from __future__ import annotations
from bs4 import BeautifulSoup
import trafilatura, json
from .models import Node, SourceMeta
from .ids import stable_id
from .normalize import normalize_text

HEADING_TAGS = ["h1","h2","h3","h4","h5","h6"]

def parse_html(manifest_path: str, source: SourceMeta) -> Node:
    with open(manifest_path) as f:
        m = json.load(f)
    with open(m["artifact_path"], "rb") as f:
        html = f.read().decode("utf-8", errors="ignore")

    # Try trafilatura to get main content
    main_html = trafilatura.extract(html, include_tables=True, output_format="xml", include_comments=False) or html
    soup = BeautifulSoup(main_html, "lxml")

    root_id = stable_id(source.sha256 or source.url, "HTML")
    root = Node(node_id=root_id, path=[], label="ROOT", text="", html=None, children=[])

    # Build outline by headings; group following siblings until the next same-or-higher level
    def level(tag_name:str)->int: return int(tag_name[1]) if tag_name and tag_name[0]=="h" and tag_name[1].isdigit() else 7
    stack: list[tuple[int, Node]] = [(0, root)]

    for el in soup.find_all(HEADING_TAGS + ["p","li","table","pre"]):
        if el.name in HEADING_TAGS:
            lvl = level(el.name)
            title = normalize_text(el.get_text(" ", strip=True))
            path = [*(n.label for _, n in stack[1:]), title]
            node = Node(
                node_id=stable_id(source.sha256 or source.url, "/".join(path)),
                path=path, label=title, title=title, text="", html=None, children=[]
            )
            while stack and stack[-1][0] >= lvl: stack.pop()
            stack[-1][1].children.append(node)
            stack.append((lvl, node))
        else:
            txt = normalize_text(el.get_text(" ", strip=True))
            if not txt: continue
            stack[-1][1].text += (("\n\n" if stack[-1][1].text else "") + txt)

    # If no headings found, dump whole text under one child
    if not root.children:
        plain = normalize_text(BeautifulSoup(main_html, "lxml").get_text(" ", strip=True))
        node = Node(
            node_id=stable_id(source.sha256 or source.url, "BODY"),
            path=["Body"], label="Body", title="Body", text=plain
        )
        root.children.append(node)
    return root