#!/usr/bin/env python
# License: GPLv3 Copyright: 2020, Kovid Goyal <kovid at kovidgoyal.net>

import weakref
from collections import deque
from contextlib import suppress
from itertools import count
from typing import Any, Deque, Dict, Iterator, List, Optional, Tuple, Union

from .types import WindowGeometry
from .typing import EdgeLiteral, TabType, WindowType

WindowOrId = Union[WindowType, int]
group_id_counter = count(start=1)


def reset_group_id_counter() -> None:
    global group_id_counter
    group_id_counter = count(start=1)


def wrap_increment(val: int, num: int, delta: int) -> int:
    mult = -1 if delta < 0 else 1
    delta = mult * (abs(delta) % num)
    return (val + num + delta) % num


class WindowGroup:

    def __init__(self) -> None:
        self.windows: List[WindowType] = []
        self.id = next(group_id_counter)

    def __len__(self) -> int:
        return len(self.windows)

    def __bool__(self) -> bool:
        return bool(self.windows)

    def __iter__(self) -> Iterator[WindowType]:
        return iter(self.windows)

    def __contains__(self, window: WindowType) -> bool:
        for w in self.windows:
            if w is window:
                return True
        return False

    @property
    def needs_attention(self) -> bool:
        for w in self.windows:
            if w.needs_attention:
                return True
        return False

    @property
    def base_window_id(self) -> int:
        return self.windows[0].id if self.windows else 0

    @property
    def active_window_id(self) -> int:
        return self.windows[-1].id if self.windows else 0

    def add_window(self, window: WindowType) -> None:
        self.windows.append(window)

    def remove_window(self, window: WindowType) -> None:
        with suppress(ValueError):
            self.windows.remove(window)

    def serialize_state(self) -> Dict[str, Any]:
        return {
            'id': self.id,
            'windows': [w.serialize_state() for w in self.windows]
        }

    def decoration(self, which: EdgeLiteral, border_mult: int = 1, is_single_window: bool = False) -> int:
        if not self.windows:
            return 0
        w = self.windows[0]
        return w.effective_margin(which, is_single_window=is_single_window) + w.effective_border() * border_mult + w.effective_padding(which)

    def effective_padding(self, which: EdgeLiteral) -> int:
        if not self.windows:
            return 0
        w = self.windows[0]
        return w.effective_padding(which)

    def effective_border(self) -> int:
        if not self.windows:
            return 0
        w = self.windows[0]
        return w.effective_border()

    def set_geometry(self, geom: WindowGeometry) -> None:
        for w in self.windows:
            w.set_geometry(geom)

    @property
    def default_bg(self) -> int:
        if self.windows:
            w: WindowType = self.windows[-1]
            return w.screen.color_profile.default_bg
        return 0

    @property
    def geometry(self) -> Optional[WindowGeometry]:
        if self.windows:
            w: WindowType = self.windows[-1]
            return w.geometry
        return None

    @property
    def is_visible_in_layout(self) -> bool:
        if self.windows:
            w: WindowType = self.windows[-1]
            return w.is_visible_in_layout
        return False


class WindowList:

    def __init__(self, tab: TabType) -> None:
        self.all_windows: List[WindowType] = []
        self.id_map: Dict[int, WindowType] = {}
        self.groups: List[WindowGroup] = []
        self._active_group_idx: int = -1
        self.active_group_history: Deque[int] = deque((), 64)
        self.tabref = weakref.ref(tab)

    def __len__(self) -> int:
        return len(self.all_windows)

    def __bool__(self) -> bool:
        return bool(self.all_windows)

    def __iter__(self) -> Iterator[WindowType]:
        return iter(self.all_windows)

    def __contains__(self, window: WindowOrId) -> bool:
        q = window if isinstance(window, int) else window.id
        return q in self.id_map

    def serialize_state(self) -> Dict[str, Any]:
        return {
            'active_group_idx': self.active_group_idx,
            'active_group_history': list(self.active_group_history),
            'window_groups': [g.serialize_state() for g in self.groups]
        }

    @property
    def active_group_idx(self) -> int:
        return self._active_group_idx

    @property
    def active_window_history(self) -> List[int]:
        ans = []
        seen = set()
        gid_map = {g.id: g for g in self.groups}
        for gid in self.active_group_history:
            g = gid_map.get(gid)
            if g is not None:
                w = g.active_window_id
                if w > 0 and w not in seen:
                    seen.add(w)
                    ans.append(w)
        return ans

    def notify_on_active_window_change(self, old_active_window: Optional[WindowType], new_active_window: Optional[WindowType]) -> None:
        if old_active_window is not None:
            old_active_window.focus_changed(False)
        if new_active_window is not None:
            new_active_window.focus_changed(True)
        tab = self.tabref()
        if tab is not None:
            tab.active_window_changed()

    def set_active_group_idx(self, i: int, notify: bool = True) -> bool:
        changed = False
        if i != self._active_group_idx and 0 <= i < len(self.groups):
            old_active_window = self.active_window
            g = self.active_group
            if g is not None:
                with suppress(ValueError):
                    self.active_group_history.remove(g.id)
                self.active_group_history.append(g.id)
            self._active_group_idx = i
            new_active_window = self.active_window
            if old_active_window is not new_active_window:
                if notify:
                    self.notify_on_active_window_change(old_active_window, new_active_window)
                changed = True
        return changed

    def set_active_group(self, group_id: int) -> bool:
        for i, gr in enumerate(self.groups):
            if gr.id == group_id:
                return self.set_active_group_idx(i)
        return False

    def change_tab(self, tab: TabType) -> None:
        self.tabref = weakref.ref(tab)

    def iter_windows_with_visibility(self) -> Iterator[Tuple[WindowType, bool]]:
        for g in self.groups:
            aw = g.active_window_id
            for window in g:
                yield window, window.id == aw

    def iter_all_layoutable_groups(self, only_visible: bool = False) -> Iterator[WindowGroup]:
        return iter(g for g in self.groups if g.is_visible_in_layout) if only_visible else iter(self.groups)

    def iter_windows_with_number(self, only_visible: bool = True) -> Iterator[Tuple[int, WindowType]]:
        for i, g in enumerate(self.groups):
            if not only_visible or g.is_visible_in_layout:
                aw = g.active_window_id
                for window in g:
                    if window.id == aw:
                        yield i, window
                        break

    def make_previous_group_active(self, which: int = 1, notify: bool = True) -> None:
        which = max(1, which)
        gid_map = {g.id: i for i, g in enumerate(self.groups)}
        num = len(self.active_group_history)
        for i in range(num):
            idx = num - i - 1
            gid = self.active_group_history[idx]
            x = gid_map.get(gid)
            if x is not None:
                which -= 1
                if which < 1:
                    self.set_active_group_idx(x, notify=notify)
                    return
        self.set_active_group_idx(len(self.groups) - 1, notify=notify)

    @property
    def num_groups(self) -> int:
        return len(self.groups)

    def group_for_window(self, x: WindowOrId) -> Optional[WindowGroup]:
        q = self.id_map[x] if isinstance(x, int) else x
        for g in self.groups:
            if q in g:
                return g
        return None

    def group_idx_for_window(self, x: WindowOrId) -> Optional[int]:
        q = self.id_map[x] if isinstance(x, int) else x
        for i, g in enumerate(self.groups):
            if q in g:
                return i
        return None

    def windows_in_group_of(self, x: WindowOrId) -> Iterator[WindowType]:
        g = self.group_for_window(x)
        if g is not None:
            return iter(g)
        return iter(())

    @property
    def active_group(self) -> Optional[WindowGroup]:
        with suppress(Exception):
            return self.groups[self.active_group_idx]
        return None

    @property
    def active_window(self) -> Optional[WindowType]:
        with suppress(Exception):
            return self.id_map[self.groups[self.active_group_idx].active_window_id]
        return None

    @property
    def active_group_base(self) -> Optional[WindowType]:
        with suppress(Exception):
            return self.id_map[self.groups[self.active_group_idx].base_window_id]
        return None

    def set_active_window_group_for(self, x: WindowOrId) -> None:
        try:
            q = self.id_map[x] if isinstance(x, int) else x
        except KeyError:
            return
        for i, group in enumerate(self.groups):
            if q in group:
                self.set_active_group_idx(i)
                break

    def add_window(
        self,
        window: WindowType,
        group_of: Optional[WindowOrId] = None,
        next_to: Optional[WindowOrId] = None,
        before: bool = False,
        make_active: bool = True
    ) -> WindowGroup:
        self.all_windows.append(window)
        self.id_map[window.id] = window
        target_group: Optional[WindowGroup] = None

        if group_of is not None:
            target_group = self.group_for_window(group_of)
        if target_group is None and next_to is not None:
            q = self.id_map[next_to] if isinstance(next_to, int) else next_to
            pos = -1
            for i, g in enumerate(self.groups):
                if q in g:
                    pos = i
                    break
            if pos > -1:
                target_group = WindowGroup()
                self.groups.insert(pos + (0 if before else 1), target_group)
        if target_group is None:
            target_group = WindowGroup()
            if before:
                self.groups.insert(0, target_group)
            else:
                self.groups.append(target_group)

        old_active_window = self.active_window
        target_group.add_window(window)
        if make_active:
            for i, g in enumerate(self.groups):
                if g is target_group:
                    self.set_active_group_idx(i, notify=False)
                    break
        new_active_window = self.active_window
        if new_active_window is not old_active_window:
            self.notify_on_active_window_change(old_active_window, new_active_window)
        return target_group

    def remove_window(self, x: WindowOrId) -> None:
        old_active_window = self.active_window
        q = self.id_map[x] if isinstance(x, int) else x
        try:
            self.all_windows.remove(q)
        except ValueError:
            pass
        self.id_map.pop(q.id, None)
        for i, g in enumerate(tuple(self.groups)):
            g.remove_window(q)
            if not g:
                del self.groups[i]
                if self.groups:
                    if self.active_group_idx == i:
                        self.make_previous_group_active(notify=False)
                    elif self.active_group_idx >= len(self.groups):
                        self._active_group_idx -= 1
                else:
                    self._active_group_idx = -1
                break
        new_active_window = self.active_window
        if old_active_window is not new_active_window:
            self.notify_on_active_window_change(old_active_window, new_active_window)

    def active_window_in_nth_group(self, n: int, clamp: bool = False) -> Optional[WindowType]:
        if clamp:
            n = max(0, min(n, self.num_groups - 1))
        if 0 <= n < self.num_groups:
            return self.id_map.get(self.groups[n].active_window_id)
        return None

    def activate_next_window_group(self, delta: int) -> None:
        self.set_active_group_idx(wrap_increment(self.active_group_idx, self.num_groups, delta))

    def move_window_group(self, by: Optional[int] = None, to_group: Optional[int] = None) -> bool:
        if self.active_group_idx < 0 or not self.groups:
            return False
        target = -1
        if by is not None:
            target = wrap_increment(self.active_group_idx, self.num_groups, by)
        if to_group is not None:
            for i, group in enumerate(self.groups):
                if group.id == to_group:
                    target = i
                    break
        if target > -1:
            if target == self.active_group_idx:
                return False
            self.groups[self.active_group_idx], self.groups[target] = self.groups[target], self.groups[self.active_group_idx]
            self.set_active_group_idx(target)
            return True
        return False

    def compute_needs_borders_map(self, draw_active_borders: bool) -> Dict[int, bool]:
        ag = self.active_group
        return {gr.id: ((gr is ag and draw_active_borders) or gr.needs_attention) for gr in self.groups}

    @property
    def num_visble_groups(self) -> int:
        ans = 0
        for gr in self.groups:
            if gr.is_visible_in_layout:
                ans += 1
        return ans