# Copyright 2015 Canonical, Ltd.
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as
# published by the Free Software Foundation, either version 3 of the
# License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

""" Filesystem

Provides storage device selection and additional storage
configuration.

"""
import logging
import re
from urwid import (ListBox, Pile, BoxAdapter, Text, Columns)
from subiquitycore.ui.lists import SimpleList
from subiquitycore.ui.buttons import (done_btn,
                                      reset_btn,
                                      cancel_btn,
                                      menu_btn)
from subiquitycore.ui.utils import Padding, Color
from subiquitycore.ui.interactive import (StringEditor, IntegerEditor,
                                          Selector, MountEditor)
from subiquitycore.models.filesystem import (_humanize_size,
                                             _dehumanize_size,
                                             HUMAN_UNITS)
from subiquitycore.view import ViewPolicy

INVALID_PARTITION_SIZE = 'Invalid Partition Size'
PARTITION_SIZE_TOO_BIG = 'Requested size too big'
PARTITION_ERRORS = [
    INVALID_PARTITION_SIZE,
    PARTITION_SIZE_TOO_BIG,
]


log = logging.getLogger('subiquitycore.ui.filesystem')


class DiskInfoView(ViewPolicy):
    def __init__(self, model, signal, selected_device, hdinfo):
        log.debug('DiskInfoView: {}'.format(selected_device))
        self.model = model
        self.signal = signal
        self.selected_device = selected_device
        hdinfo = hdinfo.split("\n")
        body = []
        for h in hdinfo:
            body.append(Text(h))
        body.append(Padding.fixed_10(self._build_buttons()))
        super().__init__(Padding.center_79(SimpleList(body)))

    def _build_buttons(self):
        done = done_btn(on_press=self.done)

        buttons = [
            Color.button(done, focus_map='button focus'),
        ]
        return Pile(buttons)

    def keypress(self, size, key):
        if key in ['tab', 'n', 'N', 'j', 'J']:
            log.debug('keypress: [{}]'.format(key))
            self.signal.emit_signal('filesystem:show-disk-info-next',
                                    self.selected_device)
            return None
        if key in ['shift tab', 'p', 'P', 'k', 'K']:
            log.debug('keypress: [{}]'.format(key))
            self.signal.emit_signal('filesystem:show-disk-info-prev',
                                    self.selected_device)
            return None

        return super().keypress(size, key)

    def done(self, result):
        ''' Return to FilesystemView '''
        self.signal.prev_signal()

    def cancel(self, button):
        self.signal.prev_signal()


class AddFormatView(ViewPolicy):
    def __init__(self, model, signal, selected_disk):
        self.model = model
        self.signal = signal
        self.selected_disk = selected_disk
        self.disk_obj = self.model.get_disk(selected_disk)

        self.mountpoint = MountEditor(caption="", edit_text="/")
        self.fstype = Selector(opts=self.model.supported_filesystems)
        body = [
            Padding.line_break(""),
            self._container(),
            Padding.line_break(""),
            Padding.fixed_10(self._build_buttons())
        ]
        format_box = Padding.center_50(ListBox(body))
        super().__init__(format_box)

    def _build_buttons(self):
        cancel = cancel_btn(on_press=self.cancel)
        done = done_btn(on_press=self.done)

        buttons = [
            Color.button(done, focus_map='button focus'),
            Color.button(cancel, focus_map='button focus')
        ]
        return Pile(buttons)

    def _format_edit(self):
        return Pile(self.fstype.group)

    def _container(self):
        total_items = [
            Columns(
                [
                    ("weight", 0.2, Text("Format", align="right")),
                    ("weight", 0.3,
                     Color.string_input(self._format_edit(),
                                        focus_map="string_input focus"))
                ], dividechars=4
            ),
            Columns(
                [
                    ("weight", 0.2, Text("Mount", align="right")),
                    ("weight", 0.3,
                     Color.string_input(self.mountpoint,
                                        focus_map="string_input focs"))
                ], dividechars=4
            )
        ]
        return Pile(total_items)

    def cancel(self, button):
        self.signal.prev_signal()

    def done(self, result):
        """ format spec

        {
          'format' Str(ext4|btrfs..,
          'mountpoint': Str
        }
        """

        result = {
            "fstype": self.fstype.value,
            "mountpoint": self.mountpoint.value
        }

        # Validate mountpoint input
        try:
            self.model.valid_mount(result)
        except ValueError as e:
            log.exception('Invalid mount point')
            self.mountpoint.set_error('Error: {}'.format(str(e)))
            log.debug('Invalid mountpoint, try again')
            return

        log.debug("Add Format Result: {}".format(result))
        self.signal.emit_signal('filesystem:finish-add-disk-format',
                                self.disk_obj.devpath, result)


class AddPartitionView(ViewPolicy):

    def __init__(self, model, signal, selected_disk):
        log.debug('AddPartitionView: selected_disk=[{}]'.format(selected_disk))
        self.model = model
        self.signal = signal
        self.selected_disk = selected_disk
        self.disk_obj = self.model.get_disk(selected_disk)

        self.partnum = IntegerEditor(
            caption="",
            default=self.disk_obj.lastpartnumber + 1)
        self.size_str = _humanize_size(self.disk_obj.freespace)
        self.size = StringEditor(
            caption="".format(self.size_str))
        self.mountpoint = MountEditor(caption="", edit_text="/")
        self.fstype = Selector(opts=self.model.supported_filesystems)
        body = [
            Columns(
                [
                    ("weight", 0.2, Text("Adding partition to {}".format(
                        self.disk_obj.devpath), align="right")),
                    ("weight", 0.3, Text(""))
                ]
            ),
            Padding.line_break(""),
            self._container(),
            Padding.line_break(""),
            Padding.fixed_10(self._build_buttons())
        ]
        partition_box = Padding.center_50(ListBox(body))
        super().__init__(partition_box)

    def _build_buttons(self):
        cancel = cancel_btn(on_press=self.cancel)
        done = done_btn(on_press=self.done)

        buttons = [
            Color.button(done, focus_map='button focus'),
            Color.button(cancel, focus_map='button focus')
        ]
        return Pile(buttons)

    def _format_edit(self):
        return Pile(self.fstype.group)

    def _container(self):
        total_items = [
            Columns(
                [
                    ("weight", 0.2, Text("Partition number", align="right")),
                    ("weight", 0.3,
                     Color.string_input(self.partnum,
                                        focus_map="string_input focus"))
                ], dividechars=4
            ),
            Columns(
                [
                    ("weight", 0.2,
                     Text("Size (max {})".format(self.size_str),
                          align="right")),
                    ("weight", 0.3,
                     Color.string_input(self.size,
                                        focus_map="string_input focus")),
                ], dividechars=4
            ),
            Columns(
                [
                    ("weight", 0.2, Text("Format", align="right")),
                    ("weight", 0.3,
                     Color.string_input(self._format_edit(),
                                        focus_map="string_input focus"))
                ], dividechars=4
            ),
            Columns(
                [
                    ("weight", 0.2, Text("Mount", align="right")),
                    ("weight", 0.3,
                     Color.string_input(self.mountpoint,
                                        focus_map="string_input focs"))
                ], dividechars=4
            )
        ]
        return Pile(total_items)

    def cancel(self, button):
        self.signal.prev_signal()

    def done(self, result):
        """ partition spec

        { 'partition_number': Int,
          'size': Int(M|G),
          'format' Str(ext4|btrfs..,
          'mountpoint': Str
        }
        """
        def __get_valid_size(size_str):
            r = '(\d*)(\d+[\.]?\d*)[{}]*$'.format(''.join(HUMAN_UNITS))
            match = re.match(r, size_str)
            log.debug('valid_size: input:{} match:{}'.format(size_str, match))
            if match:
                return match.group(0)

            return ''

        def __append_unit(input_size):
            ''' examine the input for a unit string.
                if not present, use the unit string from
                the displayed maximum size

                returns: number string with unit size
                '''
            unit_regex = '[{}]$'.format(''.join(HUMAN_UNITS))
            input_has_unit = re.findall(unit_regex, input_size)
            log.debug('input:{} re:{}'.format(input_size, input_has_unit))
            if len(input_has_unit) == 0:
                # input does not have unit string
                displayed_unit = re.search(unit_regex, self.size_str)
                log.debug('input:{} re:{}'.format(self.size_str,
                                                  displayed_unit))
                input_size += displayed_unit.group(0)

            return input_size

        def __get_size():
            log.debug('Getting partition size')
            log.debug('size.value={} size_str={} freespace={}'.format(
                      self.size.value, self.size_str,
                      self.disk_obj.freespace))
            if self.size.value == '' or \
               self.size.value == self.size_str:
                log.debug('Using default value: {}'.format(
                          self.disk_obj.freespace))
                return int(self.disk_obj.freespace)
            else:
                # 120B 120
                valid_size = __get_valid_size(self.size.value)
                if len(valid_size) == 0:
                    return INVALID_PARTITION_SIZE

                self.size.value = __append_unit(valid_size)
                log.debug('dehumanize_size({})'.format(self.size.value))
                sz = _dehumanize_size(self.size.value)
                if sz > self.disk_obj.freespace:
                    log.debug(
                        'Input size too big for device: ({} > {})'.format(
                            sz, self.disk_obj.freespace))
                    log.warn('Capping size @ max freespace: {}'.format(
                        self.disk_obj.freespace))
                    sz = self.disk_obj.freespace
                return sz

        result = {
            "partnum": self.partnum.value,
            "raw_size": self.size.value,
            "bytes": __get_size(),
            "fstype": self.fstype.value,
            "mountpoint": self.mountpoint.value
        }

        # Validate size (bytes) input
        if result['bytes'] in PARTITION_ERRORS:
            log.error(result['bytes'])
            self.size.set_error('ERROR: {}'.format(result['bytes']))
            return
        # Validate mountpoint input
        try:
            self.model.valid_mount(result)
        except ValueError as e:
            log.exception('Invalid mount point')
            self.mountpoint.set_error('Error: {}'.format(str(e)))
            log.debug("Invalid mountpoint, try again")
            return

        log.debug("Add Partition Result: {}".format(result))
        self.signal.emit_signal('filesystem:finish-add-disk-partition',
                                self.disk_obj.devpath, result)


class DiskPartitionView(ViewPolicy):
    def __init__(self, model, signal, selected_disk):
        self.model = model
        self.signal = signal
        self.selected_disk = selected_disk
        self.disk_obj = self.model.get_disk(self.selected_disk)

        self.body = [
            Padding.center_79(self._build_model_inputs()),
            Padding.line_break(""),
            Padding.center_79(self._build_menu()),
            Padding.line_break(""),
            Padding.fixed_10(self._build_buttons()),
        ]
        super().__init__(ListBox(self.body))

    def _build_buttons(self):
        cancel = cancel_btn(on_press=self.cancel)
        done = done_btn(on_press=self.done)

        buttons = [
            Color.button(done, focus_map='button focus'),
            Color.button(cancel, focus_map='button focus')
        ]
        return Pile(buttons)

    def _build_model_inputs(self):
        partitioned_disks = []

        for mnt, size, fstype, path in self.disk_obj.get_fs_table():
            mnt = Text(mnt)
            size = Text("{}".format(_humanize_size(size)))
            fstype = Text(fstype) if fstype else '-'
            path = Text(path) if path else '-'
            partition_column = Columns([
                (15, path),
                size,
                fstype,
                mnt
            ], 4)
            partitioned_disks.append(partition_column)
        free_space = _humanize_size(self.disk_obj.freespace)
        partitioned_disks.append(Columns([
            (15, Text("FREE SPACE")),
            Text(free_space),
            Text(""),
            Text("")
        ], 4))

        return BoxAdapter(SimpleList(partitioned_disks, is_selectable=False),
                          height=len(partitioned_disks))

    def _build_menu(self):
        """
        Builds the add partition menu with user visible
        changes to the button depending on if existing
        partitions exist or not.
        """
        menus = [
            self.add_partition_w(),
            self.create_swap_w(),
            self.show_disk_info_w(),
        ]
        return Pile([m for m in menus if m])

    def show_disk_info_w(self):
        """ Runs hdparm against device and displays its output
        """
        text = ("Show disk information")
        return Color.menu_button(
            menu_btn(
                label=text,
                on_press=self.show_disk_info
            ), focus_map='menu_button focus')

    def create_swap_w(self):
        """ Handles presenting an enabled create swap on
        entire device button if no partition exists, otherwise
        it is disabled.
        """
        text = ("Format or create swap on entire "
                "device (unusual, advanced)")
        if len(self.disk_obj.partitions) == 0 and \
           self.disk_obj.available:
            return Color.menu_button(menu_btn(label=text,
                                              on_press=self.create_swap),
                                     focus_map='menu_button focus')

    def add_partition_w(self):
        """ Handles presenting the add partition widget button
        depending on if partitions exist already or not.
        """
        text = "Add first GPT partition"
        if len(self.disk_obj.partitions) > 0:
            text = "Add partition (max size {})".format(
                _humanize_size(self.disk_obj.freespace))

        if self.disk_obj.available and \
           self.disk_obj.blocktype not in self.model.no_partition_blocktypes:
            return Color.menu_button(menu_btn(label=text,
                                              on_press=self.add_partition),
                                     focus_map='menu_button focus')

    def show_disk_info(self, result):
        self.signal.emit_signal('menu:filesystem:main:show-disk-information',
                                self.selected_disk)

    def add_partition(self, result):
        log.debug('add_partition: result={}'.format(result))
        self.signal.emit_signal('menu:filesystem:main:add-disk-partition',
                                self.selected_disk)

    def create_swap(self, result):
        log.debug('create_swap: result={}'.format(result))
        self.signal.emit_signal(
            'menu:filesystem:main:create-swap-entire-device',
            self.selected_disk)

    def done(self, result):
        ''' Return to FilesystemView '''
        self.signal.prev_signal()

    def cancel(self, button):
        self.signal.prev_signal()


class FilesystemView(ViewPolicy):
    def __init__(self, model, signal):
        log.debug('FileSystemView init start()')
        self.model = model
        self.signal = signal
        self.items = []
        self.model.probe_storage()  # probe before we complete
        self.body = [
            Padding.center_79(Text("FILE SYSTEM")),
            Padding.center_79(self._build_partition_list()),
            Padding.line_break(""),
            Padding.center_79(Text("AVAILABLE DISKS")),
            Padding.center_79(self._build_model_inputs()),
            Padding.line_break(""),
            Padding.center_79(self._build_menu()),
            Padding.line_break(""),
            Padding.center_79(self._build_used_disks()),
            Padding.fixed_10(self._build_buttons()),
        ]
        super().__init__(ListBox(self.body))
        log.debug('FileSystemView init complete()')

    def _build_used_disks(self):
        log.debug('FileSystemView: building used disks')
        pl = []
        for disk in self.model.get_used_disk_names():
            log.debug('used disk: {}'.format(disk))
            disk_string = disk
            disk_tag = self.model.get_tag(disk)
            if len(disk_tag):
                disk_string += " {}".format(disk_tag)
            pl.append(Color.info_minor(Text(disk_string)))
        if len(pl):
            return Pile(
                [Text("USED DISKS"),
                 Padding.line_break("")] + pl +
                [Padding.line_break("")]
            )

        return Pile(pl)

    def _build_partition_list(self):
        log.debug('FileSystemView: building part list')
        pl = []
        nr_parts = len(self.model.get_partitions())
        nr_fs = len(self.model.get_filesystems())
        if nr_parts == 0 and nr_fs == 0:
            pl.append(Color.info_minor(
                Text("No disks or partitions mounted")))
            log.debug('FileSystemView: no partitions')
            return Pile(pl)
        log.debug('FileSystemView: weve got partitions!')
        for dev in self.model.devices.values():
            for mnt, size, fstype, path in dev.get_fs_table():
                mnt = Text(mnt)
                size = Text("{}".format(_humanize_size(size)))
                fstype = Text(fstype) if fstype else '-'
                path = Text(path) if path else '-'
                partition_column = Columns([
                    (15, path),
                    size,
                    fstype,
                    mnt
                ], 4)
                pl.append(partition_column)
        log.debug('FileSystemView: build-part-list done')
        return Pile(pl)

    def _build_buttons(self):
        log.debug('FileSystemView: building buttons')
        buttons = []

        # don't enable done botton if we can't install
        if self.model.installable():
            buttons.append(
                Color.button(done_btn(on_press=self.done),
                             focus_map='button focus'))

        buttons.append(Color.button(reset_btn(on_press=self.reset),
                                    focus_map='button focus'))
        buttons.append(Color.button(cancel_btn(on_press=self.cancel),
                                    focus_map='button focus'))

        return Pile(buttons)

    def _get_percent_free(self, device):
        ''' return the device free space and percentage
            of the whole device'''
        percent = "%d" % (
            int((1.0 - (device.usedspace / device.size)) * 100))
        free = _humanize_size(device.freespace)
        rounded = "{}{}".format(int(float(free[:-1])), free[-1])
        return (rounded, percent)

    def _build_model_inputs(self):
        log.debug('FileSystemView: building model inputs')
        col_1 = []
        col_2 = []

        avail_disks = self.model.get_available_disk_names()
        if len(avail_disks) == 0:
            return Pile([Color.info_minor(Text("No available disks."))])

        for dname in avail_disks:
            disk = self.model.get_disk_info(dname)
            device = self.model.get_disk(dname)
            btn = menu_btn(label=disk.name,
                           on_press=self.show_disk_partition_view)

            col_1.append(
                Color.menu_button(btn, focus_map='menu_button focus'))
            disk_sz = _humanize_size(disk.size)
            log.debug('device partitions: {}'.format(len(device.partitions)))
            # if we've consumed some of the device, show
            # the remaining space and percentage of the whole
            if len(device.partitions) > 0:
                free, percent = self._get_percent_free(device)
                disk_sz = "{} ({}%) free".format(free, percent)
            col_2.append(Text(disk_sz))
            for partname in device.available_partitions:
                part = device.get_partition(partname)
                btn = menu_btn(label=partname,
                               on_press=self.show_disk_partition_view)
                col_1.append(
                    Color.menu_button(btn, focus_map='menu_button focus'))
                col_2.append(Text(_humanize_size(part.size)))

        col_1 = BoxAdapter(SimpleList(col_1),
                           height=len(col_1))
        col_2 = BoxAdapter(SimpleList(col_2, is_selectable=False),
                           height=len(col_2))
        return Columns([(16, col_1), col_2], 2)

    def _build_menu(self):
        log.debug('FileSystemView: building menu')
        opts = []
        avail_disks = self.model.get_available_disk_names()
        for opt, sig, _ in self.model.get_menu():
            if len(avail_disks) > 1:
                opts.append(Color.menu_button(
                            menu_btn(label=opt,
                                     on_press=self.on_fs_menu_press),
                            focus_map='menu_button focus'))
        return Pile(opts)

    def on_fs_menu_press(self, result):
        self.signal.emit_signal(
            self.model.get_signal_by_name(result.label))

    def cancel(self, button):
        self.signal.prev_signal()

    def reset(self, button):
        self.signal.emit_signal('menu:filesystem:main', True)

    def done(self, button):
        actions = self.model.get_actions()
        self.signal.emit_signal('filesystem:finish', False, actions)

    def show_disk_partition_view(self, partition):
        self.signal.emit_signal('menu:filesystem:main:show-disk-partition',
                                partition.label)