from datetime import datetime
from enum import Enum as PyEnum

from sqlalchemy import (
    Boolean,
    Column,
    DateTime,
    Enum,
    ForeignKey,
    Integer,
    String,
    Table,
    Text,
)
from sqlalchemy.orm import relationship

from app.db.base import Base


class TaskStatus(str, PyEnum):
    TODO = "todo"
    IN_PROGRESS = "in_progress"
    COMPLETED = "completed"
    CANCELLED = "cancelled"


class TaskPriority(str, PyEnum):
    LOW = "low"
    MEDIUM = "medium"
    HIGH = "high"
    URGENT = "urgent"


# Association table for task assignments
task_assignments = Table(
    "task_assignments",
    Base.metadata,
    Column("task_id", Integer, ForeignKey("tasks.id"), primary_key=True),
    Column("user_id", Integer, ForeignKey("users.id"), primary_key=True),
    Column("assigned_at", DateTime, default=datetime.utcnow),
)


class Task(Base):
    __tablename__ = "tasks"

    id = Column(Integer, primary_key=True, index=True)
    title = Column(String(255), nullable=False, index=True)
    description = Column(Text, nullable=True)
    status = Column(Enum(TaskStatus), default=TaskStatus.TODO, nullable=False)
    priority = Column(Enum(TaskPriority), default=TaskPriority.MEDIUM, nullable=False)
    due_date = Column(DateTime, nullable=True)
    owner_id = Column(Integer, ForeignKey("users.id"), nullable=False)
    is_deleted = Column(Boolean, default=False)
    created_at = Column(DateTime, default=datetime.utcnow)
    updated_at = Column(DateTime, default=datetime.utcnow, onupdate=datetime.utcnow)
    completed_at = Column(DateTime, nullable=True)

    # Relationships
    owner = relationship("User", back_populates="tasks")
    assignees = relationship("User",
                           secondary="task_assignments",
                           back_populates="assigned_tasks")

    def __repr__(self):
        return f"<Task {self.title} ({self.status})>"