"""A demo which runs object detection on camera frames."""

# export TEST_DATA=/usr/lib/python3/dist-packages/edgetpu/test_data
#
# Run face detection model:
# python3 -m edgetpuvision.detect \
#   --model ${TEST_DATA}/mobilenet_ssd_v2_face_quant_postprocess_edgetpu.tflite
#
# Run coco model:
# python3 -m edgetpuvision.detect \
#   --model ${TEST_DATA}/mobilenet_ssd_v2_coco_quant_postprocess_edgetpu.tflite \
#   --labels ${TEST_DATA}/coco_labels.txt

import argparse
import collections
import colorsys
import itertools
import time

from edgetpu.detection.engine import DetectionEngine

from . import svg
from . import utils
from .apps import run_app

CSS_STYLES = str(svg.CssStyle({'.back': svg.Style(fill='black',
                                                  stroke='black',
                                                  stroke_width='1em'),
                               '.bbox': svg.Style(fill_opacity=0.0,
                                                  stroke_width='2px')}))

BBox = collections.namedtuple('BBox', ('x', 'y', 'w', 'h'))
BBox.area = lambda self: self.w * self.h
BBox.scale = lambda self, sx, sy: BBox(x=self.x * sx, y=self.y * sy,
                                       w=self.w * sx, h=self.h * sy)
BBox.__str__ = lambda self: 'BBox(x=%.2f y=%.2f w=%.2f h=%.2f)' % self

Object = collections.namedtuple('Object', ('id', 'label', 'score', 'bbox'))
Object.__str__ = lambda self: 'Object(id=%d, label=%s, score=%.2f, %s)' % self

def size_em(length):
    return '%sem' % str(0.6 * length)

def color(i, total):
    return tuple(int(255.0 * c) for c in colorsys.hsv_to_rgb(i / total, 1.0, 1.0))

def make_palette(keys):
    return {key : svg.rgb(color(i, len(keys))) for i, key in enumerate(keys)}

def make_get_color(color, labels):
    if color:
        return lambda obj_id: color

    if labels:
        palette = make_palette(labels.keys())
        return lambda obj_id: palette[obj_id]

    return lambda obj_id: 'white'

def overlay(title, objs, get_color, inference_time, inference_rate, layout):
    x0, y0, width, height = layout.window

    defs = svg.Defs()
    defs += CSS_STYLES

    doc = svg.Svg(width=width, height=height,
                  viewBox='%s %s %s %s' % layout.window,
                  font_size='1em', font_family='monospace', font_weight=500)
    doc += defs

    for obj in objs:
        percent = int(100 * obj.score)
        if obj.label:
            caption = '%d%% %s' % (percent, obj.label)
        else:
            caption = '%d%%' % percent

        x, y, w, h = obj.bbox.scale(*layout.size)
        color = get_color(obj.id)

        doc += svg.Rect(x=x, y=y, width=w, height=h,
                        style='stroke:%s' % color, _class='bbox')
        doc += svg.Rect(x=x, y=y+h ,
                        width=size_em(len(caption)), height='1.2em', fill=color)
        t = svg.Text(x=x, y=y+h, fill='black')
        t += svg.TSpan(caption, dy='1em')
        doc += t


    ox, oy1, oy2 = x0 + 20, y0 + 20, y0 + height - 20

    # Title
    if title:
        doc += svg.Rect(x=ox, y=oy1,
                        width=size_em(len(title)), height='1em',
                        _class='back')
        t = svg.Text(x=ox, y=oy1, fill='white')
        t += svg.TSpan(title, dy='1em')
        doc +=t

    # Info
    lines = [
        'Objects: %d' % len(objs),
        'Inference time: %.2f ms (%.2f fps)' % (inference_time * 1000, 1.0 / inference_time)
    ]
    text_width = size_em(max(len(line) for line in lines))
    doc += svg.Rect(x=0, y=0, width=text_width, height='2.2em',
                    transform='translate(%s, %s) scale(1,-1)' % (ox, oy2), _class='back')
    t = svg.Text(y=oy2, fill='white')
    t += svg.TSpan(lines[0], x=ox)
    t += svg.TSpan(lines[1], x=ox, dy='-1.2em')
    doc += t

    return str(doc)


def convert(obj, labels):
    x0, y0, x1, y1 = obj.bounding_box.flatten().tolist()
    return Object(id=obj.label_id,
                  label=labels[obj.label_id] if labels else None,
                  score=obj.score,
                  bbox=BBox(x=x0, y=y0, w=x1 - x0, h=y1 - y0))

def print_results(inference_rate, objs):
    print('\nInference (rate=%.2f fps):' % inference_rate)
    for i, obj in enumerate(objs):
        print('    %d: %s, area=%.2f' % (i, obj, obj.bbox.area()))

def render_gen(args):
    fps_counter  = utils.avg_fps_counter(30)

    engines, titles = utils.make_engines(args.model, DetectionEngine)
    assert utils.same_input_image_sizes(engines)
    engines = itertools.cycle(engines)
    engine = next(engines)

    labels = utils.load_labels(args.labels) if args.labels else None
    filtered_labels = set(l.strip() for l in args.filter.split(',')) if args.filter else None
    get_color = make_get_color(args.color, labels)

    draw_overlay = True

    yield utils.input_image_size(engine)

    output = None
    while True:
        tensor, layout, command = (yield output)

        inference_rate = next(fps_counter)
        if draw_overlay:
            start = time.monotonic()
            objs = engine .DetectWithInputTensor(tensor, threshold=args.threshold, top_k=args.top_k)
            inference_time = time.monotonic() - start
            objs = [convert(obj, labels) for obj in objs]

            if labels and filtered_labels:
                objs = [obj for obj in objs if obj.label in filtered_labels]

            objs = [obj for obj in objs if args.min_area <= obj.bbox.area() <= args.max_area]

            if args.print:
                print_results(inference_rate, objs)

            title = titles[engine]
            output = overlay(title, objs, get_color, inference_time, inference_rate, layout)
        else:
            output = None

        if command == 'o':
            draw_overlay = not draw_overlay
        elif command == 'n':
            engine = next(engines)

def add_render_gen_args(parser):
    parser.add_argument('--model',
                        help='.tflite model path', required=True)
    parser.add_argument('--labels',
                        help='labels file path')
    parser.add_argument('--top_k', type=int, default=50,
                        help='Max number of objects to detect')
    parser.add_argument('--threshold', type=float, default=0.1,
                        help='Detection threshold')
    parser.add_argument('--min_area', type=float, default=0.0,
                        help='Min bounding box area')
    parser.add_argument('--max_area', type=float, default=1.0,
                        help='Max bounding box area')
    parser.add_argument('--filter', default=None,
                        help='Comma-separated list of allowed labels')
    parser.add_argument('--color', default=None,
                        help='Bounding box display color'),
    parser.add_argument('--print', default=False, action='store_true',
                        help='Print inference results')

def main():
    run_app(add_render_gen_args, render_gen)

if __name__ == '__main__':
    main()