# app/modules/messaging/models/store_email_template.py
"""
Store email template override model.

Allows stores to customize platform email templates with their own content.
Platform-only templates cannot be overridden (e.g., billing, subscription emails).
"""

from datetime import datetime

from sqlalchemy import (
    Boolean,
    Column,
    ForeignKey,
    Integer,
    String,
    Text,
    UniqueConstraint,
)
from sqlalchemy.orm import Session, relationship

from app.core.database import Base
from models.database.base import TimestampMixin


class StoreEmailTemplate(Base, TimestampMixin):
    """
    Store-specific email template override.

    Each store can customize email templates for their shop.
    Overrides are per-template-code and per-language.

    When sending emails:
    1. Check if store has an override for the template+language
    2. If yes, use store's version
    3. If no, fall back to platform template

    Platform-only templates (is_platform_only=True on EmailTemplate)
    cannot be overridden.
    """

    __tablename__ = "store_email_templates"

    id = Column(Integer, primary_key=True, index=True, autoincrement=True)

    # Store relationship
    store_id = Column(
        Integer,
        ForeignKey("stores.id", ondelete="CASCADE"),
        nullable=False,
        index=True,
    )

    # Template identification (references EmailTemplate.code, not FK)
    template_code = Column(String(100), nullable=False, index=True)
    language = Column(String(5), nullable=False, default="en")

    # Optional custom name (if None, uses platform template name)
    name = Column(String(255), nullable=True)

    # Email content
    subject = Column(String(500), nullable=False)
    body_html = Column(Text, nullable=False)
    body_text = Column(Text, nullable=True)

    # Status
    is_active = Column(Boolean, default=True, nullable=False)

    # Relationships
    store = relationship("Store", back_populates="email_templates")

    # Unique constraint: one override per store+template+language
    __table_args__ = (
        UniqueConstraint(
            "store_id",
            "template_code",
            "language",
            name="uq_store_email_template_code_language",
        ),
        {"sqlite_autoincrement": True},
    )

    def __repr__(self):
        return (
            f"<StoreEmailTemplate("
            f"store_id={self.store_id}, "
            f"code='{self.template_code}', "
            f"language='{self.language}')>"
        )

    @classmethod
    def get_override(
        cls,
        db: Session,
        store_id: int,
        template_code: str,
        language: str,
    ) -> "StoreEmailTemplate | None":
        """
        Get store's template override if it exists.

        Args:
            db: Database session
            store_id: Store ID
            template_code: Template code to look up
            language: Language code (en, fr, de, lb)

        Returns:
            StoreEmailTemplate if override exists, None otherwise
        """
        return (
            db.query(cls)
            .filter(
                cls.store_id == store_id,
                cls.template_code == template_code,
                cls.language == language,
                cls.is_active == True,  # noqa: E712
            )
            .first()
        )

    @classmethod
    def get_all_overrides_for_store(
        cls,
        db: Session,
        store_id: int,
    ) -> list["StoreEmailTemplate"]:
        """
        Get all template overrides for a store.

        Args:
            db: Database session
            store_id: Store ID

        Returns:
            List of StoreEmailTemplate objects
        """
        return (
            db.query(cls)
            .filter(
                cls.store_id == store_id,
                cls.is_active == True,  # noqa: E712
            )
            .order_by(cls.template_code, cls.language)
            .all()
        )

    @classmethod
    def create_or_update(
        cls,
        db: Session,
        store_id: int,
        template_code: str,
        language: str,
        subject: str,
        body_html: str,
        body_text: str | None = None,
        name: str | None = None,
    ) -> "StoreEmailTemplate":
        """
        Create or update a store email template override.

        Args:
            db: Database session
            store_id: Store ID
            template_code: Template code
            language: Language code
            subject: Email subject
            body_html: HTML body content
            body_text: Optional plain text body
            name: Optional custom name

        Returns:
            Created or updated StoreEmailTemplate
        """
        existing = cls.get_override(db, store_id, template_code, language)

        if existing:
            existing.subject = subject
            existing.body_html = body_html
            existing.body_text = body_text
            existing.name = name
            existing.updated_at = datetime.utcnow()
            return existing

        new_template = cls(
            store_id=store_id,
            template_code=template_code,
            language=language,
            subject=subject,
            body_html=body_html,
            body_text=body_text,
            name=name,
        )
        db.add(new_template)
        return new_template

    @classmethod
    def delete_override(
        cls,
        db: Session,
        store_id: int,
        template_code: str,
        language: str,
    ) -> bool:
        """
        Delete a store's template override (revert to platform default).

        Args:
            db: Database session
            store_id: Store ID
            template_code: Template code
            language: Language code

        Returns:
            True if deleted, False if not found
        """
        deleted = (
            db.query(cls)
            .filter(
                cls.store_id == store_id,
                cls.template_code == template_code,
                cls.language == language,
            )
            .delete()
        )
        return deleted > 0


__all__ = ["StoreEmailTemplate"]