from __future__ import print_function
from __future__ import absolute_import
__author__ = 'tsungyi'

import copy
import datetime
import time
from collections import defaultdict

import numpy as np

from . import mask

try:
    string_types = (str, unicode)  # Python 2
except NameError:
    string_types = (str, )         # Python 3


class COCOeval:
    # Interface for evaluating detection on the Microsoft COCO dataset.
    #
    # The usage for CocoEval is as follows:
    #  cocoGt=..., cocoDt=...       # load dataset and results
    #  E = CocoEval(cocoGt,cocoDt); # initialize CocoEval object
    #  E.params.recThrs = ...;      # set parameters as desired
    #  E.evaluate();                # run per image evaluation
    #  E.accumulate();              # accumulate per image results
    #  E.summarize();               # display summary metrics of results
    # For example usage see evalDemo.m and http://mscoco.org/.
    #
    # The evaluation parameters are as follows (defaults in brackets):
    #  imgIds     - [all] N img ids to use for evaluation
    #  catIds     - [all] K cat ids to use for evaluation
    #  iouThrs    - [.5:.05:.95] T=10 IoU thresholds for evaluation
    #  recThrs    - [0:.01:1] R=101 recall thresholds for evaluation
    #  areaRng    - [...] A=4 object area ranges for evaluation
    #  maxDets    - [1 10 100] M=3 thresholds on max detections per image
    #  useSegm    - [1] if true evaluate against ground-truth segments
    #  useCats    - [1] if true use category labels for evaluation    # Note: if useSegm=0 the evaluation is run on bounding boxes.
    # Note: if useCats=0 category labels are ignored as in proposal scoring.
    # Note: multiple areaRngs [Ax2] and maxDets [Mx1] can be specified.
    #
    # evaluate(): evaluates detections on every image and every category and
    # concats the results into the "evalImgs" with fields:
    #  dtIds      - [1xD] id for each of the D detections (dt)
    #  gtIds      - [1xG] id for each of the G ground truths (gt)
    #  dtMatches  - [TxD] matching gt id at each IoU or 0
    #  gtMatches  - [TxG] matching dt id at each IoU or 0
    #  dtScores   - [1xD] confidence of each dt
    #  gtIgnore   - [1xG] ignore flag for each gt
    #  dtIgnore   - [TxD] ignore flag for each dt at each IoU
    #
    # accumulate(): accumulates the per-image, per-category evaluation
    # results in "evalImgs" into the dictionary "eval" with fields:
    #  params     - parameters used for evaluation
    #  date       - date evaluation was performed
    #  counts     - [T,R,K,A,M] parameter dimensions (see above)
    #  precision  - [TxRxKxAxM] precision for every evaluation setting
    #  recall     - [TxKxAxM] max recall for every evaluation setting
    # Note: precision and recall==-1 for settings with no gt objects.
    #
    # See also coco, mask, pycocoDemo, pycocoEvalDemo
    #
    # Microsoft COCO Toolbox.      version 2.0
    # Data, paper, and tutorials available at:  http://mscoco.org/
    # Code written by Piotr Dollar and Tsung-Yi Lin, 2015.
    # Licensed under the Simplified BSD License [see coco/license.txt]
    def __init__(self, cocoGt=None, cocoDt=None):
        '''
        Initialize CocoEval using coco APIs for gt and dt
        :param cocoGt: coco object with ground truth annotations
        :param cocoDt: coco object with detection results
        :return: None
        '''
        self.cocoGt   = cocoGt              # ground truth COCO API
        self.cocoDt   = cocoDt              # detections COCO API
        self.params   = {}                  # evaluation parameters
        self.evalImgs = defaultdict(list)   # per-image per-category evaluation results [KxAxI] elements
        self.eval     = {}                  # accumulated evaluation results
        self._gts = defaultdict(list)       # gt for evaluation
        self._dts = defaultdict(list)       # dt for evaluation
        self.params = Params()              # parameters
        self._paramsEval = {}               # parameters for evaluation
        self.stats = []                     # result summarization
        self.ious = {}                      # ious between all gts and dts
        if not cocoGt is None:
            self.params.imgIds = sorted(cocoGt.getImgIds())
            self.params.catIds = sorted(cocoGt.getCatIds())


    def _prepare(self):
        '''
        Prepare ._gts and ._dts for evaluation based on params
        :return: None
        '''
        #
        def _toMask(objs, coco):
            # modify segmentation by reference
            for obj in objs:
                t = coco.imgs[obj['image_id']]
                if type(obj['segmentation']) == list:
                    if type(obj['segmentation'][0]) == dict:
                        print('debug')
                    obj['segmentation'] = mask.frPyObjects(obj['segmentation'],t['height'],t['width'])
                    if len(obj['segmentation']) == 1:
                        obj['segmentation'] = obj['segmentation'][0]
                    else:
                        # an object can have multiple polygon regions
                        # merge them into one RLE mask
                        obj['segmentation'] = mask.merge(obj['segmentation'])
                elif type(obj['segmentation']) == dict and type(obj['segmentation']['counts']) == list:
                    obj['segmentation'] = mask.frPyObjects([obj['segmentation']],t['height'],t['width'])[0]
                elif type(obj['segmentation']) == dict and \
                     type(obj['segmentation']['counts']) in string_types:
                    pass
                else:
                    raise Exception('segmentation format not supported.')
        p = self.params
        if p.useCats:
            gts=self.cocoGt.loadAnns(self.cocoGt.getAnnIds(imgIds=p.imgIds, catIds=p.catIds))
            dts=self.cocoDt.loadAnns(self.cocoDt.getAnnIds(imgIds=p.imgIds, catIds=p.catIds))
        else:
            gts=self.cocoGt.loadAnns(self.cocoGt.getAnnIds(imgIds=p.imgIds))
            dts=self.cocoDt.loadAnns(self.cocoDt.getAnnIds(imgIds=p.imgIds))

        if p.useSegm:
            _toMask(gts, self.cocoGt)
            _toMask(dts, self.cocoDt)
        self._gts = defaultdict(list)       # gt for evaluation
        self._dts = defaultdict(list)       # dt for evaluation
        for gt in gts:
            self._gts[gt['image_id'], gt['category_id']].append(gt)
        for dt in dts:
            self._dts[dt['image_id'], dt['category_id']].append(dt)
        self.evalImgs = defaultdict(list)   # per-image per-category evaluation results
        self.eval     = {}                  # accumulated evaluation results

    def evaluate(self):
        '''
        Run per image evaluation on given images and store results (a list of dict) in self.evalImgs
        :return: None
        '''
        tic = time.time()
        print('Running per image evaluation...      ')
        p = self.params
        p.imgIds = list(np.unique(p.imgIds))
        if p.useCats:
            p.catIds = list(np.unique(p.catIds))
        p.maxDets = sorted(p.maxDets)
        self.params=p

        self._prepare()
        # loop through images, area range, max detection number
        catIds = p.catIds if p.useCats else [-1]

        computeIoU = self.computeIoU
        self.ious = {(imgId, catId): computeIoU(imgId, catId) \
                        for imgId in p.imgIds
                        for catId in catIds}

        evaluateImg = self.evaluateImg
        maxDet = p.maxDets[-1]
        self.evalImgs = [evaluateImg(imgId, catId, areaRng, maxDet)
                 for catId in catIds
                 for areaRng in p.areaRng
                 for imgId in p.imgIds
             ]
        self._paramsEval = copy.deepcopy(self.params)
        toc = time.time()
        print('DONE (t=%0.2fs).'%(toc-tic))

    def computeIoU(self, imgId, catId):
        p = self.params
        if p.useCats:
            gt = self._gts[imgId,catId]
            dt = self._dts[imgId,catId]
        else:
            gt = [_ for cId in p.catIds for _ in self._gts[imgId,cId]]
            dt = [_ for cId in p.catIds for _ in self._dts[imgId,cId]]
        if len(gt) == 0 and len(dt) ==0:
            return []
        dt = sorted(dt, key=lambda x: -x['score'])
        if len(dt) > p.maxDets[-1]:
            dt=dt[0:p.maxDets[-1]]

        if p.useSegm:
            g = [g['segmentation'] for g in gt]
            d = [d['segmentation'] for d in dt]
        else:
            g = [g['bbox'] for g in gt]
            d = [d['bbox'] for d in dt]

        # compute iou between each dt and gt region
        iscrowd = [int(o['iscrowd']) for o in gt]
        ious = mask.iou(d,g,iscrowd)
        return ious

    def evaluateImg(self, imgId, catId, aRng, maxDet):
        '''
        perform evaluation for single category and image
        :return: dict (single image results)
        '''
        #
        p = self.params
        if p.useCats:
            gt = self._gts[imgId,catId]
            dt = self._dts[imgId,catId]
        else:
            gt = [_ for cId in p.catIds for _ in self._gts[imgId,cId]]
            dt = [_ for cId in p.catIds for _ in self._dts[imgId,cId]]
        if len(gt) == 0 and len(dt) ==0:
            return None

        for g in gt:
            if 'ignore' not in g:
                g['ignore'] = 0
            if g['iscrowd'] == 1 or g['ignore'] or (g['area']<aRng[0] or g['area']>aRng[1]):
                g['_ignore'] = 1
            else:
                g['_ignore'] = 0

        # sort dt highest score first, sort gt ignore last
        # gt = sorted(gt, key=lambda x: x['_ignore'])
        gtind = [ind for (ind, g) in sorted(enumerate(gt), key=lambda ind_g: ind_g[1]['_ignore']) ]

        gt = [gt[ind] for ind in gtind]
        dt = sorted(dt, key=lambda x: -x['score'])[0:maxDet]
        iscrowd = [int(o['iscrowd']) for o in gt]
        # load computed ious
        N_iou = len(self.ious[imgId, catId])
        ious = self.ious[imgId, catId][0:maxDet, np.array(gtind)] if N_iou >0 else self.ious[imgId, catId]

        T = len(p.iouThrs)
        G = len(gt)
        D = len(dt)
        gtm  = np.zeros((T,G))
        dtm  = np.zeros((T,D))
        gtIg = np.array([g['_ignore'] for g in gt])
        dtIg = np.zeros((T,D))
        if not len(ious)==0:
            for tind, t in enumerate(p.iouThrs):
                for dind, d in enumerate(dt):
                    # information about best match so far (m=-1 -> unmatched)
                    iou = min([t,1-1e-10])
                    m   = -1
                    for gind, g in enumerate(gt):
                        # if this gt already matched, and not a crowd, continue
                        if gtm[tind,gind]>0 and not iscrowd[gind]:
                            continue
                        # if dt matched to reg gt, and on ignore gt, stop
                        if m>-1 and gtIg[m]==0 and gtIg[gind]==1:
                            break
                        # continue to next gt unless better match made
                        if ious[dind,gind] < iou:
                            continue
                        # match successful and best so far, store appropriately
                        iou=ious[dind,gind]
                        m=gind
                    # if match made store id of match for both dt and gt
                    if m ==-1:
                        continue
                    dtIg[tind,dind] = gtIg[m]
                    dtm[tind,dind]  = gt[m]['id']
                    gtm[tind,m]     = d['id']
        # set unmatched detections outside of area range to ignore
        a = np.array([d['area']<aRng[0] or d['area']>aRng[1] for d in dt]).reshape((1, len(dt)))
        dtIg = np.logical_or(dtIg, np.logical_and(dtm==0, np.repeat(a,T,0)))
        # store results for given image and category
        return {
                'image_id':     imgId,
                'category_id':  catId,
                'aRng':         aRng,
                'maxDet':       maxDet,
                'dtIds':        [d['id'] for d in dt],
                'gtIds':        [g['id'] for g in gt],
                'dtMatches':    dtm,
                'gtMatches':    gtm,
                'dtScores':     [d['score'] for d in dt],
                'gtIgnore':     gtIg,
                'dtIgnore':     dtIg,
            }

    def accumulate(self, p = None):
        '''
        Accumulate per image evaluation results and store the result in self.eval
        :param p: input params for evaluation
        :return: None
        '''
        print('Accumulating evaluation results...   ')
        tic = time.time()
        if not self.evalImgs:
            print('Please run evaluate() first')
        # allows input customized parameters
        if p is None:
            p = self.params
        p.catIds = p.catIds if p.useCats == 1 else [-1]
        T           = len(p.iouThrs)
        R           = len(p.recThrs)
        K           = len(p.catIds) if p.useCats else 1
        A           = len(p.areaRng)
        M           = len(p.maxDets)
        precision   = -np.ones((T,R,K,A,M)) # -1 for the precision of absent categories
        recall      = -np.ones((T,K,A,M))

        # create dictionary for future indexing
        _pe = self._paramsEval
        catIds = _pe.catIds if _pe.useCats else [-1]
        setK = set(catIds)
        setA = set(map(tuple, _pe.areaRng))
        setM = set(_pe.maxDets)
        setI = set(_pe.imgIds)
        # get inds to evaluate
        k_list = [n for n, k in enumerate(p.catIds)  if k in setK]
        m_list = [m for n, m in enumerate(p.maxDets) if m in setM]
        a_list = [n for n, a in enumerate(map(lambda x: tuple(x), p.areaRng)) if a in setA]
        i_list = [n for n, i in enumerate(p.imgIds)  if i in setI]
        # K0 = len(_pe.catIds)
        I0 = len(_pe.imgIds)
        A0 = len(_pe.areaRng)
        # retrieve E at each category, area range, and max number of detections
        for k, k0 in enumerate(k_list):
            Nk = k0*A0*I0
            for a, a0 in enumerate(a_list):
                Na = a0*I0
                for m, maxDet in enumerate(m_list):
                    E = [self.evalImgs[Nk+Na+i] for i in i_list]
                    E = filter(None, E)
                    if len(E) == 0:
                        continue
                    dtScores = np.concatenate([e['dtScores'][0:maxDet] for e in E])

                    # different sorting method generates slightly different results.
                    # mergesort is used to be consistent as Matlab implementation.
                    inds = np.argsort(-dtScores, kind='mergesort')

                    dtm  = np.concatenate([e['dtMatches'][:,0:maxDet] for e in E], axis=1)[:,inds]
                    dtIg = np.concatenate([e['dtIgnore'][:,0:maxDet]  for e in E], axis=1)[:,inds]
                    gtIg = np.concatenate([e['gtIgnore']  for e in E])
                    npig = len([ig for ig in gtIg if ig == 0])
                    if npig == 0:
                        continue
                    tps = np.logical_and(               dtm,  np.logical_not(dtIg) )
                    fps = np.logical_and(np.logical_not(dtm), np.logical_not(dtIg) )

                    tp_sum = np.cumsum(tps, axis=1).astype(dtype=np.float)
                    fp_sum = np.cumsum(fps, axis=1).astype(dtype=np.float)
                    for t, (tp, fp) in enumerate(zip(tp_sum, fp_sum)):
                        tp = np.array(tp)
                        fp = np.array(fp)
                        nd = len(tp)
                        rc = tp / npig
                        pr = tp / (fp+tp+np.spacing(1))
                        q  = np.zeros((R,))

                        if nd:
                            recall[t,k,a,m] = rc[-1]
                        else:
                            recall[t,k,a,m] = 0

                        # numpy is slow without cython optimization for accessing elements
                        # use python array gets significant speed improvement
                        pr = pr.tolist(); q = q.tolist()

                        for i in range(nd-1, 0, -1):
                            if pr[i] > pr[i-1]:
                                pr[i-1] = pr[i]

                        inds = np.searchsorted(rc, p.recThrs)
                        try:
                            for ri, pi in enumerate(inds):
                                q[ri] = pr[pi]
                        except:
                            pass
                        precision[t,:,k,a,m] = np.array(q)
        self.eval = {
            'params': p,
            'counts': [T, R, K, A, M],
            'date': datetime.datetime.now().strftime("%Y-%m-%d %H:%M:%S"),
            'precision': precision,
            'recall':   recall,
        }
        toc = time.time()
        print('DONE (t=%0.2fs).'%( toc-tic ))

    def summarize(self):
        '''
        Compute and display summary metrics for evaluation results.
        Note this functin can *only* be applied on the default parameter setting
        '''
        def _summarize( ap=1, iouThr=None, areaRng='all', maxDets=100 ):
            p = self.params
            iStr        = ' {:<18} {} @[ IoU={:<9} | area={:>6} | maxDets={:>3} ] = {}'
            titleStr    = 'Average Precision' if ap == 1 else 'Average Recall'
            typeStr     = '(AP)' if ap==1 else '(AR)'
            iouStr      = '%0.2f:%0.2f'%(p.iouThrs[0], p.iouThrs[-1]) if iouThr is None else '%0.2f'%(iouThr)
            areaStr     = areaRng
            maxDetsStr  = '%d'%(maxDets)

            aind = [i for i, aRng in enumerate(['all', 'small', 'medium', 'large']) if aRng == areaRng]
            mind = [i for i, mDet in enumerate([1, 10, 100]) if mDet == maxDets]
            if ap == 1:
                # dimension of precision: [TxRxKxAxM]
                s = self.eval['precision']
                # IoU
                if iouThr is not None:
                    t = np.where(iouThr == p.iouThrs)[0]
                    s = s[t]
                # areaRng
                s = s[:,:,:,aind,mind]
            else:
                # dimension of recall: [TxKxAxM]
                s = self.eval['recall']
                s = s[:,:,aind,mind]
            if len(s[s>-1])==0:
                mean_s = -1
            else:
                mean_s = np.mean(s[s>-1])
            print(iStr.format(titleStr, typeStr, iouStr, areaStr, maxDetsStr, '%.3f'%(float(mean_s))))
            return mean_s

        if not self.eval:
            raise Exception('Please run accumulate() first')
        self.stats = np.zeros((12,))
        self.stats[0] = _summarize(1)
        self.stats[1] = _summarize(1,iouThr=.5)
        self.stats[2] = _summarize(1,iouThr=.75)
        self.stats[3] = _summarize(1,areaRng='small')
        self.stats[4] = _summarize(1,areaRng='medium')
        self.stats[5] = _summarize(1,areaRng='large')
        self.stats[6] = _summarize(0,maxDets=1)
        self.stats[7] = _summarize(0,maxDets=10)
        self.stats[8] = _summarize(0,maxDets=100)
        self.stats[9]  = _summarize(0,areaRng='small')
        self.stats[10] = _summarize(0,areaRng='medium')
        self.stats[11] = _summarize(0,areaRng='large')

    def __str__(self):
        self.summarize()

class Params:
    '''
    Params for coco evaluation api
    '''
    def __init__(self):
        self.imgIds = []
        self.catIds = []
        # np.arange causes trouble.  the data point on arange is slightly larger than the true value
        self.iouThrs = np.linspace(.5, 0.95, np.round((0.95-.5)/.05)+1, endpoint=True)
        self.recThrs = np.linspace(.0, 1.00, np.round((1.00-.0)/.01)+1, endpoint=True)
        self.maxDets = [1,10,100]
        self.areaRng = [ [0**2,1e5**2], [0**2, 32**2], [32**2, 96**2], [96**2, 1e5**2] ]
        self.useSegm = 0
        self.useCats = 1
