"""Tests for issue #1325 — fenced code blocks in user message bubbles."""
import os
import subprocess
import tempfile

UI_JS = os.path.join(os.path.dirname(__file__), '..', 'static', 'ui.js')


def _extract_js_functions():
    """Extract esc, fence helpers, and _renderUserFencedBlocks from ui.js."""
    src = open(UI_JS).read()

    def extract_function(name):
        start = src.find(f"function {name}(")
        if start < 0:
            raise AssertionError(f"{name} not found in ui.js")
        i = src.find("{", start)
        depth = 1
        i += 1
        while i < len(src) and depth:
            if src[i] == "{":
                depth += 1
            elif src[i] == "}":
                depth -= 1
            i += 1
        return src[start:i]

    esc_line = next(line for line in src.split("\n") if line.startswith("const esc="))
    helper_defs = "\n".join(
        extract_function(name)
        for name in ("_matchBacktickFenceLine", "_isBacktickFenceClose", "_renderUserFencedBlocks")
    )
    return esc_line, helper_defs


def _run_user_render(text_input):
    """Return the HTML output of _renderUserFencedBlocks for the given input text."""
    import json
    esc_def, fn_def = _extract_js_functions()
    js_code = esc_def + '\n' + fn_def + '\n'
    js_code += 'var input = JSON.parse(process.argv[2]);\n'
    js_code += 'process.stdout.write(_renderUserFencedBlocks(input));\n'
    tf = tempfile.NamedTemporaryFile(mode='w', suffix='.js', delete=False, encoding='utf-8')
    tf.write(js_code)
    tf.close()
    try:
        result = subprocess.run(
            ['node', tf.name, json.dumps(text_input)],
            capture_output=True, text=True, timeout=10
        )
        if result.returncode != 0:
            raise RuntimeError(f"node error: {result.stderr}")
        return result.stdout
    finally:
        os.unlink(tf.name)


class TestUserFencedBlocks:
    """Fenced code blocks in user messages should render as <pre><code>."""

    def test_simple_fenced_block(self):
        out = _run_user_render("hello\n```python\nprint(1)\n```\nworld")
        assert '<pre><code class="language-python">' in out
        assert 'print(1)' in out
        # Newlines around the fenced block become <br> (same as original plain-text path)
        assert 'hello<br>' in out
        assert '<br>world' in out

    def test_fenced_block_escaped_html(self):
        """HTML in code blocks should be escaped."""
        out = _run_user_render("```html\n<div>hi</div>\n```")
        assert '&lt;div&gt;' in out
        # No raw <div> in code content
        assert '<div>' not in out.replace('&lt;div&gt;', '').replace('&gt;', '')

    def test_plain_text_not_interpreted_as_markdown(self):
        """Bold/italic/links in non-fenced text should stay escaped."""
        out = _run_user_render("**bold** and *italic* and <script>alert(1)</script>")
        assert '**bold**' in out
        assert '*italic*' in out
        assert '&lt;script&gt;' in out
        assert '<strong>' not in out

    def test_language_header_shown(self):
        out = _run_user_render("```javascript\nconst x = 1;\n```")
        assert 'class="pre-header"' in out
        assert 'javascript' in out

    def test_no_language_no_header(self):
        out = _run_user_render("```\nsome code\n```")
        assert 'class="pre-header"' not in out
        assert '<pre><code>' in out
        assert 'some code' in out

    def test_diff_block_colored(self):
        out = _run_user_render("```diff\n+added\n-removed\n```")
        assert 'diff-block' in out
        assert 'diff-plus' in out
        assert 'diff-minus' in out

    def test_multiple_fenced_blocks(self):
        out = _run_user_render("first\n```python\n1\n```\nmiddle\n```js\n2\n```\nlast")
        assert 'language-python' in out
        assert 'language-js' in out
        assert 'first<br>' in out
        assert '<br>last' in out

    def test_fenced_block_with_ampersand(self):
        out = _run_user_render("```python\nx & y\n```")
        assert 'x &amp; y' in out

    def test_empty_code_block(self):
        out = _run_user_render("```\n```")
        assert '<pre><code>' in out

    def test_special_chars_outside_blocks_escaped(self):
        out = _run_user_render("a < b > c & d")
        assert 'a &lt; b &gt; c &amp; d' in out

    def test_links_not_rendered_in_plain_text(self):
        """URLs in plain text should NOT become clickable links."""
        out = _run_user_render("Check https://example.com for details")
        assert '<a ' not in out
        assert 'https://example.com' in out

    def test_four_backtick_outer_fence_preserves_inner_triple_fence(self):
        """User-message code fences should follow CommonMark fence-length matching too."""
        out = _run_user_render("````md\n```inner\nfoo\n```\n````")
        assert out.count("<pre>") == 1
        assert out.count("</pre>") == 1
        assert '<div class="pre-header">md</div>' in out
        assert "```inner" in out
        assert "foo" in out
        assert "<br>````" not in out

    def test_inline_backticks_not_touched(self):
        """Inline backticks (single backtick, not fenced block) should remain escaped as text."""
        out = _run_user_render("use `var x = 1` here")
        assert '`var x = 1`' in out
        assert '<code>' not in out
