from __future__ import annotations

import shutil
import subprocess
from dataclasses import dataclass, field
from html.parser import HTMLParser
from pathlib import Path

PROJECT_ROOT = Path(__file__).resolve().parents[1]
INDEX_HTML = PROJECT_ROOT / "app" / "static" / "index.html"
APP_JS = PROJECT_ROOT / "app" / "static" / "app.js"

FILTER_INPUT_IDS = {
    "instance-group-filter",
    "instance-status-filter",
    "group-status-filter",
    "history-instance-filter",
    "history-group-filter",
    "history-status-filter",
}

VOID_ELEMENTS = {
    "area",
    "base",
    "br",
    "col",
    "embed",
    "hr",
    "img",
    "input",
    "link",
    "meta",
    "param",
    "source",
    "track",
    "wbr",
}


@dataclass
class HtmlNode:
    tag: str
    attrs: dict[str, str | None]
    children: list[HtmlNode] = field(default_factory=list)


class HtmlTreeParser(HTMLParser):
    def __init__(self) -> None:
        super().__init__(convert_charrefs=True)
        self.root = HtmlNode("document", {})
        self._stack = [self.root]

    def handle_starttag(
        self, tag: str, attrs: list[tuple[str, str | None]]
    ) -> None:
        self._append_node(tag, attrs, push=tag not in VOID_ELEMENTS)

    def handle_startendtag(
        self, tag: str, attrs: list[tuple[str, str | None]]
    ) -> None:
        self._append_node(tag, attrs, push=False)

    def handle_endtag(self, tag: str) -> None:
        for index in range(len(self._stack) - 1, 0, -1):
            if self._stack[index].tag == tag:
                del self._stack[index:]
                return

    def _append_node(
        self,
        tag: str,
        attrs: list[tuple[str, str | None]],
        *,
        push: bool,
    ) -> None:
        node = HtmlNode(tag, dict(attrs))
        self._stack[-1].children.append(node)
        if push:
            self._stack.append(node)


def parse_index() -> HtmlNode:
    parser = HtmlTreeParser()
    parser.feed(INDEX_HTML.read_text(encoding="utf-8"))
    parser.close()
    return parser.root


def descendants(node: HtmlNode) -> list[HtmlNode]:
    result: list[HtmlNode] = []
    pending = list(reversed(node.children))
    while pending:
        current = pending.pop()
        result.append(current)
        pending.extend(reversed(current.children))
    return result


def has_class(node: HtmlNode, class_name: str) -> bool:
    return class_name in (node.attrs.get("class") or "").split()


def test_all_native_selects_are_replaced_by_custom_selects() -> None:
    nodes = descendants(parse_index())

    assert not [node for node in nodes if node.tag == "select"]
    assert len([node for node in nodes if "data-custom-select" in node.attrs]) == 7


def test_every_custom_select_has_scoped_hidden_input_and_valid_aria() -> None:
    nodes = descendants(parse_index())
    roots = [node for node in nodes if "data-custom-select" in node.attrs]
    controlled_ids: list[str] = []
    hidden_inputs: list[HtmlNode] = []

    for index, root in enumerate(roots, start=1):
        scoped_nodes = descendants(root)
        scoped_hidden = [
            node
            for node in scoped_nodes
            if node.tag == "input"
            and (node.attrs.get("type") or "").lower() == "hidden"
        ]
        triggers = [
            node
            for node in scoped_nodes
            if node.tag == "button" and has_class(node, "custom-select-trigger")
        ]
        listboxes = [
            node for node in scoped_nodes if node.attrs.get("role") == "listbox"
        ]
        description = root.attrs.get("id") or f"custom select #{index}"

        assert len(scoped_hidden) == 1, description
        assert len(triggers) == 1, description
        assert len(listboxes) == 1, description

        hidden_inputs.extend(scoped_hidden)
        trigger = triggers[0]
        listbox = listboxes[0]
        controls = trigger.attrs.get("aria-controls")
        listbox_id = listbox.attrs.get("id")

        assert trigger.attrs.get("aria-haspopup") == "listbox", description
        assert trigger.attrs.get("aria-expanded") in {"true", "false"}, description
        assert controls, description
        assert controls == listbox_id, description
        assert "data-custom-select-menu" in listbox.attrs, description
        controlled_ids.append(controls)

    assert len(controlled_ids) == len(set(controlled_ids)) == 7
    assert {
        node.attrs["id"] for node in hidden_inputs if node.attrs.get("id")
    } == FILTER_INPUT_IDS
    assert len(
        [node for node in hidden_inputs if node.attrs.get("name") == "group_id"]
    ) == 1


def test_shared_option_template_keeps_listbox_option_aria_contract() -> None:
    source = APP_JS.read_text(encoding="utf-8")
    marker = "function customSelectOptionMarkup("
    start = source.index(marker)
    end = source.index("\nfunction ", start + len(marker))
    function_source = source[start:end]

    assert source.count(marker) == 1
    assert source.count("customSelectOptionMarkup(") >= 2
    assert 'role="option"' in function_source
    assert 'aria-selected="${selected}"' in function_source
    assert 'tabindex="-1"' in function_source


def test_app_javascript_has_valid_syntax() -> None:
    node = shutil.which("node")
    assert node is not None, "Node.js is required to validate app/static/app.js"

    result = subprocess.run(
        [node, "--check", str(APP_JS)],
        capture_output=True,
        text=True,
        timeout=30,
        check=False,
    )

    assert result.returncode == 0, result.stderr or result.stdout