from typing import TYPE_CHECKING
from sqlalchemy import Column, DateTime, String, ForeignKey, UniqueConstraint
from sqlalchemy.sql import func
from .base import AutoID, Base

if TYPE_CHECKING:
    from .user import User
    from .project import ProjectNode
    from .workspace import Workspace

class ProjectLike(Base, AutoID):
    """项目点赞表"""
    __tablename__ = "project_likes"

    user_id = Column(
        String(User.id_length()), 
        ForeignKey("users.id", ondelete="CASCADE"), 
        index=True
    )
    project_node_id = Column(
        String(ProjectNode.id_length()), 
        ForeignKey("project_nodes.id", ondelete="CASCADE"), 
        index=True
    )
    
    created_at = Column(DateTime(timezone=True), server_default=func.now())

    # 联合唯一约束，防止同一用户重复点赞
    __table_args__ = (UniqueConstraint("user_id", "project_node_id", name="uq_user_project_like"),)


class ProjectFavorite(Base, AutoID):
    """项目收藏表"""
    __tablename__ = "project_favorites"

    user_id = Column(
        String(User.id_length()), 
        ForeignKey("users.id", ondelete="CASCADE"), 
        index=True
    )
    project_node_id = Column(
        String(ProjectNode.id_length()), 
        ForeignKey("project_nodes.id", ondelete="CASCADE"), 
        index=True
    )
    
    created_at = Column(DateTime(timezone=True), server_default=func.now())

    # 联合唯一约束，防止重复收藏
    __table_args__ = (UniqueConstraint("user_id", "project_node_id", name="uq_user_project_favorite"),)


class ProjectShare(Base, AutoID):
    """项目转发/分享记录表"""
    __tablename__ = "project_shares"

    user_id = Column(
        String(User.id_length()), 
        ForeignKey("users.id", ondelete="CASCADE"), 
        index=True
    )
    project_node_id = Column(
        String(ProjectNode.id_length()), 
        ForeignKey("project_nodes.id", ondelete="CASCADE"), 
        index=True
    )
    
    # 转发去向或渠道，例如 'internal' (转发到其他工作区), 'twitter', 'link' (复制链接)
    share_target = Column(String, default="internal", nullable=False)
    
    # 如果是转发到特定工作区，可以记录目标工作区 ID
    target_workspace_id = Column(
        String(Workspace.id_length()), 
        ForeignKey("workspaces.id", ondelete="SET NULL"), 
        nullable=True
    )

    created_at = Column(DateTime(timezone=True), server_default=func.now())