from __future__ import annotations
import stat
from typing import TYPE_CHECKING
import curses
from ..items.Symlink import Symlink
from ..items.AItems import AItem

if TYPE_CHECKING:
    from .App import App


class UI:
    def __init__(self, app: App):
        self._app = app

    HEADER_ROWS = 1

    def _get_attr(self, item: any, index: int) -> str:
        pair = self.app.config.theme.pair_for(item.color_role)
        attr = curses.color_pair(pair)
        if index == self.app.navigator.cursor.pos:
            attr |= curses.A_REVERSE
        return attr

    def render(self, stdscr: curses.window) -> None:
        stdscr.erase()
        height, width = stdscr.getmaxyx()
        navigator = self.app.navigator

        stdscr.addstr(0, 0, str(navigator.history[-1])[:width - 1])

        items = navigator.items
        available = max(0, height - self.HEADER_ROWS)
        for index in range(min(available, len(items))):
            item = items[index]
            self._render_item(stdscr, item, index, index + self.HEADER_ROWS, width)

        prompt = self.app.prompt
        if prompt:
            self._render_modal(stdscr, prompt, height, width)

    MODAL_MAX_WIDTH = 60
    MODAL_PADDING = 2

    def _modal_lines(self, prompt) -> list[str]:
        if prompt.kind == "text":
            return [prompt.message + prompt.buffer]
        if prompt.kind == "confirm":
            return [prompt.message]
        return [prompt.message, "(press any key)"]

    def _render_modal(self, stdscr: curses.window, prompt,
                       screen_height: int, screen_width: int) -> None:
        lines = self._modal_lines(prompt)
        max_line = max(len(line) for line in lines)
        inner_width = min(max_line, self.MODAL_MAX_WIDTH)
        box_width = min(inner_width + 2 * self.MODAL_PADDING + 2,
                         screen_width - 2)
        inner_width = box_width - 2 * self.MODAL_PADDING - 2
        box_height = len(lines) + 2

        top = max(0, (screen_height - box_height) // 2)
        left = max(0, (screen_width - box_width) // 2)

        attr = curses.A_NORMAL
        if prompt.kind == "error":
            attr = curses.color_pair(self.app.config.theme.pair_for("error"))

        border = "+" + "-" * (box_width - 2) + "+"
        pad = " " * self.MODAL_PADDING
        stdscr.addstr(top, left, border, attr)
        for i, line in enumerate(lines):
            text = line[:inner_width].ljust(inner_width)
            stdscr.addstr(top + 1 + i, left, "|" + pad + text + pad + "|", attr)
        stdscr.addstr(top + box_height - 1, left, border, attr)

    SIZE_UNITS = ("", "K", "M", "G", "T", "P")

    @staticmethod
    def _format_size(size: int) -> str:
        value = float(size)
        for unit in UI.SIZE_UNITS:
            if value < 1024:
                return str(int(value)) if unit == "" else f"{value:.1f}{unit}"
            value /= 1024
        return f"{value:.1f}E"

    ARROW = " -> "
    ARROW_LEN = len(ARROW)

    def _render_item(self, stdscr: curses.window, item: AItem, index: int,
                      row: int, width: int) -> None:
        name, size, perm = item.fields()
        name_len = len(name)
        col_width = int(width / 3)

        attr = self._get_attr(item, index)
        stdscr.addstr(row, 0, name.ljust(col_width), attr)

        if type(item) is Symlink:
            target_pair = self.app.config.theme.pair_for(
                Symlink.target_role(item.point_to))
            attr_arrow = curses.color_pair(0)
            attr_target = curses.color_pair(target_pair)
            if index == self.app.navigator.cursor.pos:
                attr_arrow |= curses.A_REVERSE
                attr_target |= curses.A_REVERSE
            stdscr.addstr(row, name_len, self.ARROW, attr_arrow)
            stdscr.addstr(row, name_len + self.ARROW_LEN, str(item.point_to), attr_target)

        stdscr.addstr(row, col_width, self._format_size(size).ljust(col_width * 2), attr)
        stdscr.addstr(row, col_width * 2, stat.filemode(perm), attr)

    @property
    def app(self) -> App:
        return self._app