"""US09-04: the user manual, checked against the application it describes.

The manual's most perishable claim is its error catalogue: a code renamed in a route
leaves a page confidently explaining something that can no longer happen, and the
operator meeting the new code finds nothing. So the catalogue is compared with the
codes the application can actually emit, in both directions.

The screenshots are generated and checked by
``tests/e2e/test_user_manual_screenshots.py``.
"""

from __future__ import annotations

import re
from pathlib import Path

REPO = Path(__file__).resolve().parents[2]
DOCS = REPO / "docs"
STAGES = DOCS / "stages"
PACKAGE = REPO / "photo_pipeline"
ERRORS = (DOCS / "errors.md").read_text()
ALL_DOCS = "\n".join(path.read_text() for path in DOCS.rglob("*.md"))

# The shapes an error code is emitted in. Everything the API returns goes through one
# of these, so the set they find is the set an operator can meet.
EMITTERS = (
    re.compile(r'_error\(\s*\d+,\s*"([a-z_]+)"'),
    # The status may be a literal or an exception's own code, so match either.
    re.compile(r'_envelope\(\s*[\w.]+,\s*"([a-z_]+)"'),
    re.compile(r'"code":\s*"([a-z_]+)"'),
    re.compile(r'code="([a-z_]+)"'),
    re.compile(r'Refusal\(\s*\d+,\s*"([a-z_]+)"'),
)

# Codes raised deep in a service and mapped to a response by its route; they are what
# the browser shows, so the manual owes the reader an entry.
SERVICE_CODES = {
    "lock_held",
    "path_not_allowed",
    "rename_recovery_required",
    "stale_preflight",
    "access_denied",
    "too_many_attempts",
}

STAGE_PAGES = (
    "inventory",
    "duplicates",
    "safety",
    "analysis",
    "albums",
    "renames",
    "uploads",
    "archive",
    "diagnostics",
)


def emitted_codes() -> set[str]:
    found: set[str] = set()
    for path in PACKAGE.rglob("*.py"):
        text = path.read_text()
        for pattern in EMITTERS:
            found |= set(pattern.findall(text))
    for code in SERVICE_CODES:
        assert re.search(rf'"{code}"', "\n".join(p.read_text() for p in PACKAGE.rglob("*.py"))), (
            f"{code} is documented as a service code but no longer exists"
        )
    return (found | SERVICE_CODES) - {"code"}


def documented_codes() -> set[str]:
    return set(re.findall(r"`([a-z][a-z_]{3,})`", ERRORS))


# ── the error catalogue ──────────────────────────────────────────────────────


def test_every_error_the_application_can_emit_is_documented():
    missing = sorted(emitted_codes() - documented_codes())
    assert missing == [], f"undocumented error codes: {missing}"


def test_the_catalogue_documents_no_code_that_cannot_happen():
    """Backticked snake_case in the catalogue is either a code, a setting, or one of
    the handful of prose terms below."""
    prose = {
        "diagnostics",
        "dry_run",
        "approve_dry_run",
        "current_path",
        "archived_online",
        "archived_offline",
    }
    settings = set(re.findall(r"PHOTO_PIPELINE_[A-Z_]+", ERRORS))
    invented = sorted(
        code
        for code in documented_codes()
        if code not in emitted_codes()
        and code not in prose
        and f"PHOTO_PIPELINE_{code.upper()}" not in settings
    )
    assert invented == [], f"documented but not emitted anywhere: {invented}"


def test_the_protective_refusals_are_explained_as_intentional():
    """These are the ones a reader is most likely to mistake for a broken
    application, which is exactly when they start working around them."""
    for code in ("lock_held", "rename_recovery_required", "stale_preflight", "not_runnable"):
        row = next(line for line in ERRORS.splitlines() if line.startswith(f"| `{code}`"))
        assert len(row.split("|")) >= 4, f"{code} has no cause and remedy"


# ── the stage pages ──────────────────────────────────────────────────────────


def test_there_is_one_page_per_workflow_stage():
    missing = [name for name in STAGE_PAGES if not (STAGES / f"{name}.md").is_file()]
    assert missing == [], f"stages without a page: {missing}"


def test_every_stage_page_answers_the_four_questions():
    """The shape is the point: a page that skips 'what it changes' is the page
    somebody needed."""
    for name in STAGE_PAGES:
        text = (STAGES / f"{name}.md").read_text()
        for question in ("What it is for.", "What you decide.", "What it changes.", "What it refuses."):
            assert question in text, f"{name}.md does not answer: {question}"


def test_every_stage_page_shows_a_screenshot():
    for name in STAGE_PAGES:
        text = (STAGES / f"{name}.md").read_text()
        assert re.search(r"!\[[^\]]+\]\(\.\./images/[a-z-]+\.png\)", text), (
            f"{name}.md carries no screenshot"
        )


def test_the_guided_pass_names_the_irreversible_stages():
    first_pass = (DOCS / "first-pass.md").read_text()
    for stage in ("renames", "uploads", "archive"):
        assert f"stages/{stage}.md" in first_pass
    assert "point" in first_pass.lower() and "no return" in first_pass.lower()


def test_recovery_covers_each_interruption_the_application_can_survive():
    recovery = (DOCS / "recovery.md").read_text()
    for topic in (
        "interrupted rename",
        "uncertain upload",
        "failed migration",
        "restored backup",
    ):
        assert topic in recovery.lower(), f"recovery does not cover: {topic}"


def test_the_manual_is_reachable_from_the_index():
    index = (DOCS / "index.md").read_text()
    for page in [f"stages/{name}.md" for name in STAGE_PAGES] + [
        "first-pass.md",
        "errors.md",
        "recovery.md",
    ]:
        assert page in index, f"{page} is not linked from the index"


def test_the_screenshots_are_declared_as_generated():
    """The allow list had to be widened for them, so the reason has to be visible
    where the widening is."""
    config = (REPO / "work_item" / ".work-item.yml").read_text()
    assert "docs/images/**" in config
    assert "test_user_manual_screenshots.py" in config, "no note saying who generates them"