# vim:fileencoding=utf-8
# License: GPL v3 Copyright: 2018, Kovid Goyal <kovid at kovidgoyal.net>
from __python__ import bound_methods, hash_literals

from elementmaker import E
from gettext import gettext as _, ngettext

from book_list.globals import get_session_data
from dom import unique_id
from session import get_interface_data
from utils import fmt_sidx

CONTAINER = unique_id('reader-hf-prefs')


def create_item(region, label):
    def sep():
        return E.option('\xa0', disabled=True)

    def opt(label, name, selected):
        return E.option(label, id=name, value=name, selected=bool(selected))

    return E.tr(
        E.td(label + ':', style='padding: 1ex 1rem'),
        E.td(E.select(
            data_region=region,
            opt(_('Empty'), 'empty', True),
            sep(),
            opt(_('Book title'), 'title'),
            opt(_('Authors'), 'authors'),
            opt(_('Series'), 'series'),
            sep(),
            opt(_('Top level section'), 'top-section'),
            opt(_('Current section'), 'section'),
            sep(),
            opt(_('Progress'), 'progress'),
            opt(_('Time to read book'), 'time-book'),
            opt(_('Time to read chapter'), 'time-chapter'),
            opt(_('Time to read chapter and book'), 'time-chapter-book'),
            opt(_('Clock'), 'clock'),
        ))
    )


def create_items(which):
    ans = E.table(
        data_which=which,
        create_item('left', _('Left')),
        create_item('middle', _('Middle')),
        create_item('right', _('Right'))
    )
    return ans


def apply_setting(table, val):
    for region in 'left middle right'.split(' '):
        sel = table.querySelector(f'select[data-region={region}]')
        for opt in sel.selectedOptions:
            opt.selected = False
        x = val[region] or 'empty'
        opt = sel.namedItem(x)
        if opt:
            opt.selected = True
        else:
            sel.selectedIndex = 0


def get_setting(table):
    ans = {}
    for region in 'left middle right'.split(' '):
        sel = table.querySelector(f'select[data-region={region}]')
        if sel.selectedIndex > -1:
            ans[region] = sel.options[sel.selectedIndex].value
    return ans


def create_head_foot_panel(container):
    container.appendChild(E.div(id=CONTAINER))
    container = container.lastChild
    container.appendChild(E.h4(_('Header'), style="margin: 1rem"))
    container.appendChild(create_items('header'))
    container.appendChild(E.hr())
    container.appendChild(E.h4(_('Footer'), style="margin: 1rem; margin-top: 0"))
    container.appendChild(create_items('footer'))

    sd = get_session_data()
    for which in 'header footer'.split(' '):
        table = container.querySelector(f'table[data-which={which}]')
        apply_setting(table, sd.get(which) or {})


def commit_head_foot(onchange, container):
    sd = get_session_data()
    changed = False
    for which in 'header footer'.split(' '):
        prev = sd.get(which) or {}
        table = container.querySelector(f'table[data-which={which}]')
        current = get_setting(table)
        for region in 'left middle right'.split(' '):
            if prev[region] is not current[region]:
                changed = True
        sd.set(which, get_setting(table))

    if changed:
        onchange()


if window.Intl?.DateTimeFormat:
    time_formatter = window.Intl.DateTimeFormat(undefined, {'hour':'numeric', 'minute':'numeric'})
else:
    time_formatter = {'format': def(date):
        return '{}:{}'.format(date.getHours(), date.getMinutes())
    }


def format_time_left(seconds):
    hours, minutes = divmod(int(seconds / 60), 60)
    if hours <= 0:
        if minutes < 1:
            return _('almost done')
        minutes = minutes
        return ngettext('{} min', '{} mins', minutes).format(minutes)
    if not minutes:
        return ngettext('{} hour', '{} hours', hours).format(hours)
    return _('{} h {} mins').format(hours, minutes)


def render_head_foot(div, which, region, progress_frac, metadata, current_toc_node, current_toc_toplevel_node, book_time, chapter_time):
    template = get_session_data().get(which) or {}
    field = template[region] or 'empty'
    interface_data = get_interface_data()
    text = ''
    has_clock = False
    if field is 'progress':
        percent = min(100, max(Math.round(progress_frac * 100), 0))
        text = percent + '%'
    elif field is 'title':
        text = metadata.title or _('Untitled')
    elif field is 'authors':
        text = ' & '.join(metadata.authors or v'[]')
    elif field is 'series':
        if metadata.series:
            ival = fmt_sidx(ival, use_roman=interface_data.use_roman_numerals_for_series_number)
            text = _('{0} of {1}').format(ival, metadata.series)
    elif field is 'clock':
        text = time_formatter.format(Date())
        has_clock = True
    elif field is 'section':
        text = current_toc_node.title if current_toc_node else ''
    elif field is 'top-section':
        text = current_toc_toplevel_node.title if current_toc_toplevel_node else ''
        if not text:
            text = current_toc_node.title if current_toc_node else ''
    elif field.startswith('time-'):
        if book_time is None or chapter_time is None:
            text = _('Calculating...')
        else:
            if field is 'time-book':
                text = format_time_left(book_time)
            elif field is 'time-chapter':
                text = format_time_left(chapter_time)
            else:
                text = '{} ({})'.format(format_time_left(chapter_time), format_time_left(book_time))
    if text is not div.textContent:
        div.textContent = text
    div.style.display = 'block' if text else 'none'
    return text, has_clock