"""

Part of the tagit module.
A copy of the license is provided with the project.
Author: Matthias Baumgartner, 2022
"""
# standard imports
import math
import os

# kivy imports
from kivy.lang import Builder
import kivy.properties as kp

# tagit imports
from tagit import config, dialogues
from tagit.utils import clamp
from tagit.widgets import Binding

# inner-module imports
from .action import Action

# exports
__all__ = []


## code ##

# load kv
Builder.load_file(os.path.join(os.path.dirname(__file__), 'browser.kv'))

# classes

class NextPage(Action):
    """Scroll one page downwards without moving the cursor."""
    text = kp.StringProperty('Next page')

    def ktrigger(self, evt):
        return Binding.check(evt, self.cfg('bindings', 'browser', 'page_next'))

    def apply(self):
        with self.root.browser as browser:
            browser.offset = clamp(browser.offset + browser.page_size, browser.max_offset)


class PreviousPage(Action):
    """Scroll one page upwards without moving the cursor."""
    text = kp.StringProperty('Previous page')
    def ktrigger(self, evt):
        return Binding.check(evt, self.cfg('bindings', 'browser', 'page_prev'))

    def apply(self):
        with self.root.browser as browser:
            browser.offset = max(browser.offset - browser.page_size, 0)


class ScrollUp(Action):
    """Scroll one row up without moving the cursor."""
    text = kp.StringProperty('Scroll up')

    def ktrigger(self, evt):
        return Binding.check(evt, self.cfg('bindings', 'browser', 'scroll_up'))

    def on_touch_down(self, touch):
        scrollcfg = self.cfg('ui', 'standalone', 'browser', 'scroll')
        scrolldir = 'scrolldown' if scrollcfg == 'mouse' else 'scrollup'
        if self.root.browser.collide_point(*touch.pos) \
           and not self.root.keys.ctrl_pressed:
               if touch.button == scrolldir:
                self.apply()
        return super(ScrollUp, self).on_touch_down(touch)

    def apply(self):
        with self.root.browser as browser:
            browser.offset = clamp(browser.offset - browser.cols, browser.max_offset)


class ScrollDown(Action):
    """Scroll one row down without moving the cursor."""
    text = kp.StringProperty('Scroll down')

    def ktrigger(self, evt):
        return Binding.check(evt, self.cfg('bindings', 'browser', 'scroll_down'))

    def on_touch_down(self, touch):
        scrollcfg = self.cfg('ui', 'standalone', 'browser', 'scroll')
        scrolldir = 'scrollup' if scrollcfg == 'mouse' else 'scrolldown'
        if self.root.browser.collide_point(*touch.pos) \
           and not self.root.keys.ctrl_pressed:
            if touch.button == scrolldir:
                self.apply()
        return super(ScrollDown, self).on_touch_down(touch)

    def apply(self):
        with self.root.browser as browser:
            browser.offset = clamp(browser.offset + browser.cols, browser.max_offset)


class JumpToPage(Action):
    """Jump to a specified offset."""
    text = kp.StringProperty('Go to page')

    def apply(self, offset=None):
        if offset is None:
            browser = self.root.browser
            dlg = dialogues.NumericInput(lo=0, hi=browser.max_offset, init_value=browser.offset)
            dlg.bind(on_ok=lambda wx: self.set_offset(wx.value))
            dlg.open()
        else:
            self.set_offset(offset)

    def set_offset(self, offset):
        with self.root.browser as browser:
            browser.offset = clamp(offset, browser.max_offset)

class ZoomIn(Action):
    """Decrease the grid size."""
    text = kp.StringProperty('Zoom in')

    def ktrigger(self, evt):
        return Binding.check(evt, self.cfg('bindings', 'browser', 'zoom_in'))

    # TODO: zoom by gesture

    def on_touch_down(self, touch): # not triggered (but ScrollDown is!)
        if self.root.browser.collide_point(*touch.pos) \
           and self.root.keys.ctrl_pressed:
            if touch.button == 'scrolldown':
                self.apply()
        return super(ZoomIn, self).on_touch_down(touch)

    def apply(self):
        with self.root.browser as browser:
            step = self.cfg('ui', 'standalone', 'browser', 'zoom_step')
            if browser.gridmode == browser.GRIDMODE_LIST:
                cols = browser.cols
            else:
                cols = max(1, browser.cols - step)
            rows = max(1, browser.rows - step)
            # TODO: Zoom to center? (adjust offset)
            if cols != browser.cols or rows != browser.rows:
                # clear widgets first, otherwise GridLayout will
                # complain about too many childrens.
                browser.clear_widgets()
                # adjust the grid size
                browser.cols = cols
                browser.rows = rows


class ZoomOut(Action):
    """Increase the grid size."""
    text = kp.StringProperty('Zoom out')

    def ktrigger(self, evt):
        return Binding.check(evt, self.cfg('bindings', 'browser', 'zoom_out'))

    # TODO: zoom by gesture

    def on_touch_down(self, touch):
        if self.root.browser.collide_point(*touch.pos) \
           and self.root.keys.ctrl_pressed:
            if touch.button == 'scrollup':
                self.apply()
        return super(ZoomOut, self).on_touch_down(touch)

    def apply(self):
        with self.root.browser as browser:
            # TODO: Zoom from center? (adjust offset)
            step = self.cfg('ui', 'standalone', 'browser', 'zoom_step')
            # get maxcols
            maxcols = self.cfg('ui', 'standalone', 'browser', 'maxcols')
            maxcols = float('inf') if maxcols <= 0 else maxcols
            # get maxrows
            maxrows = self.cfg('ui', 'standalone', 'browser', 'maxrows')
            maxrows = float('inf') if maxrows <= 0 else maxrows
            # set cols/rows
            if browser.gridmode != browser.GRIDMODE_LIST:
                browser.cols = min(browser.cols + step, maxcols)
            browser.rows = min(browser.rows + step, maxrows)
            # adjust offset to ensure that one full page is visible
            browser.offset = clamp(browser.offset, browser.max_offset)


class JumpToCursor(Action):
    """Focus the field of view at the cursor."""
    text = kp.StringProperty('Find cursor')

    def apply(self):
        with self.root.browser as browser:
            if browser.cursor is None:
                # cursor not set, nothing to do
                pass
            else:
                idx = browser.items.index(browser.cursor)
                if idx < browser.offset:
                    # cursor is above view, scroll up such that the cursor
                    # is in the first row.
                    offset = math.floor(idx / browser.cols) * browser.cols
                    browser.offset = clamp(offset, browser.max_offset)
                elif browser.offset + browser.page_size <= idx:
                    # cursor is below view, scroll down such that the cursor
                    # is in the last row.
                    offset = math.floor(idx / browser.cols) * browser.cols
                    offset -= (browser.page_size - browser.cols)
                    browser.offset = clamp(offset, browser.max_offset)
                else:
                    # cursor is visible, nothing to do
                    pass


class SetCursor(Action):
    """Set the cursor to a specific item."""
    text = kp.StringProperty('Set cursor')

    def apply(self, obj):
        with self.root.browser as browser:
            browser.cursor = obj
            self.root.trigger('JumpToCursor')
            # is invoked via mouse click only, hence
            # the item selection should always toggle
            self.root.trigger('Select', browser.cursor)


class MoveCursorFirst(Action):
    """Set the cursor to the first item."""
    text = kp.StringProperty('First')

    def ktrigger(self, evt):
        return Binding.check(evt, self.cfg('bindings', 'browser', 'go_first'))

    def apply(self):
        with self.root.browser as browser:
            if browser.n_items == 0:
                # browser is empty, nothing to do
                pass
            else:
                # set cursor to first item
                old = browser.cursor
                browser.cursor = browser.items[0]
                # scroll to first page if need be
                self.root.trigger('JumpToCursor')
                # fix selection
                if browser.select_mode != browser.SELECT_MULTI and \
                   (browser.select_mode != browser.SELECT_SINGLE or old != browser.cursor):
                    self.root.trigger('Select', browser.cursor)


class MoveCursorLast(Action):
    """Set the cursor to the last item."""
    text = kp.StringProperty('Last')

    def ktrigger(self, evt):
        return Binding.check(evt, self.cfg('bindings', 'browser', 'go_last'))

    def apply(self):
        with self.root.browser as browser:
            if browser.n_items == 0:
                # browser is empty, nothing to do
                pass
            else:
                # set cursor to last item
                old = browser.cursor
                browser.cursor = browser.items[-1]
                # scroll to last page if need be
                self.root.trigger('JumpToCursor')
                # fix selection
                if browser.select_mode != browser.SELECT_MULTI and \
                   (browser.select_mode != browser.SELECT_SINGLE or old != browser.cursor):
                    self.root.trigger('Select', browser.cursor)


class MoveCursorUp(Action):
    """Move the cursor one item upwards. Scroll if needbe."""
    text = kp.StringProperty('Cursor up')

    def ktrigger(self, evt):
        return Binding.check(evt, self.cfg('bindings', 'browser', 'cursor_up'))

    def apply(self):
        with self.root.browser as browser:
            if browser.n_items == 0:
                # browser is empty, nothing to do
                pass
            elif browser.cursor is None:
                # cursor wasn't set before. Set to last item
                self.root.trigger('MoveCursorLast')
            else:
                # move cursor one row up
                old = browser.items.index(browser.cursor)
                # check if the cursor is in the first row already
                if old < browser.cols: return # first row already
                # move cursor up
                new = clamp(old - browser.cols, browser.n_items - 1)
                browser.cursor = browser.items[new]
                # fix field of view
                self.root.trigger('JumpToCursor')
                # fix selection
                if browser.select_mode != browser.SELECT_MULTI and \
                   (browser.select_mode != browser.SELECT_SINGLE or old != new):
                    self.root.trigger('Select', browser.cursor)


class MoveCursorDown(Action):
    """Move the cursor one item downwards. Scroll if needbe."""
    text = kp.StringProperty('Cursor down')

    def ktrigger(self, evt):
        return Binding.check(evt, self.cfg('bindings', 'browser', 'cursor_down'))

    def apply(self):
        with self.root.browser as browser:
            if browser.n_items == 0:
                # browser is empty, nothing to do
                pass
            elif browser.cursor is None:
                # cursor wasn't set before. Set to first item
                self.root.trigger('MoveCursorFirst')
            else:
                # move cursor one row down
                old = browser.items.index(browser.cursor)
                # check if the cursor is in the last row already
                last_row = browser.n_items % browser.cols
                last_row = last_row if last_row > 0 else browser.cols
                if old >= browser.n_items - last_row: return # last row already
                # move cursor down
                new = clamp(old + browser.cols, browser.n_items - 1)
                browser.cursor = browser.items[new]
                # fix field of view
                self.root.trigger('JumpToCursor')
                # fix selection
                if browser.select_mode != browser.SELECT_MULTI and \
                   (browser.select_mode != browser.SELECT_SINGLE or old != new):
                    self.root.trigger('Select', browser.cursor)


class MoveCursorLeft(Action):
    """Move the cursor to the previous item."""
    text = kp.StringProperty('Cursor left')

    def ktrigger(self, evt):
        return Binding.check(evt, self.cfg('bindings', 'browser', 'cursor_left'))

    def apply(self):
        with self.root.browser as browser:
            if browser.n_items == 0:
                # browser is empty, nothing to do
                pass
            elif browser.cursor is None:
                # cursor wasn't set before. Set to the last item
                self.root.trigger('MoveCursorLast')
            else:
                # move cursor one position to the left
                old = browser.items.index(browser.cursor)
                new = clamp(old - 1, browser.n_items - 1)
                browser.cursor = browser.items[new]
                self.root.trigger('JumpToCursor')
                # fix selection
                if browser.select_mode != browser.SELECT_MULTI and \
                   (browser.select_mode != browser.SELECT_SINGLE or old != new):
                    self.root.trigger('Select', browser.cursor)


class MoveCursorRight(Action):
    """Move the cursor to the next item."""
    text = kp.StringProperty('Cursor right')

    def ktrigger(self, evt):
        return Binding.check(evt, self.cfg('bindings', 'browser', 'cursor_right'))

    def apply(self):
        with self.root.browser as browser:
            if browser.n_items == 0:
                # browser is empty, nothing to do
                pass
            elif browser.cursor is None:
                # cursor wasn't set before. Set to the last item
                self.root.trigger('MoveCursorFirst')
            else:
                # move cursor one position to the right
                old = browser.items.index(browser.cursor)
                new = clamp(old + 1, browser.n_items - 1)
                browser.cursor = browser.items[new]
                self.root.trigger('JumpToCursor')
                # fix selection
                if browser.select_mode != browser.SELECT_MULTI and \
                   (browser.select_mode != browser.SELECT_SINGLE or old != new):
                    self.root.trigger('Select', browser.cursor)


class SelectAll(Action):
    """Select all items."""
    text = kp.StringProperty('Select all')

    def ktrigger(self, evt):
        return Binding.check(evt, self.cfg('bindings', 'browser', 'select_all'))

    def apply(self):
        with self.root.browser as browser:
            browser.selection = browser.items.as_set().copy()


class SelectNone(Action):
    """Clear the selection."""
    text = kp.StringProperty('Clear selection')

    def ktrigger(self, evt):
        return Binding.check(evt, self.cfg('bindings', 'browser', 'select_none'))

    def apply(self):
        with self.root.browser as browser:
            browser.selection = set()


class SelectInvert(Action):
    """Invert the selection."""
    text = kp.StringProperty('Invert selection')

    def apply(self):
        with self.root.browser as browser:
            browser.selection = browser.items.as_set() - browser.selection


class SelectSingle(Action):
    """Select only the cursor."""
    text = kp.StringProperty('Select one')

    def apply(self):
        with self.root.browser as browser:
            browser.select_mode = browser.SELECT_SINGLE


class SelectAdditive(Action):
    """Set the selection mode to additive select."""
    text = kp.StringProperty('Always select')

    def apply(self):
        with self.root.browser as browser:
            browser.select_mode = browser.SELECT_ADDITIVE


class SelectSubtractive(Action):
    """Set the selection mode to subtractive select."""
    text = kp.StringProperty('Always deselect')

    def apply(self):
        with self.root.browser as browser:
            browser.select_mode = browser.SELECT_SUBTRACTIVE


class SelectMulti(Action):
    """Set the selection mode to random access."""
    text = kp.StringProperty('Select many')
    browser = kp.ObjectProperty(None, allownone=True)

    def ktrigger(self, evt):
        key, _, _ = evt
        if key in self.root.keys.modemap[self.root.keys.MODIFIERS_CTRL]:
            self.browser = self.root.browser
            self.apply()

    def on_root(self, wx, root):
        super(SelectMulti, self).on_root(wx, root)
        root.keys.bind(on_release=self.on_key_up)

    def on_key_up(self, wx, key):
        if key in self.root.keys.modemap[self.root.keys.MODIFIERS_CTRL]:
            if self.browser is not None:
                with self.browser as browser:
                    if browser.select_mode & browser.SELECT_MULTI:
                        browser.select_mode -= browser.SELECT_MULTI

    def apply(self):
        with self.root.browser as browser:
            browser.select_mode |= browser.SELECT_MULTI


class SelectRange(Action):
    """Set the selection mode to range select."""
    text = kp.StringProperty('Select range')
    browser = kp.ObjectProperty(None, allownone=True)

    def ktrigger(self, evt):
        key, _, _ = evt
        if key in self.root.keys.modemap[self.root.keys.MODIFIERS_SHIFT]:
            self.browser = self.root.browser
            self.apply()

    def on_root(self, wx, root):
        super(SelectRange, self).on_root(wx, root)
        root.keys.bind(on_release=self.on_key_up)

    def on_key_up(self, wx, key):
        if key in self.root.keys.modemap[self.root.keys.MODIFIERS_SHIFT]:
            if self.browser is not None:
                with self.browser as browser:
                    if browser.select_mode & browser.SELECT_RANGE:
                        browser.select_mode -= browser.SELECT_RANGE
                        browser.range_base = set()
                        browser.range_origin = None

    def apply(self):
        with self.root.browser as browser:
            browser.select_mode |= browser.SELECT_RANGE
            browser.range_base = browser.selection.copy()
            idx = None if browser.cursor is None else  browser.items.index(browser.cursor)
            browser.range_origin = idx


class Select(Action):
    """Select or deselect an item. How the selection changes depends on the selection mode."""
    text = kp.StringProperty('Select')

    def ktrigger(self, evt):
        return Binding.check(evt, self.cfg('bindings', 'browser', 'select'))

    def apply(self, obj=None):
        with self.root.browser as browser:
            obj = obj if obj is not None else browser.cursor

            if obj is None:
                # nothing to do
                pass

            elif browser.select_mode & browser.SELECT_ADDITIVE:
                browser.selection.add(obj)

            elif browser.select_mode & browser.SELECT_SUBTRACTIVE:
                if obj in browser.selection:
                    browser.selection.remove(obj)

            elif browser.select_mode & browser.SELECT_RANGE:
                idx = browser.items.index(obj)
                lo = min(idx, browser.range_origin)
                hi = max(idx, browser.range_origin)
                browser.selection = browser.range_base | set(browser.items[lo:hi+1])

            elif browser.select_mode & browser.SELECT_MULTI:
                # Toggle
                if obj in browser.selection:
                    browser.selection.remove(obj)
                else:
                    browser.selection.add(obj)

            elif browser.select_mode == 0: #elif browser.select_mode & browser.SELECT_SINGLE:
                # Toggle
                if obj in browser.selection:
                    browser.selection = set()
                else:
                    browser.selection = {obj}


## config ##

config.declare(('ui', 'standalone', 'browser', 'maxcols'), config.Unsigned(), 0,
    __name__, 'Column maximum', 'Maximal number of columns. This guards against aggressive zooming, because the application may become unresponsive if too many preview images are shown on the same page. A value of Infinity means that no limit is enforced.')

config.declare(('ui', 'standalone', 'browser', 'maxrows'), config.Unsigned(), 0,
    __name__, 'Row maximum', 'Maximal number of rows. This guards against aggressive zooming, because the application may become unresponsive if too many preview images are shown on the same page. A value of Infinity means that no limit is enforced.')

config.declare(('ui', 'standalone', 'browser', 'zoom_step'), config.Unsigned(), 1,
    __name__, 'Zoom step', 'Controls by how much the gridsize is increased or decreased when zoomed in or out. Affects both dimensions (cols/rows) in grid mode.')

config.declare(('ui', 'standalone', 'browser', 'scroll'), config.Enum('mouse', 'touch'), 'mouse',
    __name__, 'Inverted scroll', 'To scroll downwards, one can either move the fingers in an upward direction (touch) or use the scroll wheel in a downward direction (mouse).')

# keybindings

config.declare(('bindings', 'browser', 'page_next'),
    config.Keybind(), Binding.simple(Binding.PGDN),
    __name__, NextPage.text.defaultvalue, NextPage.__doc__)

config.declare(('bindings', 'browser', 'page_prev'),
    config.Keybind(), Binding.simple(Binding.PGUP),
    __name__, PreviousPage.text.defaultvalue, PreviousPage.__doc__)

config.declare(('bindings', 'browser', 'scroll_up'),
    config.Keybind(), Binding.simple('k', None, Binding.mALL),
    __name__, ScrollUp.text.defaultvalue, ScrollUp.__doc__)

config.declare(('bindings', 'browser', 'scroll_down'),
    config.Keybind(), Binding.simple('j', None, Binding.mALL),
    __name__, ScrollDown.text.defaultvalue, ScrollDown.__doc__)

config.declare(('bindings', 'browser', 'zoom_in'),
    config.Keybind(), Binding.simple('+'),
    __name__, ZoomIn.text.defaultvalue, ZoomIn.__doc__)

config.declare(('bindings', 'browser', 'zoom_out'),
    config.Keybind(), Binding.simple('-'),
    __name__, ZoomOut.text.defaultvalue, ZoomOut.__doc__)

config.declare(('bindings', 'browser', 'go_first'),
    config.Keybind(), Binding.simple(Binding.HOME),
    __name__, MoveCursorFirst.text.defaultvalue, MoveCursorFirst.__doc__)

config.declare(('bindings', 'browser', 'go_last'),
    config.Keybind(), Binding.simple(Binding.END),
    __name__, MoveCursorLast.text.defaultvalue, MoveCursorLast.__doc__)

config.declare(('bindings', 'browser', 'cursor_up'),
    config.Keybind(), Binding.simple(Binding.UP),
    __name__, MoveCursorUp.text.defaultvalue, MoveCursorUp.__doc__)

config.declare(('bindings', 'browser', 'cursor_down'),
    config.Keybind(), Binding.simple(Binding.DOWN),
    __name__, MoveCursorDown.text.defaultvalue, MoveCursorDown.__doc__)

config.declare(('bindings', 'browser', 'cursor_left'),
    config.Keybind(), Binding.simple(Binding.LEFT),
    __name__, MoveCursorLeft.text.defaultvalue, MoveCursorLeft.__doc__)

config.declare(('bindings', 'browser', 'cursor_right'),
    config.Keybind(), Binding.simple(Binding.RIGHT),
    __name__, MoveCursorRight.text.defaultvalue, MoveCursorRight.__doc__)

config.declare(('bindings', 'browser', 'select_all'),
    config.Keybind(), Binding.simple('a',  Binding.mCTRL, Binding.mREST),
    __name__, SelectAll.text.defaultvalue, SelectAll.__doc__)

config.declare(('bindings', 'browser', 'select_none'),
    config.Keybind(), Binding.simple('a', (Binding.mCTRL, Binding.mSHIFT), Binding.mREST),
    __name__, SelectNone.text.defaultvalue, SelectNone.__doc__)

config.declare(('bindings', 'browser', 'select'),
    config.Keybind(), Binding.simple(Binding.SPACEBAR),
    __name__, Select.text.defaultvalue, Select.__doc__)

## EOF ##