# [DEF:backend.src.services.mapping_service:Module]
#
# @SEMANTICS: service, mapping, fuzzy-matching, superset
# @PURPOSE:   Orchestrates database fetching and fuzzy matching suggestions.
# @LAYER:     Service
# @RELATION:  DEPENDS_ON -> backend.src.core.superset_client
# @RELATION:  DEPENDS_ON -> backend.src.core.utils.matching
#
# @INVARIANT: Suggestions are based on database names.

# [SECTION: IMPORTS]
from typing import List, Dict
from backend.src.core.logger import belief_scope
from backend.src.core.superset_client import SupersetClient
from backend.src.core.utils.matching import suggest_mappings
# [/SECTION]

# [DEF:MappingService:Class]
# @PURPOSE: Service for handling database mapping logic.
class MappingService:
    
    # [DEF:__init__:Function]
    # @PURPOSE: Initializes the mapping service with a config manager.
    # @PRE: config_manager is provided.
    # @PARAM: config_manager (ConfigManager) - The configuration manager.
    # @POST: Service is initialized.
    def __init__(self, config_manager):
        with belief_scope("MappingService.__init__"):
            self.config_manager = config_manager
    # [/DEF:__init__:Function]

    # [DEF:_get_client:Function]
    # @PURPOSE: Helper to get an initialized SupersetClient for an environment.
    # @PARAM: env_id (str) - The ID of the environment.
    # @PRE: environment must exist in config.
    # @POST: Returns an initialized SupersetClient.
    # @RETURN: SupersetClient - Initialized client.
    def _get_client(self, env_id: str) -> SupersetClient:
        with belief_scope("MappingService._get_client", f"env_id={env_id}"):
            envs = self.config_manager.get_environments()
            env = next((e for e in envs if e.id == env_id), None)
            if not env:
                raise ValueError(f"Environment {env_id} not found")
            
            return SupersetClient(env)
    # [/DEF:_get_client:Function]

    # [DEF:get_suggestions:Function]
    # @PURPOSE: Fetches databases from both environments and returns fuzzy matching suggestions.
    # @PARAM:   source_env_id (str) - Source environment ID.
    # @PARAM:   target_env_id (str) - Target environment ID.
    # @PRE: Both environments must be accessible.
    # @POST: Returns fuzzy-matched database suggestions.
    # @RETURN:  List[Dict] - Suggested mappings.
    async def get_suggestions(self, source_env_id: str, target_env_id: str) -> List[Dict]:
        with belief_scope("MappingService.get_suggestions", f"source={source_env_id}, target={target_env_id}"):
            """
            Get suggested mappings between two environments.
            """
            source_client = self._get_client(source_env_id)
            target_client = self._get_client(target_env_id)
            
            source_dbs = source_client.get_databases_summary()
            target_dbs = target_client.get_databases_summary()
            
            return suggest_mappings(source_dbs, target_dbs)
    # [/DEF:get_suggestions:Function]

# [/DEF:MappingService:Class]

# [/DEF:backend.src.services.mapping_service:Module]