# Copyright (C) 2024 qBraid
#
# This file is part of the qBraid-SDK
#
# The qBraid-SDK is free software released under the GNU General Public License v3
# or later. You can redistribute and/or modify it under the terms of the GPL v3.
# See the LICENSE file in the project root or <https://www.gnu.org/licenses/gpl-3.0.html>.
#
# THERE IS NO WARRANTY for the qBraid-SDK, as per Section 15 of the GPL v3.

"""
Module defining Oxford Quantum Circuits (OQC) provider class

"""
import json
import os
from typing import Any, Optional, Union

from qcaas_client.client import OQCClient

from qbraid._caching import cached_method
from qbraid.programs import ExperimentType
from qbraid.programs.spec import ProgramSpec
from qbraid.runtime.exceptions import ResourceNotFoundError
from qbraid.runtime.profile import TargetProfile
from qbraid.runtime.provider import QuantumProvider
from qbraid.runtime.schemas.base import USD

from .device import OQCDevice


class OQCProvider(QuantumProvider):
    """OQC provider class."""

    def __init__(
        self,
        token: Optional[str] = None,
        url: str = "https://cloud.oqc.app/",
        timeout: tuple[int, int] = (5, 10),
    ) -> None:
        token = token or os.getenv("OQC_AUTH_TOKEN")
        if not token:
            raise ValueError(
                "An OQC authenication token is required to initialize the provider. "
                "Please provide it directly as an argument or set it via "
                "the OQC_AUTH_TOKEN environment variable."
            )
        self.client = OQCClient(url=url, authentication_token=token, timeout=timeout)

    def _build_profile(self, data: dict[str, Any]) -> TargetProfile:
        """Build a profile for OQC device."""
        data = data.copy()
        device_id = data.get("id")
        feature_set: Union[str, dict] = data.get("feature_set", {})

        if not isinstance(feature_set, dict):
            try:
                data["feature_set"] = json.loads(feature_set)
            except json.JSONDecodeError as err:
                raise ValueError(
                    f"Failed to decode feature set data for device '{device_id}'."
                ) from err

        try:
            device_id: str = data.pop("id")
            device_name: str = data.pop("name")
            endpoint_url: str = data.pop("url")
            feauture_set: dict = data.pop("feature_set")
            num_qubits: int = feauture_set.pop("qubit_count")
            simulator: bool = feauture_set.pop("simulator", False)
        except KeyError as err:
            raise ValueError(f"Failed to gather profile data for device '{device_id}'.") from err

        dynamic_fields = {"active", "status"}
        pricing_fields = {"price_per_shot", "price_per_task"}
        static_data = {
            k: (USD(v) if k in pricing_fields else v)
            for k, v in data.items()
            if k not in dynamic_fields
        }

        return TargetProfile(
            device_id=device_id,
            simulator=simulator,
            experiment_type=ExperimentType.GATE_MODEL,
            num_qubits=num_qubits,
            program_spec=ProgramSpec(str, alias="qasm3"),
            device_name=device_name,
            endpoint_url=endpoint_url,
            provider_name="OQC",
            feature_set=feauture_set,
            **static_data,
        )

    @cached_method
    def get_devices(self) -> list[OQCDevice]:
        """Get all OQC devices."""
        devices: list[dict] = self.client.get_qpus()
        return [
            OQCDevice(profile=self._build_profile(device), client=self.client) for device in devices
        ]

    @cached_method
    def get_device(self, device_id: str) -> OQCDevice:
        """Get a specific OQC device."""
        devices: list[dict] = self.client.get_qpus()
        device = next((d for d in devices if d["id"] == device_id), None)
        if not device:
            raise ResourceNotFoundError(f"Device '{device_id}' not found.")
        return OQCDevice(profile=self._build_profile(device), client=self.client)

    def __hash__(self):
        if not hasattr(self, "_hash"):
            object.__setattr__(
                self, "_hash", hash((self.client.url, self.client._authentication_token))
            )
        return self._hash  # pylint: disable=no-member
