"""SubmissionForm -- the public submit form (plan.md §5 + demo/submit.html).

Mixes crispy-forms (FormHelper for layout consistency) with manually rendered
radio cards in the template, because the four source-type tabs need
`peer-checked/<name>:` Tailwind classes that crispy can't emit by itself.
"""

from __future__ import annotations

from urllib.parse import urlparse

from crispy_forms.helper import FormHelper
from crispy_forms.layout import Field, Layout, Submit
from django import forms

from .models import Filament, Submission

# Per plan.md §7.5.3 + the form's host allow-list. Subdomains (www. and bare)
# are both accepted.
URL_HOST_ALLOW_LIST: dict[str, set[str]] = {
    Submission.SourceType.PRINTABLES: {"printables.com", "www.printables.com"},
    Submission.SourceType.MAKERWORLD: {"makerworld.com", "www.makerworld.com"},
    Submission.SourceType.THINGIVERSE: {"thingiverse.com", "www.thingiverse.com"},
}

# Shared Tailwind class string for text-ish inputs, matched against demo/submit.html.
INPUT_CSS = (
    "w-full px-3 py-2 rounded-md border border-slate-300 bg-white "
    "focus:outline-none focus:ring-2 focus:ring-amber-500 focus:border-amber-500"
)


class SubmissionForm(forms.ModelForm):
    """Single-page submit form.

    The view passes `user=request.user` so the form can decide whether
    `guest_email` is required (anonymous) or hidden (Google-authenticated).
    """

    source_type = forms.ChoiceField(
        choices=Submission.SourceType.choices,
        initial=Submission.SourceType.UPLOAD,
        widget=forms.RadioSelect,
    )
    stl_file = forms.FileField(
        required=False,
        widget=forms.ClearableFileInput(attrs={"accept": ".stl", "class": "sr-only"}),
    )
    source_url = forms.URLField(
        required=False,
        widget=forms.URLInput(
            attrs={"placeholder": "https://...", "class": INPUT_CSS}
        ),
    )

    class Meta:
        model = Submission
        fields = (
            "source_type",
            "stl_file",
            "source_url",
            "requested_filament",
            "notes_for_op",
            "guest_email",
        )
        widgets = {
            "notes_for_op": forms.Textarea(
                attrs={
                    "rows": 3,
                    "class": INPUT_CSS,
                    "placeholder": (
                        "e.g. 0.2 mm layer height, 20% infill, pickup Saturday afternoon."
                    ),
                }
            ),
            "guest_email": forms.EmailInput(
                attrs={"class": INPUT_CSS, "placeholder": "you@example.com"}
            ),
            "requested_filament": forms.Select(attrs={"class": INPUT_CSS}),
        }

    def __init__(self, *args, user=None, **kwargs):
        super().__init__(*args, **kwargs)
        # Stash for `clean()` -- the per-email cap needs to know whether the
        # incoming submission is OAuth (user.email) or guest (guest_email).
        self.user = user

        # Filament dropdown shows only operator-curated, currently-loaded rows.
        self.fields["requested_filament"].queryset = Filament.objects.filter(
            is_available=True
        )
        self.fields["requested_filament"].label = "Filament"
        self.fields["requested_filament"].empty_label = (
            "No preference — operator's choice"
        )
        self.fields["requested_filament"].required = False
        self.fields["notes_for_op"].required = False

        if user is not None and user.is_authenticated:
            # OAuth user: email is already verified through Google, no need to
            # ask again. Drop the field so it doesn't render or accept input.
            self.fields.pop("guest_email")
        else:
            self.fields["guest_email"].required = True
            self.fields["guest_email"].label = "Your email"

        # Crispy helper -- the template still owns the <form> tag (CSRF +
        # enctype + custom radio-card markup live there), so we keep form_tag
        # off and lean on crispy only for individual {{ field|as_crispy_field }}
        # renders of the boring fields.
        self.helper = FormHelper()
        self.helper.form_tag = False
        self.helper.disable_csrf = True
        layout_fields = ["source_type", "stl_file", "source_url", "requested_filament", "notes_for_op"]
        if "guest_email" in self.fields:
            layout_fields.append("guest_email")
        self.helper.layout = Layout(*[Field(f) for f in layout_fields])
        self.helper.add_input(Submit("submit", "Submit print"))

    # --- validation ---------------------------------------------------------

    def clean(self):
        cleaned = super().clean()

        # Per-email cap (plan.md §6). Run this BEFORE the source-type checks
        # so a user already at quota doesn't get a misleading "pick a source"
        # error message; the cap is the real reason their submission failed.
        owner_email = (
            self.user.email
            if (self.user and self.user.is_authenticated)
            else cleaned.get("guest_email")
        )
        if owner_email:
            active = Submission.active_count_for_email(owner_email)
            cap = Submission.MAX_ACTIVE_SUBMISSIONS_PER_EMAIL
            if active >= cap:
                raise forms.ValidationError(
                    f"You already have {active} active submission(s) -- "
                    f"that's the per-email cap of {cap}. Wait for some to "
                    f"finish printing (or be cleaned up after rejection) "
                    f"before submitting another."
                )

        source_type = cleaned.get("source_type")
        stl_file = cleaned.get("stl_file")
        source_url = cleaned.get("source_url")

        if source_type == Submission.SourceType.UPLOAD:
            if not stl_file:
                self.add_error(
                    "stl_file",
                    "Pick an .stl file to upload (max 4 MB) or switch to a URL source.",
                )
            # The user might have left text in source_url from a prior selection;
            # silently drop it so the saved row stays consistent.
            cleaned["source_url"] = ""
        else:
            if not source_url:
                self.add_error(
                    "source_url",
                    "Paste the model URL or switch to a raw .stl upload.",
                )
            else:
                allowed = URL_HOST_ALLOW_LIST.get(source_type, set())
                host = urlparse(source_url).hostname or ""
                if host not in allowed:
                    pretty_hosts = ", ".join(sorted(allowed))
                    self.add_error(
                        "source_url",
                        f"URL host must be one of: {pretty_hosts}. Got '{host}'.",
                    )
            # Conversely, drop any uploaded file that doesn't apply.
            cleaned["stl_file"] = None

        return cleaned