet.  Alternatively, an sws file is just a bzip2 tarball; take a look inside!\n%(backlinks)s', backlinks=backlinks)
            return current_app.message(s, url_for('home', username=g.username), username=g.username)
        finally:
            # Clean up the temporarily uploaded filename.
            os.unlink(filename)
            # if a temp directory was created, we delete it now.
            if dir:
                import shutil
                shutil.rmtree(dir)

    except ValueError as msg:
        s = _("Error uploading worksheet '%(msg)s'.%(backlinks)s", msg=msg, backlinks=backlinks)
        return current_app.message(s, url_for('home', username=g.username), username=g.username)

    if new_name:
        W.set_name(new_name)

    from .worksheet import url_for_worksheet
    return redirect(url_for_worksheet(W))
