"""Models for prompt template system."""

from sqlalchemy import Column, String, Text, Float, DateTime, Boolean, Integer, JSON, ForeignKey
from sqlalchemy.orm import relationship
from sqlalchemy.types import TypeDecorator, CHAR
from sqlalchemy.dialects.postgresql import UUID
import uuid
from datetime import datetime

from backend.models.base import Model


class GUID(TypeDecorator):
    """Platform-independent GUID type for SQLite and PostgreSQL compatibility."""
    impl = CHAR
    cache_ok = True

    def load_dialect_impl(self, dialect):
        if dialect.name == 'postgresql':
            return dialect.type_descriptor(UUID())
        else:
            return dialect.type_descriptor(CHAR(32))

    def process_bind_param(self, value, dialect):
        if value is None:
            return value
        elif dialect.name == 'postgresql':
            return str(value)
        else:
            if not isinstance(value, uuid.UUID):
                return "%.32x" % uuid.UUID(value).int
            else:
                return "%.32x" % value.int

    def process_result_value(self, value, dialect):
        if value is None:
            return value
        else:
            if not isinstance(value, uuid.UUID):
                return uuid.UUID(value)
            return value


class PromptTemplate(Model):
    """Custom prompt templates for AI models."""
    __tablename__ = "prompt_templates"
    __table_args__ = {'extend_existing': True}
    
    id = Column(GUID, primary_key=True, default=uuid.uuid4)
    user_id = Column(String(36), ForeignKey("users.id"), nullable=True)
    name = Column(String(200), nullable=False)
    description = Column(Text, nullable=True)
    prompt_text = Column(Text, nullable=False)
    domain_category = Column(String(50), nullable=True)
    model_config = Column(JSON, nullable=True)
    is_public = Column(Boolean, default=False)
    usage_count = Column(Integer, default=0)
    rating = Column(Float, default=0.0)
    created_at = Column(DateTime, default=datetime.utcnow)
    updated_at = Column(DateTime, default=datetime.utcnow, onupdate=datetime.utcnow)
    
    # Relationships
    user = relationship("backend.models.user.User", back_populates="prompt_templates")
    export_metadata = relationship("backend.models.enhanced_export.ExportMetadata")
    
    def __repr__(self):
        return f"<PromptTemplate(id={self.id}, name={self.name}, public={self.is_public})>"