import os.path
import uuid
import subprocess
import base64

import magic

from django import forms
from django.shortcuts import render, redirect
from django.utils.crypto import constant_time_compare

from haystack.views import SearchView, search_view_factory
from haystack.query import SearchQuerySet
from haystack.forms import SearchForm

from whispermaphone import settings
from .models import Thought, ThoughtForm, ALLOWED_MEDIA_TYPES
from .pagination import get_all_pages, get_page_slug, get_page

def check_authenticated(request):
    authenticated = False
    try:
        if constant_time_compare(request.COOKIES["password"], settings.PASSWORD):
            authenticated = True
    except KeyError:
        pass
    return authenticated


def index(request):
    authenticated = check_authenticated(request)

    try:
        highlighted_uuid = uuid.UUID(request.GET.get("show", ""))
    except ValueError:
        highlighted_uuid = ""

    ## Figure out what page we're viewing
    pages = get_all_pages()

    requested_slug = request.GET.get("page", default="")
    requested_page = get_page(requested_slug, highlighted_uuid)

    thoughts = requested_page.get_all_entries()

    return render(request, "thoughts/index.html", {
        "thoughts": thoughts,
        "highlighted": highlighted_uuid,
        "authenticated": authenticated,
        "pages": pages,
        "current_page_slug": requested_page.slug,
        "first_page": requested_page.slug == pages[0].slug # if you're viewing the first page
    })


def login(request):
    if check_authenticated(request):
        return redirect("post")

    if request.method == "POST":
        if constant_time_compare(request.POST["password"], settings.PASSWORD):
            res = redirect("post")
            res.set_cookie("password", request.POST["password"], max_age=60*60*24*365) # 1 year
            return res

    # Returning 401 here causes `links` to always prompt for HTTP basic auth, which is annoying.
    # But the alternative is not following the HTTP spec, so I think this is fine.
    return render(request, "thoughts/login.html", status=401)


def post(request):
    if not check_authenticated(request):
        return redirect("login")

    editing = request.GET.get("editing", None)
    try:
        editing_thought = Thought.objects.get(uuid=editing)
        editing_thought.timezone_offset = - editing_thought.timezone_offset / 60
    except Thought.DoesNotExist:
        editing_thought = None

    if request.method == "POST":
        # We post in hours, so we need to convert back to minutes for saving
        # We can pass errors since form.is_valid catches most of them
        # We just need to convert hours to minutes first, because otherwise it errors on non-integer values
        values = request.POST.copy()
        try:
            values["timezone_offset"] = - float(values["timezone_offset"]) * 60
        except (ValueError, KeyError):
            pass

        thought_form = ThoughtForm(values, request.FILES, instance=editing_thought or Thought())

        if not thought_form.is_valid():
            errors = thought_form.errors.as_data()
            # Media formatting errors
            try:
                problem_field = list(errors.keys())[0]
                message = list(errors.values())[0][0].messages[0]
                error_line = f"{problem_field[0].upper()}{problem_field[1:]}: {message}"
            except:
                error_line = f"An unknown error occurred processing your request: {errors}"

            return render(request, "thoughts/post.html", {
                "form": thought_form,
                "form_error": error_line
            }, status=400)

        if editing_thought:
            thought = editing_thought
        else:
            # Create a thought object we can work with
            # But don't save it the DB yet
            thought = thought_form.save(commit=False)

        # Do media processing (already validated)
        if "media" in request.FILES:
            chunk = next(thought.media.chunks(chunk_size=2048))
            media_type = magic.from_buffer(chunk, mime="True")

            thought.media.name = f"{thought.uuid}.{ALLOWED_MEDIA_TYPES[media_type]}"

            if media_type == "audio/x-m4a" or media_type == "audio/x-hx-aac-adts":
                # This is a hack-fix because I want to be able to upload audio
                # In the future, this should be refactored to convert file types
                #   using ffmpeg.js on the client side (so there are 0 security concerns)
                #   and then the backend just has to check a 3 item whitelist
                thought.save()  # Save so that we have a file to work with
                subprocess.run(["ffmpeg",
                                "-i", thought.media.path,
                                "-codec:a", "mp3", "-vn",
                                os.path.join(settings.MEDIA_ROOT, f"{thought.uuid}.mp3")
                                ], check=True)
                os.remove(os.path.join(settings.MEDIA_ROOT, thought.media.name))  # Remove the original file
                thought.media.name = f"{thought.uuid}.mp3"  # Update the file in the DB

        # We need to make sure that if we remove an image, the alt text is removed with it
        if not thought.media:
            thought.media_alt = ""

        # Save for real
        thought.save()

        # Redirect to the same page, so that we make a GET request to /post
        if editing_thought:
            return redirect(editing_thought)
        return redirect("post")

    return render(request, "thoughts/post.html", {
        "form": ThoughtForm(instance=editing_thought) if editing_thought else ThoughtForm(),
        "editing": not not editing_thought,
    })


def about(request):
    return render(request, "thoughts/about.html", {
        "authenticated": check_authenticated(request)
    })

class ThoughtsSearchForm(SearchForm):
    q = forms.CharField(
        required=False,
        widget=forms.TextInput(attrs={"type": "search", "placeholder": "Search query"}),
    )

    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)

search = search_view_factory(
    template="thoughts/search/search.html",
    view_class=SearchView,
    form_class=ThoughtsSearchForm,
    searchqueryset=SearchQuerySet().order_by("-posted")
)