from __future__ import annotations

import json
from dataclasses import asdict, dataclass
from pathlib import Path

from PySide6.QtCore import QStandardPaths
from PySide6.QtGui import QKeySequence


SHORTCUT_DEFINITIONS: list[tuple[str, str, str]] = [
    ("open", "Открыть", "Ctrl+O"),
    ("save", "Сохранить", "Ctrl+S"),
    ("save_as", "Сохранить как", "Ctrl+Shift+S"),
    ("generate_script", "Сгенерировать скрипт", "Ctrl+G"),
    ("settings", "Параметры", "Ctrl+,"),
    ("undo", "Отменить", "Ctrl+Z"),
    ("redo", "Повторить", "Ctrl+Y"),
    ("delete", "Удалить фиксацию", "Del"),
    ("delete_points", "Удалить точки", "Ctrl+Del"),
    ("clear_all", "Удалить все", "Ctrl+Shift+Del"),
    ("clear_selection", "Очистить выбор", "Esc"),
    ("fit_view", "Показать всё", "Ctrl+0"),
    ("grid", "Сетка 34 мм", "G"),
    ("direction_arrows", "Стрелки направления", "Ctrl+Shift+A"),
    ("led_ids", "Отображать id светодиодов", "I"),
    ("background", "Подложка", "Ctrl+B"),
    ("background_visible", "Показать подложку", "Ctrl+Alt+B"),
    ("background_edit", "Редактировать подложку", "Ctrl+Shift+I"),
    ("background_reset_scale", "Сбросить масштаб подложки", "Ctrl+Alt+0"),
    ("background_clear", "Удалить подложку", "Ctrl+Alt+Backspace"),
    ("toggle_sidebar", "Скрыть боковую панель", "F9"),
    ("add_line", "Новая линия", "Ctrl+L"),
    ("add_led", "Новый светодиод", "N"),
    ("add_block", "Блок из выбора", "Ctrl+Shift+L"),
    ("auto_blocks", "Автоблоки", "Ctrl+Shift+B"),
    ("clockwise", "По часовой", "Ctrl+Alt+R"),
    ("rebuild_route", "Пересобрать", "Ctrl+Shift+R"),
    ("brush", "Кисть", "B"),
]
DEFAULT_SHORTCUTS = {key: shortcut for key, _title, shortcut in SHORTCUT_DEFINITIONS}
SETTINGS_VERSION = 2


@dataclass
class AppSettings:
    version: int = SETTINGS_VERSION
    theme: str = "system"
    show_grid_by_default: bool = False
    show_direction_arrows_by_default: bool = True
    show_led_ids_by_default: bool = True
    zoom_focus_pull: int = 35
    pan_mode: str = "middle_space"
    instant_space_pan: bool = False
    brush_radius: int = 18
    default_output_dir: str = ""
    confirm_partial_generation: bool = True
    sidebar_inner_sizes: list[int] | None = None
    shortcuts: dict[str, str] | None = None

    @classmethod
    def load(cls) -> "AppSettings":
        path = settings_path()
        if not path.exists():
            return cls()
        try:
            data = json.loads(path.read_text(encoding="utf-8"))
        except (OSError, json.JSONDecodeError):
            return cls()
        settings = cls()
        saved_version = clamp_int(data.get("version", 1), 1, SETTINGS_VERSION, 1)
        for key, value in data.items():
            if hasattr(settings, key):
                setattr(settings, key, value)
        settings.version = SETTINGS_VERSION
        settings.zoom_focus_pull = clamp_int(settings.zoom_focus_pull, 0, 100, cls.zoom_focus_pull)
        settings.brush_radius = clamp_int(settings.brush_radius, 4, 80, cls.brush_radius)
        if settings.theme not in {"system", "light", "dark"}:
            settings.theme = cls.theme
        if settings.pan_mode not in {"middle", "space", "middle_space"}:
            settings.pan_mode = cls.pan_mode
        settings.instant_space_pan = bool(settings.instant_space_pan)
        settings.show_grid_by_default = bool(settings.show_grid_by_default)
        settings.show_direction_arrows_by_default = bool(settings.show_direction_arrows_by_default)
        settings.show_led_ids_by_default = bool(settings.show_led_ids_by_default)
        settings.confirm_partial_generation = bool(settings.confirm_partial_generation)
        settings.default_output_dir = str(settings.default_output_dir or "")
        settings.sidebar_inner_sizes = normalize_splitter_sizes(settings.sidebar_inner_sizes, [360, 420])
        settings.shortcuts = normalize_shortcuts(
            settings.shortcuts,
            fill_new_defaults=saved_version < SETTINGS_VERSION,
        )
        return settings

    def save(self) -> None:
        path = settings_path()
        path.parent.mkdir(parents=True, exist_ok=True)
        path.write_text(json.dumps(asdict(self), ensure_ascii=False, indent=2), encoding="utf-8")

    def shortcut_for(self, key: str) -> str:
        if self.shortcuts is None:
            return DEFAULT_SHORTCUTS.get(key, "")
        return self.shortcuts.get(key, DEFAULT_SHORTCUTS.get(key, ""))


def settings_path() -> Path:
    config_dir = QStandardPaths.writableLocation(QStandardPaths.AppConfigLocation)
    if not config_dir:
        config_dir = str(Path.home() / ".led_mapper")
    return Path(config_dir) / "settings.json"


def clamp_int(value, minimum: int, maximum: int, fallback: int) -> int:  # noqa: ANN001
    try:
        number = int(value)
    except (TypeError, ValueError):
        return fallback
    return max(minimum, min(maximum, number))


def normalize_splitter_sizes(value, fallback: list[int]) -> list[int]:  # noqa: ANN001
    if not isinstance(value, list) or len(value) != len(fallback):
        return fallback[:]
    sizes = [clamp_int(size, 80, 10000, fallback[index]) for index, size in enumerate(value)]
    if sum(sizes) <= 0:
        return fallback[:]
    return sizes


def normalize_shortcuts(value, *, fill_new_defaults: bool = False) -> dict[str, str]:  # noqa: ANN001
    source = value if isinstance(value, dict) else {}
    shortcuts: dict[str, str] = {}
    for key, default in DEFAULT_SHORTCUTS.items():
        raw = source.get(key, default)
        if raw is None or (fill_new_defaults and raw == "" and default):
            raw = ""
            if fill_new_defaults and default:
                raw = default
        sequence = QKeySequence(str(raw))
        shortcuts[key] = sequence.toString(QKeySequence.SequenceFormat.PortableText)
    return shortcuts