"""Proposal and issue detail pages scroll with the window.

Gabriel's review of muse proposal #12 could not be reached because those
pages lock the window (`body.app-shell`) and only a short inner column
scrolls. These pages now use a normal document scroll and a 3/4 + 1/4
grid that stacks on narrow screens. The issue list and other app-shell
pages stay locked.
"""
from __future__ import annotations

import re
from pathlib import Path

ROOT = Path(__file__).resolve().parents[1]
PROPOSAL_HTML = ROOT / "musehub/templates/musehub/pages/proposal_detail.html"
ISSUE_HTML = ROOT / "musehub/templates/musehub/pages/issue_detail.html"
ISSUE_LIST_HTML = ROOT / "musehub/templates/musehub/pages/issue_list.html"
PROPOSAL_SCSS = ROOT / "src/scss/pages/_proposal-detail.scss"
ISSUES_SCSS = ROOT / "src/scss/pages/_issues.scss"
APP_CSS = ROOT / "musehub/templates/musehub/static/app.css"
MAIN_PY = ROOT / "musehub/main.py"

_GRID = "grid-template-columns: minmax(0, 3fr) minmax(0, 1fr)"
_NARROW = "grid-template-columns: minmax(0, 1fr)"


def _block(source: str, selector: str) -> str:
    """Return the first rule body whose selector line equals `selector`."""
    pattern = rf"(?m)^{re.escape(selector)}\s*\{{"
    match = re.search(pattern, source)
    assert match is not None, f"missing selector {selector}"
    start = match.end()
    depth = 1
    i = start
    while i < len(source) and depth:
        if source[i] == "{":
            depth += 1
        elif source[i] == "}":
            depth -= 1
        i += 1
    return source[start : i - 1]


def test_tier1_templates_do_not_opt_into_app_shell() -> None:
    """Unit: detail templates must not set the viewport-lock body class."""
    for path in (PROPOSAL_HTML, ISSUE_HTML):
        text = path.read_text(encoding="utf-8")
        assert "body_class" not in text, path.name
        assert "{% block body_class %}app-shell{% endblock %}" not in text


def test_tier1_issue_list_stays_on_app_shell() -> None:
    """Unit: this change does not unlock the issue list page."""
    text = ISSUE_LIST_HTML.read_text(encoding="utf-8")
    assert 'body_class %}app-shell' in text


def test_tier2_columns_are_three_quarters_and_one_quarter() -> None:
    """Integration: both detail layouts use the same 3fr / 1fr grid."""
    for path, selector in (
        (PROPOSAL_SCSS, ".prd-layout"),
        (ISSUES_SCSS, ".isd-layout"),
    ):
        block = _block(path.read_text(encoding="utf-8"), selector)
        assert _GRID in block, path.name
        assert "@media (max-width: 900px)" in block
        assert _NARROW in block


def test_tier2_detail_columns_do_not_scroll_themselves() -> None:
    """Integration: the mouse scrolls the page, not an inner box."""
    proposal = PROPOSAL_SCSS.read_text(encoding="utf-8")
    issues = ISSUES_SCSS.read_text(encoding="utf-8")
    for source, selector in (
        (proposal, ".prd-page"),
        (proposal, ".prd-main"),
        (proposal, ".proposal-sidebar"),
        (issues, ".isd-page"),
        (issues, ".isd-main"),
        (issues, ".isd-sidebar"),
    ):
        block = _block(source, selector)
        assert "overflow-y: auto" not in block, selector
        assert "overflow: hidden" not in block, selector


def test_tier3_compiled_css_matches_the_grid() -> None:
    """End to end: the stylesheet the browser loads contains the new grid."""
    css = APP_CSS.read_text(encoding="utf-8")
    wide = "grid-template-columns:minmax(0, 3fr) minmax(0, 1fr)"
    assert css.count(wide) >= 2
    assert ".prd-layout{" in css
    assert ".isd-layout{" in css
    assert ".prd-main{min-width:0;padding-bottom:var(--space-10);overflow:visible}" in css
    assert ".isd-main{min-width:0;overflow:visible}" in css


def test_tier4_narrow_breakpoint_is_present_for_both_pages() -> None:
    """Stress-shaped contract: both pages collapse at the same breakpoint."""
    css = APP_CSS.read_text(encoding="utf-8")
    narrow = "grid-template-columns:minmax(0, 1fr)"
    assert "@media(max-width: 900px){.prd-layout{" + narrow + "}" in css
    assert "@media(max-width: 900px){.isd-layout{" + narrow + "}" in css


def test_tier5_page_wrappers_are_not_height_locked() -> None:
    """Data integrity: page wrappers do not reclaim a viewport height."""
    for path, selector in (
        (PROPOSAL_SCSS, ".prd-page"),
        (ISSUES_SCSS, ".isd-page"),
    ):
        block = _block(path.read_text(encoding="utf-8"), selector)
        assert "100dvh" not in block
        assert "min-height: 0" not in block


def test_tier6_compiled_stylesheet_stays_a_single_file() -> None:
    """Performance: layout change does not add a second stylesheet."""
    assert APP_CSS.is_file()
    assert APP_CSS.stat().st_size < 2_000_000


def test_tier7_csp_still_blocks_inline_scripts() -> None:
    """Security: this layout fix must not allow unsafe-inline scripts."""
    text = MAIN_PY.read_text(encoding="utf-8")
    start = text.index('response.headers["Content-Security-Policy"]')
    header = text[start : text.index("upgrade-insecure-requests", start)]
    script_src = header.split("script-src", 1)[1].split(";", 1)[0]
    assert "unsafe-inline" not in script_src
    assert "'self'" in script_src