import re
import functools
from optparse import make_option

from django.conf import settings
from django.core.exceptions import ViewDoesNotExist
from django.core.urlresolvers import RegexURLPattern, RegexURLResolver
from django.core.management.base import BaseCommand, CommandError
from django.contrib.admindocs.views import simplify_regex
from django.utils.translation import activate

from django_extensions.management.color import color_style
from django_extensions.management.utils import signalcommand


FMTR = {
    'dense': "{url}\t{module}\t{url_name}\t{decorator}",
    'table': "{url},{module},{url_name},{decorator}",
    'aligned': "{url},{module},{url_name},{decorator}",
    'verbose': "{url}\n\tController: {module}\n\tURL Name: {url_name}\n\tDecorators: {decorator}\n",
}


def extract_views_from_urlpatterns(urlpatterns, base='', namespace=None):
    """
    Return a list of views from a list of urlpatterns.

    Each object in the returned list is a two-tuple: (view_func, regex)
    """
    views = []
    for p in urlpatterns:
        if isinstance(p, RegexURLPattern):
            try:
                if not p.name:
                    name = p.name
                elif namespace:
                    name = '{0}:{1}'.format(namespace, p.name)
                else:
                    name = p.name
                views.append((p.callback, base + p.regex.pattern, name))
            except ViewDoesNotExist:
                continue
        elif isinstance(p, RegexURLResolver):
            try:
                patterns = p.url_patterns
            except ImportError:
                continue
            views.extend(extract_views_from_urlpatterns(patterns, base + p.regex.pattern, namespace=(namespace or p.namespace)))
        elif hasattr(p, '_get_callback'):
            try:
                views.append((p._get_callback(), base + p.regex.pattern, p.name))
            except ViewDoesNotExist:
                continue
        elif hasattr(p, 'url_patterns') or hasattr(p, '_get_url_patterns'):
            try:
                patterns = p.url_patterns
            except ImportError:
                continue
            views.extend(extract_views_from_urlpatterns(patterns, base + p.regex.pattern, namespace=namespace))
        else:
            raise TypeError("%s does not appear to be a urlpattern object" % p)
    return views


class Command(BaseCommand):
    option_list = BaseCommand.option_list + (
        make_option("--unsorted", "-u", action="store_true", dest="unsorted",
                    help="Show urls unsorted but same order as found in url patterns"),
        make_option("--language", "-l", dest="language",
                    help="Set the language code (useful for i18n_patterns)"),
        make_option("--decorator", "-d", action="append", dest="decorator", default=[],
                    help="Show the presence of given decorator on views"),
        make_option("--format", "-f", dest="format_style", default="dense",
                    help="Style of the output. Choices: %s" % FMTR.keys())
    )

    help = "Displays all of the url matching routes for the project."

    @signalcommand
    def handle(self, *args, **options):
        if args:
            appname, = args

        style = color_style()

        if getattr(settings, 'ADMIN_FOR', None):
            settings_modules = [__import__(m, {}, {}, ['']) for m in settings.ADMIN_FOR]
        else:
            settings_modules = [settings]

        language = options.get('language', None)
        if language is not None:
            activate(language)

        decorator = options.get('decorator')
        if not decorator:
            decorator = ['login_required']

        format_style = options.get('format_style')
        if format_style not in FMTR:
            raise CommandError("Format style '%s' does not exist. Options: %s" % (format_style, FMTR.keys()))
        fmtr = FMTR[format_style]

        views = []
        for settings_mod in settings_modules:
            try:
                urlconf = __import__(settings_mod.ROOT_URLCONF, {}, {}, [''])
            except Exception as e:
                if options.get('traceback', None):
                    import traceback
                    traceback.print_exc()
                print(style.ERROR("Error occurred while trying to load %s: %s" % (settings_mod.ROOT_URLCONF, str(e))))
                continue

            view_functions = extract_views_from_urlpatterns(urlconf.urlpatterns)
            for (func, regex, url_name) in view_functions:

                if hasattr(func, '__globals__'):
                    func_globals = func.__globals__
                elif hasattr(func, 'func_globals'):
                    func_globals = func.func_globals
                else:
                    func_globals = {}

                decorators = [d for d in decorator if d in func_globals]

                if isinstance(func, functools.partial):
                    func = func.func
                    decorators.insert(0, 'functools.partial')

                if hasattr(func, '__name__'):
                    func_name = func.__name__
                elif hasattr(func, '__class__'):
                    func_name = '%s()' % func.__class__.__name__
                else:
                    func_name = re.sub(r' at 0x[0-9a-f]+', '', repr(func))

                views.append(fmtr.format(
                    module='{0}.{1}'.format(style.MODULE(func.__module__), style.MODULE_NAME(func_name)),
                    url_name=style.URL_NAME(url_name or ''),
                    url=style.URL(simplify_regex(regex)),
                    decorator=', '.join(decorators),
                ))

        if not options.get('unsorted', False):
            views = sorted(views)

        if format_style == 'aligned':
            views = [row.split(',', 3) for row in views]
            widths = [len(max(columns, key=len)) for columns in zip(*views)]
            views = [
                '   '.join('{0:<{1}}'.format(cdata, width) for width, cdata in zip(widths, row))
                for row in views
            ]
        elif format_style == 'table':
            # Reformat all data and show in a table format

            views = [row.split(',', 3) for row in views]
            widths = [len(max(columns, key=len)) for columns in zip(*views)]
            table_views = []

            header = (style.MODULE_NAME('URL'), style.MODULE_NAME('Module'), style.MODULE_NAME('Name'), style.MODULE_NAME('Decorator'))
            table_views.append(
                ' | '.join('{0:<{1}}'.format(title, width) for width, title in zip(widths, header))
            )
            table_views.append('-+-'.join('-' * width for width in widths))

            for row in views:
                table_views.append(
                    ' | '.join('{0:<{1}}'.format(cdata, width) for width, cdata in zip(widths, row))
                )

            # Replace original views so we can return the same object
            views = table_views

        return "\n".join([v for v in views]) + "\n"
