"""Regression guards for canonical documentation and instruction contracts."""

from __future__ import annotations

import re
from pathlib import Path

from transcription.config import Settings

PROJECT_ROOT = Path(__file__).resolve().parents[1]


ACTIVE_CONTRACT_FILES = (
    ".github/instructions/services.instructions.md",
    ".github/instructions/ui.instructions.md",
    ".github/instructions/error-handling.instructions.md",
    ".github/skills/python-code-reviewer/skill.md",
    ".github/skills/evidence-provenance-auditor/skill.md",
    "docs/index.md",
    "docs/architecture.md",
    "docs/requirements.md",
    "docs/schema.md",
    "docs/error_handling.md",
    "docs/ui/README.md",
)


LEGACY_REFERENCE_MARKERS = (
    "docs-v4x-archive",
    "docs/ver4/history.md",
    "docs/ver4.0",
    "docs/ver4.1",
    "docs/ver4.2",
    "docs/ver4.3",
    "docs/ver4.4",
    "docs/ver4.5",
    "docs/ver4.6",
    "docs/ver4.7",
)


def _read(relative_path: str) -> str:
    return (PROJECT_ROOT / relative_path).read_text(encoding="utf-8")


BASELINE_SOURCE = "docs/index.md"

# Docs that legitimately discuss versions other than the current baseline: the roadmap plans
# future work, and migration/deployment notes describe historical phases by name.
BASELINE_SCAN_EXCLUSIONS = frozenset(
    {
        "docs/roadmap_plan.md",
        "docs/data_migration.md",
        "docs/cloudflare_tunnel_access.md",
        "docs/production-runbook.md",
        "docs/backup_restore.md",
    }
)

_BASELINE_DECLARATION = re.compile(r"Current Baseline:\s*V(\d+\.\d+)")
_CURRENT_VERSION_CLAIM = re.compile(r"\b(?:current|active)\s+V(\d+\.\d+)", re.IGNORECASE)


def _declared_baseline() -> str:
    """Return the one baseline version the canonical doc set must agree on."""
    match = _BASELINE_DECLARATION.search(_read(BASELINE_SOURCE))
    assert match is not None, f"{BASELINE_SOURCE} must declare 'Current Baseline: V<major>.<minor>'"
    return match.group(1)


def _baseline_scanned_docs() -> list[Path]:
    docs_root = PROJECT_ROOT / "docs"
    return sorted(
        path
        for path in docs_root.rglob("*.md")
        # docs/reviews/** are dated, non-canonical snapshots and are pinned to the version
        # that was current when they were written.
        if "reviews" not in path.relative_to(docs_root).parts
        and path.relative_to(PROJECT_ROOT).as_posix() not in BASELINE_SCAN_EXCLUSIONS
    )


def test_canonical_docs_declare_one_consistent_baseline():
    """A stale baseline label makes canonical docs read as drift against current code.

    Every canonical doc that names the current baseline must name the same one, so a version
    bump cannot leave half the authority set describing a superseded release as current.
    """
    baseline = _declared_baseline()
    violations: dict[str, list[str]] = {}

    for path in _baseline_scanned_docs():
        relative = path.relative_to(PROJECT_ROOT).as_posix()
        text = path.read_text(encoding="utf-8")
        stale = {
            version
            for pattern in (_BASELINE_DECLARATION, _CURRENT_VERSION_CLAIM)
            for version in pattern.findall(text)
            if version != baseline
        }
        if stale:
            violations[relative] = sorted(stale)

    assert violations == {}, (
        f"Canonical baseline is V{baseline} (declared in {BASELINE_SOURCE}), "
        f"but these docs claim another version is current: {violations}"
    )


def test_active_contract_files_are_present():
    """Guard the guard: ensure all expected authority files are scanned."""
    missing = [path for path in ACTIVE_CONTRACT_FILES if not (PROJECT_ROOT / path).exists()]
    assert missing == []


def test_no_legacy_authority_references_in_active_contract_files():
    """Active contracts must not route authority through removed revision trees."""
    violations: dict[str, list[str]] = {}
    for relative_path in ACTIVE_CONTRACT_FILES:
        text = _read(relative_path)
        found = [marker for marker in LEGACY_REFERENCE_MARKERS if marker in text]
        if found:
            violations[relative_path] = found
    assert violations == {}


def test_canonical_authority_references_are_present():
    """Critical instruction and skill files must keep canonical references explicit."""
    required_fragments = {
        ".github/instructions/services.instructions.md": (
            "docs/",
            "./error-handling.instructions.md",
            "src/transcription/db/models.py",
            "docs/schema.md",
            "append-only",
        ),
        ".github/instructions/ui.instructions.md": (
            "docs/",
            "./error-handling.instructions.md",
            "src/transcription/db/models.py",
            "docs/schema.md",
        ),
        ".github/instructions/error-handling.instructions.md": (
            "docs/error_handling.md",
            "docs/requirements.md",
        ),
        ".github/skills/python-code-reviewer/skill.md": (
            "docs/*",
            "docs/schema.md",
            ".github/instructions/error-handling.instructions.md",
        ),
        ".github/skills/evidence-provenance-auditor/skill.md": (
            "docs/schema.md",
            "docs/requirements.md",
            "docs/error_handling.md",
        ),
    }

    missing: dict[str, list[str]] = {}
    for relative_path, fragments in required_fragments.items():
        text = _read(relative_path)
        absent = [fragment for fragment in fragments if fragment not in text]
        if absent:
            missing[relative_path] = absent
    assert missing == {}


def _declared_env_production_example_keys(*, include_commented: bool) -> set[str]:
    text = _read(".env.production.example")
    pattern = r"^\s*#?\s*([A-Z0-9_]+)\s*=" if include_commented else r"^\s*([A-Z0-9_]+)\s*="
    return {match.group(1) for match in re.finditer(pattern, text, flags=re.MULTILINE)}


def _active_env_production_example_values() -> dict[str, str]:
    text = _read(".env.production.example")
    return {key: value.strip() for key, value in re.findall(r"^\s*([A-Z0-9_]+)\s*=\s*(.*)$", text, flags=re.MULTILINE)}


def _normalize_env_path_value(value: str | None) -> str | None:
    if value is None:
        return None
    normalized = value.strip().replace("\\", "/")
    while normalized.startswith("./"):
        normalized = normalized[2:]
    return normalized


def test_env_production_example_keys_match_runtime_settings_contract():
    """Guard against .env.production.example drift from Settings keys."""
    declared = _declared_env_production_example_keys(include_commented=True)
    settings_keys = {field.upper() for field in Settings.model_fields if field != "database"}
    database_keys = {
        "DATABASE__DRIVER",
        "DATABASE__PATH",
        "DATABASE__HOST",
        "DATABASE__PORT",
        "DATABASE__DATABASE",
        "DATABASE__USER",
        "DATABASE__PASSWORD",
    }
    deployment_helper_keys = {
        "CLOUDFLARE_TUNNEL_TOKEN",
        "RUNTIME_SETTINGS_ENV_FILE",
        "BACKUP_DIR",
        "BACKUP_RETENTION_DAYS",
    }
    allowed = settings_keys | database_keys | deployment_helper_keys

    missing = sorted(allowed - declared)
    unknown = sorted(declared - allowed)
    assert missing == []
    assert unknown == []


def test_env_production_example_builds_settings_and_keeps_production_defaults():
    """The production template must parse into Settings and preserve intended production posture."""
    active = _active_env_production_example_values()
    Settings(_env_file=PROJECT_ROOT / ".env.production.example", _cli_parse_args=False)

    assert active["ENVIRONMENT"] == "production"
    assert active["RUN_EMBEDDED_WORKER"] == "false"
    assert active["DATABASE__DRIVER"] == "postgres"