from __future__ import annotations
from pydantic import BaseModel, HttpUrl, Field
from typing import List, Optional, Tuple, Literal, Dict
from datetime import datetime

class SourceMeta(BaseModel):
    jurisdiction: Literal["HK", "EU", "ICAO", "SESAR", "ASTM", "ISO", "OTHER"] = "OTHER"
    authority: Optional[str] = None
    collection: Optional[str] = None
    canonical_id: Optional[str] = None
    title: Optional[str] = None
    lang: str = "en"
    version: Optional[str] = None
    effective_date: Optional[datetime] = None
    publication_date: Optional[datetime] = None
    retrieved_at: datetime = Field(default_factory=datetime.utcnow)
    url: HttpUrl
    media_type: Literal["application/pdf", "text/html", "application/xhtml+xml", "text/plain"]
    etag: Optional[str] = None
    last_modified: Optional[str] = None
    sha256: Optional[str] = None
    pages: Optional[int] = None
    notes: Optional[str] = None

class Node(BaseModel):
    node_id: str
    path: List[str]
    label: str
    title: Optional[str] = None
    page_span: Optional[Tuple[int, int]] = None
    text: str
    html: Optional[str] = None
    numbering: Optional[str] = None
    children: List["Node"] = Field(default_factory=list)
    node_hash: Optional[str] = None

Node.model_rebuild()

class Chunk(BaseModel):
    source: SourceMeta
    node_id: str
    chunk_id: str
    path: List[str]
    text: str
    html: Optional[str] = None
    page_span: Optional[Tuple[int, int]] = None
    token_count: int
    heading_breadcrumb: Optional[str] = None
    numbering: Optional[str] = None
    citations_in: Optional[List[Dict[str, str]]] = None
    tags: Optional[List[str]] = None
    concepts: Optional[List[str]] = None