from __future__ import annotations

import json
import os
import tempfile
from pathlib import Path
from threading import Lock
from typing import Any

from app.models import ChannelSettings, BackendCredential, BackendRecord, OutlookSettings, UserRecord, utcnow_iso


class JsonStore:
    def __init__(self, data_dir: Path):
        self.data_dir = data_dir
        self.data_dir.mkdir(parents=True, exist_ok=True)
        self._lock = Lock()

    @property
    def backends_path(self) -> Path:
        return self.data_dir / "backends.json"

    @property
    def credentials_path(self) -> Path:
        return self.data_dir / "backend_credentials.json"

    @property
    def permissions_path(self) -> Path:
        return self.data_dir / "permissions.json"

    @property
    def users_path(self) -> Path:
        return self.data_dir / "users.json"

    @property
    def settings_path(self) -> Path:
        return self.data_dir / "settings.json"

    def _read_json(self, path: Path, default: dict[str, Any]) -> dict[str, Any]:
        if not path.exists():
            return default
        try:
            return json.loads(path.read_text(encoding="utf-8"))
        except (OSError, ValueError, json.JSONDecodeError):
            return default

    def _write_json(self, path: Path, payload: dict[str, Any]) -> None:
        with self._lock:
            path.parent.mkdir(parents=True, exist_ok=True)
            fd, tmp_name = tempfile.mkstemp(dir=str(path.parent), prefix=path.name, suffix=".tmp")
            try:
                with os.fdopen(fd, "w", encoding="utf-8") as handle:
                    json.dump(payload, handle, indent=2, ensure_ascii=False)
                os.replace(tmp_name, path)
            finally:
                if os.path.exists(tmp_name):
                    os.unlink(tmp_name)

    def list_backends(self) -> list[BackendRecord]:
        raw = self._read_json(self.backends_path, {"backends": []})
        items = raw.get("backends", [])
        if not isinstance(items, list):
            return []
        return [BackendRecord.model_validate(item) for item in items if isinstance(item, dict)]

    def get_backend(self, backend_id: str) -> BackendRecord | None:
        for backend in self.list_backends():
            if backend.backend_id == backend_id:
                return backend
        return None

    def save_backend(self, backend: BackendRecord) -> None:
        backends = [item for item in self.list_backends() if item.backend_id != backend.backend_id]
        backends.append(backend)
        backends.sort(key=lambda item: item.backend_id)
        self._write_json(
            self.backends_path,
            {"backends": [item.model_dump(mode="json") for item in backends]},
        )

    def list_credentials(self) -> list[BackendCredential]:
        raw = self._read_json(self.credentials_path, {"credentials": []})
        items = raw.get("credentials", [])
        if not isinstance(items, list):
            return []
        return [BackendCredential.model_validate(item) for item in items if isinstance(item, dict)]

    def get_credential_by_client_id(self, client_id: str) -> BackendCredential | None:
        for item in self.list_credentials():
            if item.client_id == client_id:
                return item
        return None

    def save_credential(self, credential: BackendCredential) -> None:
        creds = [item for item in self.list_credentials() if item.backend_id != credential.backend_id]
        creds.append(credential)
        creds.sort(key=lambda item: item.backend_id)
        self._write_json(
            self.credentials_path,
            {"credentials": [item.model_dump(mode="json") for item in creds]},
        )

    def list_users(self) -> list[UserRecord]:
        raw = self._read_json(self.users_path, {"users": []})
        items = raw.get("users", [])
        if not isinstance(items, list):
            return []
        return [UserRecord.model_validate(item) for item in items if isinstance(item, dict)]

    def get_user(self, username: str) -> UserRecord | None:
        for item in self.list_users():
            if item.username == username:
                return item
        return None

    def save_user(self, user: UserRecord) -> None:
        users = [item for item in self.list_users() if item.username != user.username]
        users.append(user)
        users.sort(key=lambda item: item.username)
        self._write_json(
            self.users_path,
            {"users": [item.model_dump(mode="json") for item in users]},
        )

    def get_permissions(self, backend_id: str) -> dict[str, Any]:
        raw = self._read_json(self.permissions_path, {"permissions": {}})
        permissions = raw.get("permissions", {})
        if not isinstance(permissions, dict):
            return {}
        value = permissions.get(backend_id, {})
        return value if isinstance(value, dict) else {}

    def save_permissions(self, backend_id: str, permissions: dict[str, Any]) -> dict[str, Any]:
        raw = self._read_json(self.permissions_path, {"permissions": {}})
        root = raw.get("permissions", {})
        if not isinstance(root, dict):
            root = {}
        root[backend_id] = permissions
        self._write_json(self.permissions_path, {"permissions": root})
        return permissions

    def get_outlook_settings(self, backend_id: str) -> OutlookSettings | None:
        raw = self._read_json(self.settings_path, {"settings": {}})
        root = raw.get("settings", {})
        if not isinstance(root, dict):
            return None
        backend_settings = root.get(backend_id, {})
        if not isinstance(backend_settings, dict):
            return None
        outlook = backend_settings.get("outlook")
        if not isinstance(outlook, dict):
            return None
        return OutlookSettings.model_validate(outlook)

    def list_channel_settings(self, backend_id: str) -> dict[str, ChannelSettings]:
        raw = self._read_json(self.settings_path, {"settings": {}})
        root = raw.get("settings", {})
        if not isinstance(root, dict):
            return {}
        backend_settings = root.get(backend_id, {})
        if not isinstance(backend_settings, dict):
            return {}
        channels = backend_settings.get("channels", {})
        if not isinstance(channels, dict):
            return {}
        return {
            str(channel_id): ChannelSettings.model_validate(settings)
            for channel_id, settings in channels.items()
            if isinstance(channel_id, str) and channel_id.strip() and isinstance(settings, dict)
        }

    def get_channel_settings(self, backend_id: str, channel_id: str) -> ChannelSettings | None:
        return self.list_channel_settings(backend_id).get(channel_id)

    def save_outlook_settings(self, backend_id: str, settings: OutlookSettings) -> dict[str, Any]:
        raw = self._read_json(self.settings_path, {"settings": {}})
        root = raw.get("settings", {})
        if not isinstance(root, dict):
            root = {}
        backend_settings = root.get(backend_id, {})
        if not isinstance(backend_settings, dict):
            backend_settings = {}
        backend_settings["outlook"] = settings.model_dump(mode="json")
        root[backend_id] = backend_settings
        self._write_json(self.settings_path, {"settings": root})
        return backend_settings

    def save_channel_settings(self, backend_id: str, channel_id: str, settings: ChannelSettings) -> dict[str, Any]:
        raw = self._read_json(self.settings_path, {"settings": {}})
        root = raw.get("settings", {})
        if not isinstance(root, dict):
            root = {}
        backend_settings = root.get(backend_id, {})
        if not isinstance(backend_settings, dict):
            backend_settings = {}
        channels = backend_settings.get("channels", {})
        if not isinstance(channels, dict):
            channels = {}
        channels[channel_id] = settings.model_dump(mode="json")
        backend_settings["channels"] = channels
        root[backend_id] = backend_settings
        self._write_json(self.settings_path, {"settings": root})
        return channels[channel_id]

    def delete_outlook_settings(self, backend_id: str) -> bool:
        raw = self._read_json(self.settings_path, {"settings": {}})
        root = raw.get("settings", {})
        if not isinstance(root, dict):
            return False
        backend_settings = root.get(backend_id)
        if not isinstance(backend_settings, dict) or "outlook" not in backend_settings:
            return False
        backend_settings.pop("outlook", None)
        if backend_settings:
            root[backend_id] = backend_settings
        else:
            root.pop(backend_id, None)
        self._write_json(self.settings_path, {"settings": root})
        return True

    def delete_channel_settings(self, backend_id: str, channel_id: str) -> bool:
        raw = self._read_json(self.settings_path, {"settings": {}})
        root = raw.get("settings", {})
        if not isinstance(root, dict):
            return False
        backend_settings = root.get(backend_id)
        if not isinstance(backend_settings, dict):
            return False
        channels = backend_settings.get("channels")
        if not isinstance(channels, dict) or channel_id not in channels:
            return False
        channels.pop(channel_id, None)
        if channels:
            backend_settings["channels"] = channels
        else:
            backend_settings.pop("channels", None)
        if backend_settings:
            root[backend_id] = backend_settings
        else:
            root.pop(backend_id, None)
        self._write_json(self.settings_path, {"settings": root})
        return True

    def disable_backend(self, backend_id: str) -> BackendRecord | None:
        backend = self.get_backend(backend_id)
        if backend is None:
            return None
        backend.status = "disabled"
        backend.updated_at = utcnow_iso()
        self.save_backend(backend)
        return backend

    def enable_backend(self, backend_id: str) -> BackendRecord | None:
        backend = self.get_backend(backend_id)
        if backend is None:
            return None
        backend.status = "active"
        backend.updated_at = utcnow_iso()
        self.save_backend(backend)
        return backend

    def touch_backend(self, backend_id: str) -> BackendRecord | None:
        backend = self.get_backend(backend_id)
        if backend is None:
            return None
        backend.updated_at = utcnow_iso()
        self.save_backend(backend)
        return backend