# [DEF:backend.src.api.routes.mappings:Module]
#
# @TIER: STANDARD
# @SEMANTICS: api, mappings, database, fuzzy-matching
# @PURPOSE:   API endpoints for managing database mappings and getting suggestions.
# @LAYER:     API
# @RELATION:  DEPENDS_ON -> backend.src.dependencies
# @RELATION:  DEPENDS_ON -> backend.src.core.database
# @RELATION:  DEPENDS_ON -> backend.src.services.mapping_service
#
# @INVARIANT: Mappings are persisted in the SQLite database.

# [SECTION: IMPORTS]
from fastapi import APIRouter, Depends, HTTPException
from sqlalchemy.orm import Session
from typing import List, Optional
from ...core.logger import belief_scope
from ...dependencies import get_config_manager, has_permission
from ...core.database import get_db
from ...models.mapping import DatabaseMapping
from pydantic import BaseModel
# [/SECTION]

router = APIRouter(tags=["mappings"])

# [DEF:MappingCreate:DataClass]
class MappingCreate(BaseModel):
    source_env_id: str
    target_env_id: str
    source_db_uuid: str
    target_db_uuid: str
    source_db_name: str
    target_db_name: str
    engine: Optional[str] = None
# [/DEF:MappingCreate:DataClass]

# [DEF:MappingResponse:DataClass]
class MappingResponse(BaseModel):
    id: str
    source_env_id: str
    target_env_id: str
    source_db_uuid: str
    target_db_uuid: str
    source_db_name: str
    target_db_name: str
    engine: Optional[str] = None

    class Config:
        from_attributes = True
# [/DEF:MappingResponse:DataClass]

# [DEF:SuggestRequest:DataClass]
class SuggestRequest(BaseModel):
    source_env_id: str
    target_env_id: str
# [/DEF:SuggestRequest:DataClass]

# [DEF:get_mappings:Function]
# @PURPOSE: List all saved database mappings.
# @PRE:     db session is injected.
# @POST:    Returns filtered list of DatabaseMapping records.
@router.get("", response_model=List[MappingResponse])
async def get_mappings(
    source_env_id: Optional[str] = None,
    target_env_id: Optional[str] = None,
    db: Session = Depends(get_db),
    _ = Depends(has_permission("plugin:mapper", "EXECUTE"))
):
    with belief_scope("get_mappings"):
        query = db.query(DatabaseMapping)
    if source_env_id:
        query = query.filter(DatabaseMapping.source_env_id == source_env_id)
    if target_env_id:
        query = query.filter(DatabaseMapping.target_env_id == target_env_id)
    return query.all()
# [/DEF:get_mappings:Function]

# [DEF:create_mapping:Function]
# @PURPOSE: Create or update a database mapping.
# @PRE:     mapping is valid MappingCreate, db session is injected.
# @POST:    DatabaseMapping created or updated in database.
@router.post("", response_model=MappingResponse)
async def create_mapping(
    mapping: MappingCreate,
    db: Session = Depends(get_db),
    _ = Depends(has_permission("plugin:mapper", "EXECUTE"))
):
    with belief_scope("create_mapping"):
        # Check if mapping already exists
        existing = db.query(DatabaseMapping).filter(
            DatabaseMapping.source_env_id == mapping.source_env_id,
            DatabaseMapping.target_env_id == mapping.target_env_id,
            DatabaseMapping.source_db_uuid == mapping.source_db_uuid
        ).first()
        
        if existing:
            existing.target_db_uuid = mapping.target_db_uuid
            existing.target_db_name = mapping.target_db_name
            existing.engine = mapping.engine
            db.commit()
            db.refresh(existing)
            return existing
        
        new_mapping = DatabaseMapping(**mapping.dict())
        db.add(new_mapping)
        db.commit()
        db.refresh(new_mapping)
        return new_mapping
# [/DEF:create_mapping:Function]

# [DEF:suggest_mappings_api:Function]
# @PURPOSE: Get suggested mappings based on fuzzy matching.
# @PRE:     request is valid SuggestRequest, config_manager is injected.
# @POST:    Returns mapping suggestions.
@router.post("/suggest")
async def suggest_mappings_api(
    request: SuggestRequest,
    config_manager=Depends(get_config_manager),
    _ = Depends(has_permission("plugin:mapper", "EXECUTE"))
):
    with belief_scope("suggest_mappings_api"):
        from ...services.mapping_service import MappingService
        service = MappingService(config_manager)
        try:
            return await service.get_suggestions(request.source_env_id, request.target_env_id)
        except Exception as e:
            raise HTTPException(status_code=500, detail=str(e))
# [/DEF:suggest_mappings_api:Function]

# [/DEF:backend.src.api.routes.mappings:Module]