from functools import lru_cache
from mimetypes import common_types, types_map

import pygments
from django.http import HttpResponse, HttpResponseRedirect
from django.shortcuts import get_object_or_404, render
from django.template import RequestContext, loader
from django.urls import reverse
from django.views.decorators.csrf import csrf_exempt
from pygments.formatters import HtmlFormatter
from pygments.lexers import get_lexer_by_name, get_lexer_for_filename
from tabulate import tabulate

from paste.models import Paste
from webtools import settings

NON_STANDARD_TYPES_INV = {value: key for key, value in common_types.items()}
STANDARD_TYPES_INV = {value: key for key, value in types_map.items()}
HARDCODED_TYPES_INV = {"text/plain": ".txt"}
TYPES_INV = NON_STANDARD_TYPES_INV | STANDARD_TYPES_INV | HARDCODED_TYPES_INV


def get_files(request):
    """Get one or multiple files from either a multipart/form-data or
    raw request body with a Content-Type header."""
    if request.FILES:
        return request.FILES
    content_type = request.headers.get("content-type", "")
    ext = TYPES_INV.get(content_type, "")
    return {"request" + ext: request}


@csrf_exempt
def index(request):
    """Displays form."""
    if request.method == "GET":
        return render(request, "paste/index.html")
    if request.headers.get("Expect") == "100-continue":
        return HttpResponse("")
    pastes = []
    for filename, the_file in get_files(request).items():
        paste = Paste(
            filename=filename.split("/")[-1].split("\\")[-1],
            content=the_file.read().decode("UTF-8"),
        )
        paste.choose_slug()
        paste.compute_size()
        paste.save()
        pastes.append(
            (
                request.build_absolute_uri(
                    reverse("short_paste", kwargs={"slug": paste.slug})
                ),
                paste.size,
                paste.filename,
            )
        )

    if not pastes:
        return HttpResponse("error: Please provide a file.")

    return HttpResponse(
        tabulate(pastes, headers=("URL", "size", "filename"), tablefmt="github") + "\n",
        content_type="text/plain",
    )


def show(request, slug):
    """Display paste."""

    paste = get_object_or_404(Paste, slug=slug)
    paste.incr_viewcount()

    if "html" in request.headers["accept"]:
        return HttpResponse(pygmentize(paste.filename, paste.content))
    else:
        return HttpResponse(paste.content, content_type="text/plain")


@lru_cache(1024)
def pygmentize(filename, filecontents):
    try:
        lexer = get_lexer_for_filename(filename)
    except pygments.util.ClassNotFound:
        lexer = get_lexer_by_name(settings.PASTE["default_language"])
    formatter = HtmlFormatter(style="emacs")
    data = {}
    data["filename"] = filename
    data["highlighted"] = pygments.highlight(filecontents, lexer, formatter)
    return loader.render_to_string("paste/show-pygments.html", data)