# [DEF:backend.src.core.migration.archive_parser:Module]
# @TIER: STANDARD
# @SEMANTICS: migration, zip, parser, yaml, metadata
# @PURPOSE: Parse Superset export ZIP archives into normalized object catalogs for diffing.
# @LAYER: Core
# @RELATION: DEPENDS_ON -> backend.src.core.logger
# @INVARIANT: Parsing is read-only and never mutates archive files.

import json
import tempfile
import zipfile
from pathlib import Path
from typing import Any, Dict, List, Optional

import yaml

from ..logger import logger, belief_scope


# [DEF:MigrationArchiveParser:Class]
# @PURPOSE: Extract normalized dashboards/charts/datasets metadata from ZIP archives.
class MigrationArchiveParser:
    # [DEF:extract_objects_from_zip:Function]
    # @PURPOSE: Extract object catalogs from Superset archive.
    # @PRE: zip_path points to a valid readable ZIP.
    # @POST: Returns object lists grouped by resource type.
    # @RETURN: Dict[str, List[Dict[str, Any]]]
    def extract_objects_from_zip(self, zip_path: str) -> Dict[str, List[Dict[str, Any]]]:
        with belief_scope("MigrationArchiveParser.extract_objects_from_zip"):
            result: Dict[str, List[Dict[str, Any]]] = {
                "dashboards": [],
                "charts": [],
                "datasets": [],
            }
            with tempfile.TemporaryDirectory() as temp_dir_str:
                temp_dir = Path(temp_dir_str)
                with zipfile.ZipFile(zip_path, "r") as zip_file:
                    zip_file.extractall(temp_dir)

                result["dashboards"] = self._collect_yaml_objects(temp_dir, "dashboards")
                result["charts"] = self._collect_yaml_objects(temp_dir, "charts")
                result["datasets"] = self._collect_yaml_objects(temp_dir, "datasets")

            return result
    # [/DEF:extract_objects_from_zip:Function]

    # [DEF:_collect_yaml_objects:Function]
    # @PURPOSE: Read and normalize YAML manifests for one object type.
    # @PRE: object_type is one of dashboards/charts/datasets.
    # @POST: Returns only valid normalized objects.
    def _collect_yaml_objects(self, root_dir: Path, object_type: str) -> List[Dict[str, Any]]:
        with belief_scope("MigrationArchiveParser._collect_yaml_objects"):
            files = list(root_dir.glob(f"**/{object_type}/**/*.yaml")) + list(root_dir.glob(f"**/{object_type}/*.yaml"))
            objects: List[Dict[str, Any]] = []
            for file_path in set(files):
                try:
                    with open(file_path, "r") as file_obj:
                        payload = yaml.safe_load(file_obj) or {}
                    normalized = self._normalize_object_payload(payload, object_type)
                    if normalized:
                        objects.append(normalized)
                except Exception as exc:
                    logger.reflect(
                        "[MigrationArchiveParser._collect_yaml_objects][REFLECT] skip_invalid_yaml path=%s error=%s",
                        file_path,
                        exc,
                    )
            return objects
    # [/DEF:_collect_yaml_objects:Function]

    # [DEF:_normalize_object_payload:Function]
    # @PURPOSE: Convert raw YAML payload to stable diff signature shape.
    # @PRE: payload is parsed YAML mapping.
    # @POST: Returns normalized descriptor with `uuid`, `title`, and `signature`.
    def _normalize_object_payload(self, payload: Dict[str, Any], object_type: str) -> Optional[Dict[str, Any]]:
        with belief_scope("MigrationArchiveParser._normalize_object_payload"):
            if not isinstance(payload, dict):
                return None
            uuid = payload.get("uuid")
            if not uuid:
                return None

            if object_type == "dashboards":
                title = payload.get("dashboard_title") or payload.get("title")
                signature = {
                    "title": title,
                    "slug": payload.get("slug"),
                    "position_json": payload.get("position_json"),
                    "json_metadata": payload.get("json_metadata"),
                    "description": payload.get("description"),
                    "owners": payload.get("owners"),
                }
                return {
                    "uuid": str(uuid),
                    "title": title or f"Dashboard {uuid}",
                    "signature": json.dumps(signature, sort_keys=True, default=str),
                    "owners": payload.get("owners") or [],
                }

            if object_type == "charts":
                title = payload.get("slice_name") or payload.get("name")
                signature = {
                    "title": title,
                    "viz_type": payload.get("viz_type"),
                    "params": payload.get("params"),
                    "query_context": payload.get("query_context"),
                    "datasource_uuid": payload.get("datasource_uuid"),
                    "dataset_uuid": payload.get("dataset_uuid"),
                }
                return {
                    "uuid": str(uuid),
                    "title": title or f"Chart {uuid}",
                    "signature": json.dumps(signature, sort_keys=True, default=str),
                    "dataset_uuid": payload.get("datasource_uuid") or payload.get("dataset_uuid"),
                }

            if object_type == "datasets":
                title = payload.get("table_name") or payload.get("name")
                signature = {
                    "title": title,
                    "schema": payload.get("schema"),
                    "database_uuid": payload.get("database_uuid"),
                    "sql": payload.get("sql"),
                    "columns": payload.get("columns"),
                    "metrics": payload.get("metrics"),
                }
                return {
                    "uuid": str(uuid),
                    "title": title or f"Dataset {uuid}",
                    "signature": json.dumps(signature, sort_keys=True, default=str),
                    "database_uuid": payload.get("database_uuid"),
                }

            return None
    # [/DEF:_normalize_object_payload:Function]


# [/DEF:MigrationArchiveParser:Class]
# [/DEF:backend.src.core.migration.archive_parser:Module]