"""Our custom Jinja filters and other template stuff."""

import logging

import flask
import jinja2.filters
import jinja2.utils
import werkzeug.exceptions as wz_exceptions

import pillar.api.utils
from pillar.web.utils import pretty_date
from pillar.web.nodes.routes import url_for_node
import pillar.markdown

log = logging.getLogger(__name__)


def format_pretty_date(d):
    return pretty_date(d)


def format_pretty_date_time(d):
    return pretty_date(d, detail=True)


def format_undertitle(s):
    """Underscore-replacing title filter.

    Replaces underscores with spaces, and then applies Jinja2's own title filter.
    """

    # Just keep empty strings and Nones as they are.
    if not s:
        return s

    return jinja2.filters.do_title(s.replace('_', ' '))


def do_hide_none(s):
    """Returns the input, or an empty string if the input is None."""

    if s is None:
        return ''
    return s


# Source: Django, django/template/defaultfilters.py
def do_pluralize(value, arg='s'):
    """
    Returns a plural suffix if the value is not 1. By default, 's' is used as
    the suffix:

    * If value is 0, vote{{ value|pluralize }} displays "0 votes".
    * If value is 1, vote{{ value|pluralize }} displays "1 vote".
    * If value is 2, vote{{ value|pluralize }} displays "2 votes".

    If an argument is provided, that string is used instead:

    * If value is 0, class{{ value|pluralize:"es" }} displays "0 classes".
    * If value is 1, class{{ value|pluralize:"es" }} displays "1 class".
    * If value is 2, class{{ value|pluralize:"es" }} displays "2 classes".

    If the provided argument contains a comma, the text before the comma is
    used for the singular case and the text after the comma is used for the
    plural case:

    * If value is 0, cand{{ value|pluralize:"y,ies" }} displays "0 candies".
    * If value is 1, cand{{ value|pluralize:"y,ies" }} displays "1 candy".
    * If value is 2, cand{{ value|pluralize:"y,ies" }} displays "2 candies".
    """

    if ',' not in arg:
        arg = ',' + arg
    bits = arg.split(',')
    if len(bits) > 2:
        return ''
    singular_suffix, plural_suffix = bits[:2]

    try:
        if float(value) != 1:
            return plural_suffix
    except ValueError:  # Invalid string that's not a number.
        pass
    except TypeError:  # Value isn't a string or a number; maybe it's a list?
        try:
            if len(value) != 1:
                return plural_suffix
        except TypeError:  # len() of unsized object.
            pass
    return singular_suffix


def do_markdown(s):
    # FIXME: get rid of this filter altogether and cache HTML of comments.
    safe_html = pillar.markdown.markdown(s)
    return jinja2.utils.Markup(safe_html)


def do_url_for_node(node_id=None, node=None):
    try:
        return url_for_node(node_id=node_id, node=node)
    except wz_exceptions.NotFound:
        log.info('%s: do_url_for_node(node_id=%r, ...) called for non-existing node.',
                 flask.request.url, node_id)
        return None


# Source: Django 1.9 defaultfilters.py
def do_yesno(value, arg=None):
    """
    Given a string mapping values for true, false and (optionally) None,
    returns one of those strings according to the value:

    ==========  ======================  ==================================
    Value       Argument                Outputs
    ==========  ======================  ==================================
    ``True``    ``"yeah,no,maybe"``     ``yeah``
    ``False``   ``"yeah,no,maybe"``     ``no``
    ``None``    ``"yeah,no,maybe"``     ``maybe``
    ``None``    ``"yeah,no"``           ``"no"`` (converts None to False
                                        if no mapping for None is given.
    ==========  ======================  ==================================
    """
    if arg is None:
        arg = 'yes,no,maybe'
    bits = arg.split(',')
    if len(bits) < 2:
        return value  # Invalid arg.
    try:
        yes, no, maybe = bits
    except ValueError:
        # Unpack list of wrong size (no "maybe" value provided).
        yes, no, maybe = bits[0], bits[1], bits[1]
    if value is None:
        return maybe
    if value:
        return yes
    return no


def setup_jinja_env(jinja_env):
    jinja_env.filters['pretty_date'] = format_pretty_date
    jinja_env.filters['pretty_date_time'] = format_pretty_date_time
    jinja_env.filters['undertitle'] = format_undertitle
    jinja_env.filters['hide_none'] = do_hide_none
    jinja_env.filters['pluralize'] = do_pluralize
    jinja_env.filters['gravatar'] = pillar.api.utils.gravatar
    jinja_env.filters['markdown'] = do_markdown
    jinja_env.filters['yesno'] = do_yesno
    jinja_env.globals['url_for_node'] = do_url_for_node