import io
from pathlib import Path

import django.forms as forms
import piexif
from django.http import JsonResponse
from django.shortcuts import render
from django.template import loader
from django.urls import reverse
from django.views.decorators.csrf import ensure_csrf_cookie
from PIL import Image

import troggle.settings as settings
from troggle.core.utils import WriteAndCommitError, write_and_commit

from .auth import login_required_if_public

MAX_IMAGE_WIDTH = 1000
MAX_IMAGE_HEIGHT = 800

THUMBNAIL_WIDTH = 200
THUMBNAIL_HEIGHT = 200

"""This is all written by Martin Green, and completely undocumented.

It uses a lot of opinionated Django default magic, none of which I am familiar with.
Philip

The function image_selector() is only called from a template file doing a popup input form,
but it stores files directly in expoweb/i /l /t instead of in
/expoweb/1623/2018-MS-01/i , /l, /t
so ALL new caves have photos in the smae place, which makes the default upload EXTREMELY CONFUSING
"""

def get_dir(path):
    "From a path sent from urls.py, determine the directory."
    # todo re-write this to use modern pathlib functions
    if "/" in path:
        return path.rsplit("/", 1)[0]
    else:
        return ""


def image_selector(request, path):
    """Returns available images
    called from 
    templates/html_editor_scripts_css.html:          $('#image_popup_content').load("{% url 'image_selector' path %}" + path, function() {
    """
    directory = get_dir(path)
    print(f" - image selector {directory=} {path=}")
    thumbnailspath = Path(settings.EXPOWEB) / directory / "t"
    thumbnails = []
    if thumbnailspath.is_dir():
        for f in thumbnailspath.iterdir():
            if f.is_file():
                if directory:
                    base = f"{directory}/"
                else:
                    base = ""
                thumbnail_url = reverse("expopage", args=[f"{base}t/{f.name}"])
                name_base = f.name.rsplit(".", 1)[0]
                page_path_base = Path(settings.EXPOWEB) / directory / "l"
                if (page_path_base / (f"{name_base}.htm")).is_file():
                    page_url = reverse("expopage", args=[f"{base}l/{name_base}.htm"])
                else:
                    page_url = reverse("expopage", args=[f"{base}l/{name_base}.html"])

                thumbnails.append({"thumbnail_url": thumbnail_url, "page_url": page_url})

    return render(request, "image_selector.html", {"thumbnails": thumbnails})
    
def reorient_image(img, exif_dict):
     if piexif.ImageIFD.Orientation in exif_dict["0th"]:
            print(exif_dict)
            orientation = exif_dict["0th"].pop(piexif.ImageIFD.Orientation)
            
            if orientation == 2:
                img = img.transpose(Image.FLIP_LEFT_RIGHT)
            elif orientation == 3:
                img = img.rotate(180)
            elif orientation == 4:
                img = img.rotate(180).transpose(Image.FLIP_LEFT_RIGHT)
            elif orientation == 5:
                img = img.rotate(-90, expand=True).transpose(Image.FLIP_LEFT_RIGHT)
            elif orientation == 6:
                img = img.rotate(-90, expand=True)
            elif orientation == 7:
                img = img.rotate(90, expand=True).transpose(Image.FLIP_LEFT_RIGHT)
            elif orientation == 8:
                img = img.rotate(90, expand=True)
     return img


@login_required_if_public
@ensure_csrf_cookie
def new_image_form(request, path):
    """Manages a form to upload new images"""
    directory = get_dir(path)
    print(f"new_image_form():  {directory=}  {path=}")
    if request.method == "POST":
        print(f"new_image_form():  POST ")
        form = NewWebImageForm(request.POST, request.FILES, directory=directory)
        if form.is_valid():
            print(f"new_image_form():  form is valid ")
            print(f"new_image_form():  files: {request.FILES['file_']}")
            f = request.FILES["file_"]
            binary_data = io.BytesIO()
            for chunk in f.chunks():
                binary_data.write(chunk)
            print(f"new_image_form():  binary chnks written")
            i = Image.open(binary_data)
            print(f"new_image_form():  {i=}")
            if "exif" in i.info:
                print(f"new_image_form(): exif: {i=}")

                exif_dict = piexif.load(i.info["exif"])
                i = reorient_image(i, exif_dict)
                exif_dict['Exif'][41729] = b'1'
                # can crash here with bad exif data
                try:
                    exif = piexif.dump(exif_dict)
                except:
                    exif = None
            else:
                exif = None
            
            print(f"new_image_form():  No exif problems")
            width, height = i.size
            print(f"new_image_form():  {i.size=}")
            if width > MAX_IMAGE_WIDTH or height > MAX_IMAGE_HEIGHT:
                print(f"new_image_form():  rescaling ")
                scale = max(width / MAX_IMAGE_WIDTH, height / MAX_IMAGE_HEIGHT)
                print(f"new_image_form():  rescaling {scale=}")
                try:
                    i = i.resize((int(width / scale), int(height / scale)), Image.LANCZOS)
                except Exception as e:
                    print(f"new_image_form():  rescaling exception: {e} ")
                    
                print(f"new_image_form():  rescaled ")
            tscale = max(width / THUMBNAIL_WIDTH, height / THUMBNAIL_HEIGHT)
            thumbnail = i.resize((int(width / tscale), int(height / tscale)), Image.LANCZOS)
            ib = io.BytesIO()
            i = i.convert('RGB')
            i.save(ib, format="jpeg", quality = 75)
            tb = io.BytesIO()
            thumbnail = thumbnail.convert('RGB')
            thumbnail.save(tb, format="jpeg", quality = 70)
            image_rel_path, thumb_rel_path, desc_rel_path = form.get_rel_paths()
            print(f"new_image_form(): \n {image_rel_path=}\n {thumb_rel_path=}\n {desc_rel_path=}")
            image_page_template = loader.get_template("image_page_template.html") # this is the .html file in the /l/ folder
            image_page = image_page_template.render(
                {
                    "header": form.cleaned_data["header"],
                    "description": form.cleaned_data["description"],
                    "photographer": form.cleaned_data["photographer"],
                    "year": form.cleaned_data["year"],
                    "filepath": f"/{image_rel_path}",
                }
            )
            image_path, thumb_path, desc_path = form.get_full_paths()
            # Create directories if required
            for full_path in image_path, thumb_path, desc_path:
                print(full_path, full_path.parent)
                full_path.parent.mkdir(parents=True, exist_ok=True)
            try:
                change_message = form.cleaned_data["change_message"]
                write_and_commit(
                    [
                        (desc_path, image_page, "utf-8"),
                        (image_path, ib.getbuffer(), False),
                        (thumb_path, tb.getbuffer(), False),
                    ],
                    f"{change_message} - online adding of an image",
                )
            except WriteAndCommitError as e:
                print(f"new_image_form(): WriteAndCommitError: {e.message}")
                return JsonResponse({"error": e.message})
            except Exception as e:
                print(f"new_image_form(): EXCEPTION: {e.message}")
                return JsonResponse({"error": e.message})
                
            linked_image_template = loader.get_template("linked_image_template.html")
            html_snippet = linked_image_template.render(
                {"thumbnail_url": f"/{thumb_rel_path}", "page_url": f"/{desc_rel_path}"}, request
            )
            return JsonResponse({"html": html_snippet})
    else:
        print(f"new_image_form():  not POST ")
        form = NewWebImageForm(directory=directory)
    print(f"new_image_form():  POST and not POST ")
    template = loader.get_template("new_image_form.html")
    htmlform = template.render({"form": form, "path": path}, request)
    return JsonResponse({"form": htmlform})


class NewWebImageForm(forms.Form):
    """The form used by the editexpopage function"""

    header = forms.CharField(
        widget=forms.TextInput(
            attrs={"size": "60", "placeholder": "Enter title (displayed as a header and in the tab)"}
        )
    )
    file_ = forms.FileField()
    description = forms.CharField(
        widget=forms.Textarea(attrs={"cols": 80, "rows": 20, "placeholder": "Describe the photo (using HTML)"})
    )
    photographer = forms.CharField(
        widget=forms.TextInput(attrs={"size": "60", "placeholder": "Photographers name"}), required=False
    )
    year = forms.CharField(
        widget=forms.TextInput(attrs={"size": "60", "placeholder": "Year photo was taken"}), required=False
    )
    change_message = forms.CharField(
        widget=forms.Textarea(attrs={"cols": 80, "rows": 3, "placeholder": "Descibe the change made (for git)"})
    )

    def __init__(self, *args, **kwargs):
        self.directory = Path(kwargs.pop("directory"))
        super(forms.Form, self).__init__(*args, **kwargs)

    def get_rel_paths(self):
        f = self.cleaned_data["file_"]
        return [
            self.directory / "i" / (f.name.rsplit(".", 1)[0] + ".jpg"),
            self.directory / "t" / (f.name.rsplit(".", 1)[0] + ".jpg"),
            self.directory / "l" / (f.name.rsplit(".", 1)[0] + ".html"),
        ]

    def get_full_paths(self):
        return [Path(settings.EXPOWEB) / x for x in self.get_rel_paths()] # this is where we would want to insert the /caveid/ ?!

    def clean_file_(self):
        for rel_path, full_path in zip(self.get_rel_paths(), self.get_full_paths()):
            if full_path.exists():
                raise forms.ValidationError(f"File already exists in {rel_path}")
        return self.cleaned_data["file_"]


class HTMLarea(forms.Textarea):
    """This is called from CaveForm in core/forms.py which is called from core/views/caves.py when editing a cave description
    (and similarly for Entrance Descriptions). It is alls called from core/views/expo.py when editing expo (i.e. handbook) pages.
    """
    template_name = "widgets/HTMLarea.html"

    def __init__(self, *args, **kwargs):
        self.preview = kwargs.pop("preview", False)
        super(forms.Textarea, self).__init__(*args, **kwargs)

    def get_context(self, name, value, attrs):
        c = super(forms.Textarea, self).get_context(name, value, attrs)
        c["preview"] = self.preview
        return c