import numpy as np
from shapely.geometry import *

def py_cpu_nms(dets, thresh):
    """Pure Python NMS baseline."""
    x1 = dets[:, 0]
    y1 = dets[:, 1]
    x2 = dets[:, 2]
    y2 = dets[:, 3]
    scores = dets[:, 4]

    areas = (x2 - x1 + 1) * (y2 - y1 + 1)
    order = scores.argsort()[::-1]

    keep = []
    while order.size > 0:
        i = order[0]
        keep.append(i)
        xx1 = np.maximum(x1[i], x1[order[1:]])
        yy1 = np.maximum(y1[i], y1[order[1:]])
        xx2 = np.minimum(x2[i], x2[order[1:]])
        yy2 = np.minimum(y2[i], y2[order[1:]])

        w = np.maximum(0.0, xx2 - xx1 + 1)
        h = np.maximum(0.0, yy2 - yy1 + 1)
        inter = w * h
        ovr = inter / (areas[i] + areas[order[1:]] - inter)

        inds = np.where(ovr <= thresh)[0]
        order = order[inds + 1]

    return keep

# @yl
def py_cpu_pnms(dets, thresh):
    bbox = dets[:, :4]
    scores = dets[:, 4]
    info_bbox = dets[:, 5:33] # syn
    
    pts = []
    for i in xrange(dets.shape[0]):
        pts.append([[int(bbox[i, 0]) + info_bbox[i, j], int(bbox[i, 1]) + info_bbox[i, j+1]] for j in xrange(0,28,2)])

    order = scores.argsort()[::-1]
    areas = np.zeros(scores.shape)
    order = scores.argsort()[::-1]
    inter_areas = np.zeros((scores.shape[0], scores.shape[0]))
    for il in xrange(len(pts)):
        poly = Polygon(pts[il])
        areas[il] = poly.area
        for jl in xrange(il, len(pts)):
            polyj = Polygon(pts[jl])
            inS = poly.intersection(polyj)
            inter_areas[il][jl] = inS.area
            inter_areas[jl][il] = inS.area

    keep = []
    while order.size > 0:
        i = order[0]
        keep.append(i)

        ovr = inter_areas[i][order[1:]] / (areas[i] + areas[order[1:]] - inter_areas[i][order[1:]])

        inds = np.where(ovr <= thresh)[0]
        order = order[inds + 1]

    return keep