hoàn thành phần Authentication

backend/app/models.py

@@ -0,0 +1,66 @@
+from datetime import datetime, timezone
+from sqlalchemy import (
+    Column,
+    Integer,
+    String,
+    Text,
+    ForeignKey,
+    DateTime,
+    UniqueConstraint,
+)
+from sqlalchemy.dialects.postgresql import JSONB
+from sqlalchemy.orm import relationship
+from .database import Base
+
+
+class User(Base):
+    __tablename__ = "users"
+
+    id = Column(Integer, primary_key=True, index=True)
+    username = Column(String(64), unique=True, nullable=False, index=True)
+    email = Column(String(255), unique=True, nullable=False, index=True)
+    password_hash = Column(String(255), nullable=False)
+    created_at = Column(DateTime(timezone=True), default=lambda: datetime.now(timezone.utc), nullable=False)
+
+    # Relationships
+    pdfs = relationship("PDF", back_populates="owner", cascade="all, delete-orphan")
+    annotations = relationship("Annotation", back_populates="owner", cascade="all, delete-orphan")
+
+
+class PDF(Base):
+    __tablename__ = "pdfs"
+
+    id = Column(Integer, primary_key=True, index=True)
+    user_id = Column(Integer, ForeignKey("users.id", ondelete="CASCADE"), nullable=False, index=True)
+    title = Column(String(255), nullable=False)
+    file_path = Column(Text, nullable=False)       # path inside Docker volume
+    total_pages = Column(Integer, nullable=True)   # populated after upload processing
+    created_at = Column(DateTime(timezone=True), default=lambda: datetime.now(timezone.utc), nullable=False)
+
+    # Relationships
+    owner = relationship("User", back_populates="pdfs")
+    annotations = relationship("Annotation", back_populates="pdf", cascade="all, delete-orphan")
+
+
+class Annotation(Base):
+    __tablename__ = "annotations"
+    __table_args__ = (
+        # One annotation record per (pdf, user, page) — upsert target
+        UniqueConstraint("pdf_id", "user_id", "page_number", name="uq_annotation_pdf_user_page"),
+    )
+
+    id = Column(Integer, primary_key=True, index=True)
+    pdf_id = Column(Integer, ForeignKey("pdfs.id", ondelete="CASCADE"), nullable=False, index=True)
+    user_id = Column(Integer, ForeignKey("users.id", ondelete="CASCADE"), nullable=False, index=True)
+    page_number = Column(Integer, nullable=False)   # 1-based
+    canvas_data = Column(JSONB, nullable=False, default=dict)  # Fabric.js JSON state
+    updated_at = Column(
+        DateTime(timezone=True),
+        default=lambda: datetime.now(timezone.utc),
+        onupdate=lambda: datetime.now(timezone.utc),
+        nullable=False,
+    )
+
+    # Relationships
+    pdf = relationship("PDF", back_populates="annotations")
+    owner = relationship("User", back_populates="annotations")