import datetime
from sqlalchemy import String, Text, DateTime, Integer, ForeignKey
from sqlalchemy.orm import Mapped, mapped_column, relationship
from app.database import Base
from app.models.tag import publication_tags


class Publication(Base):
    __tablename__ = "publications"

    id: Mapped[int] = mapped_column(primary_key=True, index=True)
    title: Mapped[str] = mapped_column(String(500), index=True)
    abstract: Mapped[str | None] = mapped_column(Text, nullable=True)
    content: Mapped[str | None] = mapped_column(Text, nullable=True)
    doi: Mapped[str | None] = mapped_column(String(255), unique=True, nullable=True, index=True)
    publication_type: Mapped[str] = mapped_column(String(50), default="article")
    journal: Mapped[str | None] = mapped_column(String(300), nullable=True)
    year: Mapped[int | None] = mapped_column(Integer, nullable=True, index=True)
    git_repo_url: Mapped[str | None] = mapped_column(String(500), nullable=True)
    video_url: Mapped[str | None] = mapped_column(String(500), nullable=True)
    view_count: Mapped[int] = mapped_column(Integer, default=0)
    citation_count: Mapped[int] = mapped_column(Integer, default=0)
    author_id: Mapped[int] = mapped_column(ForeignKey("users.id"), index=True)
    field_id: Mapped[int | None] = mapped_column(ForeignKey("fields.id"), nullable=True, index=True)
    created_at: Mapped[datetime.datetime] = mapped_column(DateTime, default=datetime.datetime.utcnow, index=True)
    updated_at: Mapped[datetime.datetime] = mapped_column(DateTime, default=datetime.datetime.utcnow, onupdate=datetime.datetime.utcnow)

    author = relationship("User", back_populates="publications")
    field = relationship("Field", back_populates="publications")
    files = relationship("PublicationFile", back_populates="publication", cascade="all, delete-orphan")
    comments = relationship("PublicationComment", back_populates="publication", cascade="all, delete-orphan")
    tags = relationship("Tag", secondary=publication_tags, back_populates="publications")
    citations = relationship("Citation", back_populates="publication", foreign_keys="Citation.publication_id", cascade="all, delete-orphan")
    cited_by = relationship("Citation", back_populates="cited_publication", foreign_keys="Citation.cited_publication_id")

    @property
    def pdf_file(self):
        for f in self.files:
            if f.file_type == "pdf":
                return f
        return None


class PublicationFile(Base):
    __tablename__ = "publication_files"

    id: Mapped[int] = mapped_column(primary_key=True, index=True)
    publication_id: Mapped[int] = mapped_column(ForeignKey("publications.id", ondelete="CASCADE"), index=True)
    file_path: Mapped[str] = mapped_column(String(500))
    file_type: Mapped[str] = mapped_column(String(50))
    original_name: Mapped[str] = mapped_column(String(300))
    file_size: Mapped[int] = mapped_column(Integer, default=0)
    created_at: Mapped[datetime.datetime] = mapped_column(DateTime, default=datetime.datetime.utcnow)

    publication = relationship("Publication", back_populates="files")


class PublicationComment(Base):
    __tablename__ = "publication_comments"

    id: Mapped[int] = mapped_column(primary_key=True, index=True)
    publication_id: Mapped[int] = mapped_column(ForeignKey("publications.id", ondelete="CASCADE"), index=True)
    author_id: Mapped[int] = mapped_column(ForeignKey("users.id"), index=True)
    parent_id: Mapped[int | None] = mapped_column(ForeignKey("publication_comments.id"), nullable=True)
    content: Mapped[str] = mapped_column(Text)
    created_at: Mapped[datetime.datetime] = mapped_column(DateTime, default=datetime.datetime.utcnow)

    publication = relationship("Publication", back_populates="comments")
    author = relationship("User")
    parent = relationship("PublicationComment", remote_side="PublicationComment.id", backref="replies")


class Citation(Base):
    __tablename__ = "citations"

    id: Mapped[int] = mapped_column(primary_key=True, index=True)
    publication_id: Mapped[int] = mapped_column(ForeignKey("publications.id", ondelete="CASCADE"), index=True)
    cited_publication_id: Mapped[int | None] = mapped_column(ForeignKey("publications.id"), nullable=True)
    citation_text: Mapped[str] = mapped_column(Text)
    created_at: Mapped[datetime.datetime] = mapped_column(DateTime, default=datetime.datetime.utcnow)

    publication = relationship("Publication", back_populates="citations", foreign_keys=[publication_id])
    cited_publication = relationship("Publication", back_populates="cited_by", foreign_keys=[cited_publication_id])