import mediapipe as mp
import cv2, numpy as np, time, fitz
from helper import compute_distance
from config import PINCH_THRESHOLD, RELEASE_THRESHOLD

# ----- Initialize Hand Detector -----
mp_hands = mp.solutions.hands
mp_draw  = mp.solutions.drawing_utils
hands = mp_hands.Hands(
    static_image_mode=False,
    max_num_hands=2,
    min_detection_confidence=0.7,
    min_tracking_confidence=0.5
)

start_pt = None               # measurement start point
measuring = False             # measurement in progress

def detect_hands(frame):
    rgb = cv2.cvtColor(frame, cv2.COLOR_BGR2RGB)
    rgb.flags.writeable = False
    results = hands.process(rgb)

    return results


def check_hand(hand, frame_vis, object_calibrating):
    h, w, _ = frame_vis.shape

    fingertip_idx = None
    fingertip_mid = None
    
    mp_draw.draw_landmarks(frame_vis, hand, mp_hands.HAND_CONNECTIONS)
    # get index and middle finger tips and PIP joints
    idx_tip = hand.landmark[mp_hands.HandLandmark.INDEX_FINGER_TIP]
    mid_tip = hand.landmark[mp_hands.HandLandmark.MIDDLE_FINGER_TIP]
    ix, iy = int(idx_tip.x * w), int(idx_tip.y * h)
    mx, my = int(mid_tip.x * w), int(mid_tip.y * h)
    fingertip_idx = (ix, iy)
    fingertip_mid = (mx, my)

    # draw fingertips
    cv2.circle(frame_vis, fingertip_idx, 8, (255,255,0), -1)
    cv2.circle(frame_vis, fingertip_mid,  8, (0,255,0), -1)

    measuring, start_pt = is_measuring(frame_vis, hand, object_calibrating)

    return fingertip_idx, measuring, start_pt

def is_measuring(frame_vis, hand, object_calibrating):
    global measuring, start_pt
    h, w, _ = frame_vis.shape

    idx_tip = hand.landmark[mp_hands.HandLandmark.INDEX_FINGER_TIP]
    idx_pip = hand.landmark[mp_hands.HandLandmark.INDEX_FINGER_PIP]
    mid_tip = hand.landmark[mp_hands.HandLandmark.MIDDLE_FINGER_TIP]
    mid_pip = hand.landmark[mp_hands.HandLandmark.MIDDLE_FINGER_PIP]

    ix, iy = int(idx_tip.x * w), int(idx_tip.y * h)
    mx, my = int(mid_tip.x * w), int(mid_tip.y * h)
    fingertip_idx = (ix, iy)
    fingertip_mid = (mx, my)

    # check extension
    index_ext = idx_tip.y < idx_pip.y
    middle_ext = mid_tip.y < mid_pip.y

    # if measurement in progress but fingers no longer both extended, stop measuring
    if measuring and not (index_ext and middle_ext):
        measuring = False

    # pinch distance
    pinch = compute_distance(fingertip_idx, fingertip_mid)
    cv2.putText(frame_vis, f"Pinch: {int(pinch)} px", (10,30), cv2.FONT_HERSHEY_SIMPLEX, 0.6, (0,255,0),2)

    # measurement gesture
    if not object_calibrating and index_ext and middle_ext:
        if pinch < PINCH_THRESHOLD and not measuring:
            measuring = True
            start_pt = fingertip_idx
        elif pinch > RELEASE_THRESHOLD and measuring:
            measuring = False

    return measuring, start_pt