"""
    This file defines and handles all the errors
    The ExceptionHandlerRoute class is used by all the routes
"""

from enum            import Enum
from typing          import Any, Coroutine, Type
from fastapi         import Request, Response
from fastapi.routing import APIRoute
from pydantic        import BaseModel, ConfigDict
from collections.abc import Callable
from sqlalchemy.exc  import NoResultFound, SQLAlchemyError


class ProblemType(str, Enum):
    ITEM_NOT_FOUND        = 'ITEM_NOT_FOUND'
    INTERNAL_SERVER_ERROR = 'INTERNAL_SERVER_ERROR'
    INVALID_CREDENTIALS   = 'INVALID_CREDENTIALS'
    UNIQUE_CONSTRAINT     = 'UNIQUE_CONSTRAINT'
    INVALID_REQUEST       = 'INVALID_REQUEST'
    BLANK                 = 'BLANK'

class ProblemDetail(BaseModel):
    """ RFC 7807 Problem Details for HTTP APIs """
    type   : ProblemType = ProblemType.BLANK
    status : int | None  = None
    title  : str | None  = None
    detail : str | None  = None

model_config = ConfigDict(from_attributes=True)

class ItemNotFoundException(Exception):
    def __init__(self, model: Type, key : Any = ""):
        self.model = model.__name__
        self.key   = str(key)


class ExceptionHandlerRoute(APIRoute):
    def get_route_handler(self) -> Callable:
        original_route_handler = super().get_route_handler()

        async def custom_route_handler(request: Request) -> Response:
            try:
                return await original_route_handler(request)
            except SQLAlchemyError as exc:

                problem = ProblemDetail(status = 422)

                if type(exc) == NoResultFound:
                    problem.type   = ProblemType.ITEM_NOT_FOUND
                    problem.title  = f'{exc.model} Not Found'
                    problem.detail = { 'key' : exc.key}
                    problem.status = 404

                elif type(exc.orig) == UniqueViolation:
                    problem.detail = str(exc.orig).split('\n')[1].split(':  ')[1]
                    problem.type   = ProblemType.UNIQUE_VALIDATION
                    problem.title  = 'Unique violation'

                elif type(exc.orig) == ForeignKeyViolation:
                    problem.type   = ProblemType.FOREIGN_KEY_VIOLATION
                    problem.title  = 'Foreign Key Violation'
                    problem.detail = str(exc.orig).split('\n')[1].split(':  ')[1]

                return JSONResponse(
                    status_code = problem.status,
                    content     = problem.model_dump(exclude_none = True),
                    headers     = {'Content-Type': 'application/problem+json'} 
                )
                raise HTTPException(status_code = 422, detail = detail)

            except Exception as exc:
                problem        = ProblemDetail(status = 500)
                problem.title  = 'Internal Server Error please report the bug'
                problem.type   = ProblemType.INTERNAL_SERVER_ERROR
                problem.detail = str(exc)

                if type(exc) == ItemNotFoundException:
                    problem.type   = ProblemType.ITEM_NOT_FOUND
                    problem.title  = f'{exc.model} Not Found'
                    problem.detail = { 'key' : exc.key}
                    problem.status = 404

                if type(exc) == RequestValidationError:
                    problem.type   = ProblemType.INVALID_REQUEST
                    problem.title  = "Input validation error" 
                    problem.detail = exc.errors()
                    problem.status = 422

                if type(exc) == HTTPException:
                    print(exc.status_code)
                    problem.title  = "Credientials error" 
                    problem.detail = exc.detail
                    problem.status = exc.status_code


                if problem.status == 401:
                    problem.type = ProblemType.INVALID_CREDENTIALS

                return JSONResponse(
                    status_code = problem.status,
                    content     = problem.model_dump(exclude_none = True),
                    headers     = {'Content-Type': 'application/problem+json'} 
                )

        return custom_route_handler