from django import forms
from django.forms import inlineformset_factory
from django.db.models import Q

from .models import (
    Inventory,
    InventoryItem,
    Product,
    ProductCategory,
    PurchaseOrder,
    PurchaseOrderItem,
    PreparationOrder,
    PreparationOrderItem,
    ProductionOrder,
    ProductionOrderComponent,
    Supplier,
    Warehouse,
    WarehouseLocation,
    RequestForQuote,
    RequestForQuoteItem,
)


class PreparationOrderForm(forms.ModelForm):
    class Meta:
        model = PreparationOrder
        fields = ["order_number", "status", "requester", "priority", "is_loan", "estimated_return_date"]
        widgets = {
            "requester": forms.TextInput(attrs={
                "class": "form-control",
                "placeholder": "Nom, service ou équipe à l'origine de la demande",
            }),
            "estimated_return_date": forms.DateInput(attrs={
                "type": "date",
                "class": "form-control",
            }),
        }

    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        for field_name in self.fields:
            if field_name != "requester":
                if isinstance(self.fields[field_name].widget, forms.Select):
                    self.fields[field_name].widget.attrs['class'] = 'form-select'
                elif isinstance(self.fields[field_name].widget, forms.CheckboxInput):
                    self.fields[field_name].widget.attrs['class'] = 'form-check-input'
                else:
                    self.fields[field_name].widget.attrs['class'] = 'form-control'
        self.fields["requester"].required = False


# class PreparationOrderDesignForm(forms.Form):
#     """Formulaire utilisé côté serveur pour valider une ligne conception."""
#     design_id = forms.IntegerField()
#     quantity = forms.IntegerField(min_value=1, initial=1)


class PreparationOrderItemForm(forms.ModelForm):
    class Meta:
        model = PreparationOrderItem
        fields = ["product", "quantity"]

    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        if self.instance and self.instance.pk and self.instance.product:
            self.fields["product"].queryset = Product.objects.filter(
                Q(is_active=True) | Q(pk=self.instance.product.pk)
            ).order_by("name")
        else:
            self.fields["product"].queryset = Product.objects.filter(is_active=True).order_by("name")


class RequestForQuoteForm(forms.ModelForm):
    class Meta:
        model = RequestForQuote
        fields = ["warehouse", "suppliers", "notes", "status"]
        widgets = {
            "warehouse": forms.Select(attrs={"class": "form-select"}),
            "suppliers": forms.SelectMultiple(attrs={"class": "form-select", "size": "6"}),
            "notes": forms.Textarea(attrs={"class": "form-control", "rows": 3}),
            "status": forms.Select(attrs={"class": "form-select"}),
        }

    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        self.fields["suppliers"].required = False
        self.fields["notes"].required = False
        self.fields["suppliers"].queryset = Supplier.objects.filter(is_active=True).order_by("name")


class RequestForQuoteItemForm(forms.ModelForm):
    class Meta:
        model = RequestForQuoteItem
        fields = ["product", "num_articles", "quantity_per_article", "quantity"]
        widgets = {
            "num_articles": forms.NumberInput(attrs={"class": "form-control", "min": "1", "placeholder": "ex: 10"}),
            "quantity_per_article": forms.NumberInput(attrs={"class": "form-control", "min": "0.001", "step": "any", "placeholder": "ex: 10"}),
            "quantity": forms.NumberInput(attrs={"class": "form-control", "min": "0"}),
        }

    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        self.fields["num_articles"].required = False
        self.fields["quantity_per_article"].required = False
        self.fields["quantity"].required = False
        if not self.instance.pk:
            self.fields["quantity_per_article"].initial = 1
        if self.instance and self.instance.pk and self.instance.product:
            self.fields["product"].queryset = Product.objects.filter(
                Q(is_active=True) | Q(pk=self.instance.product.pk)
            ).order_by("name")
        else:
            self.fields["product"].queryset = Product.objects.filter(is_active=True).order_by("name")

    def clean(self):
        cleaned_data = super().clean()
        num_articles = cleaned_data.get("num_articles")
        quantity_per_article = cleaned_data.get("quantity_per_article")
        quantity = cleaned_data.get("quantity")

        if num_articles and quantity_per_article:
            cleaned_data["quantity"] = int(num_articles * quantity_per_article)
        elif not quantity:
            raise forms.ValidationError(
                "Indiquez soit une quantité totale, soit un nombre d'articles et une quantité par article."
            )
        return cleaned_data


RequestForQuoteItemFormSet = inlineformset_factory(
    RequestForQuote,
    RequestForQuoteItem,
    form=RequestForQuoteItemForm,
    extra=1,
    can_delete=True,
)


class PurchaseOrderForm(forms.ModelForm):
    class Meta:
        model = PurchaseOrder
        fields = ["supplier", "warehouse", "status", "request_for_quote"]
        widgets = {
            "request_for_quote": forms.HiddenInput(),
        }


class PurchaseOrderItemForm(forms.ModelForm):
    class Meta:
        model = PurchaseOrderItem
        fields = ["product", "location", "num_articles", "quantity_per_article", "quantity", "unit_price", "vat_rate"]
        widgets = {
            "num_articles": forms.NumberInput(attrs={"class": "form-control", "min": "1", "placeholder": "ex: 10"}),
            "quantity_per_article": forms.NumberInput(attrs={"class": "form-control", "min": "0.001", "step": "any", "placeholder": "ex: 10"}),
            "quantity": forms.NumberInput(attrs={"class": "form-control", "min": "0"}),
            "unit_price": forms.NumberInput(attrs={"class": "form-control", "min": "0", "step": "0.01", "placeholder": "ex: 47.11"}),
            "vat_rate": forms.NumberInput(attrs={"class": "form-control", "min": "0", "step": "0.01", "placeholder": "ex: 21.00"}),
        }

    def __init__(self, *args, **kwargs):
        warehouse = kwargs.pop("warehouse", None)
        super().__init__(*args, **kwargs)
        if warehouse:
            self.fields["location"].queryset = WarehouseLocation.objects.filter(
                warehouse=warehouse
            )
            if not self.instance.pk:
                default_loc = WarehouseLocation.objects.filter(
                    warehouse=warehouse, is_default=True
                ).first()
                if default_loc:
                    self.initial.setdefault("location", default_loc.pk)
        self.fields["num_articles"].required = False
        self.fields["quantity_per_article"].required = False
        self.fields["quantity"].required = False
        self.fields["unit_price"].required = False
        self.fields["vat_rate"].required = False
        if not self.instance.pk:
            self.fields["quantity_per_article"].initial = 1
            self.fields["vat_rate"].initial = 21.00
        if self.instance and self.instance.pk and self.instance.product:
            self.fields["product"].queryset = Product.objects.filter(
                Q(is_active=True) | Q(pk=self.instance.product.pk)
            ).order_by("name")
        else:
            self.fields["product"].queryset = Product.objects.filter(is_active=True).order_by("name")

    def clean(self):
        cleaned_data = super().clean()
        num_articles = cleaned_data.get("num_articles")
        quantity_per_article = cleaned_data.get("quantity_per_article")
        quantity = cleaned_data.get("quantity")

        if num_articles and quantity_per_article:
            from decimal import Decimal
            cleaned_data["quantity"] = int(num_articles * quantity_per_article)
        elif not quantity:
            raise forms.ValidationError(
                "Indiquez soit une quantité totale, soit un nombre d'articles et une quantité par article."
            )

        # Validation des emplacements autorisés pour ce produit
        product = cleaned_data.get("product")
        location = cleaned_data.get("location")
        if product and location:
            if product.authorized_locations.exists() and location not in product.authorized_locations.all():
                from django.utils.translation import gettext_lazy as _
                self.add_error('location', _("L'emplacement '%(loc)s' n'est pas autorisé pour le produit '%(prod)s'.") % {
                    'loc': location.name,
                    'prod': product.name
                })
        return cleaned_data


PurchaseOrderItemFormSet = inlineformset_factory(
    PurchaseOrder,
    PurchaseOrderItem,
    form=PurchaseOrderItemForm,
    extra=1,
    can_delete=True,
)


class InventoryForm(forms.ModelForm):
    class Meta:
        model = Inventory
        fields = ["warehouse_location", "performed_by", "status"]

    def __init__(self, *args, **kwargs):
        warehouse = kwargs.pop("warehouse", None)
        super().__init__(*args, **kwargs)
        if warehouse:
            self.fields["warehouse_location"].queryset = WarehouseLocation.objects.filter(
                warehouse=warehouse
            ).order_by("name")
            if not self.instance.pk:
                default_loc = WarehouseLocation.objects.filter(
                    warehouse=warehouse, is_default=True
                ).first()
                if default_loc:
                    self.initial.setdefault("warehouse_location", default_loc.pk)


class InventoryItemForm(forms.ModelForm):
    class Meta:
        model = InventoryItem
        fields = ["product", "expected_quantity", "counted_quantity", "comment"]
        widgets = {
            "comment": forms.Textarea(attrs={"rows": 1, "placeholder": "Commentaire optionnel…"}),
        }

    def __init__(self, *args, **kwargs):
        kwargs.pop("warehouse", None)
        super().__init__(*args, **kwargs)
        if self.instance and self.instance.pk and self.instance.product:
            self.fields["product"].queryset = Product.objects.filter(
                Q(is_active=True) | Q(pk=self.instance.product.pk)
            ).order_by("name")
        else:
            self.fields["product"].queryset = Product.objects.filter(is_active=True).order_by("name")


InventoryItemFormSet = inlineformset_factory(
    Inventory,
    InventoryItem,
    form=InventoryItemForm,
    extra=1,
    can_delete=True,
)


class InventoryItemEditForm(forms.ModelForm):
    """Formulaire pour l'édition d'un article d'inventaire existant.

    Le champ produit est rendu en HiddenInput pour les articles existants,
    évitant de charger un <select> de tous les produits pour chaque ligne
    (ce qui causerait un DOM très volumineux et un temps de chargement élevé).
    """

    class Meta:
        model = InventoryItem
        fields = ["product", "expected_quantity", "counted_quantity", "comment"]
        widgets = {
            "product": forms.HiddenInput(),
            "comment": forms.Textarea(attrs={"rows": 1, "placeholder": "Commentaire optionnel…"}),
        }

    def __init__(self, *args, **kwargs):
        kwargs.pop("warehouse", None)
        super().__init__(*args, **kwargs)


class SupplierForm(forms.ModelForm):
    class Meta:
        model = Supplier
        fields = ["name", "enterprise_number", "contact_email", "phone_number", "address", "is_active"]
        widgets = {
            "name": forms.TextInput(attrs={"class": "form-control"}),
            "enterprise_number": forms.TextInput(attrs={"class": "form-control"}),
            "contact_email": forms.EmailInput(attrs={"class": "form-control"}),
            "phone_number": forms.TextInput(attrs={"class": "form-control"}),
            "address": forms.Textarea(attrs={"class": "form-control", "rows": 3}),
            "is_active": forms.CheckboxInput(attrs={"class": "form-check-input"}),
        }


# class ProductDesignForm(forms.ModelForm):
#     class Meta:
#         model = ProductDesign
#         fields = ["code", "name", "description", "image", "status", "category", "warehouse", "default_location", "output_product"]
#         widgets = {
#             "code": forms.TextInput(attrs={"class": "form-control"}),
#             "name": forms.TextInput(attrs={"class": "form-control"}),
#             "description": forms.Textarea(attrs={"class": "form-control", "rows": 3}),
#             "image": forms.ClearableFileInput(attrs={"class": "form-control"}),
#             "status": forms.Select(attrs={"class": "form-select"}),
#             "category": forms.Select(attrs={"class": "form-select"}),
#             "warehouse": forms.Select(attrs={"class": "form-select", "id": "id_warehouse"}),
#             "default_location": forms.Select(attrs={"class": "form-select", "id": "id_default_location"}),
#             "output_product": forms.Select(attrs={"class": "form-select"}),
#         }
#
#     def __init__(self, *args, **kwargs):
#         super().__init__(*args, **kwargs)
#         if self.instance and self.instance.pk and self.instance.warehouse_id:
#             self.fields['default_location'].queryset = WarehouseLocation.objects.filter(
#                 warehouse=self.instance.warehouse
#             ).order_by('name')
#             if not self.instance.default_location_id:
#                 default_loc = WarehouseLocation.objects.filter(
#                     warehouse=self.instance.warehouse, is_default=True
#                 ).first()
#                 if default_loc:
#                     self.initial.setdefault('default_location', default_loc.pk)
#         else:
#             self.fields['default_location'].queryset = WarehouseLocation.objects.none()
#         self.fields['output_product'].required = False
#         self.fields['output_product'].queryset = Product.objects.all().order_by('name')
#         self.fields['output_product'].empty_label = "— Aucun produit par défaut —"


# class ProductDesignComponentForm(forms.ModelForm):
#     class Meta:
#         model = ProductDesignComponent
#         fields = ["product", "quantity", "notes"]
#         widgets = {
#             "product": forms.Select(attrs={"class": "form-select product-select"}),
#             "quantity": forms.NumberInput(attrs={"class": "form-control", "min": 1}),
#             "notes": forms.TextInput(attrs={"class": "form-control"}),
#         }


# ProductDesignComponentFormSet = inlineformset_factory(
#     ProductDesign,
#     ProductDesignComponent,
#     form=ProductDesignComponentForm,
#     extra=1,
#     can_delete=True,
# )


class ProductionOrderComponentForm(forms.ModelForm):
    class Meta:
        model = ProductionOrderComponent
        fields = ["product", "quantity", "notes"]
        widgets = {
            "product": forms.Select(attrs={"class": "form-select product-select"}),
            "quantity": forms.NumberInput(attrs={"class": "form-control", "min": 1}),
            "notes": forms.TextInput(attrs={"class": "form-control"}),
        }

    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        if self.instance and self.instance.pk and self.instance.product:
            self.fields["product"].queryset = Product.objects.filter(
                Q(is_active=True) | Q(pk=self.instance.product.pk)
            ).order_by("name")
        else:
            self.fields["product"].queryset = Product.objects.filter(is_active=True).order_by("name")


ProductionOrderComponentFormSet = inlineformset_factory(
    ProductionOrder,
    ProductionOrderComponent,
    form=ProductionOrderComponentForm,
    extra=1,
    can_delete=True,
)


class ProductionOrderForm(forms.ModelForm):
    class Meta:
        model = ProductionOrder
        fields = [
            "warehouse", "quantity", "status", "destination",
            "preparation_order", "notes",
            "output_product", "output_product_name", "output_location",
        ]
        widgets = {
            "warehouse": forms.Select(attrs={"class": "form-select"}),
            "quantity": forms.NumberInput(attrs={"class": "form-control", "min": 1}),
            "status": forms.Select(attrs={"class": "form-select"}),
            "destination": forms.Select(attrs={"class": "form-select"}),
            "preparation_order": forms.Select(attrs={"class": "form-select"}),
            "notes": forms.Textarea(attrs={"class": "form-control", "rows": 3}),
            "output_product": forms.Select(attrs={"class": "form-select"}),
            "output_product_name": forms.TextInput(attrs={"class": "form-control"}),
            "output_location": forms.Select(attrs={"class": "form-select"}),
        }

    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        self.fields["preparation_order"].required = False
        self.fields["preparation_order"].queryset = PreparationOrder.objects.filter(
            status__in=["to_process", "pending"]
        )
        self.fields["output_product"].required = False
        # Pour Select2 AJAX : on ne charge que le produit actuellement sélectionné (0-1 option)
        # La validation est gérée par clean_output_product
        current_pk = None
        if self.instance and self.instance.pk:
            current_pk = self.instance.output_product_id
        elif self.is_bound:
            current_pk = self.data.get("output_product") or None
        elif self.initial.get("output_product"):
            current_pk = self.initial.get("output_product")
        if current_pk:
            self.fields["output_product"].queryset = Product.objects.filter(pk=current_pk)
        else:
            self.fields["output_product"].queryset = Product.objects.none()
        self.fields["output_product"].empty_label = "— Sélectionner un produit existant —"
        self.fields["output_product_name"].required = False
        self.fields["output_location"].required = False
        self.fields["output_location"].queryset = WarehouseLocation.objects.all().select_related("warehouse").order_by("warehouse__name", "name")
        self.fields["output_location"].empty_label = "— Emplacement par défaut de la conception —"

    def clean_output_product(self):
        """Valide l'ID soumis par Select2 AJAX contre tous les produits réels."""
        product_id = self.data.get("output_product")
        if not product_id:
            return None
        try:
            return Product.objects.get(pk=product_id)
        except (Product.DoesNotExist, ValueError, TypeError):
            raise forms.ValidationError("Produit invalide.")


class ProductForm(forms.ModelForm):
    class Meta:
        model = Product
        fields = ["code", "name", "category", "sku", "description", "price", "unit", "threshold", "is_serialized", "authorized_locations"]
        widgets = {
            "code": forms.TextInput(attrs={"class": "form-control"}),
            "name": forms.TextInput(attrs={"class": "form-control"}),
            "category": forms.Select(attrs={"class": "form-select"}),
            "sku": forms.TextInput(attrs={"class": "form-control"}),
            "description": forms.Textarea(attrs={"class": "form-control", "rows": 3}),
            "price": forms.NumberInput(attrs={"class": "form-control", "min": "0", "step": "0.01"}),
            "unit": forms.Select(attrs={"class": "form-select"}),
            "threshold": forms.NumberInput(attrs={"class": "form-control", "min": "0"}),
            "is_serialized": forms.CheckboxInput(attrs={"class": "form-check-input"}),
            "authorized_locations": forms.SelectMultiple(attrs={"class": "form-select", "size": "6"}),
        }

    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        self.fields["category"].queryset = ProductCategory.objects.all().order_by("name_fr")
        self.fields["category"].empty_label = "— Sélectionner une catégorie —"
        self.fields["category"].required = False
        self.fields["description"].required = False
        self.fields["price"].required = False
        # Code and SKU are auto-generated and locked
        self.fields["code"].widget.attrs["readonly"] = True
        self.fields["sku"].widget.attrs["readonly"] = True

        from django.utils.translation import gettext_lazy as _
        self.fields["authorized_locations"].queryset = WarehouseLocation.objects.select_related("warehouse").order_by("warehouse__name", "name")
        self.fields["authorized_locations"].required = False
        self.fields["authorized_locations"].help_text = _("Si vide, le produit est autorisé dans tous les emplacements.")


class ProductAtLocationForm(ProductForm):
    quantity = forms.IntegerField(
        min_value=0,
        initial=0,
        label=forms.CharField().label, # just fallback
        widget=forms.NumberInput(attrs={"class": "form-control"}),
    )

    class Meta(ProductForm.Meta):
        fields = ProductForm.Meta.fields + ["quantity"]

    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        from django.utils.translation import gettext_lazy as _
        self.fields["quantity"].label = _("Quantité initiale")


class WarehouseLocationForm(forms.ModelForm):
    class Meta:
        model = WarehouseLocation
        fields = ["warehouse", "code", "name", "description", "is_default"]
        widgets = {
            "warehouse": forms.Select(attrs={"class": "form-select"}),
            "code": forms.TextInput(attrs={"class": "form-control"}),
            "name": forms.TextInput(attrs={"class": "form-control"}),
            "description": forms.Textarea(attrs={"class": "form-control", "rows": 3}),
            "is_default": forms.CheckboxInput(attrs={"class": "form-check-input"}),
        }

    def __init__(self, *args, warehouse=None, **kwargs):
        super().__init__(*args, **kwargs)
        self.fields["description"].required = False
        if warehouse is not None:
            self.fields["warehouse"].initial = warehouse
            self.fields["warehouse"].queryset = Warehouse.objects.filter(pk=warehouse.pk)
            self.fields["warehouse"].widget = forms.HiddenInput()
        else:
            self.fields["warehouse"].queryset = Warehouse.objects.all().order_by("name")