"""Load and validate the routing pointer catalog.

The catalog lives at ``registry/routing/catalog.yaml`` in the repo root. Resolution
order:

1. ``WARDEN_ROUTING_CATALOG`` env var, if set (used by tests / overrides).
2. Walk upward from this module looking for ``registry/routing/catalog.yaml``.

Validation enforces the **no-double-source rule**: only ``warden_executes: true``
entries may carry an authored ``steps`` block or a ``cert_command``. Any non-SSH
entry that does so is a validation error — ops-warden points at the owner's doc, it
never restates another subsystem's procedure.
"""
from __future__ import annotations

import os
import re
from dataclasses import dataclass
from datetime import date
from pathlib import Path
from typing import List, Optional

import yaml

from warden.routing.models import RouteEntry

# Structured handoff string fields (WP-0014) — templates and pointers only.
# Every one is scanned for accidental secret material; see _assert_no_secret_material.
_HANDOFF_STR_FIELDS = ("auth_method", "path_template", "fetch_command", "policy_ref")

# Known secret-bearing token prefixes — a literal here means a value leaked into
# the catalog (which is git-tracked and agent-visible). Templates use `<...>`.
_SECRET_PREFIXES = (
    "ghp_", "gho_", "ghs_", "github_pat_",  # GitHub
    "sk-", "sk_live_", "sk_test_",           # OpenAI / Stripe
    "xoxb-", "xoxp-",                          # Slack
    "AKIA", "ASIA",                            # AWS access key ids
    "hvs.", "hvb.", "s.",                      # Vault/OpenBao service tokens
    "AIza",                                    # Google
    "eyJ",                                     # JWT
)
# A long unbroken high-entropy run that is not a placeholder — likely a raw value.
_HIGH_ENTROPY_RUN = re.compile(r"[A-Za-z0-9_\-]{32,}")

_REQUIRED_FIELDS = (
    "id",
    "title",
    "need_keywords",
    "owner_repo",
    "subsystem",
    "warden_executes",
    "wiki_ref",
    "canon_ref",
    "reviewed",
    "status",
)
_VALID_STATUS = ("active", "draft")

# Default review cadence — see wiki/AccessRouting.md#drift-review-cadence
DEFAULT_STALE_DAYS = 90


def days_since_review(reviewed: str, *, today: Optional[date] = None) -> int:
    """Calendar days between reviewed date (YYYY-MM-DD) and today."""
    reviewed_date = date.fromisoformat(reviewed)
    ref = today or date.today()
    return (ref - reviewed_date).days


def is_review_stale(
    reviewed: str,
    *,
    threshold_days: int = DEFAULT_STALE_DAYS,
    today: Optional[date] = None,
) -> bool:
    """True when reviewed date is older than the cadence threshold."""
    return days_since_review(reviewed, today=today) > threshold_days


class CatalogError(Exception):
    """Raised when the routing catalog is missing or invalid."""


def find_catalog_path(start: Optional[Path] = None) -> Path:
    """Locate registry/routing/catalog.yaml.

    Honors WARDEN_ROUTING_CATALOG first; otherwise walks up from `start`
    (default: this module) until a repo root containing the catalog is found.
    """
    override = os.environ.get("WARDEN_ROUTING_CATALOG")
    if override:
        return Path(os.path.expanduser(override))

    rel = Path("registry") / "routing" / "catalog.yaml"
    here = (start or Path(__file__)).resolve()
    for parent in [here, *here.parents]:
        candidate = parent / rel
        if candidate.exists():
            return candidate
    raise CatalogError(
        f"Routing catalog not found ({rel}). Set WARDEN_ROUTING_CATALOG to override."
    )


@dataclass
class Catalog:
    path: Path
    entries: List[RouteEntry]

    # --- lookup helpers ---------------------------------------------------

    def get(self, entry_id: str) -> Optional[RouteEntry]:
        for e in self.entries:
            if e.id == entry_id:
                return e
        return None

    def listed(self, include_draft: bool = False) -> List[RouteEntry]:
        if include_draft:
            return list(self.entries)
        return [e for e in self.entries if e.is_active]

    def find(self, query: str, include_draft: bool = False, limit: int = 5) -> List[RouteEntry]:
        """Rank entries by keyword overlap with the query. Highest first."""
        tokens = [t for t in query.lower().replace("-", " ").split() if t]
        pool = self.listed(include_draft=include_draft)
        scored = [(e.match_score(tokens), e) for e in pool]
        scored = [(s, e) for s, e in scored if s > 0]
        scored.sort(key=lambda pair: (-pair[0], pair[1].id))
        return [e for _, e in scored[:limit]]

    def stale(
        self,
        include_draft: bool = False,
        threshold_days: int = DEFAULT_STALE_DAYS,
        *,
        today: Optional[date] = None,
    ) -> List[RouteEntry]:
        """Entries whose reviewed date is past the cadence threshold."""
        return [
            e
            for e in self.listed(include_draft=include_draft)
            if is_review_stale(e.reviewed, threshold_days=threshold_days, today=today)
        ]


def _assert_no_secret_material(entry_id: str, field_name: str, value: str) -> None:
    """Reject a handoff field that appears to embed a literal secret value.

    The structured handoff fields are command/path *templates*: concrete values
    must be placeholders (`<...>`) or field names, never a real credential. The
    catalog is git-tracked and agent-visible, so a leaked value here is the exact
    custody failure WP-0014 forbids. We screen for known token prefixes and for a
    long high-entropy run that is not a placeholder.
    """
    lowered = value.lower()
    for prefix in _SECRET_PREFIXES:
        if prefix.lower() in lowered:
            raise CatalogError(
                f"entry {entry_id!r} field {field_name!r} appears to contain a literal "
                f"secret (matched {prefix!r}). Handoff fields are templates — use "
                "placeholders like <FIELD>/<PATH>, never a real value."
            )
    for run in _HIGH_ENTROPY_RUN.findall(value):
        # Allow long placeholder/path/identifier tokens; flag anything else.
        if "<" in run or ">" in run:
            continue
        if run.replace("_", "").replace("-", "").isalpha():
            continue  # all-letters run (e.g. a long word) — not a credential
        raise CatalogError(
            f"entry {entry_id!r} field {field_name!r} contains a high-entropy token "
            f"({run[:8]}…) that is not a placeholder — suspected leaked secret value."
        )


def _parse_entry(raw: dict, index: int) -> RouteEntry:
    if not isinstance(raw, dict):
        raise CatalogError(f"entry #{index} is not a mapping")

    missing = [f for f in _REQUIRED_FIELDS if f not in raw]
    if missing:
        ident = raw.get("id", f"#{index}")
        raise CatalogError(f"entry {ident!r} missing required field(s): {', '.join(missing)}")

    warden_executes = bool(raw["warden_executes"])
    steps = raw.get("steps") or []
    cert_command = raw.get("cert_command")
    status = str(raw["status"])

    if status not in _VALID_STATUS:
        raise CatalogError(
            f"entry {raw['id']!r} has invalid status {status!r} (expected one of {_VALID_STATUS})"
        )

    # No-double-source rule: authored procedure only on the SSH lane.
    if not warden_executes and steps:
        raise CatalogError(
            f"entry {raw['id']!r} is not warden_executes but carries a `steps` block "
            "— routed needs point at the owner's doc; they must not restate procedure "
            "(no-double-source rule)."
        )
    if not warden_executes and cert_command:
        raise CatalogError(
            f"entry {raw['id']!r} is not warden_executes but carries a `cert_command`."
        )

    if not isinstance(raw["need_keywords"], list):
        raise CatalogError(f"entry {raw['id']!r} need_keywords must be a list")

    # Structured handoff fields (WP-0014) — optional, screened for secret material.
    entry_id = str(raw["id"])
    handoff: dict[str, Optional[str]] = {}
    for fname in _HANDOFF_STR_FIELDS:
        val = raw.get(fname)
        if val is None or val == "":
            handoff[fname] = None
            continue
        sval = str(val)
        _assert_no_secret_material(entry_id, fname, sval)
        handoff[fname] = sval

    exec_capable = bool(raw.get("exec_capable", False))
    # A lane cannot be proxy-executable without a fetch_command to run.
    if exec_capable and not handoff["fetch_command"]:
        raise CatalogError(
            f"entry {entry_id!r} sets exec_capable: true but has no fetch_command — "
            "a proxyable lane must declare the command warden runs as the caller."
        )

    return RouteEntry(
        id=entry_id,
        title=str(raw["title"]),
        need_keywords=[str(k) for k in raw["need_keywords"]],
        owner_repo=str(raw["owner_repo"]),
        subsystem=str(raw["subsystem"]),
        warden_executes=warden_executes,
        wiki_ref=str(raw["wiki_ref"]),
        canon_ref=str(raw["canon_ref"]),
        reviewed=str(raw["reviewed"]),
        status=status,
        steps=[str(s) for s in steps],
        cert_command=str(cert_command) if cert_command else None,
        auth_method=handoff["auth_method"],
        path_template=handoff["path_template"],
        fetch_command=handoff["fetch_command"],
        exec_capable=exec_capable,
        policy_ref=handoff["policy_ref"],
    )


def load_catalog(path: Optional[Path] = None) -> Catalog:
    """Load, parse, and validate the routing catalog."""
    catalog_path = path or find_catalog_path()
    if not catalog_path.exists():
        raise CatalogError(f"Routing catalog not found: {catalog_path}")

    try:
        with catalog_path.open() as f:
            raw = yaml.safe_load(f)
    except yaml.YAMLError as e:
        raise CatalogError(f"Invalid YAML in {catalog_path}: {e}") from e

    if not isinstance(raw, dict):
        raise CatalogError("Catalog must be a YAML mapping")

    raw_entries = raw.get("entries")
    if not isinstance(raw_entries, list) or not raw_entries:
        raise CatalogError("Catalog has no `entries` list")

    entries: List[RouteEntry] = []
    seen: set[str] = set()
    for i, raw_entry in enumerate(raw_entries):
        entry = _parse_entry(raw_entry, i)
        if entry.id in seen:
            raise CatalogError(f"duplicate entry id: {entry.id!r}")
        seen.add(entry.id)
        entries.append(entry)

    return Catalog(path=catalog_path, entries=entries)