from datetime import datetime
from functools import lru_cache
from mimetypes import common_types, types_map

from django.http import Http404, HttpResponse, HttpResponseRedirect
from django.shortcuts import get_object_or_404, render
from django.template import RequestContext, loader
from django.views.decorators.csrf import csrf_exempt
from tabulate import tabulate

from paste.models import Paste
from paste.utils import markdown_to_html, pygmentize
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, "")
    if ext:
        return {"request" + ext: request}
    return {"": request}


def pastes_as_table(request, pastes, headers=("URL", "size", "filename")):
    def paste_attr(paste, attr):
        if attr == "URL":
            return request.build_absolute_uri(paste.get_absolute_url())
        value = getattr(paste, attr)
        if isinstance(value, datetime):
            return value.isoformat(timespec="seconds")
        return value

    values = []
    for paste in pastes:
        values.append([paste_attr(paste, attr) for attr in headers])
    return tabulate(values, headers=headers, tablefmt="github") + "\n"


@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 = []
    files = get_files(request)
    prefix = Paste.choose_prefix(list(files.keys()))
    for filename, the_file in files.items():
        filename = filename.replace("\\", "/")
        paste = Paste(
            slug=f"{prefix}/{filename}".rstrip("/"),
            filename=filename.split("/")[-1],
            content=the_file.read().decode("UTF-8"),
        )
        paste.set_secret(request.headers.get("Authorization"))
        paste.compute_size()
        paste.save()
        pastes.append(paste)

    return HttpResponse(pastes_as_table(request, pastes), content_type="text/plain")


def list_view(request):
    secret = request.headers.get("Authorization")
    pastes = []
    if secret:
        pastes = Paste.objects.by_secret(secret).order_by("paste_time")
    table = pastes_as_table(
        request,
        pastes,
        headers=("filename", "size", "URL", "paste_time", "access_time"),
    )
    if "html" in request.headers["accept"]:
        return HttpResponse(
            loader.render_to_string(
                "paste/show-markdown.html", {"highlighted": markdown_to_html(table)}
            )
        )
    else:
        return HttpResponse(table, content_type="text/plain")


def show(request, slug):
    """Display paste."""
    if slug.startswith("::"):
        raise Http404()
    paste = get_object_or_404(Paste, slug=slug)
    paste.incr_viewcount()

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


@lru_cache(1024)
def paste_to_html(filename, filecontents):
    data = {}
    data["filename"] = filename
    if filename.endswith(".md") or filename.endswith(".txt") or "." not in filename:
        data["highlighted"] = markdown_to_html(filecontents)
        return loader.render_to_string("paste/show-markdown.html", data)
    else:
        data["highlighted"] = pygmentize(filename, filecontents)
        return loader.render_to_string("paste/show-pygments.html", data)