# vim:fileencoding=utf-8
# License: GPL v3 Copyright: 2016, Kovid Goyal <kovid at kovidgoyal.net>
from __python__ import bound_methods, hash_literals

from elementmaker import E
from gettext import gettext as _

from book_list.globals import get_session_data
from book_list.theme import get_color
from dom import add_extra_css, rule, unique_id
from read_book.globals import ui_operations
from session import session_defaults
from widgets import create_button

CONTAINER = unique_id('font-size-prefs')
MIN_FONT_SIZE = 8
MAX_FONT_SIZE = 80

add_extra_css(def ():
    style = rule(CONTAINER, 'option.current', background_color='var(--calibre-color-primary-light)')
    style += rule(CONTAINER, 'option:hover', background_color='var(--calibre-color-primary-light)')
    return style
)


def change_font_size(sz):
    sd = get_session_data()
    if sd.get('base_font_size') is not sz:
        sd.set('base_font_size', sz)
        ui_operations.update_font_size()


def apply_font_size():
    fs = int(document.getElementById(CONTAINER).dataset.cfs)
    change_font_size(fs)


def set_quick_size(ev):
    newval = ev.currentTarget.value
    try:
        int(newval)
    except:
        return
    if newval is not document.getElementById(CONTAINER).dataset.cfs:
        display_changed_font_size(newval)


def change_font_size_by(frac):
    sd = get_session_data()
    sz = sd.get('base_font_size')
    amt = sz * frac
    if abs(amt) < 1:
        amt = -1 if amt < 0 else 1
    nsz = Math.round(sz + amt)
    nsz = max(MIN_FONT_SIZE, min(nsz, MAX_FONT_SIZE))
    change_font_size(nsz)


def restore_default_font_size():
    change_font_size(session_defaults().base_font_size)


def display_changed_font_size(sz):
    sz = max(MIN_FONT_SIZE, min(int(sz), MAX_FONT_SIZE))
    sz += ''
    c = document.getElementById(CONTAINER)
    c.dataset.cfs = sz
    for option in c.querySelectorAll('option'):
        if option.value is sz:
            option.classList.add('current')
        else:
            option.classList.remove('current')
    for input in c.querySelectorAll('input'):
        input.value = sz
    c.querySelector('.cfs_preview').style.fontSize = f'{sz}px'


def create_font_size_panel(container, close):
    sd = get_session_data()
    cfs = sd.get('base_font_size')
    container.appendChild(E.div(
        style='width: 100%; height: 100%; display: flex; justify-content: center; align-items: center',
        E.div(
            id=CONTAINER,
            style='max-width: 500px; width: 80vw; border-radius: 8px; border: solid 1px currentColor; padding:1ex 1rem;',
            onclick=def (ev): ev.preventDefault(), ev.stopPropagation()
    )))
    container = container.lastChild.lastChild
    container.style.backgroundColor = get_color('window-background')
    container.dataset.cfs = cfs + ''
    quick = E.datalist(style='display:flex; justify-content:space-around; flex-wrap: wrap; align-items: baseline;')
    container.appendChild(quick)
    for sz in (10, 12, 14, 16, 18, 20, 22):
        quick.appendChild(E.option(
            'Aa', title='{} px'.format(sz),
            class_='current' if cfs is sz else '',
            value=sz + '',
            style=f'display: inline-block; font-size:{sz}px; padding: 5px; cursor: pointer; border-radius: 4px; margin: 0 0.5rem',
            onclick=def (ev):
                set_quick_size(ev)
        ))

    def set_size(ev):
        newval = ev.currentTarget.value
        try:
            q = int(newval)
        except:
            return
        if MIN_FONT_SIZE <= q <= MAX_FONT_SIZE:
            set_quick_size(ev)

    container.appendChild(E.div(
        style='display: flex; margin-top: 1rem',
        E.input(
            type='range', min=MIN_FONT_SIZE + '', max=MAX_FONT_SIZE + '', value=cfs + '', style='flex-grow: 4',
            oninput=set_quick_size,
        ),
        E.span('\xa0', E.input(
            value=f'{cfs}', oninput=set_size, type='number', min=MIN_FONT_SIZE + '', max=MAX_FONT_SIZE + '',
            step='1',
        ), '\xa0px')
    ))

    container.appendChild(E.div(
        style=f'font-size: {cfs}px; margin-top: 1rem; min-height: 60px; max-height: 60px; overflow: hidden; display: flex;',
        E.div(class_='cfs_preview', _('Sample to preview font size'))
    ))

    container.appendChild(E.div(
        style='margin-top: 1rem; text-align: right',
        create_button(_('OK'), highlight=True, action=def ():
            apply_font_size()
            close()
        ),
        '\xa0\xa0',
        create_button(_('Cancel'), action=close),
    ))


def develop(container):
    create_font_size_panel(container, def (): pass;)
