from __future__ import annotations

import logging
from datetime import datetime, timezone
from typing import Iterable

from spooler.store import get_recent_sessions, get_session_activity


SNAPSHOT_SCHEMA = "openclaw.session.v1"
log = logging.getLogger("session_snapshot")


def _now() -> str:
    return datetime.now(timezone.utc).isoformat()


def _parse_ts(value: str | None) -> datetime | None:
    if not value:
        return None
    try:
        return datetime.fromisoformat(value.replace("Z", "+00:00"))
    except (TypeError, ValueError):
        log.debug("invalid session timestamp", extra={"timestamp_value": value})
        return None


def _age_seconds(value: str | None) -> int | None:
    ts = _parse_ts(value)
    if not ts:
        return None
    if ts.tzinfo is None:
        ts = ts.replace(tzinfo=timezone.utc)
    return max(0, int((datetime.now(timezone.utc) - ts).total_seconds()))


def _classify_activity(row: dict) -> dict:
    role = row.get("role") or ""
    tool_name = row.get("tool_name") or ""
    clean_text = row.get("clean_text") or ""
    preview = row.get("preview") or clean_text[:300]
    is_error = bool(row.get("is_error"))

    if role == "toolResult":
        event_type = "tool_error" if is_error else "tool_result"
        summary = f"✗ {tool_name or 'tool'}" if is_error else f"✓ {tool_name or 'tool'}"
    elif role == "assistant":
        event_type = "assistant_text"
        summary = preview[:140] or "assistant"
    elif role == "user":
        event_type = "user_message"
        summary = preview[:140] or "user"
    elif role in ("system", "developer"):
        event_type = role
        summary = preview[:120] or role
    else:
        event_type = "event"
        summary = preview[:120] or role or "event"

    return {
        "timestamp": row.get("timestamp") or row.get("indexed_at"),
        "entry_idx": row.get("entry_idx"),
        "event_type": event_type,
        "role": role,
        "tool_name": tool_name,
        "summary": summary,
        "is_error": is_error,
    }


def _risk_flags(activity: Iterable[dict]) -> list[str]:
    flags: set[str] = set()
    for row in activity:
        text = f"{row.get('clean_text') or ''}\n{row.get('preview') or ''}".lower()
        if any(token in text for token in ("approve", "approval", "permission")):
            flags.add("approval_or_permission")
        if any(token in text for token in ("delete", "rm -rf", "drop table", "destroy", "rollback")):
            flags.add("destructive_or_rollback_language")
        if any(token in text for token in ("public deploy", "dns", "domain", "cloud run", "gcloud")):
            flags.add("external_infra")
        if any(token in text for token in ("api key", "secret", "password", "token")):
            flags.add("secret_sensitive")
    return sorted(flags)


def _health_from_summary(summary: dict, last_event_age_seconds: int | None) -> dict:
    error_count = int(summary.get("error_count") or 0)
    event_count = int(summary.get("event_count") or 0)
    noisy = int(summary.get("noisy_tool_results") or 0)
    state = "active"
    reasons: list[str] = []

    if last_event_age_seconds is not None and last_event_age_seconds > 30 * 24 * 60 * 60:
        state = "stale"
        reasons.append("no_recent_activity_30d")
    elif error_count > 0:
        state = "warning"
        reasons.append("errors_present")
    elif noisy > 2:
        state = "warning"
        reasons.append("noisy_tool_outputs")
    elif event_count == 0:
        state = "unknown"
        reasons.append("no_spooled_events")

    return {
        "state": state,
        "reasons": reasons,
        "last_event_age_seconds": last_event_age_seconds,
    }


def build_session_snapshot(session_summary: dict, activity_limit: int = 80) -> dict:
    """Build a canonical, backend-neutral OpenClaw session snapshot.

    This is intentionally sidecar-local and read-only. It gives dashboards and
    reviewers one stable shape without requiring gateway core changes.
    """
    session_id = session_summary.get("session_id")
    activity = get_session_activity(session_id, activity_limit) if session_id else []
    recent_events = [_classify_activity(row) for row in activity]
    last_event_at = session_summary.get("last_event_at")
    age = _age_seconds(last_event_at)
    tool_result_count = int(session_summary.get("tool_result_count") or 0)
    event_count = int(session_summary.get("event_count") or 0)
    error_count = int(session_summary.get("error_count") or 0)
    tool_ratio = round(tool_result_count / event_count, 3) if event_count else 0.0

    pressure_flags = []
    if event_count > 1000:
        pressure_flags.append("long_running_session")
    if tool_ratio > 0.7:
        pressure_flags.append("tool_heavy")
    if int(session_summary.get("noisy_tool_results") or 0) > 2:
        pressure_flags.append("noisy_tool_outputs")

    return {
        "schema": SNAPSHOT_SCHEMA,
        "generated_at": _now(),
        "id": session_id,
        "kind": "transcript_session",
        "owner": {"agent_id": session_summary.get("agent_id")},
        "state": _health_from_summary(session_summary, age),
        "runtime": {
            "adapter": "session-amplifier-spooler",
            "source": "spooled_transcript",
        },
        "health": {
            "event_count": event_count,
            "tool_result_count": tool_result_count,
            "error_count": error_count,
            "tool_ratio": tool_ratio,
            "pressure_flags": pressure_flags,
            "hints": session_summary.get("hints") or [],
        },
        "risk": {
            "flags": _risk_flags(activity),
            "policy": "signal_only_non_destructive",
        },
        "outputs": {
            "last_event_at": last_event_at,
            "last_entry_idx": session_summary.get("last_entry_idx"),
            "recent_events": recent_events,
        },
        "rollback": {
            "note": "Snapshot generation is read-only; remove session_snapshot.py and route imports to roll back this sidecar feature.",
        },
    }


def build_recent_session_snapshots(limit: int = 40, activity_limit: int = 80) -> dict:
    sessions = get_recent_sessions(limit)
    return {
        "schema": f"{SNAPSHOT_SCHEMA}.collection",
        "generated_at": _now(),
        "count": len(sessions),
        "snapshots": [build_session_snapshot(row, activity_limit=activity_limit) for row in sessions],
    }