from sqlalchemy import Boolean, Column, DateTime, Enum, ForeignKey, Integer, String, Text, UniqueConstraint
from sqlalchemy.orm import relationship
from sqlalchemy.sql import func

from .db import Base


class User(Base):
    __tablename__ = "users"

    id = Column(Integer, primary_key=True)
    username = Column(String(50), unique=True, nullable=False)
    email = Column(String(120), unique=True, nullable=False)
    password_hash = Column(String(255), nullable=False)
    profile_photo_path = Column(String(255), nullable=True)
    role = Column(Enum("admin", "user", name="user_role"), nullable=False, default="user")
    is_active = Column(Boolean, default=True, nullable=False)
    created_at = Column(DateTime, server_default=func.now(), nullable=False)

    tasks_assigned = relationship("Task", back_populates="assigned_user", foreign_keys="Task.assigned_user_id")
    tasks_created = relationship("Task", back_populates="created_by", foreign_keys="Task.created_by_id")
    memberships = relationship("ProjectMember", back_populates="user")


class Project(Base):
    __tablename__ = "projects"

    id = Column(Integer, primary_key=True)
    name = Column(String(120), nullable=False)
    description = Column(Text, nullable=True)
    is_group = Column(Boolean, default=False, nullable=False)
    created_at = Column(DateTime, server_default=func.now(), nullable=False)

    tasks = relationship("Task", back_populates="project")
    members = relationship("ProjectMember", back_populates="project")


class ProjectMember(Base):
    __tablename__ = "project_members"
    __table_args__ = (UniqueConstraint("project_id", "user_id", name="uq_project_member"),)

    id = Column(Integer, primary_key=True)
    project_id = Column(Integer, ForeignKey("projects.id"), nullable=False)
    user_id = Column(Integer, ForeignKey("users.id"), nullable=False)
    role = Column(Enum("member", "owner", name="project_role"), nullable=False, default="member")

    project = relationship("Project", back_populates="members")
    user = relationship("User", back_populates="memberships")


class Task(Base):
    __tablename__ = "tasks"

    id = Column(Integer, primary_key=True)
    project_id = Column(Integer, ForeignKey("projects.id"), nullable=False)
    title = Column(String(200), nullable=False)
    description = Column(Text, nullable=True)
    priority = Column(Enum("low", "medium", "high", name="task_priority"), nullable=False, default="medium")
    status = Column(Enum("not_started", "in_progress", "done", name="task_status"), nullable=False, default="not_started")
    duration_days = Column(Integer, nullable=False, default=1)
    started_at = Column(DateTime, nullable=True)
    support_url = Column(String(500), nullable=True)
    assigned_user_id = Column(Integer, ForeignKey("users.id"), nullable=True)
    created_by_id = Column(Integer, ForeignKey("users.id"), nullable=False)
    overdue_alert_sent_at = Column(DateTime, nullable=True)
    created_at = Column(DateTime, server_default=func.now(), nullable=False)
    updated_at = Column(DateTime, server_default=func.now(), onupdate=func.now(), nullable=False)

    project = relationship("Project", back_populates="tasks")
    assigned_user = relationship("User", back_populates="tasks_assigned", foreign_keys=[assigned_user_id])
    created_by = relationship("User", back_populates="tasks_created", foreign_keys=[created_by_id])
    requests = relationship(
        "TaskRequest",
        back_populates="task",
        cascade="all, delete-orphan",
    )


class TaskRequest(Base):
    __tablename__ = "task_requests"

    id = Column(Integer, primary_key=True)
    task_id = Column(Integer, ForeignKey("tasks.id", ondelete="CASCADE"), nullable=False)
    requester_id = Column(Integer, ForeignKey("users.id"), nullable=False)
    target_user_id = Column(Integer, ForeignKey("users.id"), nullable=False)
    status = Column(Enum("pending", "accepted", "rejected", name="request_status"), nullable=False, default="pending")
    created_at = Column(DateTime, server_default=func.now(), nullable=False)
    responded_at = Column(DateTime, nullable=True)

    task = relationship("Task", back_populates="requests")
    requester = relationship("User", foreign_keys=[requester_id])
    target_user = relationship("User", foreign_keys=[target_user_id])