import json

import yaml
from django import forms
from django.core.exceptions import ValidationError
from django.utils.translation import gettext_lazy as _

from netbox.forms import (
    NetBoxModelBulkEditForm,
    NetBoxModelFilterSetForm,
    NetBoxModelForm,
    NetBoxModelImportForm,
    PrimaryModelForm,
)
from tenancy.models import Tenant
from utilities.forms.fields import (
    DynamicModelChoiceField,
    DynamicModelMultipleChoiceField,
    TagFilterField,
)
from utilities.forms.rendering import FieldSet

from .models import (
    Service,
    ServiceStatusChoices,
    ServiceTemplate,
    ServiceTemplateStatusChoices,
    validate_tree,
)


# ── Service Template ─────────────────────────────────────────────────

class ServiceTemplateForm(PrimaryModelForm):
    tree_raw = forms.CharField(
        label=_("Requirement tree"),
        required=False,
        widget=forms.Textarea(
            attrs={
                "rows": 20,
                "class": "font-monospace",
                "placeholder": (
                    '- name: routers\n'
                    '  object_type: dcim.device\n'
                    '  quantity: 2\n'
                    '  selector:\n'
                    '    type: netbox_filter\n'
                    '    filters:\n'
                    '      role: router\n'
                    '  children:\n'
                    '    - name: mgmt-ip\n'
                    '      object_type: ipam.ipaddress\n'
                    '      allocation:\n'
                    '        strategy: first_free\n'
                    '        prefix:\n'
                    '          type: prefix\n'
                    '          filters: {}\n'
                ),
            },
        ),
        help_text=_("Enter the requirement tree as YAML or JSON."),
    )

    fieldsets = (
        FieldSet("name", "status", "tree_raw", name=_("Service Template")),
        FieldSet("description", "tags", name=_("Metadata")),
    )

    class Meta:
        model = ServiceTemplate
        fields = ("name", "status", "description", "comments")

    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        if self.instance and self.instance.pk and self.instance.tree:
            self.fields["tree_raw"].initial = yaml.dump(
                self.instance.tree, default_flow_style=False, sort_keys=False,
            )

    def clean(self):
        super().clean()
        raw = self.cleaned_data.get("tree_raw", "").strip()
        if not raw:
            self.instance.tree = []
            return self.cleaned_data

        tree = None
        try:
            tree = json.loads(raw)
        except (json.JSONDecodeError, ValueError):
            pass

        if tree is None:
            try:
                tree = yaml.safe_load(raw)
            except yaml.YAMLError as exc:
                self.add_error("tree_raw", _(f"Invalid YAML or JSON: {exc}"))
                return self.cleaned_data

        if tree is None:
            tree = []

        self.instance.tree = tree
        self.instance._tree_validated_by_form = True

        try:
            validate_tree(tree)
        except ValidationError as exc:
            self.add_error("tree_raw", ValidationError(exc.messages))

        return self.cleaned_data


class ServiceTemplateFilterSetForm(NetBoxModelFilterSetForm):
    model = ServiceTemplate
    name = forms.CharField(required=False)
    status = forms.MultipleChoiceField(
        choices=ServiceTemplateStatusChoices,
        required=False,
    )
    tag = TagFilterField(model)


class ServiceTemplateBulkEditForm(NetBoxModelBulkEditForm):
    model = ServiceTemplate
    status = forms.ChoiceField(
        choices=ServiceTemplateStatusChoices,
        required=False,
    )
    description = forms.CharField(required=False)
    nullable_fields = ("description",)


class ServiceTemplateImportForm(NetBoxModelImportForm):
    class Meta:
        model = ServiceTemplate
        fields = ("name", "status", "description", "comments", "tags")


# ── Service ──────────────────────────────────────────────────────────

class ServiceForm(PrimaryModelForm):
    service_template = DynamicModelChoiceField(
        queryset=ServiceTemplate.objects.all(),
    )
    tenant = DynamicModelChoiceField(
        queryset=Tenant.objects.all(),
    )

    fieldsets = (
        FieldSet("name", "service_template", "tenant", "status", "description", "tags", name=_("Service")),
    )

    class Meta:
        model = Service
        fields = ("name", "service_template", "tenant", "status", "description", "comments")


class ServiceFilterSetForm(NetBoxModelFilterSetForm):
    model = Service
    name = forms.CharField(required=False)
    service_template = DynamicModelMultipleChoiceField(
        queryset=ServiceTemplate.objects.all(),
        required=False,
    )
    tenant = DynamicModelMultipleChoiceField(
        queryset=Tenant.objects.all(),
        required=False,
    )
    status = forms.MultipleChoiceField(
        choices=ServiceStatusChoices,
        required=False,
    )
    tag = TagFilterField(model)


class ServiceBulkEditForm(NetBoxModelBulkEditForm):
    model = Service
    status = forms.ChoiceField(
        choices=ServiceStatusChoices,
        required=False,
    )
    description = forms.CharField(required=False)
    nullable_fields = ("description",)


# ── Resolve form ─────────────────────────────────────────────────────

class ResolveForm(forms.Form):
    mode = forms.ChoiceField(
        choices=(
            ("dry_run", _("Dry Run")),
            ("commit", _("Commit")),
        ),
        initial="dry_run",
        widget=forms.RadioSelect,
    )