"""Unit: the phase-37 "calling tool" frontend contract (task 05).

No new Python app logic exists for this task — the behavior lives in
``frontend/assets/app.js`` + ``styles.css`` and is E2E-gated by the story
suite (task 06). Like the other frontend-adjacent unit files, this module
pins the JS/CSS markers the story depends on, so a silent regression in
the tool branch, the persistence shape, or the tool-line styling 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_tool_branch_is_a_first_class_turn_branch() -> None:
    """The turn handler must branch on `tool` frames BETWEEN the
    thinking and delta branches: the stream stays alive (guard clears),
    the brain wrap is created on demand, and the label state is
    applied only while the UI state is still "thinking" (a late frame
    after the first delta just appends the line — never a crash)."""
    js = _js()
    thinking_idx = js.find('ev.type === "thinking"')
    tool_idx = js.find('ev.type === "tool"')
    delta_idx = js.find('ev.type === "delta"')
    assert -1 < thinking_idx < tool_idx < delta_idx, (
        "the turn handler must branch on tool frames"
    )
    branch = js[tool_idx:delta_idx]
    assert "toolAcc.push" in branch, "every tool frame is recorded for persistence"
    assert "clearTurnTimeout()" in branch, "a tool frame proves the stream is alive"
    assert 'addMessage("brain", "")' in branch, "first frame creates the brain wrap"
    assert "uiState === UI_STATE.thinking" in branch, (
        "label updates only while the state is still thinking"
    )
    assert "appendToolLine(wrap, name, argument)" in branch
    # No setUiState in the branch: the state stays "thinking" (never stale).
    assert "setUiState" not in branch, (
        "the tool branch must keep uiState=thinking (button stays disabled)"
    )


def test_calling_tool_label_strings() -> None:
    """The 'calling tool' label strings the story keys off: the button
    text and the status/typing-indicator labels. Phase 39 centralizes
    the brand prefix: the name resolves from window.BOR_BRAND at call
    time via brand() (the default name renders the same bytes)."""
    js = _js()
    tool_idx = js.find('ev.type === "tool"')
    delta_idx = js.find('ev.type === "delta"')
    branch = js[tool_idx:delta_idx]
    assert '"Calling tool…"' in branch, "the button carries the calling-tool text"
    assert "`${brand()} is listing documents`" in branch
    assert "`${brand()} is reading ${argument}`" in branch
    assert "sendStatus.textContent = toolStatus" in branch, (
        "the #send-status live region announces what Brain is doing"
    )
    assert 'setAttribute("aria-label", toolStatus)' in branch, (
        "the typing indicator label follows the tool state"
    )
    # The elapsed-seconds hint keeps running through tool frames: the
    # branch must not stop/restart the clock.
    assert "stopThinkingClock" not in branch
    assert "startThinkingClock" not in branch


def test_tool_lines_render_into_the_bubble_wrap() -> None:
    """appendToolLine: first frame creates the .tool-calls list (role=list
    + accessible name) BEFORE the bubble — below an existing Thinking
    block — and each line is a .tool-call listitem with the exact marks:
    🔎 Listing documents / 📄 Reading <code>path</code>. The path goes
    through textContent (storage can never inject HTML)."""
    js = _js()
    fn = js.find("function appendToolLine")
    assert fn != -1, "appendToolLine must exist"
    body = js[fn : js.find("\n}\n", fn)]
    assert 'querySelector(".tool-calls")' in body, "idempotent per wrap"
    assert 'className = "tool-calls"' in body
    assert 'setAttribute("role", "list")' in body
    assert 'setAttribute("aria-label", "Tool calls")' in body
    assert 'insertBefore(container, body.querySelector(".bubble"))' in body, (
        "the list sits ABOVE the answer"
    )
    assert 'className = "tool-call"' in body
    assert 'setAttribute("role", "listitem")' in body
    assert 'line.textContent = "📄 Reading "' in body
    assert 'line.textContent = "🔎 Listing documents"' in body
    assert "code.textContent = argument" in body, (
        "the path is data — textContent, never innerHTML"
    )
    assert "name === \"read_document\" && argument" in body


def test_tool_branch_is_append_only_and_interleaving_safe() -> None:
    """Append-only, the same rule as thinking: multiple calls append
    multiple lines in order, and a tool frame after the first delta
    (should not happen in v1) still appends — the branch has no early
    return gated on acc/delta state."""
    js = _js()
    tool_idx = js.find('ev.type === "tool"')
    delta_idx = js.find('ev.type === "delta"')
    branch = js[tool_idx:delta_idx]
    assert "if (aborted) return" not in branch, (
        "the aborted guard lives at the dispatch top, not per branch"
    )
    assert "acc" not in branch.split("appendToolLine")[0].replace("toolAcc", ""), (
        "the tool branch must not depend on accumulated answer text"
    )


def test_tool_frames_persist_next_to_thinking() -> None:
    """The `done` save point gains an optional `tools` key next to
    `thinking` (empty turns persist exactly as before — `undefined`
    drops the key from the JSON), and the accumulator is turn-scoped
    in handleSend."""
    js = _js()
    assert "let toolAcc = []" in js
    done_idx = js.find('ev.type === "done"')
    error_idx = js.find('ev.type === "error"')
    assert -1 < done_idx < error_idx
    done_block = js[done_idx:error_idx]
    assert "thinking: thinkingAcc || undefined" in done_block
    assert "tools: toolAcc.length ? toolAcc : undefined" in done_block, (
        "tools persisted next to thinking, optional like it"
    )


def test_tool_lines_re_render_on_restore() -> None:
    """Phase 14 convention: a stored brain record with `tools` re-renders
    the lines on load through the SAME append helper (after the thinking
    re-render, before the deflected/sources additions)."""
    js = _js()
    fn = js.find("function renderStoredMessage")
    assert fn != -1
    end = js.find("function restoreConversation")
    body = js[fn:end]
    assert "Array.isArray(m.tools)" in body
    assert "appendToolLine(wrap, t.name, arg)" in body
    thinking_restore = body.find("if (m.thinking)")
    tools_restore = body.find("Array.isArray(m.tools)")
    assert -1 < thinking_restore < tools_restore, (
        "tools restore sits after the thinking restore (same order as live)"
    )
    assert "typeof t.name !== \"string\"" in body, "malformed entries skipped"


def test_thinking_block_stays_on_top_of_tool_lines() -> None:
    """If a tool frame precedes the first thinking frame, the Thinking
    block is still created ABOVE the tool lines (scratchpad on top),
    not below them."""
    js = _js()
    fn = js.find("function ensureThinkingBlock")
    assert fn != -1
    body = js[fn : js.find("\n}\n", fn)]
    assert 'querySelector(".tool-calls")' in body, (
        "the thinking anchor must account for existing tool lines"
    )
    assert 'querySelector(".bubble")' in body
    assert "insertBefore" in body
    assert "block.open = true" in body


def test_tool_call_style_is_accent_and_contrast_safe() -> None:
    """styles.css: .tool-call is an inline row with the accent palette
    (distinct from the brand-ink Thinking block) and mono `code` styling
    for the path; the wrapper stacks lines without shifting the column."""
    css = _css()
    assert ".tool-calls" in css
    assert ".tool-call" in css
    m = re.search(r"\.tool-call \{([^}]*)\}", css)
    assert m, "the .tool-call rule must exist"
    row = m.group(1)
    assert "display: flex" in row, "inline row: icon + text"
    assert "var(--accent-ink)" in row, (
        "accent color distinguishes it from the thinking block (≈10.4:1 on surface)"
    )
    assert "var(--accent-line)" in row, "accent left border"
    code = re.search(r"\.tool-call code \{([^}]*)\}", css)
    assert code, "the path `code` must be styled"
    assert "var(--mono)" in code.group(1)
    assert "var(--ink)" in code.group(1)  # ≈11.5:1 on --brand-soft
    assert "gap" in css.split(".tool-calls {")[1].split("}")[0], (
        "lines stack with a gap — append-only, no reflow"
    )


def test_no_cdn_added() -> None:
    """AGENTS.md rule 6: the tool state adds no external script/link."""
    index = (FRONTEND / "index.html").read_text(encoding="utf-8")
    assert 'src="http' not in index and 'href="http' not in index