"""Unit: the loading-feedback contract in the static frontend (phase 06).

The JS behavior itself is E2E-covered (tests/e2e/test_loading_feedback.py);
here we pin the exported constants and state-machine markers that the
story depends on, so a silent regression in app.js/styles.css is caught
without a browser.
"""
from __future__ import annotations

import re
from pathlib import Path

FRONTEND = Path(__file__).resolve().parents[2] / "frontend"
APP_JS = FRONTEND / "assets" / "app.js"
STYLES_CSS = FRONTEND / "assets" / "styles.css"


def _js() -> str:
    return APP_JS.read_text(encoding="utf-8")


def _css() -> str:
    return STYLES_CSS.read_text(encoding="utf-8")


def test_turn_timeout_constant_exported_at_120s() -> None:
    """The 120s client-side guard (PLAN §7.4) must be an *exported*
    constant — testable, and the single value the E2E timeout story keys
    off."""
    js = _js()
    match = re.search(r"export\s+const\s+TURN_TIMEOUT_MS\s*=\s*120_?000\s*;", js)
    assert match, "app.js must export `const TURN_TIMEOUT_MS = 120000`"


def test_state_machine_has_all_four_states() -> None:
    """idle → thinking → streaming → done | error → idle (PLAN §7.4).

    `done` is not a UI state: it settles into `idle` in the turn handler's
    finally block, so the state machine itself has exactly four states.
    """
    js = _js()
    for state in ("idle", "thinking", "streaming", "error"):
        assert re.search(rf'{state}:\s*"{state}"', js), f"state {state!r} missing"
    assert "function setUiState" in js, "setUiState must exist as the single entry point"
    assert "export function setUiState" in js, "setUiState must be exported (testable)"


def test_typing_indicator_contract_strings() -> None:
    """The indicator's accessible label and the 10s elapsed-seconds hint
    are the strings screen readers (and the E2E) rely on."""
    js = _js()
    assert 'TYPING_LABEL = "Brain of Reese is thinking"' in js
    assert "still thinking" in js, "elapsed-seconds hint must update the aria label"
    assert "secs < 10" in js, "the hint must only appear after 10s of silence"
    assert "role=\"status\"" in js, "typing bubble must be role=status"


def test_error_banner_has_actionable_hint() -> None:
    """Every error path (SSE error event, non-2xx, 120s timeout) must
    surface the same actionable retry hint (story AC4)."""
    js = _js()
    assert "check the LLM is reachable" in js
    assert '"role", "alert"' in js, "error banner must be role=alert"
    # the banner must be the red error variant
    assert "is-error" in js


def test_reduced_motion_calm_not_removed() -> None:
    """prefers-reduced-motion: feedback is calmed, never removed (story
    AC7). Dots go static; the spinner only slows down."""
    css = _css()
    blocks = re.findall(
        r"@media \(prefers-reduced-motion: reduce\) \{([\s\S]*?)\n\}", css
    )
    assert blocks, "styles.css must contain prefers-reduced-motion rules"
    assert any(".typing span" in b and "animation: none" in b for b in blocks), (
        "typing dots must have a static fallback under reduced motion"
    )
    assert any(".spinner" in b and "animation-duration" in b for b in blocks), (
        "spinner must slow down (not vanish) under reduced motion"
    )


def test_busy_button_style_tokens() -> None:
    """Story spec: busy send button is #a5b4fc with the 16px white-arc
    spinner; the label swaps Send ↔ Thinking…."""
    css = _css()
    js = _js()
    assert ".send-btn:disabled" in css
    assert "#a5b4fc" in css
    assert re.search(r"\.spinner \{[^}]*width: 16px", css)
    assert "Thinking…" in js
    assert 'sendLabel.textContent' in js