# ===== 循行者 8 路 讀值小工具（樂高 MINDSTORMS Robot Inventor App 玩具版 Python，照抄就好、不用改）=====
# ===== Pathfinder 8-Way reading helper (LEGO MINDSTORMS Robot Inventor App, Python: copy as is) =====
# 循行者在 Robot Inventor App 裡是「顏色感應器」：反射光＝線寬、RGB 強度第 1 個值＝細位置＋100（2026-10-29 實機量過）。
# In the Robot Inventor App the Pathfinder is a colour sensor: reflected light = line width, first RGB intensity value = fine position + 100.
# get_color() 只有少數位置有顏色名稱，不能當位置；粗位置和每一路的光值這個 App 讀不到，要用請改用 Pybricks。
# get_color() only names a few positions, so it is not a position; coarse position and per-channel readings need Pybricks.
# LEGO 已在 2026-10-01 停止支援 Robot Inventor App；新專案建議用 SPIKE App 3 或 Pybricks。
# LEGO ended support for the Robot Inventor App on 2026-10-01; new projects should use SPIKE App 3 or Pybricks.
# 站在車後往前看：線在左＝負、在右＝正 / seen from behind the robot: line on the left = negative
from mindstorms import ColorSensor


class Line8RI:
    def __init__(self, port_letter):
        self.sensor = ColorSensor(port_letter)  # 孔位字母，例如 'C' / port letter, e.g. 'C'
        self.r = 0
        self.red = 100

    def update(self):
        """讀一次最新資料 / read once"""
        self.r = int(self.sensor.get_reflected_light()) & 255           # 線寬 / line width
        self.red = int(self.sensor.get_rgb_intensity()[0]) & 0xFFFF     # 細位置＋100 / fine position + 100
        return True

    def pos100(self):
        """細位置 −100~+100，循線用這個；看不到線時停在最後離開的那一側（−100 或 +100）/ fine position −100~+100 for line following; keeps the last side (−100 or +100) when the line is lost"""
        return self.red - 100

    def width(self):
        """線寬 0~8：幾路踩在線上，0＝看不到線 / line width 0~8: channels on the line, 0 = no line"""
        return self.r
# ===== 小工具到這裡結束 / end of helper =====