from typing import Optional, List

from highlight import Highlight
from highlighted_range import HighlightedRange
from line import Line
from PyQt6.QtCore import *
from PyQt6.QtGui import *
from PyQt6.QtWidgets import *

from settings import Settings


class HighlightSelection(Highlight):

    def __init__(self, start_byte: int, end_byte: int):
        self.start_byte = start_byte
        self.end_byte = end_byte

    def set_start(self, start_byte):
        self.start_byte = start_byte

    def set_end_byte(self, end_byte):
        self.end_byte = end_byte

    def compute_highlight(self, line: Line) -> Optional[List[HighlightedRange]]:
        begin = min(self.start_byte, self.end_byte)
        end = max(self.start_byte, self.end_byte)

        if line.intersects(begin, end):
            if line.includes_byte(begin):
                start = begin - line.byte_offset()
            else:
                start = 0

            if line.includes_byte(end):
                length = end - line.byte_offset()  - start
            else:
                length = Settings.max_line_length() -start

            return [HighlightedRange(start, length, brush=QBrush(QColor(255, 255, 0)), pen=Qt.PenStyle.NoPen)]
        else:
            return None