from __future__ import annotations

from datetime import date, datetime

from pydantic import BaseModel, ConfigDict, Field

from .models import BaseUnit, DatePrecision, Role, UnitKind


# ---- Units ----
class UnitOut(BaseModel):
    model_config = ConfigDict(from_attributes=True)
    id: int
    name: str
    kind: UnitKind
    factor: float
    is_builtin: bool


class UnitCreate(BaseModel):
    name: str = Field(min_length=1, max_length=64)
    kind: UnitKind
    factor: float = Field(gt=0)


# ---- API-Tokens (externe Zugriffe, z.B. Home Assistant) ----
class ApiTokenOut(BaseModel):
    model_config = ConfigDict(from_attributes=True)
    id: int
    name: str
    created_at: datetime
    last_used_at: datetime | None = None


class ApiTokenCreate(BaseModel):
    name: str = Field(min_length=1, max_length=120)


class ApiTokenCreated(ApiTokenOut):
    token: str   # nur einmalig beim Anlegen


# ---- Barcodes ----
class BarcodeOut(BaseModel):
    model_config = ConfigDict(from_attributes=True)
    id: int
    code: str
    note: str | None = None
    # Nur bei Gruppen-Codes gefüllt: der Artikel, über den der Code hier steht.
    product_name: str | None = None


class ProductBarcodeOut(BaseModel):
    """Code, der über einen Artikel dieser Kategorie angehört.

    Rein informativ: Er steht am Artikel, nicht an der Kategorie. Beim Scannen
    findet die Suche immer zuerst den Artikel (siehe routers/products.lookup),
    weshalb ein gleichlautender Kategorie-Eintrag nie greifen könnte.
    """
    code: str
    product_id: int
    product_name: str


# ---- Auth / Users ----
class Token(BaseModel):
    access_token: str
    token_type: str = "bearer"
    role: Role
    username: str


class UserOut(BaseModel):
    model_config = ConfigDict(from_attributes=True)
    id: int
    username: str
    role: Role
    created_at: datetime


class UserCreate(BaseModel):
    username: str = Field(min_length=1, max_length=64)
    password: str = Field(min_length=4, max_length=255)
    role: Role = Role.user


class UserUpdate(BaseModel):
    password: str | None = Field(default=None, min_length=4, max_length=255)
    role: Role | None = None


# ---- Groups ----
class GroupOut(BaseModel):
    model_config = ConfigDict(from_attributes=True)
    id: int
    name: str
    min_stock: float | None = None
    min_stock_unit_id: int | None = None
    # angereichert:
    product_count: int = 0
    stock: float = 0.0            # Bestand in Basiseinheiten
    min_stock_unit_name: str | None = None
    kind: str | None = None       # Art der Mindestbestand-Einheit
    barcodes: list[BarcodeOut] = []   # EANs, die dieser Gruppe zugeordnet sind
    # EANs der Artikel in dieser Gruppe - nur zur Anzeige, nicht bearbeitbar.
    product_barcodes: list[ProductBarcodeOut] = []


class GroupCreate(BaseModel):
    name: str = Field(min_length=1, max_length=120)
    min_stock: float | None = Field(default=None, ge=0)
    min_stock_unit_id: int | None = None


class GroupUpdate(BaseModel):
    name: str | None = Field(default=None, min_length=1, max_length=120)
    min_stock: float | None = Field(default=None, ge=0)
    min_stock_unit_id: int | None = None


# ---- Categories ----
class CategoryOut(BaseModel):
    """Reine Ordnungshilfe – kein Bestand, kein Mindestbestand, keine EAN-Codes."""
    model_config = ConfigDict(from_attributes=True)
    id: int
    name: str
    parent_id: int | None = None
    is_builtin: bool = False
    product_count: int = 0


class CategoryCreate(BaseModel):
    name: str = Field(min_length=1, max_length=120)
    parent_id: int | None = None


class CategoryUpdate(BaseModel):
    name: str | None = Field(default=None, min_length=1, max_length=120)
    parent_id: int | None = None


# ---- Locations ----
class LocationOut(BaseModel):
    model_config = ConfigDict(from_attributes=True)
    id: int
    name: str
    parent_id: int | None = None


class LocationCreate(BaseModel):
    name: str = Field(min_length=1, max_length=120)
    parent_id: int | None = None


# ---- Products ----
class ProductBase(BaseModel):
    barcode: str | None = None
    name: str = Field(min_length=1, max_length=255)
    brand: str | None = None
    image_url: str | None = None
    base_unit: BaseUnit = BaseUnit.piece
    # Optionale verwaltete Einheit; setzt base_unit anhand ihrer Art und die Anzeigeeinheit.
    unit_id: int | None = None
    package_size: float | None = Field(default=None, gt=0)
    # Bezeichnung eines Gebindes ("Packung", "Glas", "Tüte", …)
    package_label: str | None = Field(default=None, max_length=32)
    # Voreingestellte MHD-Genauigkeit dieses Produkts (z.B. Konserven: nur Monat).
    date_precision: DatePrecision = DatePrecision.day
    group_id: int | None = None
    # Kategorie: nur fuer den Ueberblick, unabhaengig von der Gruppe.
    category_id: int | None = None
    min_stock: float | None = Field(default=None, ge=0)  # immer in Basiseinheiten
    # Nur für die Anzeige: in welcher Einheit der Mindestbestand erfasst wurde.
    min_stock_unit_id: int | None = None
    min_stock_in_packages: bool = False


class ProductCreate(ProductBase):
    pass


class ProductUpdate(BaseModel):
    barcode: str | None = None
    name: str | None = Field(default=None, min_length=1, max_length=255)
    brand: str | None = None
    image_url: str | None = None
    base_unit: BaseUnit | None = None
    unit_id: int | None = None
    package_size: float | None = Field(default=None, gt=0)
    package_label: str | None = Field(default=None, max_length=32)
    date_precision: DatePrecision | None = None
    group_id: int | None = None
    category_id: int | None = None
    min_stock: float | None = Field(default=None, ge=0)
    min_stock_unit_id: int | None = None
    min_stock_in_packages: bool | None = None


class ProductOut(BaseModel):
    model_config = ConfigDict(from_attributes=True)
    id: int
    barcode: str | None
    name: str
    brand: str | None
    image_url: str | None
    base_unit: BaseUnit
    display_unit_id: int | None = None
    package_size: float | None
    package_label: str | None = None
    date_precision: DatePrecision = DatePrecision.day
    group_id: int | None
    category_id: int | None = None
    category_name: str | None = None
    min_stock: float | None
    min_stock_unit_id: int | None = None
    min_stock_in_packages: bool = False
    source: str
    created_at: datetime
    # angereichert:
    stock: float = 0.0
    expired_count: int = 0
    kind: str = ""
    unit_name: str = ""
    unit_factor: float = 1.0
    # Mindestbestand in der erfassten Einheit (für die Anzeige):
    min_stock_display: float | None = None
    min_stock_unit_label: str = ""
    # Zusätzliche EAN-Codes (neben dem Haupt-Barcode):
    barcodes: list[BarcodeOut] = []


class LookupResult(BaseModel):
    found: bool
    existing_product: ProductOut | None = None
    suggestion: dict | None = None
    # Ist der Code einer Gruppe zugeordnet (z.B. "Mehl"), wird sie hier gemeldet.
    group_id: int | None = None
    group_name: str | None = None
    # Aus der Open-Food-Facts-Kategorie abgeleiteter Vorschlag (nur Vorschlag).
    category_id: int | None = None
    category_name: str | None = None


class BarcodeCreate(BaseModel):
    code: str = Field(min_length=4, max_length=64)
    note: str | None = Field(default=None, max_length=120)


class BarcodeNoteUpdate(BaseModel):
    """Notiz zu einem Code nachtragen oder ändern."""
    note: str | None = Field(default=None, max_length=120)


# ---- Stock movements ----
class CheckInRequest(BaseModel):
    product_id: int | None = None
    barcode: str | None = None
    quantity: float = Field(gt=0)
    unit: str
    best_before: date | None = None
    # "month" legt das MHD auf den Monatsletzten (siehe services/dates.py).
    best_before_precision: DatePrecision = DatePrecision.day
    location_id: int | None = None
    note: str | None = None


class CheckOutRequest(BaseModel):
    product_id: int | None = None
    barcode: str | None = None
    quantity: float = Field(gt=0)
    unit: str
    # Optional: gezielt aus dieser Charge abbuchen (sonst automatisch FEFO).
    lot_id: int | None = None
    note: str | None = None


class LotOut(BaseModel):
    model_config = ConfigDict(from_attributes=True)
    id: int
    product_id: int
    quantity: float
    best_before: date | None
    best_before_precision: DatePrecision = DatePrecision.day
    location_id: int | None
    created_at: datetime


class LotUpdate(BaseModel):
    """Korrektur einer Charge (Vertipper beim Einlagern o.ä.)."""
    quantity: float | None = Field(default=None, gt=0)
    best_before: date | None = None
    best_before_precision: DatePrecision | None = None
    location_id: int | None = None


class CheckInResponse(BaseModel):
    lot: LotOut
    product_stock: float


class CheckInLine(BaseModel):
    """Eine Charge innerhalb eines Sammel-Einlagerns (Menge + eigenes MHD)."""
    quantity: float = Field(gt=0)
    best_before: date | None = None
    best_before_precision: DatePrecision = DatePrecision.day
    location_id: int | None = None


class BatchCheckInRequest(BaseModel):
    product_id: int | None = None
    barcode: str | None = None
    unit: str
    lines: list[CheckInLine] = Field(min_length=1)
    note: str | None = None


class BatchCheckInResponse(BaseModel):
    lots: list[LotOut]
    product_stock: float


class CheckOutResponse(BaseModel):
    affected_lots: list[dict]
    product_stock: float


# ---- Views ----
class ShoppingItem(BaseModel):
    product_id: int
    name: str
    base_unit: BaseUnit
    package_size: float | None = None
    stock: float
    min_stock: float
    deficit: float


class ExpiringItem(BaseModel):
    lot_id: int
    product_id: int
    product_name: str
    quantity: float          # in Basiseinheiten
    base_unit: BaseUnit
    best_before: date
    best_before_precision: DatePrecision = DatePrecision.day
    days_left: int
    # Für die Anzeige in Artikeleinheiten:
    package_size: float | None = None
    package_label: str | None = None
    unit_name: str = ""
    unit_factor: float = 1.0


class GroupShoppingItem(BaseModel):
    group_id: int
    name: str
    stock: float
    min_stock: float
    deficit: float
    unit_name: str = ""
    product_count: int


class MovementOut(BaseModel):
    id: int
    product_id: int
    product_name: str
    type: str
    quantity: float          # in Basiseinheiten
    base_unit: BaseUnit
    unit_used: str
    username: str | None
    note: str | None
    created_at: datetime
    # Für die Anzeige in Artikeleinheiten:
    package_size: float | None = None
    package_label: str | None = None
    unit_name: str = ""
    unit_factor: float = 1.0


class SettingOut(BaseModel):
    key: str
    value: str