from sqlalchemy import Column, String, Text, Integer, Boolean, DateTime, Numeric, Enum, ForeignKey
from sqlalchemy.orm import relationship
from sqlalchemy.sql import func
from app.core.database import Base
import enum


class Priority(str, enum.Enum):
    LOW = "low"
    MEDIUM = "medium"
    HIGH = "high"
    URGENT = "urgent"


class Task(Base):
    __tablename__ = "pjctrl_tasks"

    id = Column(String(36), primary_key=True)
    project_id = Column(String(36), ForeignKey("pjctrl_projects.id", ondelete="CASCADE"), nullable=False)
    parent_task_id = Column(String(36), ForeignKey("pjctrl_tasks.id", ondelete="CASCADE"), nullable=True)
    title = Column(String(500), nullable=False)
    description = Column(Text, nullable=True)
    assignee_id = Column(String(36), ForeignKey("pjctrl_users.id"), nullable=True)
    status_id = Column(String(36), ForeignKey("pjctrl_task_statuses.id"), nullable=True)
    priority = Column(
        Enum("low", "medium", "high", "urgent", name="priority_enum"),
        default="medium",
        nullable=False
    )
    original_estimate = Column(Numeric(8, 2), nullable=True)
    time_spent = Column(Numeric(8, 2), default=0, nullable=False)
    blocker_flag = Column(Boolean, default=False, nullable=False)
    due_date = Column(DateTime, nullable=True)
    position = Column(Integer, default=0, nullable=False)
    created_by = Column(String(36), ForeignKey("pjctrl_users.id"), nullable=False)
    created_at = Column(DateTime, server_default=func.now(), nullable=False)
    updated_at = Column(DateTime, server_default=func.now(), onupdate=func.now(), nullable=False)

    # Relationships
    project = relationship("Project", back_populates="tasks")
    parent_task = relationship("Task", remote_side=[id], back_populates="subtasks")
    subtasks = relationship("Task", back_populates="parent_task", cascade="all, delete-orphan")
    assignee = relationship("User", foreign_keys=[assignee_id], back_populates="assigned_tasks")
    creator = relationship("User", foreign_keys=[created_by], back_populates="created_tasks")
    status = relationship("TaskStatus", back_populates="tasks")

    # Collaboration relationships
    comments = relationship("Comment", back_populates="task", cascade="all, delete-orphan")
    blockers = relationship("Blocker", back_populates="task", cascade="all, delete-orphan")