"""Compact, scrollable shortcut reference for the Hub popups."""
from __future__ import annotations

import curses
from dataclasses import dataclass
import unicodedata


@dataclass(frozen=True)
class KeyMapping:
    keys: str
    action: str


KEY_SECTIONS: tuple[tuple[str, tuple[KeyMapping, ...]], ...] = (
    (
        "Hub",
        (
            KeyMapping("Ctrl+A ?", "打开快捷键帮助"),
            KeyMapping("Ctrl+A g", "打开 Sessions"),
            KeyMapping("Ctrl+A h", "打开 Herdr 命令"),
            KeyMapping("Ctrl+A p / n", "上一个 / 下一个 Hub Tab"),
            KeyMapping("Ctrl+A 0..9", "按编号切换 Hub Tab"),
            KeyMapping("Ctrl+A r", "扫描新增 Sessions"),
            KeyMapping("Ctrl+A R", "重连当前 Tab"),
            KeyMapping("Ctrl+A q", "关闭当前 Hub Tab（需确认）"),
            KeyMapping("Ctrl+A d", "Detach Hub"),
        ),
    ),
    (
        "Sessions 弹窗",
        (
            KeyMapping("↑ / ↓", "移动选择"),
            KeyMapping("Enter / 单击", "执行主操作"),
            KeyMapping("Space / [操作]", "打开管理菜单"),
            KeyMapping("/", "搜索"),
            KeyMapping("Ctrl+R", "刷新远端状态"),
            KeyMapping("Esc", "返回或关闭"),
        ),
    ),
    (
        "Herdr 命令弹窗",
        (
            KeyMapping("Enter / 单击", "执行命令"),
            KeyMapping("Esc", "关闭"),
        ),
    ),
)


def display_width(value: str) -> int:
    return sum(
        0
        if unicodedata.combining(character)
        else 2
        if unicodedata.east_asian_width(character) in {"W", "F"}
        else 1
        for character in value
    )


def truncate(value: str, width: int) -> str:
    if width <= 0:
        return ""
    result = ""
    used = 0
    for character in value:
        size = display_width(character)
        if used + size > width:
            break
        result += character
        used += size
    return result


def pad(value: str, width: int) -> str:
    clipped = truncate(value, width)
    return clipped + " " * max(0, width - display_width(clipped))


class KeyHelpPopup:
    def __init__(self) -> None:
        self.scroll = 0

    @staticmethod
    def lines(width: int) -> list[tuple[str, int]]:
        lines: list[tuple[str, int]] = []
        wide = width >= 52
        key_width = min(20, max(12, width // 3))
        for section_index, (heading, mappings) in enumerate(KEY_SECTIONS):
            if section_index:
                lines.append(("", curses.A_NORMAL))
            lines.append((heading, curses.A_BOLD))
            for mapping in mappings:
                if wide:
                    lines.append(
                        (
                            f"  {pad(mapping.keys, key_width)}  {mapping.action}",
                            curses.A_NORMAL,
                        )
                    )
                else:
                    lines.append((f"  {mapping.keys}", curses.A_BOLD))
                    lines.append((f"    {mapping.action}", curses.A_DIM))
        return lines

    def run(self, screen) -> int:  # type: ignore[no-untyped-def]
        screen.keypad(True)
        screen.timeout(100)
        try:
            curses.set_escdelay(25)
            curses.curs_set(0)
            curses.use_default_colors()
            curses.mousemask(curses.ALL_MOUSE_EVENTS)
        except (AttributeError, curses.error):
            pass

        while True:
            screen.erase()
            height, width = screen.getmaxyx()
            content = self.lines(max(1, width - 4))
            visible_height = max(1, height - 3)
            self.scroll = max(
                0,
                min(self.scroll, max(0, len(content) - visible_height)),
            )
            for offset, (value, attribute) in enumerate(
                content[self.scroll : self.scroll + visible_height]
            ):
                self._add(screen, 1 + offset, 2, value, attribute)

            footer = (
                "↑↓ / PgUp PgDn 滚动 · Esc / q 关闭"
                if len(content) > visible_height
                else "Esc / q 关闭"
            )
            self._add(screen, height - 1, 1, footer, curses.A_DIM)
            screen.refresh()
            try:
                key = screen.get_wch()
            except curses.error:
                continue
            if key in {"\x1b", "q", "Q", "\n", "\r", curses.KEY_ENTER}:
                return 0
            if key == curses.KEY_UP:
                self.scroll -= 1
            elif key == curses.KEY_DOWN:
                self.scroll += 1
            elif key == curses.KEY_PPAGE:
                self.scroll -= visible_height
            elif key == curses.KEY_NPAGE:
                self.scroll += visible_height
            elif key == curses.KEY_MOUSE:
                try:
                    _, _, _, _, state = curses.getmouse()
                except curses.error:
                    continue
                if state & getattr(curses, "BUTTON4_PRESSED", 0):
                    self.scroll -= 3
                elif state & getattr(curses, "BUTTON5_PRESSED", 0):
                    self.scroll += 3

    @staticmethod
    def _add(
        screen,
        y: int,
        x: int,
        value: str,
        attribute: int = curses.A_NORMAL,
    ) -> None:  # type: ignore[no-untyped-def]
        height, width = screen.getmaxyx()
        if y < 0 or y >= height or x >= width:
            return
        try:
            screen.addstr(y, x, truncate(value, max(0, width - x - 1)), attribute)
        except curses.error:
            pass