"""Compose runtime health + inventory into a sessions/runtime view (#641).

Phase 1 is read-only. It correlates namespaces, sessions, capabilities,
worktree bindings, lease ownership, stale flags, and contamination markers
when they are detectable on disk (#630 / #671). It never restarts, kills, or
takes over a session.

Sources:

* :mod:`webui.runtime_health` — profile, role, stale runtime, shell health.
* :mod:`webui.inventory` — sessions, leases, locks, worktrees, namespaces
  and collision signals from the control-plane DB + filesystem.
* :mod:`mcp_session_state` — durable contamination markers (inspect only).

Secrets are never read. Absolute paths are collapsed by inventory redaction.
"""

from __future__ import annotations

from dataclasses import dataclass, field
from typing import Any, Callable

import mcp_session_state
from webui.inventory import (
    InventorySnapshot,
    load_inventory_snapshot,
    snapshot_to_dict as inventory_snapshot_to_dict,
)
from webui.runtime_health import (
    RuntimeSnapshot,
    load_runtime_snapshot,
    snapshot_to_dict as runtime_snapshot_to_dict,
)

# Sanctioned recovery pointers only — never pkill / killall (#630).
SANCTIONED_RECOVERY_DOCS: tuple[dict[str, str], ...] = (
    {
        "label": "MCP namespace EOF recovery (reconnect only)",
        "path": "docs/mcp-namespace-eof-recovery.md",
        "note": "IDE/client reconnect or operator-owned restart; never kill daemons.",
    },
    {
        "label": "MCP namespace health",
        "path": "docs/mcp-namespace-health.md",
        "note": "client_namespace probe proves namespace health.",
    },
    {
        "label": "Restart path inventory",
        "path": "docs/mcp-restart-path-inventory.md",
        "note": "Catalog of sanctioned reconnect/restart paths.",
    },
    {
        "label": "Local web UI recovery",
        "path": "docs/webui-local-dev.md",
        "note": "Operator console start and documented recovery sequence.",
    },
)

_CONTAMINATION_KINDS: tuple[str, ...] = (
    mcp_session_state.KIND_RUNTIME_RECOVERY_CONTAMINATION,
    mcp_session_state.KIND_STABLE_BRANCH_CONTAMINATION,
)


@dataclass(frozen=True)
class ContaminationMarker:
    """A detectable durable contamination marker (audit-safe summary)."""

    kind: str
    on_disk: bool
    has_payload: bool
    summary: str
    reason_class: str | None = None
    session_id: str | None = None
    role: str | None = None
    command_summary: str | None = None
    cleared: bool = False

    def to_dict(self) -> dict[str, Any]:
        return {
            "kind": self.kind,
            "on_disk": self.on_disk,
            "has_payload": self.has_payload,
            "summary": self.summary,
            "reason_class": self.reason_class,
            "session_id": self.session_id,
            "role": self.role,
            "command_summary": self.command_summary,
            "cleared": self.cleared,
            "active": self.on_disk and self.has_payload and not self.cleared,
        }


@dataclass(frozen=True)
class SessionRow:
    """One correlated session row for the sessions table."""

    session_id: str
    role: str | None
    profile: str | None
    namespace: str | None
    pid: int | None
    pid_alive: bool | None
    status: str | None
    started_at: str | None
    last_heartbeat_at: str | None
    lease_ids: tuple[str, ...] = ()
    work_refs: tuple[str, ...] = ()
    worktree_paths: tuple[str, ...] = ()
    stale_flags: tuple[str, ...] = ()
    contamination_flags: tuple[str, ...] = ()

    def to_dict(self) -> dict[str, Any]:
        return {
            "session_id": self.session_id,
            "role": self.role,
            "profile": self.profile,
            "namespace": self.namespace,
            "pid": self.pid,
            "pid_alive": self.pid_alive,
            "status": self.status,
            "started_at": self.started_at,
            "last_heartbeat_at": self.last_heartbeat_at,
            "lease_ids": list(self.lease_ids),
            "work_refs": list(self.work_refs),
            "worktree_paths": list(self.worktree_paths),
            "stale_flags": list(self.stale_flags),
            "contamination_flags": list(self.contamination_flags),
            "is_stale": bool(self.stale_flags),
            "is_contaminated": bool(self.contamination_flags),
        }


@dataclass(frozen=True)
class SessionViewSnapshot:
    """Composed runtime + session inventory view (#641)."""

    runtime: RuntimeSnapshot
    inventory: InventorySnapshot
    sessions: tuple[SessionRow, ...]
    contamination_markers: tuple[ContaminationMarker, ...]
    recovery_docs: tuple[dict[str, str], ...] = SANCTIONED_RECOVERY_DOCS
    fetch_error: str | None = None

    @property
    def stale_session_count(self) -> int:
        return sum(1 for row in self.sessions if row.stale_flags)

    @property
    def contaminated_session_count(self) -> int:
        return sum(1 for row in self.sessions if row.contamination_flags)

    @property
    def active_contamination(self) -> tuple[ContaminationMarker, ...]:
        return tuple(m for m in self.contamination_markers if m.to_dict()["active"])


def _inspect_contamination(
    kind: str,
    *,
    remote: str | None,
    inspect: Callable[..., dict[str, Any]] | None = None,
    load: Callable[..., dict[str, Any] | None] | None = None,
) -> ContaminationMarker:
    """Inspect one contamination kind; never raises into the page render path."""
    inspect_fn = inspect or mcp_session_state.inspect_state_envelope
    load_fn = load or mcp_session_state.load_state
    try:
        envelope = inspect_fn(kind=kind, remote=remote)
    except Exception as exc:  # noqa: BLE001 — fail soft for the dashboard
        return ContaminationMarker(
            kind=kind,
            on_disk=False,
            has_payload=False,
            summary=f"contamination inspect failed: {type(exc).__name__}",
        )

    reason_class = None
    session_id = None
    role = None
    command_summary = None
    cleared = False
    summary = str(envelope.get("summary") or "")

    if envelope.get("on_disk") and envelope.get("has_payload"):
        try:
            payload = load_fn(kind=kind, remote=remote) or {}
        except Exception:  # noqa: BLE001
            payload = {}
        if isinstance(payload, dict):
            reason_class = payload.get("reason_class")
            session_id = payload.get("session_id")
            role = payload.get("role")
            command_summary = payload.get("command_summary") or payload.get("detail")
            cleared = bool(payload.get("cleared_by_reconciler"))
            if not summary:
                summary = (
                    f"{kind}: {reason_class or 'present'}"
                    + (" (cleared)" if cleared else "")
                )

    return ContaminationMarker(
        kind=kind,
        on_disk=bool(envelope.get("on_disk")),
        has_payload=bool(envelope.get("has_payload")),
        summary=summary or f"{kind}: not present",
        reason_class=str(reason_class) if reason_class else None,
        session_id=str(session_id) if session_id else None,
        role=str(role) if role else None,
        command_summary=str(command_summary) if command_summary else None,
        cleared=cleared,
    )


def _load_contamination_markers(
    *,
    remote: str | None,
    inspect: Callable[..., dict[str, Any]] | None = None,
    load: Callable[..., dict[str, Any] | None] | None = None,
) -> tuple[ContaminationMarker, ...]:
    return tuple(
        _inspect_contamination(kind, remote=remote, inspect=inspect, load=load)
        for kind in _CONTAMINATION_KINDS
    )


def _build_session_rows(
    inventory: InventorySnapshot,
    contamination: tuple[ContaminationMarker, ...],
) -> tuple[SessionRow, ...]:
    sessions_section = inventory.section("sessions")
    leases_section = inventory.section("leases")
    locks_section = inventory.section("locks")

    leases_by_session: dict[str, list[dict[str, Any]]] = {}
    for lease in (leases_section.items if leases_section else ()):
        sid = str(lease.get("session_id") or "")
        if sid:
            leases_by_session.setdefault(sid, []).append(lease)

    locks_by_session_hint: dict[str, list[dict[str, Any]]] = {}
    for lock in (locks_section.items if locks_section else ()):
        # Locks carry claimant profile/username, not control-plane session ids.
        # Correlate later by matching lease work_number ↔ lock issue_number.
        pass

    active_markers = [m for m in contamination if m.to_dict()["active"]]
    marker_session_ids = {
        m.session_id for m in active_markers if m.session_id
    }

    rows: list[SessionRow] = []
    for raw in sessions_section.items if sessions_section else ():
        sid = str(raw.get("session_id") or "")
        if not sid:
            continue
        session_leases = leases_by_session.get(sid, [])
        lease_ids = tuple(
            str(lease["lease_id"])
            for lease in session_leases
            if lease.get("lease_id")
        )
        work_refs: list[str] = []
        work_numbers: list[int] = []
        for lease in session_leases:
            kind = lease.get("work_kind")
            number = lease.get("work_number")
            if kind and number is not None:
                work_refs.append(f"{kind}#{number}")
                try:
                    work_numbers.append(int(number))
                except (TypeError, ValueError):
                    pass

        worktree_paths: list[str] = []
        for lock in (locks_section.items if locks_section else ()):
            try:
                issue_no = int(lock.get("issue_number"))
            except (TypeError, ValueError):
                continue
            if issue_no in work_numbers and lock.get("worktree_path"):
                worktree_paths.append(str(lock["worktree_path"]))

        stale_flags: list[str] = []
        if raw.get("pid_alive") is False:
            stale_flags.append("pid-dead")
        status = str(raw.get("status") or "").lower()
        if status and status not in {"active", "alive", "running", "ok"}:
            stale_flags.append(f"status:{status}")
        for lease in session_leases:
            if lease.get("expired") is True:
                stale_flags.append("lease-expired")
            if str(lease.get("status") or "").lower() == "active" and lease.get(
                "expired"
            ) is True:
                stale_flags.append("active-lease-past-expiry")

        contamination_flags: list[str] = []
        if sid in marker_session_ids:
            for marker in active_markers:
                if marker.session_id == sid:
                    contamination_flags.append(marker.kind)
        # Process-wide contamination with no session binding still surfaces
        # against every live session so it cannot be silent (#630).
        for marker in active_markers:
            if not marker.session_id and marker.kind not in contamination_flags:
                contamination_flags.append(f"{marker.kind}:process-wide")

        rows.append(
            SessionRow(
                session_id=sid,
                role=raw.get("role"),
                profile=raw.get("profile"),
                namespace=raw.get("namespace"),
                pid=raw.get("pid") if isinstance(raw.get("pid"), int) else None,
                pid_alive=raw.get("pid_alive")
                if isinstance(raw.get("pid_alive"), bool)
                else None,
                status=raw.get("status"),
                started_at=raw.get("started_at"),
                last_heartbeat_at=raw.get("last_heartbeat_at"),
                lease_ids=lease_ids,
                work_refs=tuple(work_refs),
                worktree_paths=tuple(worktree_paths),
                stale_flags=tuple(dict.fromkeys(stale_flags)),
                contamination_flags=tuple(dict.fromkeys(contamination_flags)),
            )
        )

    # Silence unused variable for the locks_by_session_hint placeholder path.
    _ = locks_by_session_hint
    return tuple(rows)


def load_session_view_snapshot(
    *,
    load_runtime: Callable[..., RuntimeSnapshot] | None = None,
    load_inventory: Callable[..., InventorySnapshot] | None = None,
    inspect_contamination: Callable[..., dict[str, Any]] | None = None,
    load_contamination_payload: Callable[..., dict[str, Any] | None] | None = None,
) -> SessionViewSnapshot:
    """Build the composed sessions/runtime view. Fail-soft on partial sources."""
    runtime_loader = load_runtime or load_runtime_snapshot
    inventory_loader = load_inventory or load_inventory_snapshot
    fetch_error: str | None = None

    try:
        runtime = runtime_loader()
    except Exception as exc:  # noqa: BLE001
        fetch_error = f"runtime snapshot failed: {type(exc).__name__}: {exc}"
        # Minimal placeholder so the page still renders inventory + recovery.
        from webui.runtime_health import RuntimeSnapshot as _RS

        runtime = _RS(
            project_id="unknown",
            repo_root="",
            remote="",
            host="",
            profile_name="unknown",
            role_kind="unknown",
            config_model="unknown",
            profile_mode="unknown",
            profile_source="unknown",
            authenticated_username=None,
            identity_error=str(exc),
            repo_sha=None,
            remote_master_sha=None,
            commits_behind_master=None,
            stale_runtime_warning=None,
            shell_health={},
            workflow_hashes=(),
            schema_hashes=(),
            restart_guidance="docs/mcp-namespace-eof-recovery.md",
            fetch_error=str(exc),
        )

    try:
        inventory = inventory_loader()
    except Exception as exc:  # noqa: BLE001
        msg = f"inventory snapshot failed: {type(exc).__name__}: {exc}"
        fetch_error = f"{fetch_error}; {msg}" if fetch_error else msg
        inventory = load_inventory_snapshot(
            db_path="/nonexistent-for-fail-soft",
            lock_dir="/nonexistent-for-fail-soft",
        )

    remote = getattr(runtime, "remote", None)
    contamination = _load_contamination_markers(
        remote=remote,
        inspect=inspect_contamination,
        load=load_contamination_payload,
    )
    sessions = _build_session_rows(inventory, contamination)
    return SessionViewSnapshot(
        runtime=runtime,
        inventory=inventory,
        sessions=sessions,
        contamination_markers=contamination,
        fetch_error=fetch_error,
    )


def snapshot_to_dict(snapshot: SessionViewSnapshot) -> dict[str, Any]:
    """JSON export for ``/api/sessions`` (read-only)."""
    return {
        "api_version": "v1",
        "view": "runtime-sessions",
        "issue": 641,
        "fetch_error": snapshot.fetch_error,
        "runtime": runtime_snapshot_to_dict(snapshot.runtime),
        "inventory": inventory_snapshot_to_dict(snapshot.inventory),
        "sessions": [row.to_dict() for row in snapshot.sessions],
        "session_counts": {
            "total": len(snapshot.sessions),
            "stale": snapshot.stale_session_count,
            "contaminated": snapshot.contaminated_session_count,
        },
        "contamination_markers": [
            marker.to_dict() for marker in snapshot.contamination_markers
        ],
        "active_contamination": [
            marker.to_dict() for marker in snapshot.active_contamination
        ],
        "recovery_docs": [dict(doc) for doc in snapshot.recovery_docs],
        "read_only": True,
        "phase": 1,
        "mutations": [],
    }