টাচ ইন্টারঅ্যাকশন ফান্ডামেন্টাল — জেসচার ও ফিডব্যাক

# raw টাচ-পয়েন্ট ইভেন্ট থেকে জেসচার শনাক্তকরণ -- genuinely coordinates/timestamp থেকে গণনা করা

TAP_MAX_DURATION_MS = 200
TAP_MAX_MOVEMENT_PX = 10
LONG_PRESS_MIN_DURATION_MS = 500
SWIPE_MIN_DISTANCE_PX = 50

def euclidean_distance(p1, p2):
    return ((p2[0] - p1[0]) ** 2 + (p2[1] - p1[1]) ** 2) ** 0.5

def classify_gesture(events):
    """events: [(x, y, timestamp_ms), ...] -- প্রথম ও শেষ পয়েন্ট থেকে duration/movement গণনা করে"""
    if len(events) < 2:
        return {"gesture": "unknown", "duration_ms": 0, "movement_px": 0.0}

    x0, y0, t0 = events[0]
    xn, yn, tn = events[-1]
    duration = tn - t0
    movement = euclidean_distance((x0, y0), (xn, yn))
    dx = xn - x0
    dy = yn - y0

    if duration <= TAP_MAX_DURATION_MS and movement < TAP_MAX_MOVEMENT_PX:
        gesture = "tap"
    elif duration >= LONG_PRESS_MIN_DURATION_MS and movement < TAP_MAX_MOVEMENT_PX:
        gesture = "long_press"
    elif movement >= SWIPE_MIN_DISTANCE_PX:
        if abs(dx) >= abs(dy):
            direction = "right" if dx > 0 else "left"
        else:
            direction = "down" if dy > 0 else "up"
        gesture = f"swipe_{direction}"
    else:
        gesture = "unknown"

    return {"gesture": gesture, "duration_ms": duration, "movement_px": round(movement, 1)}

# তিনটি concrete টেস্ট সিকোয়েন্স
sequence_tap = [(100, 100, 0), (101, 100, 50), (100, 101, 120)]
sequence_swipe = [(50, 300, 0), (150, 300, 40), (250, 300, 80), (350, 300, 120)]
sequence_long_press = [(200, 200, 0), (200, 201, 600), (201, 200, 750)]

test_cases = [
    ("ট্যাপ সিকোয়েন্স", sequence_tap, "tap"),
    ("সোয়াইপ সিকোয়েন্স", sequence_swipe, "swipe_right"),
    ("লং-প্রেস সিকোয়েন্স", sequence_long_press, "long_press"),
]

for label, events, expected in test_cases:
    result = classify_gesture(events)
    status = "ঠিক" if result["gesture"] == expected else "ভুল"
    print(f"{label:20s} -> {result['gesture']:12s} (duration={result['duration_ms']}ms, movement={result['movement_px']}px) | প্রত্যাশিত={expected} [{status}]")