from datetime import datetime
from enum import Enum
from sqlalchemy import String, Text, DateTime, ForeignKey, Boolean, UniqueConstraint
from sqlalchemy.orm import Mapped, mapped_column, relationship

from app.core.database import Base


class DisputeStatus(str, Enum):
    OPEN = "open"
    RESOLVED_VALID = "valid"
    RESOLVED_INVALID = "invalid"


class Dispute(Base):
    """Dispute against a completed assignment's proof"""
    __tablename__ = "disputes"

    id: Mapped[int] = mapped_column(primary_key=True)
    assignment_id: Mapped[int] = mapped_column(ForeignKey("assignments.id", ondelete="CASCADE"), unique=True, index=True)
    raised_by_id: Mapped[int] = mapped_column(ForeignKey("users.id", ondelete="CASCADE"))
    reason: Mapped[str] = mapped_column(Text, nullable=False)
    status: Mapped[str] = mapped_column(String(20), default=DisputeStatus.OPEN.value)
    created_at: Mapped[datetime] = mapped_column(DateTime, default=datetime.utcnow)
    resolved_at: Mapped[datetime | None] = mapped_column(DateTime, nullable=True)

    # Relationships
    assignment: Mapped["Assignment"] = relationship("Assignment", back_populates="dispute")
    raised_by: Mapped["User"] = relationship("User", foreign_keys=[raised_by_id])
    comments: Mapped[list["DisputeComment"]] = relationship("DisputeComment", back_populates="dispute", cascade="all, delete-orphan")
    votes: Mapped[list["DisputeVote"]] = relationship("DisputeVote", back_populates="dispute", cascade="all, delete-orphan")


class DisputeComment(Base):
    """Comment in a dispute discussion"""
    __tablename__ = "dispute_comments"

    id: Mapped[int] = mapped_column(primary_key=True)
    dispute_id: Mapped[int] = mapped_column(ForeignKey("disputes.id", ondelete="CASCADE"), index=True)
    user_id: Mapped[int] = mapped_column(ForeignKey("users.id", ondelete="CASCADE"))
    text: Mapped[str] = mapped_column(Text, nullable=False)
    created_at: Mapped[datetime] = mapped_column(DateTime, default=datetime.utcnow)

    # Relationships
    dispute: Mapped["Dispute"] = relationship("Dispute", back_populates="comments")
    user: Mapped["User"] = relationship("User")


class DisputeVote(Base):
    """Vote in a dispute (valid or invalid)"""
    __tablename__ = "dispute_votes"

    id: Mapped[int] = mapped_column(primary_key=True)
    dispute_id: Mapped[int] = mapped_column(ForeignKey("disputes.id", ondelete="CASCADE"), index=True)
    user_id: Mapped[int] = mapped_column(ForeignKey("users.id", ondelete="CASCADE"))
    vote: Mapped[bool] = mapped_column(Boolean, nullable=False)  # True = valid, False = invalid
    created_at: Mapped[datetime] = mapped_column(DateTime, default=datetime.utcnow)

    # Unique constraint: one vote per user per dispute
    __table_args__ = (
        UniqueConstraint("dispute_id", "user_id", name="uq_dispute_vote_user"),
    )

    # Relationships
    dispute: Mapped["Dispute"] = relationship("Dispute", back_populates="votes")
    user: Mapped["User"] = relationship("User")