import os

from django.conf import settings
from django.core.exceptions import PermissionDenied
from django.http import Http404, HttpResponse, HttpResponseNotModified
from django.shortcuts import get_object_or_404
from shapely.geometry import box

from c3nav.mapdata.cache import MapHistory
from c3nav.mapdata.models import Level, MapUpdate, Source
from c3nav.mapdata.render.svg import SVGRenderer


def tile(request, level, zoom, x, y, format):
    import cProfile
    import pstats
    pr = cProfile.Profile()
    pr.enable()

    zoom = int(zoom)
    if not (0 <= zoom <= 10):
        raise Http404

    bounds = Source.max_bounds()

    x, y = int(x), int(y)
    size = 256/2**zoom
    minx = size * x
    miny = size * (-y-1)
    maxx = minx + size
    maxy = miny + size

    if not box(bounds[0][1], bounds[0][0], bounds[1][1], bounds[1][0]).intersects(box(minx, miny, maxx, maxy)):
        raise Http404

    renderer = SVGRenderer(level, miny, minx, maxy, maxx, scale=2**zoom, user=request.user)

    update_cache_key = MapUpdate.current_cache_key()
    access_cache_key = renderer.access_cache_key
    etag = update_cache_key+'_'+access_cache_key

    if_none_match = request.META.get('HTTP_IF_NONE_MATCH')
    if if_none_match == etag:
        return HttpResponseNotModified()

    f = None
    if settings.CACHE_TILES:
        dirname = os.path.sep.join((settings.TILES_ROOT, update_cache_key, level, str(zoom), str(x), str(y)))
        filename = os.path.sep.join((dirname, access_cache_key+'.'+format))

        try:
            f = open(filename, 'rb')
        except FileNotFoundError:
            pass

    content_type = 'image/svg+xml' if format == 'svg' else 'image/png'

    if not settings.CACHE_TILES or f is None:
        try:
            renderer.check_level()
        except Level.DoesNotExist:
            raise Http404

        svg = renderer.render()
        if format == 'svg':
            data = svg.get_xml()
            filemode = 'w'
        elif format == 'png':
            data = svg.get_png()
            filemode = 'wb'
        else:
            raise ValueError

        if settings.CACHE_TILES:
            # noinspection PyUnboundLocalVariable
            os.makedirs(dirname, exist_ok=True)
            # noinspection PyUnboundLocalVariable
            with open(filename, filemode) as f:
                f.write(data)
    else:
        data = f.read()

    pr.disable()
    s = open('/tmp/profiled', 'w')
    sortby = 'cumulative'
    ps = pstats.Stats(pr, stream=s).sort_stats(sortby)
    ps.print_stats()

    response = HttpResponse(data, content_type)
    response['ETag'] = etag
    response['Cache-Control'] = 'no-cache'

    return response


def history(request, level, mode, format):
    if not request.user.is_superuser:
        raise PermissionDenied
    level = get_object_or_404(Level, pk=level)

    if mode == 'render' and level.on_top_of_id is None:
        raise Http404

    history = MapHistory.open(os.path.join(settings.CACHE_ROOT, 'level_%s_%d' % (mode, level.pk)))
    if format == 'png':
        response = HttpResponse(content_type='image/png')
        history.to_image().save(response, format='PNG')
    elif format == 'data':
        response = HttpResponse(content_type='application/octet-stream')
        history.write(response)
    else:
        raise ValueError
    return response