Add FastAPI backend with agent system

backend/app/models/__init__.py

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+from app.models.base import Base
+from app.models.user import User
+from app.models.document import Document, DocumentChunk
+from app.models.task import Task, TaskHistory
+from app.models.forum import ForumPost, ForumReply
+from app.models.agent import Agent, AgentMessage
+from app.models.conversation import Conversation, Message
+from app.models.knowledge_graph import KGNode, KGEdge
+from app.models.memory import MemorySummary, UserMemory
+from app.models.todo import DailyTodo, TodoSource
+
+__all__ = [
+    "Base",
+    "User",
+    "Document",
+    "DocumentChunk",
+    "Task",
+    "TaskHistory",
+    "ForumPost",
+    "ForumReply",
+    "Agent",
+    "AgentMessage",
+    "Conversation",
+    "Message",
+    "KGNode",
+    "KGEdge",
+    "MemorySummary",
+    "UserMemory",
+    "DailyTodo",
+    "TodoSource",
+]

backend/app/models/agent.py

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+from sqlalchemy import Column, String, Text, Boolean, ForeignKey, Integer
+from sqlalchemy.orm import relationship
+from app.models.base import BaseModel
+
+
+class Agent(BaseModel):
+    __tablename__ = "agents"
+
+    name = Column(String(100), nullable=False)
+    role = Column(String(100), nullable=False)  # master, planner, executor, librarian, analyst
+    description = Column(Text, nullable=True)
+    system_prompt = Column(Text, nullable=False)
+    is_active = Column(Boolean, default=True)
+    is_default = Column(Boolean, default=False)
+
+    messages = relationship("AgentMessage", back_populates="agent", cascade="all, delete-orphan")
+    replies = relationship("ForumReply", back_populates="agent")
+
+
+class AgentMessage(BaseModel):
+    __tablename__ = "agent_messages"
+
+    agent_id = Column(String(36), ForeignKey("agents.id"), nullable=False, index=True)
+    conversation_id = Column(String(36), ForeignKey("conversations.id"), nullable=False, index=True)
+    role = Column(String(20), nullable=False)  # system, user, assistant
+    content = Column(Text, nullable=False)
+
+    agent = relationship("Agent", back_populates="messages")

backend/app/models/base.py

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+import uuid
+from datetime import datetime
+from sqlalchemy import Column, String, DateTime
+from app.database import Base
+
+
+class BaseModel(Base):
+    __abstract__ = True
+
+    id = Column(String(36), primary_key=True, default=lambda: str(uuid.uuid4()))
+    created_at = Column(DateTime, default=datetime.utcnow, nullable=False)
+    updated_at = Column(DateTime, default=datetime.utcnow, onupdate=datetime.utcnow, nullable=False)

backend/app/models/conversation.py

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+from sqlalchemy import Column, String, Text, Integer, ForeignKey, JSON
+from sqlalchemy.orm import relationship
+from app.models.base import BaseModel
+
+
+class Conversation(BaseModel):
+    __tablename__ = "conversations"
+
+    user_id = Column(String(36), ForeignKey("users.id"), nullable=False, index=True)
+    title = Column(String(500), nullable=True)
+    message_count = Column(Integer, default=0)
+
+    messages = relationship("Message", back_populates="conversation", cascade="all, delete-orphan")
+
+
+class Message(BaseModel):
+    __tablename__ = "messages"
+
+    conversation_id = Column(String(36), ForeignKey("conversations.id"), nullable=False, index=True)
+    role = Column(String(20), nullable=False)  # user, assistant, system
+    content = Column(Text, nullable=False)
+    model = Column(String(100), nullable=True)
+    tokens_used = Column(Integer, nullable=True)
+    attachments = Column(JSON, nullable=True)  # 新增: [{file_id, filename, file_type, file_size}]
+
+    conversation = relationship("Conversation", back_populates="messages")

backend/app/models/document.py

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+from sqlalchemy import Column, String, Integer, Text, ForeignKey, Boolean
+from sqlalchemy.orm import relationship
+from app.models.base import BaseModel
+
+
+class Document(BaseModel):
+    __tablename__ = "documents"
+
+    user_id = Column(String(36), ForeignKey("users.id"), nullable=False, index=True)
+    title = Column(String(500), nullable=False)
+    filename = Column(String(500), nullable=False)
+    file_type = Column(String(50), nullable=False)  # pdf, md, txt, docx
+    file_size = Column(Integer, nullable=False)
+    file_path = Column(String(1000), nullable=False)
+    folder_id = Column(String(36), ForeignKey("folders.id"), nullable=True)  # 新增
+    summary = Column(Text, nullable=True)
+    chunk_count = Column(Integer, default=0)
+    is_indexed = Column(Boolean, default=False)
+
+    chunks = relationship("DocumentChunk", back_populates="document", cascade="all, delete-orphan")
+
+
+class DocumentChunk(BaseModel):
+    __tablename__ = "document_chunks"
+
+    document_id = Column(String(36), ForeignKey("documents.id"), nullable=False, index=True)
+    chunk_index = Column(Integer, nullable=False)
+    content = Column(Text, nullable=False)
+    metadata_ = Column(String(2000), nullable=True)  # JSON 存储元数据
+    chroma_collection = Column(String(255), nullable=True)
+    chroma_id = Column(String(255), nullable=True)
+
+    document = relationship("Document", back_populates="chunks")

backend/app/models/folder.py

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+from sqlalchemy import Column, String, ForeignKey, UniqueConstraint
+from app.models.base import BaseModel
+
+
+class Folder(BaseModel):
+    __tablename__ = "folders"
+    __table_args__ = (
+        UniqueConstraint('user_id', 'parent_id', 'name', name='uq_user_parent_name'),
+    )
+
+    user_id = Column(String(36), ForeignKey("users.id"), nullable=False, index=True)
+    name = Column(String(255), nullable=False)
+    parent_id = Column(String(36), ForeignKey("folders.id"), nullable=True)

backend/app/models/forum.py

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+from sqlalchemy import Column, String, Text, Integer, ForeignKey, Boolean
+from sqlalchemy.orm import relationship
+from app.models.base import BaseModel
+
+
+class ForumPost(BaseModel):
+    __tablename__ = "forum_posts"
+
+    user_id = Column(String(36), ForeignKey("users.id"), nullable=False, index=True)
+    title = Column(String(500), nullable=False)
+    content = Column(Text, nullable=False)
+    category = Column(String(100), nullable=True)  # instruction, discussion, question
+    is_executed = Column(Boolean, default=False)
+    execution_result = Column(Text, nullable=True)
+    reply_count = Column(Integer, default=0)
+
+    replies = relationship("ForumReply", back_populates="post", cascade="all, delete-orphan")
+
+
+class ForumReply(BaseModel):
+    __tablename__ = "forum_replies"
+
+    post_id = Column(String(36), ForeignKey("forum_posts.id"), nullable=False, index=True)
+    user_id = Column(String(36), ForeignKey("users.id"), nullable=True)
+    agent_id = Column(String(36), ForeignKey("agents.id"), nullable=True)
+    content = Column(Text, nullable=False)
+    is_ai_reply = Column(Boolean, default=False)
+
+    post = relationship("ForumPost", back_populates="replies")
+    agent = relationship("Agent", back_populates="replies")

backend/app/models/knowledge_graph.py

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+from sqlalchemy import Column, String, Text, Integer, Float, ForeignKey, JSON
+from sqlalchemy.orm import relationship
+from app.models.base import BaseModel
+
+
+class KGNode(BaseModel):
+    __tablename__ = "kg_nodes"
+
+    user_id = Column(String(36), ForeignKey("users.id"), nullable=False, index=True)
+    name = Column(String(500), nullable=False)
+    entity_type = Column(String(100), nullable=False)  # person, concept, task, document, chunk, tag
+    description = Column(Text, nullable=True)
+    properties_ = Column(JSON, nullable=True)  # 额外属性
+    source_document_id = Column(String(36), ForeignKey("documents.id"), nullable=True)
+    importance = Column(Float, default=0.5)  # 重要性 0-1
+    last_updated_by = Column(String(36), nullable=True)  # 哪个 agent 更新过
+
+    outgoing_edges = relationship("KGEdge", foreign_keys="KGEdge.source_id", back_populates="source_node", cascade="all, delete-orphan")
+    incoming_edges = relationship("KGEdge", foreign_keys="KGEdge.target_id", back_populates="target_node", cascade="all, delete-orphan")
+
+
+class KGEdge(BaseModel):
+    __tablename__ = "kg_edges"
+
+    source_id = Column(String(36), ForeignKey("kg_nodes.id"), nullable=False, index=True)
+    target_id = Column(String(36), ForeignKey("kg_nodes.id"), nullable=False, index=True)
+    relation_type = Column(String(100), nullable=False)  # related_to, part_of, caused_by, depends_on, etc.
+    weight = Column(Float, default=0.5)  # 关系强度 0-1
+    properties_ = Column(JSON, nullable=True)
+
+    source_node = relationship("KGNode", foreign_keys=[source_id], back_populates="outgoing_edges")
+    target_node = relationship("KGNode", foreign_keys=[target_id], back_populates="incoming_edges")

backend/app/models/memory.py

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+from sqlalchemy import Column, String, Text, Integer, ForeignKey, Boolean, DateTime, Enum as SQLEnum
+from datetime import datetime
+from app.models.base import BaseModel
+
+
+class MemorySummary(BaseModel):
+    """
+    对话摘要 — 中期记忆
+    当一段对话超过阈值轮数时，自动生成摘要存入此表
+    """
+    __tablename__ = "memory_summaries"
+
+    user_id = Column(String(36), ForeignKey("users.id"), nullable=False, index=True)
+    conversation_id = Column(String(36), ForeignKey("conversations.id"), nullable=False, index=True)
+    summary_text = Column(Text, nullable=False)           # 摘要内容
+    turn_count = Column(Integer, default=0)                # 摘要时累计轮数
+    summary_at = Column(DateTime, default=datetime.utcnow, nullable=False)
+
+
+class UserMemory(BaseModel):
+    """
+    用户画像记忆 — 长期记忆
+    从对话中提取的用户事实、偏好、目标
+    """
+    __tablename__ = "user_memories"
+
+    user_id = Column(String(36), ForeignKey("users.id"), nullable=False, index=True)
+    memory_type = Column(String(50), nullable=False)       # fact | preference | goal | habit | other
+    content = Column(Text, nullable=False)                  # 记忆内容
+    importance = Column(Integer, default=5)                # 重要程度 1-10
+    is_recalled = Column(Boolean, default=False)           # 是否在当前对话中被召回
+    recall_count = Column(Integer, default=0)            # 被召回次数
+    source_conversation_id = Column(String(36), nullable=True)  # 来源对话
+    extracted_at = Column(DateTime, default=datetime.utcnow, nullable=False)
+    last_recalled_at = Column(DateTime, nullable=True)

backend/app/models/task.py

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+from sqlalchemy import Column, String, Text, Integer, ForeignKey, DateTime, Enum
+from sqlalchemy.orm import relationship
+from datetime import datetime
+from enum import Enum as PyEnum
+from app.models.base import BaseModel
+
+
+class TaskStatus(str, PyEnum):
+    TODO = "todo"
+    IN_PROGRESS = "in_progress"
+    DONE = "done"
+    CANCELLED = "cancelled"
+
+
+class TaskPriority(str, PyEnum):
+    LOW = "low"
+    MEDIUM = "medium"
+    HIGH = "high"
+    URGENT = "urgent"
+
+
+class Task(BaseModel):
+    __tablename__ = "tasks"
+
+    user_id = Column(String(36), ForeignKey("users.id"), nullable=False, index=True)
+    title = Column(String(500), nullable=False)
+    description = Column(Text, nullable=True)
+    status = Column(Enum(TaskStatus), default=TaskStatus.TODO, nullable=False, index=True)
+    priority = Column(Enum(TaskPriority), default=TaskPriority.MEDIUM, nullable=False)
+    due_date = Column(DateTime, nullable=True)
+    completed_at = Column(DateTime, nullable=True)
+    tags = Column(String(1000), nullable=True)  # JSON 数组
+
+    history = relationship("TaskHistory", back_populates="task", cascade="all, delete-orphan")
+
+
+class TaskHistory(BaseModel):
+    __tablename__ = "task_histories"
+
+    task_id = Column(String(36), ForeignKey("tasks.id"), nullable=False, index=True)
+    action = Column(String(100), nullable=False)  # created, status_changed, updated, deleted
+    old_value = Column(Text, nullable=True)
+    new_value = Column(Text, nullable=True)
+
+    task = relationship("Task", back_populates="history")

backend/app/models/test_folder.py

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+import pytest
+from app.models.folder import Folder
+
+
+def test_folder_model_creation():
+    folder = Folder(user_id="test-user", name="Test Folder")
+    assert folder.name == "Test Folder"
+    assert folder.parent_id is None

backend/app/models/todo.py

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+import uuid
+from datetime import datetime
+from sqlalchemy import Column, String, Boolean, DateTime, Enum
+from enum import Enum as PyEnum
+from app.models.base import BaseModel
+
+
+class TodoSource(str, PyEnum):
+    AI_KANBAN = "ai_kanban"
+    AI_CHAT = "ai_chat"
+    MANUAL = "manual"
+
+
+class DailyTodo(BaseModel):
+    __tablename__ = "daily_todos"
+
+    user_id = Column(String(36), nullable=False, index=True)
+    title = Column(String(500), nullable=False)
+    is_completed = Column(Boolean, default=False, nullable=False)
+    source = Column(Enum(TodoSource), default=TodoSource.MANUAL, nullable=False)
+    source_detail = Column(String(500), nullable=True)
+    source_ref_id = Column(String(36), nullable=True)
+    todo_date = Column(String(10), nullable=False)  # YYYY-MM-DD
+    completed_at = Column(DateTime, nullable=True)

backend/app/models/user.py

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+from sqlalchemy import Column, String, Boolean, JSON
+from app.models.base import BaseModel
+
+
+class User(BaseModel):
+    __tablename__ = "users"
+
+    email = Column(String(255), unique=True, nullable=False, index=True)
+    hashed_password = Column(String(255), nullable=False)
+    full_name = Column(String(255), nullable=True)
+    is_active = Column(Boolean, default=True, nullable=False)
+    is_superuser = Column(Boolean, default=False, nullable=False)
+    # 用户级配置
+    llm_config = Column(JSON, nullable=True)  # LLM 模型配置
+    scheduler_config = Column(JSON, nullable=True)  # 定时任务配置