"""State machine, advisory file locking, and JSON storage."""

from __future__ import annotations

import contextlib
import json
import os
import time
import uuid
from contextlib import contextmanager
from datetime import UTC, datetime
from pathlib import Path
from typing import Any

from filelock import FileLock

# Constants

DEFAULT_SYNC_CREDIT = 5
COMMAND_INTERVAL = 50
MAX_BURST_COMMANDS = 20
PHASE_SYNC_CREDIT = {
    "RECON": 10,
    "VULN_RESEARCH": 10,
    "EXPLOITATION": 20,
    "POST_EXPLOITATION": 20,
    "PRIVESC": 20,
    "FLAGS": 20,
}

# Local tools
LOCAL_TOOLS = {"echo", "true", "false", "printf", "pwd", "ls", "cat", "date"}

_STATE_DIR = "state"
_SYNC_FILE = "sync.json"
_HEARTBEAT_FILE = "heartbeat.json"
_COUNTS_FILE = "counts.json"
_SESSION_FILE = "session.json"
_SEMANTIC_FILE = "semantic-progress.json"


# Path helpers


def _eng_root() -> Path:
    """Return Violin's stable profile/repository root for relative paths."""
    override = os.environ.get("VIOLIN_ENG_ROOT", "").strip()
    if override:
        return Path(override).expanduser().resolve()
    container_root = Path("/violin")
    if container_root.exists() and (container_root / "engagements").exists():
        return container_root.resolve()
    return Path(__file__).resolve().parents[2]


def resolve_eng_dir(eng_dir: str | Path) -> Path:
    """Resolve an engagement directory path (absolute or relative to profile root)."""
    if not str(eng_dir).strip() or str(eng_dir).strip() == ".":
        env_eng = os.environ.get("ENG_DIR", "").strip()
        if env_eng:
            return Path(env_eng).expanduser().resolve()
        cwd = Path.cwd().resolve()
        if (cwd / "scope" / "scope.yaml").exists() or (cwd / "hypotheses.md").exists():
            return cwd
        return _eng_root()

    path = Path(eng_dir).expanduser()
    if not path.is_absolute():
        profile_candidate = (_eng_root() / path).resolve()
        cwd_candidate = (Path.cwd() / path).resolve()
        if not profile_candidate.exists() and cwd_candidate.exists():
            return cwd_candidate
        return profile_candidate
    return path.resolve()


def resolve_session_id(eng_dir: str | Path, session_id: str | None = None) -> str:
    """Return an explicit session id or the engagement's recorded session.

    Tool calls should not fail merely because the runtime omitted a value it
    already supplied to the lifecycle hook.  Older engagements are supported
    by inferring the id when they contain exactly one skill-load marker.
    """
    if session_id and session_id.strip():
        return session_id.strip()
    root = resolve_eng_dir(eng_dir)
    recorded = str(read_json(root / _STATE_DIR / _SESSION_FILE).get("session_id") or "").strip()
    if recorded:
        return recorded
    markers = (
        list((root / _STATE_DIR).glob(".skill-loaded-*")) if (root / _STATE_DIR).exists() else []
    )
    return markers[0].name.removeprefix(".skill-loaded-") if len(markers) == 1 else ""


def record_session_id(eng_dir: str | Path, session_id: str | None) -> None:
    if session_id and session_id.strip():
        path = _state_dir(eng_dir) / _SESSION_FILE
        with lock_file(path):
            atomic_json(path, {"session_id": session_id.strip()})


def ensure_dir(path: Path) -> Path:
    """Ensure directory exists fail-safe against symlinks and cross-platform FileExistsError [Errno 17]."""
    try:
        path.mkdir(parents=True, exist_ok=True)
    except FileExistsError:
        if not path.exists():
            raise
    return path


def _state_dir(eng_dir: str | Path) -> Path:
    p = resolve_eng_dir(eng_dir) / _STATE_DIR
    ensure_dir(p)
    return p


# Storage primitives


@contextmanager
def lock_file(path: Path):
    """Acquire an exclusive advisory lock on ``path`` for the duration of a ``with`` block."""
    lock_path = path.with_suffix(path.suffix + ".lock")
    ensure_dir(lock_path.parent)
    with FileLock(str(lock_path), timeout=20):
        yield


@contextmanager
def workflow_lock(eng_dir: str | Path):
    """Serialize multi-file workflow transitions for one engagement.

    Callers acquire this lock before any narrower JSON or receipt file lock.
    """
    lock_path = _state_dir(eng_dir) / "workflow.lock"
    with FileLock(str(lock_path), timeout=20):
        yield


def read_json(path: Path) -> dict[str, Any]:
    """Read a JSON document, returning an empty dict on missing file or non-dict root.

    Raises OSError or json.JSONDecodeError on corrupt/locked file reads when the file exists,
    preventing mutate_json from overwriting existing state with empty dictionaries.
    """
    if not path.exists():
        return {}
    try:
        data = json.loads(path.read_text(encoding="utf-8"))
        return data if isinstance(data, dict) else {}
    except (OSError, json.JSONDecodeError):
        # On read failure when file exists, attempt up to 3 retries for transient locks
        for attempt in range(3):
            time.sleep(0.02 * (attempt + 1))
            try:
                data = json.loads(path.read_text(encoding="utf-8"))
                return data if isinstance(data, dict) else {}
            except (OSError, json.JSONDecodeError):
                pass
        raise


def atomic_json(path: Path, data: dict[str, Any]) -> None:
    """Write JSON atomically by replacing a temporary swap file."""
    ensure_dir(path.parent)
    tmp = path.with_name(f"{path.name}.{uuid.uuid4().hex}.tmp")
    tmp.write_text(json.dumps(data, indent=2, sort_keys=True), encoding="utf-8")
    try:
        for attempt in range(5):
            try:
                tmp.replace(path)
                return
            except PermissionError:
                if attempt == 4:
                    raise
                time.sleep(0.02 * (attempt + 1))
    finally:
        if tmp.exists():
            with contextlib.suppress(OSError):
                tmp.unlink()


def atomic_text(path: Path, content: str) -> None:
    """Write one UTF-8 text document with an atomic replace."""
    ensure_dir(path.parent)
    tmp = path.with_name(f"{path.name}.{uuid.uuid4().hex}.tmp")
    tmp.write_text(content, encoding="utf-8")
    try:
        for attempt in range(5):
            try:
                tmp.replace(path)
                return
            except PermissionError:
                if attempt == 4:
                    raise
                time.sleep(0.02 * (attempt + 1))
    finally:
        if tmp.exists():
            with contextlib.suppress(OSError):
                tmp.unlink()


def mutate_json(path: Path, mutation) -> Any:
    """Apply ``mutation`` to one state document under a single file lock."""
    with lock_file(path):
        data = read_json(path)
        result = mutation(data)
        atomic_json(path, data)
        return result


# Local command classification


def is_local_bookkeeping_command(command: str) -> bool:
    """Whether a command is a harmless local bookkeeping action."""
    from .bash_ast import parse_bash_segments
    from .targets import extract_target_candidates

    segments = parse_bash_segments(command)
    if len(segments) != 1:
        return False
    segment = segments[0]
    if segment.executable not in LOCAL_TOOLS or segment.redirects:
        return False
    return not extract_target_candidates(command)


# Sync credit / pending sync


def _sync_path(eng_dir: str | Path) -> Path:
    return _state_dir(eng_dir) / _SYNC_FILE


def sync_credit_limit(phase: str | None = None) -> int:
    key = str(phase or "").strip().upper().replace("-", "_")
    return PHASE_SYNC_CREDIT.get(key, DEFAULT_SYNC_CREDIT)


def sync_credit_remaining(eng_dir: str | Path, phase: str | None = None) -> int:
    data = read_json(_sync_path(eng_dir))
    return max(0, data.get("credit", sync_credit_limit(phase)))


def spend_sync_credit(eng_dir: str | Path, phase: str) -> int:
    path = _sync_path(eng_dir)

    def spend(data: dict[str, Any]) -> int:
        starting_credit = data.get("credit", sync_credit_limit(phase))
        credit = max(0, starting_credit - 1)
        data["credit"] = credit
        return credit

    return mutate_json(path, spend)


def reserve_sync_credit(eng_dir: str | Path, phase: str, count: int) -> str:
    """Atomically reserve credit for a burst before any command starts."""
    if count < 1:
        raise ValueError("a sync reservation must contain at least one command")
    path = _sync_path(eng_dir)

    def reserve(data: dict[str, Any]) -> str:
        credit = max(0, int(data.get("credit", sync_credit_limit(phase))))
        if credit < count:
            raise ValueError(f"insufficient sync credit for burst: need {count}, have {credit}")
        reservation_id = f"burst-{uuid.uuid4().hex}"
        data["credit"] = credit - count
        data.setdefault("reservations", {})[reservation_id] = {
            "phase": phase,
            "remaining": count,
            "created_at": datetime.now(UTC).isoformat().replace("+00:00", "Z"),
        }
        return reservation_id

    return mutate_json(path, reserve)


def consume_reserved_sync_credit(eng_dir: str | Path, reservation_id: str) -> int:
    """Consume one previously reserved slot without decrementing credit twice."""
    path = _sync_path(eng_dir)

    def consume(data: dict[str, Any]) -> int:
        reservation = (data.get("reservations") or {}).get(reservation_id)
        if not reservation or int(reservation.get("remaining", 0)) < 1:
            raise ValueError("sync reservation is missing or exhausted")
        reservation["remaining"] = int(reservation["remaining"]) - 1
        if reservation["remaining"] == 0:
            data["reservations"].pop(reservation_id, None)
        return max(0, int(data.get("credit", 0)))

    return mutate_json(path, consume)


def release_reserved_sync_credit(eng_dir: str | Path, reservation_id: str) -> int:
    """Return every unconsumed slot in a reservation to the sync window."""
    path = _sync_path(eng_dir)

    def release(data: dict[str, Any]) -> int:
        reservation = (data.get("reservations") or {}).pop(reservation_id, None)
        if reservation:
            data["credit"] = int(data.get("credit", 0)) + max(
                0, int(reservation.get("remaining", 0))
            )
        return max(0, int(data.get("credit", 0)))

    return mutate_json(path, release)


def mark_pending_sync(
    eng_dir: str | Path,
    command: str,
    command_phase: str,
    ptt_task_id: str,
) -> None:
    path = _sync_path(eng_dir)

    def mark(data: dict[str, Any]) -> None:
        old = data.get("pending") or {}
        commands = list(old.get("commands") or [])
        if old.get("command") and not commands:
            commands = [{"command": old["command"], "phase": old.get("phase", command_phase)}]
        commands.append({"command": command, "phase": command_phase})
        task_id = old.get("ptt_task_id") or ptt_task_id
        if not task_id:
            raise ValueError("pending execution requires a captured active PTT task")
        data["pending"] = {
            "batch_id": old.get("batch_id") or str(uuid.uuid4()),
            "commands": commands,
            "phase": command_phase,
            "created_at": old.get("created_at")
            or datetime.now(UTC).isoformat().replace("+00:00", "Z"),
            "ptt_task_id": task_id,
            "ptt_reviewed": False,
            "credit_limit": old.get("credit_limit") or sync_credit_limit(command_phase),
        }

    mutate_json(path, mark)


def clear_pending_sync(eng_dir: str | Path) -> None:
    path = _sync_path(eng_dir)

    def clear(data: dict[str, Any]) -> None:
        data.pop("pending", None)
        data.pop("credit", None)
        data.pop("reservations", None)

    mutate_json(path, clear)


def has_pending_sync(eng_dir: str | Path) -> bool:
    data = read_json(_sync_path(eng_dir))
    return "pending" in data


def get_pending_sync(eng_dir: str | Path) -> dict | None:
    data = read_json(_sync_path(eng_dir))
    return data.get("pending")


def rebind_pending_sync(
    eng_dir: str | Path,
    *,
    expected_batch_id: str,
    current_task_id: str,
    replacement_task_id: str,
    note: str,
) -> dict[str, Any]:
    """Rebind a completed pending batch without certifying its PTT review."""
    path = _sync_path(eng_dir)

    def rebind(data: dict[str, Any]) -> dict[str, Any]:
        pending = data.get("pending")
        if not pending:
            raise ValueError("no pending execution batch")
        batch_id = str(pending.get("batch_id") or "")
        if batch_id != expected_batch_id:
            raise ValueError(
                f"stale batch id {expected_batch_id!r}; current pending batch is {batch_id!r}"
            )
        captured = str(pending.get("ptt_task_id") or "")
        if captured != current_task_id:
            raise ValueError(
                f"current task {current_task_id!r} does not match batch task {captured!r}"
            )
        if current_task_id == replacement_task_id:
            raise ValueError("replacement task must differ from the current batch task")

        entry = {
            "timestamp": datetime.now(UTC).isoformat().replace("+00:00", "Z"),
            "batch_id": batch_id,
            "old_task_id": current_task_id,
            "new_task_id": replacement_task_id,
            "note": note.strip(),
        }
        data.setdefault("rebind_audit", []).append(entry)
        pending["ptt_task_id"] = replacement_task_id
        pending["ptt_reviewed"] = False
        pending.pop("ptt_note", None)
        pending.pop("ptt_reviewed_at", None)
        data["pending"] = pending
        return entry

    return mutate_json(path, rebind)


def mark_ptt_reviewed(eng_dir: str | Path, task_id: str, note: str) -> None:
    path = _sync_path(eng_dir)

    def mark(data: dict[str, Any]) -> None:
        pending = data.get("pending")
        if not pending:
            raise ValueError("no pending execution batch")
        pending["ptt_reviewed"] = True
        pending["ptt_task_id"] = task_id
        pending["ptt_note"] = note.strip()
        pending["ptt_reviewed_at"] = datetime.now(UTC).isoformat().replace("+00:00", "Z")
        data["pending"] = pending

    mutate_json(path, mark)


def record_semantic_review(
    eng_dir: str | Path,
    *,
    task_id: str,
    hypothesis_id: str,
    skill: str,
    technique: str,
    outcome: str,
    evidence_paths: list[str],
    next_action: str,
    next_technique: str,
    research_attempted: bool = False,
) -> dict[str, Any]:
    """Track evidence-backed technique-pivot progress and the anti-stuck lock.

    The anti-stuck lock is meant to catch *circular* recon — repeating the same
    path without learning.  It therefore counts *distinct technique pivots*
    (each ``technique`` key, tracked via ``violin_record_hypothesis`` / the
    ``technique`` argument), not raw ``violin_review_batch`` calls.  A review
    resets the no-progress counter when it is either:

    * **evidence-backed** — ``outcome`` is progress/validated/rejected *and*
      the batch carried completed execution evidence, or
    * **a genuine pivot** — ``next_technique`` differs from the current
      ``technique`` (a new attack path), which is exactly the behaviour the
      lock exists to encourage.

    Low-evidence iterative CTF recon therefore never accumulates toward a lock
    as long as each step pivots to a new technique or records evidence.
    """

    path = _state_dir(eng_dir) / _SEMANTIC_FILE
    key = "|".join((task_id, hypothesis_id, skill, technique.strip().lower()))
    clean_evidence_paths = [p for p in evidence_paths if p]
    has_evidence = bool(clean_evidence_paths)
    positive = outcome in {"progress", "validated", "rejected"} and has_evidence
    pivoted = bool(
        next_technique.strip().lower()
        and next_technique.strip().lower() != technique.strip().lower()
    )

    def record(data: dict[str, Any]) -> dict[str, Any]:
        entries = data.setdefault("entries", {})
        entry = entries.get(key, {"count": 0})
        # Reset the per-technique no-progress counter on evidence-backed output
        # or a real pivot; otherwise increment it as a stuck repetition.
        count = 0 if (positive or pivoted) else int(entry.get("count") or 0) + 1
        entry.update(
            {
                "count": count,
                "outcome": outcome,
                "evidence_paths": clean_evidence_paths,
                "next_action": next_action,
                "next_technique": next_technique,
                "pivoted": pivoted,
                "updated_at": datetime.now(UTC).isoformat().replace("+00:00", "Z"),
            }
        )
        entries[key] = entry
        lock = data.get("lock") or {}
        # Whole-engagement stuck signal: total no-progress reviews across all
        # keys.  Pivots and evidence reset it, so a busy CTF loop stays open.
        total_stuck = sum(
            int(item.get("count") or 0) for item in entries.values() if not item.get("pivoted")
        )
        if lock and (has_evidence or (data.get("research_attempts") and pivoted)):
            data.pop("lock", None)
        elif total_stuck >= 5 and not pivoted and not has_evidence:
            data["lock"] = {
                "key": key,
                "count": total_stuck,
                "reason": "five technique no-progress reviews without a pivot or evidence",
            }
        return {
            "count": count,
            "warning": total_stuck >= 3,
            "locked": bool(data.get("lock")),
        }

    return mutate_json(path, record)


def record_research_attempt(eng_dir: str | Path, tool_name: str, success: bool) -> None:
    """Record an actual web research-tool attempt for semantic-lock recovery."""

    path = _state_dir(eng_dir) / _SEMANTIC_FILE

    def record(data: dict[str, Any]) -> None:
        attempts = data.setdefault("research_attempts", [])
        attempts.append(
            {
                "tool": tool_name,
                "success": success,
                "timestamp": datetime.now(UTC).isoformat().replace("+00:00", "Z"),
            }
        )
        data["research_attempts"] = attempts[-20:]

    mutate_json(path, record)


def semantic_lock(eng_dir: str | Path) -> dict[str, Any] | None:
    return read_json(_state_dir(eng_dir) / _SEMANTIC_FILE).get("lock")


# ---------------------------------------------------------------------------
# Heartbeat
# ---------------------------------------------------------------------------


def _heartbeat_path(eng_dir: str | Path) -> Path:
    return _state_dir(eng_dir) / _HEARTBEAT_FILE


def set_heartbeat_pending(eng_dir: str | Path, reason: str) -> None:
    path = _heartbeat_path(eng_dir)

    def mark(data: dict[str, Any]) -> None:
        data["pending"] = True
        data["reason"] = reason
        data["created_at"] = datetime.now(UTC).isoformat().replace("+00:00", "Z")

    mutate_json(path, mark)


def clear_heartbeat_pending(eng_dir: str | Path) -> None:
    path = _heartbeat_path(eng_dir)

    def clear(data: dict[str, Any]) -> None:
        data["pending"] = False
        data.pop("reason", None)

    mutate_json(path, clear)


def has_heartbeat_pending(eng_dir: str | Path) -> bool:
    data = read_json(_heartbeat_path(eng_dir))
    return data.get("pending", False)


def get_heartbeat_reason(eng_dir: str | Path) -> str | None:
    data = read_json(_heartbeat_path(eng_dir))
    return data.get("reason")


# ---------------------------------------------------------------------------
# Command / message counters
# ---------------------------------------------------------------------------


def _counts_path(eng_dir: str | Path) -> Path:
    return _state_dir(eng_dir) / _COUNTS_FILE


def read_counts(eng_dir: str | Path) -> dict[str, int]:
    data = read_json(_counts_path(eng_dir))
    return {
        "commands": data.get("commands", 0),
        "messages": data.get("messages", 0),
    }


def tick_command(eng_dir: str | Path) -> int:
    path = _counts_path(eng_dir)

    def tick(data: dict[str, Any]) -> int:
        data["commands"] = data.get("commands", 0) + 1
        return data["commands"]

    return mutate_json(path, tick)


def tick_message(eng_dir: str | Path) -> int:
    path = _counts_path(eng_dir)

    def tick(data: dict[str, Any]) -> int:
        data["messages"] = data.get("messages", 0) + 1
        return data["messages"]

    # Windows can briefly deny the replace/read sequence immediately after a
    # prior hook writes this same file.  Lifecycle hooks intentionally do not
    # fail the model turn, so retry here rather than silently dropping a tick.
    for attempt in range(3):
        try:
            return mutate_json(path, tick)
        except OSError:
            if attempt == 2:
                raise
            time.sleep(0.02 * (attempt + 1))
    raise RuntimeError("unreachable")


def record_ok_check(eng_dir: str | Path, command: str, phase: str) -> None:
    path = _counts_path(eng_dir)

    def record(data: dict[str, Any]) -> None:
        data["last_check"] = {
            "command": command,
            "phase": phase,
            "at": datetime.now(UTC).isoformat().replace("+00:00", "Z"),
        }

    mutate_json(path, record)