"""Pydantic schemas for the Knowledge Base feature."""
from pydantic import BaseModel
from typing import Optional, List
from datetime import datetime


# --------------------------------------------------------------------------
# Knowledge Base
# --------------------------------------------------------------------------
class KnowledgeBaseBase(BaseModel):
    title: str
    description: Optional[str] = None


class KnowledgeBaseCreate(KnowledgeBaseBase):
    pass


class KnowledgeBaseUpdate(BaseModel):
    title: Optional[str] = None
    description: Optional[str] = None


class KnowledgeBaseResponse(BaseModel):
    id: int
    knowledge_base_code: Optional[str] = None
    title: str
    description: Optional[str] = None
    created_by: int
    created_at: Optional[datetime] = None
    last_updated_at: Optional[datetime] = None

    class Config:
        from_attributes = True


# --------------------------------------------------------------------------
# Topic
# --------------------------------------------------------------------------
class KnowledgeTopicBase(BaseModel):
    topic: str
    description: Optional[str] = None


class KnowledgeTopicCreate(KnowledgeTopicBase):
    pass


class KnowledgeTopicUpdate(BaseModel):
    topic: Optional[str] = None
    description: Optional[str] = None


class KnowledgeTopicResponse(BaseModel):
    id: int
    topic: str
    knowledge_base_id: int
    description: Optional[str] = None
    created_by: int
    created_at: Optional[datetime] = None
    last_updated_at: Optional[datetime] = None

    class Config:
        from_attributes = True


# --------------------------------------------------------------------------
# Category
# --------------------------------------------------------------------------
class KnowledgeCategoryBase(BaseModel):
    name: str
    description: Optional[str] = None


class KnowledgeCategoryCreate(KnowledgeCategoryBase):
    topic_id: int
    parent: Optional[int] = None


class KnowledgeCategoryUpdate(BaseModel):
    name: Optional[str] = None
    description: Optional[str] = None
    parent: Optional[int] = None


class KnowledgeCategoryResponse(BaseModel):
    id: int
    name: str
    parent: Optional[int] = None
    topic_id: int
    description: Optional[str] = None
    created_by: Optional[int] = None
    last_updated_by: Optional[int] = None

    class Config:
        from_attributes = True


# --------------------------------------------------------------------------
# Fact
# --------------------------------------------------------------------------
class KnowledgeFactBase(BaseModel):
    fact: str


class KnowledgeFactCreate(KnowledgeFactBase):
    topic_id: int
    category_id: Optional[int] = None


class KnowledgeFactUpdate(BaseModel):
    fact: Optional[str] = None
    category_id: Optional[int] = None


class KnowledgeFactResponse(BaseModel):
    id: int
    category_id: Optional[int] = None
    topic_id: int
    fact: str
    last_updated_at: Optional[datetime] = None

    class Config:
        from_attributes = True


# --------------------------------------------------------------------------
# Project <-> KnowledgeBase link
# --------------------------------------------------------------------------
class ProjectKnowledgeBaseLink(BaseModel):
    # Accept either a numeric id or a knowledge_base_code (mirrors how
    # projects are referenced elsewhere).
    knowledge_base: str


# --------------------------------------------------------------------------
# Nested tree (read-only aggregate)
# --------------------------------------------------------------------------
class CategoryTreeNode(BaseModel):
    id: int
    name: str
    parent: Optional[int] = None
    topic_id: int
    description: Optional[str] = None
    categories: List["CategoryTreeNode"] = []
    facts: List[KnowledgeFactResponse] = []


class TopicTreeNode(BaseModel):
    id: int
    topic: str
    knowledge_base_id: int
    description: Optional[str] = None
    categories: List[CategoryTreeNode] = []
    facts: List[KnowledgeFactResponse] = []


class KnowledgeBaseTree(BaseModel):
    id: int
    knowledge_base_code: Optional[str] = None
    title: str
    description: Optional[str] = None
    topics: List[TopicTreeNode] = []


CategoryTreeNode.model_rebuild()