"""Unit: the shared header module contract (phase 19).

The browser behavior is E2E-covered (tests/e2e/test_shared_header.py);
here we pin the source-level wiring — the header.js exports, the cached
whoami promise, the per-page HTML ids (anonymous-safe hidden-by-default
controls), the sign-out binding move out of app.js, the non-chat New
Chat bindings, and the viewer-bar CSS — so a silent regression is caught
without a browser.
"""
from __future__ import annotations

import re
from pathlib import Path

FRONTEND = Path(__file__).resolve().parents[2] / "frontend"
ASSETS = FRONTEND / "assets"

HEADER_JS = ASSETS / "header.js"
APP_JS = ASSETS / "app.js"
SOURCES_JS = ASSETS / "sources.js"
DOCUMENT_JS = ASSETS / "document.js"
LOGIN_JS = ASSETS / "login.js"
TUNING_JS = ASSETS / "tuning.js"
STYLES_CSS = ASSETS / "styles.css"

INDEX_HTML = FRONTEND / "index.html"
SOURCES_HTML = FRONTEND / "sources.html"
DOCUMENT_HTML = FRONTEND / "document.html"
LOGIN_HTML = FRONTEND / "login.html"
TUNING_HTML = FRONTEND / "tuning.html"


def _text(path: Path) -> str:
    assert path.is_file(), f"missing frontend file: {path}"
    return path.read_text(encoding="utf-8")


def _script_srcs(path: Path) -> list[str]:
    return re.findall(r'<script[^>]*src="([^"]+)"', _text(path))


# ---------- header.js: the module itself ----------


def test_header_module_exports_the_three_functions() -> None:
    """header.js must export the three functions every page script
    imports (fetchIsAdmin / initSharedHeader / clearChatStorage)."""
    js = _text(HEADER_JS)
    assert "export function fetchIsAdmin" in js
    assert "export async function initSharedHeader" in js
    assert "export function clearChatStorage" in js


def test_whoami_fetch_is_cached_in_a_module_level_promise() -> None:
    """The whoami fetch is cached in the module-level `adminPromise`
    marker — first call stores the promise, later calls return it, so a
    page makes exactly ONE /api/whoami request per load no matter how
    many consumers await it. Anonymous-safe: a failure resolves to
    false."""
    js = _text(HEADER_JS)
    assert re.search(r"let\s+adminPromise\s*=\s*null", js), (
        "module-level adminPromise marker missing"
    )
    assert 'fetch("/api/whoami")' in js
    assert "if (!adminPromise)" in js, "fetchIsAdmin must reuse the stored promise"
    assert "return adminPromise" in js
    assert ".catch(() => false)" in js, "network failure must resolve to anonymous"


def test_init_shared_header_toggles_only_elements_that_exist() -> None:
    """initSharedHeader awaits the cached whoami, toggles ONLY the
    controls present on the page (querySelector, null-safe), and returns
    the admin flag for reuse."""
    js = _text(HEADER_JS)
    fn = js.find("function initSharedHeader")
    assert fn != -1
    body = js[fn : js.find("\n}", fn)]
    assert "await fetchIsAdmin()" in body
    for selector in ("#sign-in-link", "#sign-out-btn", "#nav-sources", "#nav-tuning"):
        assert f'querySelector("{selector}")' in body
    assert "return admin" in body, "callers may reuse the flag"


def test_clear_chat_storage_removes_the_phase14_key_silently() -> None:
    """clearChatStorage removes the SAME phase-14 key as app.js, inside
    a try/catch (private mode / storage errors are swallowed — the
    navigation still happens)."""
    js = _text(HEADER_JS)
    fn = js.find("function clearChatStorage")
    assert fn != -1
    body = js[fn : js.find("\n}", fn)]
    assert 'localStorage.removeItem("bor.chat.v1")' in body
    assert "try" in body and "catch" in body


def test_sign_out_binding_lives_in_the_shared_module() -> None:
    """The #sign-out-btn click binding (disable → POST /api/logout →
    reload) is owned by header.js at module import — exactly one
    implementation for every page that loads it."""
    js = _text(HEADER_JS)
    assert "querySelector(\"#sign-out-btn\")" in js
    assert "signOutBtn.addEventListener" in js
    assert "signOutBtn.disabled = true" in js
    assert 'fetch("/api/logout", { method: "POST" })' in js
    assert "location.reload()" in js


# ---------- HTML wiring: one shared bar on every page ----------


def test_nav_sources_ships_hidden_on_every_nav_page() -> None:
    """Phase 19 UX revision (owner permission 2026-08-23): the Sources
    nav link is hidden for anonymous — so it SHIPS with the hidden
    attribute (anonymous-safe default) on every page that has a nav
    (chat, sources, login)."""
    for html in (INDEX_HTML, SOURCES_HTML, LOGIN_HTML, TUNING_HTML):
        text = _text(html)
        assert re.search(r'id="nav-sources"[^>]*\bhidden\b', text), (
            f"{html.name}: #nav-sources must ship hidden"
        )


def test_nav_tuning_ships_hidden_on_the_tuning_page() -> None:
    """Phase 27: the Global Tuning page reuses the shared header — the
    "Tuning" nav link is admin-only, so it SHIPS hidden (revealed by
    initSharedHeader once whoami says admin), is the page's active link
    (is-active + aria-current), and the page loads markdown.js (classic)
    + the tuning.js module with NO direct header.js <script> tag
    (single-evaluation design)."""
    text = _text(TUNING_HTML)
    tag = re.search(r'<a[^>]*id="nav-tuning"[^>]*>', text)
    assert tag, "tuning.html must carry the #nav-tuning nav link"
    assert 'class="nav-link is-active"' in tag.group(0), "the Tuning link is the active one"
    assert 'aria-current="page"' in tag.group(0)
    assert "hidden" in tag.group(0), "#nav-tuning must ship hidden (admin-only)"
    srcs = _script_srcs(TUNING_HTML)
    assert [s for s in srcs if "header.js" in s] == [], "no direct header.js <script> tag"
    assert [s for s in srcs if "markdown.js" in s]
    assert [s for s in srcs if "tuning.js" in s]


def test_nav_sources_is_absent_from_the_viewer() -> None:
    """The document viewer has no nav — no #nav-sources element there (the
    module's missing-element no-op keeps it out)."""
    assert 'id="nav-sources"' not in _text(DOCUMENT_HTML)


def test_sources_and_viewer_carry_the_shared_controls() -> None:
    """Sources AND the document viewer gain the New Chat button + the
    Sign in / Sign out pair (both starting hidden — initSharedHeader
    reveals exactly one after whoami), and their page scripts load
    header.js (phase 23: via the page script's relative import, not a
    direct script tag)."""
    for html in (SOURCES_HTML, DOCUMENT_HTML):
        text = _text(html)
        assert 'id="new-chat-btn"' in text
        assert re.search(r'id="sign-in-link"[^>]*\bhidden\b', text)
        assert re.search(r'id="sign-out-btn"[^>]*\bhidden\b', text)
    for js_file in (SOURCES_JS, DOCUMENT_JS):
        assert 'from "./header.js"' in _text(js_file), (
            f"{js_file.name}: page script must load the shared header module"
        )
    # Each page's Sign in link returns to ITS OWN page after login.
    assert 'href="/login.html?next=/sources.html"' in _text(SOURCES_HTML)
    assert 'href="/login.html?next=/document.html"' in _text(DOCUMENT_HTML)


def test_header_module_loads_before_the_page_script() -> None:
    """Phase 23 (owner-confirmed single-evaluation design): NO page loads
    header.js with a direct <script> tag anymore. Each page script
    imports it relatively (`from "./header.js"`) — a hoisted import that
    the browser evaluates BEFORE the page script body runs, and that the
    image bundler inlines into the page bundle. The sign-out binding and
    the whoami cache therefore exist when the page script boots, and
    header.js can never be evaluated twice on a page (a tag + import pair
    would double-bind the sign-out listener)."""
    cases = [
        (INDEX_HTML, "app.js"),
        (SOURCES_HTML, "sources.js"),
        (DOCUMENT_HTML, "document.js"),
        (LOGIN_HTML, "login.js"),
    ]
    for html, page_script in cases:
        srcs = _script_srcs(html)
        assert [s for s in srcs if "header.js" in s] == [], (
            f"{html.name}: no direct header.js <script> tag (single-evaluation design)"
        )
        assert [s for s in srcs if page_script in s], (
            f"{html.name}: must load {page_script}"
        )
        js = _text(ASSETS / page_script)
        assert 'from "./header.js"' in js, (
            f"{page_script}: must import the shared header module relatively"
        )
        assert 'from "/assets/header.js"' not in js, (
            f"{page_script}: absolute header import would break the esbuild bundle"
        )


def test_login_page_carries_no_chat_controls() -> None:
    """Noted boundary (owner-confirmed): the login page is the auth page,
    not an app page — no New Chat / Sign in / Sign out controls there;
    header.js only toggles the Sources link."""
    text = _text(LOGIN_HTML)
    assert "new-chat-btn" not in text
    assert "sign-in-link" not in text
    assert "sign-out-btn" not in text


# ---------- page-script adaptations ----------


def test_app_js_delegates_the_shared_controls_to_header_module() -> None:
    """app.js imports the shared module, runs initSharedHeader() at boot
    (BEFORE the phase-14 restore), takes its isAdmin from the cached
    fetchIsAdmin(), and owns NO whoami fetch and NO sign-out binding
    anymore (both moved to header.js). Phase 23: the import is relative
    (`./header.js`) so esbuild can bundle it into the image."""
    js = _text(APP_JS)
    assert 'from "./header.js"' in js
    assert "fetchIsAdmin" in js and "initSharedHeader" in js
    assert "signOutBtn.addEventListener" not in js, (
        "the sign-out binding moved to header.js"
    )
    assert 'fetch("/api/whoami")' not in js, (
        "app.js must not fetch whoami itself — header.js caches it (one request/page)"
    )
    assert "loadAuthState" not in js, "loadAuthState was deleted in phase 19"
    assert "function applyAuthState" in js, "chat-page tuning gate stays"
    assert "isAdmin = await fetchIsAdmin();" in js
    init_idx = js.find("await initSharedHeader();")
    restore_idx = js.find("restoreConversation();")
    assert -1 < init_idx < restore_idx, (
        "header init must run before the phase-14 restore"
    )


def test_login_js_uses_the_shared_fetch_is_admin() -> None:
    """login.js switches its whoami check to the shared cached promise
    (one request per page) and calls initSharedHeader for the Sources
    link; its already-admin → redirect behavior is unchanged. Phase 23:
    the import is relative (`./header.js`)."""
    js = _text(LOGIN_JS)
    assert 'from "./header.js"' in js
    assert "fetchIsAdmin" in js
    assert "fetchIsAdmin()" in js
    assert "initSharedHeader()" in js
    assert 'fetch("/api/whoami")' not in js
    assert "window.location.replace(safeNext())" in js


def test_non_chat_pages_bind_new_chat_to_the_chat_page() -> None:
    """On sources, the viewer, and the tuning page, New Chat means "go to
    the chat, fresh": the binding clears the phase-14 key
    (clearChatStorage) and navigates to "/" — and each page runs
    initSharedHeader() at boot on the shared cached whoami. Phase 23:
    the import is relative (`./header.js`)."""
    for js_file in (SOURCES_JS, DOCUMENT_JS, TUNING_JS):
        js = _text(js_file)
        assert 'from "./header.js"' in js
        assert "initSharedHeader()" in js
        btn_idx = js.find("new-chat-btn")
        clear_idx = js.find("clearChatStorage();")
        nav_idx = js.find('window.location.href = "/"')
        assert -1 < btn_idx < clear_idx < nav_idx, (
            f"{js_file.name}: #new-chat-btn must clear storage then navigate to '/'"
        )
        assert 'fetch("/api/whoami")' not in js, (
            f"{js_file.name}: whoami goes through the shared cached promise"
        )


# ---------- viewer-bar CSS ----------


def test_viewer_bar_css_pushes_actions_right_and_title_clips() -> None:
    """styles.css defines .doc-header-actions (margin-left:auto flex
    cluster) and the title block keeps min-width: 0 so
    #doc-title/#doc-meta clip instead of overflowing the --header-h bar."""
    css = _text(STYLES_CSS)
    block = re.search(r"\.doc-header-actions\s*\{([^}]*)\}", css)
    assert block, "styles.css must define .doc-header-actions"
    body = block.group(1)
    assert "margin-left: auto" in body
    assert "display: flex" in body
    assert re.search(r"\.doc-title-block\s*\{[^}]*min-width:\s*0", css), (
        "the title block must keep clipping while the pills fit"
    )