"""Unit: the phase-50 task-04 History-page contract.

The browser behavior itself is E2E-gated by the story suite (task 05);
like the other frontend-adjacent unit files, this module pins the
JS/CSS/HTML markers the History page depends on, so a silent
regression is caught without a browser:

* the anonymous no-fetch gate (the gate in, the table out, and the
  single ``GET /api/chats`` fetch lives ONLY in ``loadChats`` —
  unreachable from the anonymous branch);
* the inline two-step Delete (the "Delete? [Yes] [No]" pair, focus to
  Yes, the row kept on No / a failed request, ``Deleted "<title>".``
  on success) and the ``window.confirm`` absence in ``history.js``
  (owner-locked 2026-08-29: no native confirm dialog on this page);
* the ``/?chat=<id>`` Open-link href shape (TODO.md L5 — "return to
  that history with a click");
* ``#nav-history`` on ALL SEVEN pages (the phase-34 one-bar contract)
  + ``header.js``'s reveal-for-admin block;
* the full-width table CSS (AGENTS.md rule 5) + the confirm pair +
  the empty-state row.

The Containerfile stage-1 coverage (history.html copied, history.js
bundled) is pinned dynamically by
``tests/integration/test_containerfile_assets.py`` — a page or module
missing from stage 1 fails there.
"""
from __future__ import annotations

import re
from pathlib import Path

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

INDEX_HTML = FRONTEND / "index.html"
SOURCES_HTML = FRONTEND / "sources.html"
GIT_SOURCES_HTML = FRONTEND / "git-sources.html"
TUNING_HTML = FRONTEND / "tuning.html"
DOCUMENT_HTML = FRONTEND / "document.html"
LOGIN_HTML = FRONTEND / "login.html"
HISTORY_HTML = FRONTEND / "history.html"
HISTORY_JS = ASSETS / "history.js"
HEADER_JS = ASSETS / "header.js"
STYLES_CSS = ASSETS / "styles.css"

#: The phase-34 one-bar contract + the new History page: SEVEN pages.
ALL_PAGES = (
    INDEX_HTML,
    SOURCES_HTML,
    GIT_SOURCES_HTML,
    TUNING_HTML,
    DOCUMENT_HTML,
    LOGIN_HTML,
    HISTORY_HTML,
)


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


def _js() -> str:
    return _text(HISTORY_JS)


def _css() -> str:
    return _text(STYLES_CSS)


def _fn(js: str, name: str) -> str:
    """The source of a top-level ``function <name>(...)`` (to its close)."""
    start = js.find(f"function {name}(")
    assert start != -1, f"{name}() must exist in history.js"
    return js[start : js.find("\n}\n", start) + 4]


def _nav_history_tag(html: str) -> str:
    tag = re.search(r'<a[^>]*id="nav-history"[^>]*>', html)
    assert tag, "the #nav-history link is missing"
    return tag.group(0)


# ---------- the #nav-history link: all seven pages ----------


def test_nav_history_present_on_all_seven_pages() -> None:
    """The phase-34 one-bar contract extended by phase 50: the admin-only
    History link SHIPS hidden (revealed by header.js for admin) on every
    page, after the Tuning link, pointing at /history.html. The page's
    own link is the active one (is-active + aria-current)."""
    for html in ALL_PAGES:
        text = _text(html)
        tag = _nav_history_tag(text)
        assert 'href="/history.html"' in tag
        assert "hidden" in tag, f"{html.name}: #nav-history must ship hidden"
        # Placed after the Tuning link (the owner-locked position).
        assert text.find('id="nav-tuning"') < text.find('id="nav-history"'), (
            f"{html.name}: #nav-history must follow #nav-tuning"
        )
    # The history page is the only one whose link is active.
    for html in ALL_PAGES:
        tag = _nav_history_tag(_text(html))
        if html.name == "history.html":
            assert 'class="nav-link is-active"' in tag
            assert 'aria-current="page"' in tag
        else:
            assert "is-active" not in tag, (
                f"{html.name}: no nav link is current there"
            )


def test_nav_history_count_is_exactly_seven_pages() -> None:
    """The pin counting occurrences across ``frontend/*.html`` — exactly
    one ``id="nav-history"`` per page, seven pages, no duplicates and no
    extra page that forgot (or added twice)."""
    total = 0
    for html in sorted(FRONTEND.glob("*.html")):
        count = html.read_text(encoding="utf-8").count('id="nav-history"')
        assert count in (0, 1), f"{html.name}: #nav-history appears {count} times"
        total += count
    assert total == 7, f"expected #nav-history on 7 pages, found {total}"


def test_header_js_reveals_nav_history_for_admin() -> None:
    """header.js reveals #nav-history for admin exactly like
    #nav-tuning — the same ship-hidden / reveal-for-admin contract,
    inside initSharedHeader (null-safe: a page without the link is a
    no-op)."""
    js = _text(HEADER_JS)
    fn = js.find("function initSharedHeader")
    assert fn != -1
    body = js[fn : js.find("\n}", fn)]
    assert 'querySelector("#nav-history")' in body
    assert "navHistory.hidden = !admin" in body


# ---------- history.html: the page scaffold ----------


def test_history_page_scaffold_and_landmarks() -> None:
    """The standard page scaffold (AGENTS.md rule 5): skip link, the
    shared header, the steering panel + announcer (phase 34 — ships on
    every page), the page-head, the gate (ship-hidden), the
    role="status" live region, and the table inside the
    .table-wrap card. Footer with the version span (the index.html
    shape)."""
    html = _text(HISTORY_HTML)
    assert '<a class="skip-link" href="#main">' in html
    assert 'class="app-header"' in html
    assert 'nav class="app-nav" id="app-nav" aria-label="Primary"' in html
    tag = re.search(r'<section[^>]*id="steering-panel"[^>]*>', html)
    assert tag and "hidden" in tag.group(0), "the steering panel ships hidden"
    assert re.search(r'<p[^>]*id="steering-announcer"[^>]*role="status"[^>]*>', html)
    assert "<main id=\"main\" class=\"app-main\" tabindex=\"-1\">" in html
    assert '<h1>Saved chats</h1>' in html
    # The anonymous gate — the #sources-gate pattern, ship-hidden.
    gate = re.search(r'<section[^>]*id="history-gate"[^>]*>', html)
    assert gate and "hidden" in gate.group(0), "#history-gate must ship hidden"
    assert 'href="/login.html?next=/history.html"' in html, (
        "the gate's Sign in returns to the History page (no-JS fallback)"
    )
    # The action-feedback live region.
    assert re.search(r'<span[^>]*id="history-status"[^>]*role="status"[^>]*>', html)
    # The table wrapper: the .table-wrap card (scrollable) with its
    # own id, a labeled region, focusable.
    wrap = re.search(r'<div[^>]*class="table-wrap history-table-wrap"[^>]*>', html)
    assert wrap, "the table must live in the .table-wrap card"
    assert 'id="history-table-wrap"' in wrap.group(0)
    assert 'role="region"' in wrap.group(0) and 'tabindex="0"' in wrap.group(0)
    # Footer with the version span.
    assert 'class="footer-version" id="app-version"' in html


def test_history_table_skeleton() -> None:
    """The table skeleton: ``.history-table`` with the four columns —
    Title | Messages | Updated | Actions (the Actions header text is
    visually-hidden — the row buttons carry their own aria-labels) —
    and the empty-state row (ship-hidden, the exact copy)."""
    html = _text(HISTORY_HTML)
    assert '<table class="history-table">' in html
    for col in ('<th scope="col">Title</th>', '<th scope="col">Messages</th>',
                '<th scope="col">Updated</th>'):
        assert col in html
    actions_th = re.search(
        r'<th scope="col">([^<]*)<span class="visually-hidden">Actions</span></th>',
        html,
    )
    assert actions_th, "the Actions column header must be visually-hidden text"
    assert actions_th.group(1) == "", "no visible text beside the hidden header"
    # The empty-state row: ship-hidden, colspan 4, the exact copy.
    row = re.search(r'<tr[^>]*class="history-empty-row"[^>]*>', html)
    assert row, "the empty-state row must ship in the skeleton"
    assert "hidden" in row.group(0)
    assert 'id="history-empty-row"' in row.group(0)
    assert "<td colspan=\"4\">" in html
    assert (
        "No saved chats yet — finish a conversation and press"
        " <strong>Save</strong> in the chat."
    ) in html


def test_history_page_scripts_and_no_cdn() -> None:
    """Script load order (the house pattern): brand.js classic FIRST,
    the history.js module second, NO direct header.js <script> tag
    (single-evaluation design — history.js imports it relatively).
    No-CDN rule (AGENTS.md rule 6): no external script/link tags."""
    html = _text(HISTORY_HTML)
    srcs = re.findall(r'<script[^>]*src="([^"]+)"', html)
    assert srcs == ["assets/brand.js", "/assets/history.js"], (
        f"history.html must load brand.js (classic, first) + the history.js "
        f"module, got {srcs}"
    )
    js = _js()
    assert 'from "./header.js"' in js, (
        "history.js must import the shared header module relatively"
    )
    assert '"/assets/header.js"' not in js
    assert 'src="http' not in html and 'href="http' not in html, (
        "no CDN: every asset is local (AGENTS.md rule 6)"
    )


# ---------- the anonymous no-fetch gate ----------


def test_anonymous_boot_makes_no_chats_request() -> None:
    """The whoami gate in the boot IIFE: ``initSharedHeader()`` first
    (shared-header contract), then the anonymous branch hides the
    table, shows the gate, and RETURNS — no ``/api/chats`` request on
    the wire (the router 403s anonymous; the story E2E pins the
    request log). Only the admin path reaches ``loadChats()``. The
    single ``fetch("/api/chats")`` in the file lives in loadChats."""
    js = _js()
    assert js.count('fetch("/api/chats")') == 1, (
        "exactly ONE list fetch — the anonymous path must never add one"
    )
    load = _fn(js, "loadChats")
    assert 'fetch("/api/chats")' in load, "the list fetch lives in loadChats"

    boot = js[js.find("(async () => {"):]
    assert boot, "the boot IIFE must exist"
    assert "await initSharedHeader()" in boot
    gate_i = boot.find("if (!(await fetchIsAdmin()))")
    assert gate_i != -1, "the whoami gate must run in boot"
    # The anonymous branch: gate in, table out, then a bare return —
    # and NO fetch call anywhere inside it.
    branch = boot[gate_i : boot.find("return;", gate_i)]
    assert "fetch(" not in branch, "the anonymous branch must not fetch anything"
    assert "tableWrap.hidden = true" in branch
    assert "gateEl.hidden = false" in branch
    # The admin path: the gate hides, then the list loads.
    after = boot[boot.find("return;", gate_i):]
    assert "gateEl.hidden = true" in after
    assert "loadChats();" in after


def test_admin_load_renders_rows_or_empty_state() -> None:
    """loadChats: a 0-row fetch (and non-2xx / a network failure)
    reveals the empty-state row; a populated fetch renders one row per
    chat, in the server's order (latest activity first)."""
    js = _js()
    load = _fn(js, "loadChats")
    # Every no-data outcome lands on the empty state.
    assert load.count("showEmptyState()") == 3, (
        "network failure, non-2xx and a 0-row list all show the empty state"
    )
    assert "chats.length" in load
    assert "makeRow(chat)" in load
    empty = _fn(js, "showEmptyState")
    assert "emptyRow.hidden = false" in empty


# ---------- the /?chat=<id> Open link ----------


def test_open_link_is_the_title_with_chat_href() -> None:
    """makeRow: the Title cell is the Open link — ``/?chat=<id>``
    ("return to that history with a click", TODO.md L5) — rendered
    through textContent (the auto-title is user-derived; never
    innerHTML). The Updated cell carries the locale date+time with the
    full ISO in the title attribute; Messages is the message_count."""
    js = _js()
    row = _fn(js, "makeRow")
    assert 'link.href = "/?chat=" + chat.id' in row, (
        "the Open link returns to /?chat=<id> (task 03's boot load)"
    )
    assert 'link.className = "history-title-link"' in row
    assert "link.textContent = chat.title" in row, "XSS contract: textContent only"
    assert 'innerHTML' not in row, "makeRow must never build HTML"
    assert "String(chat.message_count)" in row
    assert "updatedTd.title = chat.updated_at" in row, "full ISO on hover"
    assert "fmtDate(chat.updated_at)" in row
    assert "link.title" in row or "titleTd.title = chat.title" in row


# ---------- the inline two-step Delete ----------


def test_two_step_delete_confirm_pair() -> None:
    """makeDeleteControl: the first click swaps the Delete button for
    the "Delete? [Yes] [No]" pair IN PLACE (keyboard-reachable — focus
    moves to Yes); No restores the Delete button (focus returns); the
    Delete button carries a labeled aria-name."""
    js = _js()
    # Owner-locked 2026-08-29: no native confirm dialog in the file.
    assert "window.confirm" not in js, "history.js must use the inline two-step only"
    fn = _fn(js, "makeDeleteControl")
    assert 'del.className = "history-delete"' in fn
    assert 'del.setAttribute("aria-label", `Delete saved chat: ${chat.title}`)' in fn
    assert 'label.textContent = "Delete?"' in fn
    assert 'yes.className = "history-confirm-yes"' in fn
    assert 'no.className = "history-confirm-no"' in fn
    # The shipped state of the actions cell IS the Delete button
    # (before any click) — a cell that only gains the button on
    # restore would render an empty Actions column.
    append = fn.find("cell.appendChild(del)")
    ret = fn.rfind("return cell")
    assert -1 < append < ret, "the Delete button is appended before the return"
    # The swap + the focus handoff.
    assert "cell.replaceChildren(label, yes, no)" in fn
    yes_swap = fn.find("cell.replaceChildren(label, yes, no)")
    assert fn.find("yes.focus()", yes_swap) > 0, "focus moves to Yes after the swap"
    # No (and the restore helper) bring the Delete button back, focused.
    restore_start = fn.find("function restoreDelete")
    restore_end = fn.find("\n  }", restore_start)
    restore = fn[restore_start:restore_end]
    assert "cell.replaceChildren(del)" in restore
    assert "del.focus()" in restore
    assert 'no.addEventListener("click", restoreDelete)' in fn


def test_confirmed_delete_outcomes() -> None:
    """confirmDelete: double-fire guarded; 2xx → the row is removed +
    the empty-state row reappears when it was the last + the live
    region `Deleted "<title>".`; a 404 (already gone) drops the stale
    row and says so; any other failure / a network error KEEPS the row
    (restore) and lands the error line."""
    js = _js()
    fn = _fn(js, "confirmDelete")
    assert "yesBtn.disabled = true" in fn
    assert "fetch(`/api/chats/${chat.id}`, { method: \"DELETE\" })" in fn
    # Success: remove + empty-state check + the exact live-region line.
    assert "row.remove()" in fn
    assert "showEmptyIfLast()" in fn
    assert 'announce(`Deleted "${chat.title}".`)' in fn
    # 404: the row is stale — drop it, no restore. (The branch slices
    # stop at the NEXT branch boundary — a template-literal `}` inside
    # an announce line must not end the slice early.)
    nf = fn.find("r.status === 404")
    assert nf != -1, "the 404 branch must be handled"
    notok = fn.find("if (!r.ok)")
    nf_branch = fn[nf:notok]
    assert "row.remove()" in nf_branch
    assert "already deleted" in nf_branch
    assert "restoreDelete()" not in nf_branch
    # !ok (non-404) and network: the row stays, the button is
    # retryable, and the error line lands.
    # !ok (non-404) and network: the row stays, the button is
    # retryable, and the error line lands. (The try/catch wraps the
    # FETCH, so it precedes the status branches; the !ok slice runs to
    # the function's close — the success tail after it carries neither
    # a restore nor that line.)
    assert notok != -1
    notok_branch = fn[notok:]
    assert "restoreDelete()" in notok_branch
    assert "try again" in notok_branch
    # The network-error catch: the reachable? line + the restore (the
    # catch wraps the fetch, so it precedes the status branches).
    catch_i = fn.find("} catch {")
    assert catch_i != -1
    catch_branch = fn[catch_i : fn.find("if (r.status === 404)")]
    assert "is the app reachable?" in catch_branch
    assert "restoreDelete()" in catch_branch
    # The empty-state row reappears exactly when the last data row is
    # gone (the hidden empty row itself ships in the tbody).
    empty = _fn(js, "showEmptyIfLast")
    assert "querySelectorAll(\"tr\").length > 1" in empty


# ---------- the table CSS ----------


def test_history_table_css_full_width_and_palette() -> None:
    """styles.css: .history-table is the full-width sources-table family
    (width 100%, --line borders, the brand-soft thead, row hover); the
    title link is the accent link (brand-ink, focus-visible); the
    confirm pair is Yes-on-error-rose + No-ghost; the empty-state row
    is the muted centered message. Every pair is Phase-08 AA
    (brand-ink/brand-soft 6.9:1, err 9.1:1, ink-soft >=6.9:1)."""
    css = _css()
    block = re.search(r"\.history-table \{([\s\S]*?)\n\}", css)
    assert block, "styles.css must style .history-table"
    body = block.group(1)
    assert "width: 100%" in body, "the table is FULL-WIDTH (AGENTS.md rule 5)"
    assert "min-width: 640px" in body
    th = re.search(r"\.history-table th \{([\s\S]*?)\n\}", css)
    assert th and "var(--brand-soft)" in th.group(1) and "var(--brand-ink)" in th.group(1)
    hover = re.search(r"\.history-table tbody tr:hover \{([^}]*)\}", css)
    assert hover, "row hover is part of the table family"
    link = re.search(r"\.history-title-link \{([\s\S]*?)\n\}", css)
    assert link and "var(--brand-ink)" in link.group(1), "the Open link is the accent link"
    assert re.search(r"\.history-title-link:focus-visible \{[^}]*outline[^}]*3px", css), (
        "the Open link keeps a :focus-visible outline"
    )
    yes = re.search(r"\.history-confirm-yes \{([\s\S]*?)\n\}", css)
    assert yes, "the confirm Yes button must be styled"
    ybody = yes.group(1)
    assert "var(--err-bg)" in ybody and "var(--err-ink)" in ybody and "var(--err-line)" in ybody
    no = re.search(r"\.history-confirm-no \{([\s\S]*?)\n\}", css)
    assert no and "background: transparent" in no.group(1), "No is the ghost"
    empty = re.search(r"\.history-empty-row td \{([\s\S]*?)\n\}", css)
    assert empty, "the empty-state row must be styled"
    ebody = empty.group(1)
    assert "text-align: center" in ebody and "var(--ink-soft)" in ebody


def test_history_table_mobile_behavior() -> None:
    """≤640px (the phase-07 responsive contract): the table keeps its
    full width (the .table-wrap's horizontal scroll already covers
    it) and the actions cell wraps so the two-step confirm pair fits
    the phone width."""
    css = _css()
    mobile = re.search(r"@media \(max-width: 640px\) \{([\s\S]*?)\n\}\n", css)
    assert mobile, "the mobile media query must exist"
    mbody = mobile.group(1)
    assert ".history-actions-cell { white-space: normal; }" in mbody
    assert ".history-actions { flex-wrap: wrap; }" in mbody