"""Shared-state store for brain runtime via Google Drive, local files, or Firebase."""

from __future__ import annotations

import json
import logging
import os
import threading
import time
from pathlib import Path
from typing import Any

from shared.google_drive_state import GoogleDriveStateClient


class FirebaseStore:
    def __init__(self, component: str, logger_name: str = "kapo.brain.firebase") -> None:
        self.component = component
        self.logger = logging.getLogger(logger_name)
        self._db = None
        self._lock = threading.Lock()
        self._read_cache: dict[str, tuple[float, Any]] = {}
        self._list_cache: dict[str, tuple[float, list[dict[str, Any]]]] = {}
        self._write_cache: dict[str, tuple[float, str]] = {}
        self._quota_backoff_until: float = 0.0
        self._drive = GoogleDriveStateClient(self.logger)

    def backend(self) -> str:
        configured = str(os.getenv("KAPO_SHARED_STATE_BACKEND", "")).strip().lower()
        if configured in {"google_drive", "drive", "gdrive"}:
            return "google_drive"
        if configured in {"file", "files"}:
            return "file"
        if configured in {"firebase", "firestore"}:
            return "firebase"
        if configured in {"disabled", "off", "none"}:
            return "disabled"
        if self._drive.enabled():
            return "google_drive"
        if str(os.getenv("FIREBASE_ENABLED", "0")).strip().lower() in {"1", "true", "yes", "on"}:
            return "firebase"
        return "file"

    def enabled(self) -> bool:
        return self.backend() != "disabled"

    def namespace(self) -> str:
        return str(os.getenv("FIREBASE_NAMESPACE", "kapo")).strip() or "kapo"

    def storage_root(self) -> Path:
        configured = str(os.getenv("KAPO_SHARED_STATE_DIR", "")).strip()
        if configured:
            root = Path(configured).expanduser()
            if not root.is_absolute():
                root = Path.cwd().resolve() / root
        else:
            root = (Path.cwd().resolve() / "data" / "local" / "shared_state").resolve()
        root.mkdir(parents=True, exist_ok=True)
        return root

    def _service_payload(self) -> dict[str, Any] | None:
        raw = str(os.getenv("FIREBASE_SERVICE_ACCOUNT_JSON", "")).strip()
        if not raw:
            return None
        try:
            return json.loads(raw)
        except Exception:
            self.logger.exception("Invalid Firebase service account JSON")
            return None

    @staticmethod
    def _service_path() -> str:
        return str(os.getenv("FIREBASE_SERVICE_ACCOUNT_PATH", "")).strip()

    def _client(self):
        if self.backend() != "firebase":
            return None
        with self._lock:
            if self._db is not None:
                return self._db
            try:
                import firebase_admin
                from firebase_admin import credentials, firestore

                if not firebase_admin._apps:
                    payload = self._service_payload()
                    if payload:
                        cred = credentials.Certificate(payload)
                    else:
                        service_path = self._service_path()
                        if not service_path:
                            return None
                        path_obj = Path(service_path).expanduser()
                        if not path_obj.exists() or not path_obj.is_file():
                            self.logger.warning(
                                "Firebase service account path is unavailable on this runtime: %s",
                                service_path,
                            )
                            return None
                        cred = credentials.Certificate(str(path_obj.resolve()))
                    options = {}
                    project_id = str(os.getenv("FIREBASE_PROJECT_ID", "")).strip()
                    if project_id:
                        options["projectId"] = project_id
                    firebase_admin.initialize_app(cred, options or None)
                self._db = firestore.client()
                return self._db
            except Exception:
                self.logger.exception("Failed to initialize Firebase client")
                return None

    def _collection(self, name: str) -> str:
        return f"{self.namespace()}_{name}"

    @staticmethod
    def _safe_id(value: str, default: str = "default") -> str:
        text = str(value or "").strip() or default
        return "".join(ch if ch.isalnum() or ch in {"-", "_", "."} else "_" for ch in text)[:180]

    @staticmethod
    def _payload_hash(payload: Any) -> str:
        return json.dumps(payload, ensure_ascii=False, sort_keys=True, default=str)

    @staticmethod
    def _is_quota_error(exc: Exception) -> bool:
        text = str(exc or "").lower()
        return "resourceexhausted" in text or "quota exceeded" in text or "429" in text

    def _quota_backoff_active(self) -> bool:
        return time.time() < self._quota_backoff_until

    def _activate_quota_backoff(self, seconds: float | None = None) -> None:
        delay = float(seconds or os.getenv("FIREBASE_QUOTA_BACKOFF_SEC", "120") or 120)
        self._quota_backoff_until = max(self._quota_backoff_until, time.time() + max(5.0, delay))

    def _should_skip_write(self, key: str, payload: Any, min_interval_sec: float) -> bool:
        now = time.time()
        payload_hash = self._payload_hash(payload)
        last = self._write_cache.get(key)
        if last and last[1] == payload_hash and (now - last[0]) < min_interval_sec:
            return True
        self._write_cache[key] = (now, payload_hash)
        return False

    def _file_collection_dir(self, collection: str) -> Path:
        path = self.storage_root() / self._safe_id(collection, "collection")
        path.mkdir(parents=True, exist_ok=True)
        return path

    def _file_doc_path(self, collection: str, doc_id: str) -> Path:
        return self._file_collection_dir(collection) / f"{self._safe_id(doc_id)}.json"

    def _write_json_atomic(self, path: Path, payload: dict[str, Any]) -> None:
        path.parent.mkdir(parents=True, exist_ok=True)
        tmp = path.with_suffix(f"{path.suffix}.tmp")
        tmp.write_text(json.dumps(payload, ensure_ascii=False, indent=2, sort_keys=True), encoding="utf-8")
        tmp.replace(path)

    def get_document(self, collection: str, doc_id: str, ttl_sec: float = 12.0) -> dict[str, Any]:
        safe_doc = self._safe_id(doc_id)
        cache_key = f"{collection}:{safe_doc}"
        now = time.time()
        cached = self._read_cache.get(cache_key)
        if cached and (now - cached[0]) < ttl_sec:
            return dict(cached[1] or {})
        backend = self.backend()
        if backend == "google_drive":
            payload = self._drive.get_document(collection, safe_doc)
            self._read_cache[cache_key] = (now, payload)
            return dict(payload or {})
        if backend == "file":
            path = self._file_doc_path(collection, safe_doc)
            if not path.exists():
                return {}
            try:
                payload = json.loads(path.read_text(encoding="utf-8"))
            except Exception:
                self.logger.warning("Failed to read shared-state file %s", path, exc_info=True)
                return {}
            self._read_cache[cache_key] = (now, payload)
            return dict(payload or {})
        if self._quota_backoff_active():
            return dict(cached[1] or {}) if cached else {}
        db = self._client()
        if db is None:
            return dict(cached[1] or {}) if cached else {}
        try:
            snapshot = db.collection(self._collection(collection)).document(safe_doc).get()
            payload = snapshot.to_dict() if snapshot.exists else {}
            self._read_cache[cache_key] = (now, payload)
            return dict(payload or {})
        except Exception as exc:
            if self._is_quota_error(exc):
                self._activate_quota_backoff()
                self.logger.warning("Firebase quota exceeded while reading %s/%s; using cache/backoff", collection, safe_doc)
            else:
                self.logger.exception("Failed to read Firebase document %s/%s", collection, safe_doc)
            return dict(cached[1] or {}) if cached else {}

    def set_document(self, collection: str, doc_id: str, payload: dict[str, Any], merge: bool = True, min_interval_sec: float = 5.0) -> bool:
        safe_doc = self._safe_id(doc_id)
        cache_key = f"{collection}:{safe_doc}"
        body = dict(payload or {})
        body["component"] = self.component
        body["updated_at"] = time.time()
        if self._should_skip_write(cache_key, body, min_interval_sec):
            return True
        backend = self.backend()
        if backend == "google_drive":
            stored = self._drive.set_document(collection, safe_doc, body, merge=merge)
            if stored:
                self._read_cache.pop(cache_key, None)
                stale_prefix = f"{collection}:list:"
                for key in list(self._list_cache.keys()):
                    if key.startswith(stale_prefix):
                        self._list_cache.pop(key, None)
            return stored
        if backend == "file":
            try:
                path = self._file_doc_path(collection, safe_doc)
                existing = {}
                if merge and path.exists():
                    existing = json.loads(path.read_text(encoding="utf-8"))
                combined = {**existing, **body} if merge else body
                combined.setdefault("id", safe_doc)
                self._write_json_atomic(path, combined)
                self._read_cache.pop(cache_key, None)
                stale_prefix = f"{collection}:list:"
                for key in list(self._list_cache.keys()):
                    if key.startswith(stale_prefix):
                        self._list_cache.pop(key, None)
                return True
            except Exception:
                self.logger.warning("Failed to write shared-state file %s/%s", collection, safe_doc, exc_info=True)
                return False
        if self._quota_backoff_active():
            return False
        db = self._client()
        if db is None:
            return False
        try:
            if self._should_skip_write(cache_key, body, min_interval_sec):
                return True
            db.collection(self._collection(collection)).document(safe_doc).set(body, merge=merge)
            self._read_cache.pop(cache_key, None)
            stale_prefix = f"{collection}:list:"
            for key in list(self._list_cache.keys()):
                if key.startswith(stale_prefix):
                    self._list_cache.pop(key, None)
            return True
        except Exception as exc:
            if self._is_quota_error(exc):
                self._activate_quota_backoff()
                self.logger.warning("Firebase quota exceeded while writing %s/%s; write skipped", collection, safe_doc)
            else:
                self.logger.exception("Failed to write Firebase document %s/%s", collection, safe_doc)
            return False

    def list_documents(self, collection: str, limit: int = 200, ttl_sec: float = 30.0) -> list[dict[str, Any]]:
        cache_key = f"{collection}:list:{max(1, int(limit))}"
        now = time.time()
        cached = self._list_cache.get(cache_key)
        if cached and (now - cached[0]) < ttl_sec:
            return [dict(item) for item in (cached[1] or [])]
        backend = self.backend()
        if backend == "google_drive":
            items = self._drive.list_documents(collection, limit=max(1, int(limit)))
            self._list_cache[cache_key] = (now, [dict(item) for item in items])
            return items
        if backend == "file":
            items: list[dict[str, Any]] = []
            try:
                paths = sorted(
                    self._file_collection_dir(collection).glob("*.json"),
                    key=lambda path: path.stat().st_mtime,
                    reverse=True,
                )
                for path in paths[: max(1, int(limit))]:
                    payload = json.loads(path.read_text(encoding="utf-8"))
                    payload.setdefault("id", path.stem)
                    items.append(payload)
            except Exception:
                self.logger.warning("Failed to list shared-state files for %s", collection, exc_info=True)
            self._list_cache[cache_key] = (now, [dict(item) for item in items])
            return items
        if self._quota_backoff_active():
            return [dict(item) for item in ((cached[1] if cached else []) or [])]
        db = self._client()
        if db is None:
            return [dict(item) for item in ((cached[1] if cached else []) or [])]
        try:
            docs = db.collection(self._collection(collection)).limit(max(1, int(limit))).stream()
            items: list[dict[str, Any]] = []
            for doc in docs:
                payload = doc.to_dict() or {}
                payload.setdefault("id", doc.id)
                items.append(payload)
            self._list_cache[cache_key] = (now, [dict(item) for item in items])
            return items
        except Exception as exc:
            if self._is_quota_error(exc):
                self._activate_quota_backoff()
                self.logger.warning("Firebase quota exceeded while listing %s; using cache/backoff", collection)
            else:
                self.logger.exception("Failed to list Firebase collection %s", collection)
            return [dict(item) for item in ((cached[1] if cached else []) or [])]

    def delete_document(self, collection: str, doc_id: str) -> bool:
        safe_doc = self._safe_id(doc_id)
        backend = self.backend()
        if backend == "google_drive":
            deleted = self._drive.delete_document(collection, safe_doc)
            if deleted:
                self._read_cache.pop(f"{collection}:{safe_doc}", None)
                self._write_cache.pop(f"{collection}:{safe_doc}", None)
                stale_prefix = f"{collection}:list:"
                for key in list(self._list_cache.keys()):
                    if key.startswith(stale_prefix):
                        self._list_cache.pop(key, None)
            return deleted
        if backend == "file":
            try:
                path = self._file_doc_path(collection, safe_doc)
                if path.exists():
                    path.unlink()
                self._read_cache.pop(f"{collection}:{safe_doc}", None)
                self._write_cache.pop(f"{collection}:{safe_doc}", None)
                stale_prefix = f"{collection}:list:"
                for key in list(self._list_cache.keys()):
                    if key.startswith(stale_prefix):
                        self._list_cache.pop(key, None)
                return True
            except Exception:
                self.logger.warning("Failed to delete shared-state file %s/%s", collection, safe_doc, exc_info=True)
                return False
        if self._quota_backoff_active():
            return False
        db = self._client()
        if db is None:
            return False
        try:
            db.collection(self._collection(collection)).document(safe_doc).delete()
            self._read_cache.pop(f"{collection}:{safe_doc}", None)
            self._write_cache.pop(f"{collection}:{safe_doc}", None)
            stale_prefix = f"{collection}:list:"
            for key in list(self._list_cache.keys()):
                if key.startswith(stale_prefix):
                    self._list_cache.pop(key, None)
            return True
        except Exception as exc:
            if self._is_quota_error(exc):
                self._activate_quota_backoff()
                self.logger.warning("Firebase quota exceeded while deleting %s/%s; delete skipped", collection, safe_doc)
            else:
                self.logger.exception("Failed to delete Firebase document %s/%s", collection, safe_doc)
            return False