import os.path
import django
import SocketServer

from django.conf import settings
from django.views.debug import linebreak_iter

# Figure out some paths
django_path = os.path.realpath(os.path.dirname(django.__file__))
socketserver_path = os.path.realpath(os.path.dirname(SocketServer.__file__))

def ms_from_timedelta(td):
    """
    Given a timedelta object, returns a float representing milliseconds
    """
    return (td.seconds * 1000) + (td.microseconds / 1000.0)

def tidy_stacktrace(stack):
    """
    Clean up stacktrace and remove all entries that:
    1. Are part of Django (except contrib apps)
    2. Are part of SocketServer (used by Django's dev server)
    3. Are the last entry (which is part of our stacktracing code)
    
    ``stack`` should be a list of frame tuples from ``inspect.stack()``
    """
    trace = []
    for frame, path, line_no, func_name, text in (f[:5] for f in stack):
        s_path = os.path.realpath(path)
        # Support hiding of frames -- used in various utilities that provide
        # inspection.
        if '__traceback_hide__' in frame.f_locals:
            continue
        if getattr(settings, 'DEBUG_TOOLBAR_CONFIG', {}).get('HIDE_DJANGO_SQL', True) \
            and django_path in s_path and not 'django/contrib' in s_path:
            continue
        if socketserver_path in s_path:
            continue
        trace.append((path, line_no, func_name, (''.join(text)).strip()))
    return trace

def get_template_info(source, context_lines=3):
    line = 0
    upto = 0
    source_lines = []
    before = during = after = ""

    origin, (start, end) = source
    template_source = origin.reload()

    for num, next in enumerate(linebreak_iter(template_source)):
        if start >= upto and end <= next:
            line = num
            before = template_source[upto:start]
            during = template_source[start:end]
            after = template_source[end:next]
        source_lines.append((num, template_source[upto:next]))
        upto = next

    top = max(1, line - context_lines)
    bottom = min(len(source_lines), line + 1 + context_lines)

    context = []
    for num, content in source_lines[top:bottom]:
        context.append({
            'num': num,
            'content': content,
            'highlight': (num == line),
        })

    return {
        'name': origin.name,
        'context': context,
    }